;b 117 D984 :opy 1 THE Vitality and Germination of Seeds. A THESIS PRESENTED FOR THE DEGREE OF DOCTOR OF SCIENCE AT THE UNIVERSITY OF MICHIGAN IN JUNE. 1902. BY J. W. T. DUVEL. Holder of the Dexter M. Ferry Fellowship in Botany. / THE Vitality and Germination of Seeds. A THESIS PRESENTED FOR THE DEGREE OF DOCTOR OF SCIENCE AT THE UNIVERSITY OF MICHIGAN IN JUNE, 1902. BY J. W. T. DUVEL, Holder of the Dexter M. Ferry Fellowship in Botany. ^^Y""" Gift The University ^ ^ CONTENTS. Introduction 9 Materials and methods 10 Seeds 10 Germination tests and ai)panitns 11 Effect of climatic conditions on the vitality of seeds 13 Causes of the losses in vitality in different climates 22 Effect of moisture and temperature u])on vitality - 24 Seeds packed in ice 26 Effect of moisture on vitality at higher temperatures 29 Summary 35 Effect of definite quantities of moisture on the vitality of seeds when they are kept within certain known limits of temperature 36 A comparison of methods of storing and shipping seeds in order to protect them from moisture, and consequently to insure a better preservation of vitality 44 Suggestions of earlier investigators 44 The necessity for thoroughly curing and drying seeds 45 Character of the seed warehouse or storage room 46 The value of good seed to the market gardener 46 Shipping seeds in charcoal, moss, eti 47 Nature of the experiments 47 Disposition of the samples 48 Results of the germination tests 50 Experiments in keeping and shipping seeds in special packages 65 Respiration of seeds 74 Summary 81 Enzymes in seeds and the jiart thej^ play in the preservation of vitality 82 Sununary 87 Literature cited 90 7 I L L U S T R A T I N S TEXT FIGURES. Page. Fig. 1. Apparatus used to determine the effect of moisture and temperature on the vitality of seeds in communication with free air ?>0 2. Ai>paratus used to determine tlie effect of moisture and teniperatui-e on the vitaUty of seeds not in connnuni(!ation with free air oO 8 THE VITALITY AND GERMINATION OF SEEDS. INTRODUCTION. It has long- been known that the conditions under which plants are grown and the degree of maturity at the time of liarAcsting are fac- tors which pla}^ an important part in the life of seeds. But, granting that seeds are of strong vitality at the time of harvesting, there remain to be considered the methods of gathering and curing, the water content of the seed at the time of storing, the methods of stor- age, the humidit}' and temperature of the surrounding atmosphere, the composition of the seed, the nature of the seed coats, activities within the cells, and numerous other factors which play important parts in the life of the seed. The conditions necessary for the successful germination of a seed of good vitalit}" and the chemical transformations accompanying these earl}' stages of development have received considerable attention from numerous investigators. These changes and conditions are fairly well understood for many of our conmion seeds. However, several impor- tant facts still remain unexplained, and our knowledge will not be complete until each and every species has been carefully studied. On the other hand, the conditions influencing the vitalit}^ of seeds as commercial!}' handled are but little understood and have been almost wholly neglected in research work. Likewise, but little attention has been given to the complex chemical and physical changes which take place in mature seed during the slow process of devitalization. It was in order to determine some of these factors that the work described in these pages was begun, and the results are thus of considerable practi- cal value as well as of scientific importance. The present paper treats chiefly of the conditions influencing the vitality and germination of seeds when subjected to such methods of treatment as are generally met with in the ordinary handling of seed. Particular attention has been given to the efl'ect of climate, moisture, and temperature on vitality, supplemented with a discussion of the changes taking place in mature seeds, especially the respiratory activities and the part played by enzymes. 9 10 THE VITALITY AND GERMINATION OF SEEDS. Tli(^ rt'sults of the iil)ovc (!xperinicnt,s luive .su*4"gcsted improved luethod.s of .storing- and shipping- seed.s so as to prolong their vitality and also to secure the ^^I'oduction of more vigorous seedlings. The work for the present paper was begun in 1899 at the University of Michigan and was continued for three consecutive years while the writer held the Dexter M. Ferry Botanical Fellowship in that institu- tion. During this time the investigation was under the direction of Prof. Y. M. Spalding, Ph.D., and Dr. F. C. Newcoml)e, who showed great interest in it and gave valuable suggestions as the work pro- gressed, at the same time placing the facilities of the laboratory and of the library at the disposal of the writei-. Since September 1, 1902, the work has been continued in the Seed Laboratory of the U. S. Department of Agriculture. Valua])le assistance in storing seeds was rendered l)y Prof. C. W. Burkett, at Durham, N. H. ; Mr. E. E. Smith, Wagoner, Ind. T. ; Prof. W. R. Dodson, Baton Rouge, La. ; Prof. F. S. Earle, Auburn, Ala.; Zinuuer Brothers, Mobile, Ala.; Prof. H. H. HuDie, Lake City, Fla., and Prof. Charles B. Scott, San Juan, Porto Rico. MATERIALS AND METHODS. SEEDS. For these experiments thirteen different samples of seeds were used, being so selected as to include representatives of ten different families and twelve genera and species, as follows: Poacese — Zea mays, sweet corn (two samples). Liliacese, — Allium, eepa L., onion. Ijrassicacesd — jBras.s-lca oleracea. L., cabbage; Rn}>h(nuis mthnm L., radish. Apiacesd — Daticus carota L., carrot. Fabacese — Pisum sativum. L., pea; Pha.seola,s' vidga7'is L., bean. Yiolacese, — Viola tricolor L., pansy. PolemoniacedR — Phlox drmnmondii Hook, phlox. Solanacede — Lycopersicon lycopersicum (L.) Karst., tomato. Cn^curbitaceae, — Citridhis citridhis (L.) Karst., watermelon. Asteraeepe — Lactuca sativa L. , lettuce. It will thus be seen that the seeds used cover a wide range as to family characteristics, as well as size, structure, and composition of seed. Likewise they are all from plants of the garden or iield that have undergone a high degree of cultivation, thus enabling the seeds to withstand more or less variation as to conditions of vitality and growth. All seeds used throughout these experiments were provided by D. M. Ferry & Co., of Detroit, Mich., and the seed furnished was of strong vitalit}^ and of known age and origin. The corn "A" (Minne- sota Sweet), onion (Yellow Danvers), pea (D, M. Ferry Extra Early), bean (Yellow Kidney, Six Weeks), tomato (Dwarf Champion), and the MATERIALS AND METHODS. 11 watermelon (Sweet Mountain) were grown in Michigan. The corn "B" (Minnesota Sweet), was grown in Nebraska, the cabbage (Win- ningstcdt), in Washington, and the lettuce (Black-Seeded Simpson), in California, while the radish (Early Scarlet Turnip-Rooted), carrot (Chantenay), pansy (mixed), and Phlox drut/miondii (mixed) were grown in France. The seed was all of the harvest of 1899 and was received at the botanical laboratory' of the University of Michigan on January 27, 1900. On January 30, 1900, germination tests were made, showing the vitality of the seeds to be as follows: Vitality of seeds tested January SO, 1900. Kind of seed. Percent- age of germina- tion. Kind of seed. Percent- age of germina- tion. 100 93 83.5 94 88 . 87.5 98 Pansy 69.5 Pea 97 Phlox 78 Radish 81 Tomato 98 Watermelon 99 Onion GERMINATION TESTS AND APPARATUS. In the preliminary work several methods of testing were tried, but as none proved as serviceable as the "Geneva tester," this apparatus was adopted for all subsequent tests as recorded in the following pages. The detailed construction of this tester need not be described, for it is simple and quite familiar to all. However, some modifications were made in the preparation of the apparatus, and some precautions taken in the manipulation, which have proved to be of much value. The brass wires originally and ordinaril}^ used to support the folds of cloth were replaced by glass rods of 6 to T mm. diameter. Rods of this size are much heavier than is necessary to support the folds of cloth, but the chief advantage in having rods of large diameter is that in case of the germination of large seeds the folds can be drawn near together at the top and still have sufficient space within the fold for the seeds. On the other hand, in the germination of small seeds that require considerable quantities of air, the folds can be closed at the top bj'^ bringing the rods together, thus insuring more uniform condi- tions throughout the fold and at the same time leaving sufficient space above the seeds for an abundant supply of air. The chief advantage in substituting glass rods for brass wires is in removing the possible source of injury resulting from the poisonous action of the dissolved copper. Another error frequently, if not alwaj^s, made in using such a tester is in allowing the ends of the cloths, or sometimes the bottoms of the 12 THE VITALITY AND GERMINATION OF SEEDS. folds, to dip into water in the pan. This should never be permitted, for in that way seeds are kept too moist, especiall}^ near the ends of the folds. Likewise such methods give an opportunity for the trans- mission of dissolved copper and a resultino- injury to the seeds. For this same reason the strips of cloth should be made sufficiently narrow not to come into contact with the sides of the pan. Much better results are o])tained if the seeds, before being placed in the germinator, are soaked in water for several hours, the length of time depending on the power of absorption of the seeds. In these experiments the seeds were always soaked in distilled water for twelve or tifteen hours before transferring them to the germinator. This preliminary soaking gives a more speedy germination, which is always advantageous, especially in making comparative germination tests. In order to supply the requisite amount of moisture for subse(|uent growth, the cloths were iirst uniformly and completel}" wet with dis- tilled water; moreover much care was taken to see that there was only a very small quantity of water in the l)ottom of the pan. In case of seeds that germinate readily, such as cabbage, lettuce, and onion, it is necessary that all surface water be removed from the bottom of the germinator if good results are desired. The pan then being covered with a glass plate. It is seldom necessary to increase the amount of moisture, for seeds when once soaked need only to be kept slightly moist and not wet, as must necessarily^ be true if the ends of the cloths or ))ottoms of the folds dip into the water. After soaking, the water in the seeds and cloths is ample for the completion of most germina- tion tests. However, in an occasional test the seeds may become slightly dry, which happens when the cover is kept off the pan for a considerable time while counting geriuinated seeds. In such cases the remedy is to pour a small quantity of water in the bottom of the pan, or in extreme cases to moisten the folds with a fine spray. If the above modifications be adopted and the necessary precautions taken, mau}^ of the olijections frequently made to the Geneva tester will be removed and the difficulties will be overcome; at least it is a most excellent method of testing seeds where comparative results are especially desired. It must also be borne in mind that the Canton flan- nel (which is generally used in making the pockets) should always be of the best grade and should never be used a second time without l)eing thoroughly cleaned and sterilized. In selecting samples for germination the impurities and the imma- ture seeds were first removed. The samples for test were then made up of the remaining large and small seed. For the most part 200 seeds were taken for a test, but with the larger seeds — corn, pea, bean, and watermelon — 100 seeds were usually used. In all cases where any irregularity was apparent, tests were repeated. The controls are based on the results of several duplicate tests. EFFECT OP CLIMATIC CONDITIONS. 13 All germination tests were made in a dark room where the temper- ature could be comparatively well regulated and was maintained nearly constant throughout most tests. Germinated seeds were removed daily during early stages of the tests and a complete record of the number germinating each day was kept. This is of value in seed testing, because the germinative energy of a seed tells much as to its vitality. If seeds have a high vitality, the germinative energy will be very strong, i. e. , germination will take place rapidly, giving rise to strong and vigorous seedlings; but if the seeds are of very low vitality, there will be a corresponding retardation in germination, giving rise to weak seedlings, i. e., showing a low germinative energy. In most cases throughout this work only the final percentages of germination are tabulated. EFFECT OF ClilMATIC CONDITIONS ON THE VITALITY OF SEEDS. It has long since been known that seeds under ordinarj^ conditions lose their power of germination after the lapse of a few years, or in some cases within a few weeks or months. Many investigators have also learned that the rapidity with which seeds lose their vitality, when stored under ordinary conditions, varies greatly with the section of the country in which such seeds are kept. This loss in vitality is espe- ciall}" marked in the case of seeds stored in places of relatively high humidity. The rapid deterioration of seeds in localities having a humid atmosphere has become a source of much embarrassment to seedsmen, for they have experienced many difficulties in shipping seed to such places. This is especially marked in the case of seeds sent to growers or dealers in the vicinity of the Gulf of Mexico. Gardeners and planters in that part of the United States are continually com- plaining about the nonviable seeds sent out by seedsmen. Some grow- ers have learned how to guard against this difficulty to a certain extent. Zimmer Brothers, of Mobile, Ala. , wrote, on February 28, 1900, con- cerning this matter, as follows: During thirty years' experience in market gardening, we have learned that seeds of many hardy plants will not keep in our climate, and when ordering we so time our order that we can plant the seeds as soon as received. If such be impossible, we are very careful to keep the original package unoiiened until conditions are favorable for planting. If we find it necessary to keep seeds of hardy plants for some months, we put them up on arrival in dry bottles, put on top a bit of cotton saturated with chloroform and cork tightly. We have kept, in that way, cauliflower seed satisfac- torily for twelve months. At the shore seeds keep very badly; one-half mile back they do much better. As a rule seeds of tender plants give but little trouble. As far as has been ascertained, no definite experiments have been made with these points in view, and especially with the idea of deter- mining the cause or causes of this deterioration of vital energy. In order to obtain reliable data on these points, a series of experiments was undertaken in February, 1900, to determine how seeds are affected 14 THE VITALITY AND GERMINATION OF SEEDS. when (listril)uted to diti'crciit parts of the United States andsnl)niitted to the free influence of various climates. Likewise at tlie various points where tests were made the seeds were subjected to diflerent treatments. The pUices selected for these tests were San Juan, P. R., Lake City, Fla. , Mobile, Ala. , Auburn, Ala. , Baton Rouge, La. , Wagoner, Ind. T. , Durham, N. H., and Ann ArVjor, Mich. A sample of each species of seed was put up separately in double manila coin envelopes and in closely corked bottles. Duplicate sets of each series were then subjected at each of the above-named places to the following conditions: Trade conditions. — Conditions similar to those in which seeds are kept when offered for sale by retail dealers, the seed being more or less exposed to meteorological changes and subjected to natural varia- tions in temperature and humidity. For the most part the seeds were in rooms that were never heated. Dry rooms. — Rooms in the interior of buildings which were artifi- cially heated during cold weather, and where the (piantity of moisture was relatively small and the temperature comparativel}^ constant. Basements. — Rooms where the temperature was comparatively low and uniform, and the relative humidity of the surrounding air was much higher than in "trade conditions" and "dry rooms." These conditions varied in the different places at which tests were made, and a more detailed description will be given when the residts of the germination tests are discussed. For the first part of this paper, treating of the influence of climate on vitality, none of the seeds need to be considered save those pre- pared in paper packages and kept under trade conditions, these coming more nearly under the direct action of the surrounding atmosphere. A sample of each kind of seed was put up in a manila (No. 2) coin envelope, and each of these packages was then inserted in a second (No. 3) coin envelope. Duplicate samples of every kind of seed were sent to the various testing places, where they were subjected to trade conditions. At San Juan the packages of seeds were kept in an open room, being subjected to the full action of the atmosphere but pro- tected from the direct rays of the sun and from rain. At Lake City the packages were kept in a one-story frame Ijuilding which was not artificially heated and the doors of which were open the greater portion of the time. At Mobile the packages of seeds were stored in a comparativel}' open attic of a private dwelling. At Auburn the seeds were stored in a greenhouse office, with the doors frequently standing open. At Baton Rouge the packages were kept on a shelf in a grocery store, the doors of which were closed onh' during the night. At Wagoner the conditions were very similar to those of Baton Rouge, save that the packages of seeds were kept in a drug store. At Dur- ham the seeds were kept over a door at the entrance of one of the EFFECT OF CLIMATIC CONDITIONS. 15 college buildings. Tliis door opens into a hall wliieli coiinnuniciites Avith the offices, chemical l;i])oratorv, and the basement. At Ann Arbor the seeds Avere stored in the botanical laboratoiy, with slightlj vaiying conditions, they being near a window which was frequently open during the sunnuer, and at irregular intervals during the earl}^ part of the summer the packages were placed in the window so as to receive the direct rays of the sun. The seeds stored at Ann Arbor served partially as controls for those sent to the various other places, and, in addition to the last-named series, seeds from the original packages, as received from D. M. Ferry & Co., were kept in a dry and comparatively cool closet on the fourth floor of the botanical lab- oratory. These seeds served as checks for the complete set of exper- iments, and are designated throughout this paper as "Control." The samples were sent out to the above-named places in February, 1*J00. The first complete set was returned in June, or early July, of that year. The second complete set was allowed to remain throughout the entire summer, and was returned in Octoljer and earl}^ November of the same year. The average time of treatment for the two series of experiments was 12S and 251 days respectively. When the seeds were returned, germination tests were made as soon as possible. The length of time that the seeds were in the various places and the vitality as shown by the germination tests are given in Tables I and II. In both tables the columns from left to right, beginning with Mobile, Ala., arc in the order of the degree to which the seeds were injured. Table 1.— Effect of climate on vitality, as shown by j)ercentage of germination — -fjr! III. These results show to a good advantage the degree to which germina- tion has been retarded. 25037— No. 58—04 2 18 THE VITALITY AND GERMINATION OF SEEDS. T.\iii,K III. — lictdnhiliini in (/n-inhialioii. due to hijiinj cdtised hij imfarorable (ihnatic conditions. Corn "A." Peas. Watermelon. Tomato. Place where secd.s were kept. Germi- nation at end of 64 hours. Final germi- nation. Germi- nation at end of 40 hours. Final germi- nation. Germi- nation at end of 84 hours. Final germi- nation. Germi- nation at end of 83 hours. Germi- nation at end of 107 hours. Final germi- nation. Control Per cent. 81.3 4.0 01.0 50. 64. 68.0 80.0 80. 82. Per cent. 94.5 20.0 92.0 88.0 90.0 92.0 96.0 88.0 98.0 Per cent. 79.0 a 24. 60.0 36.0 36.0 50.0 54.0 « 93. 7 82. Per cent. 95. 7 41.0 98. SO.O 80.0 SO. 91. 97.9 98. Per cent. 98.0 0.0 12.0 0.0 2.0 0.0 0.0 22. 91. Per cent. 99.0 04.0 88.0 92.0 94.0 92.0 82.0 86.0 96.0 Per cent. ■ 78. 1.5 3S.5 9.0 40.0 16.5 0.5 59.0 7.5.5 Per cent. 92.7 12.5 78.0 50. 81.5 0.5.0 5. 5 75. 5 91.0 Per cent. 97.5 Mobile, Ala San Juan, P. R Baton Rouge, La . . Wagoner, Ind. T .. Lake City, Fla Durham, N. H Auburn, Ala Ann Arbor, Mich.. 79.5 96.5 96.0 94.0 94.0 87.0 94.0 98.5 a After 62 hours. In order that the results of Tables I and II may be more readil}' and f ulh' comprehended, it has been deemed advisable to summarize them in another table. For this purpose the average percentages of germi- nation of all of the different samples of seed have been determined for each of the different places. From these average percentages of ger- mination the deterioration in vitality, as shown })y both the first and second tests as given in Tables I and II, have been calculated, the ger- mination of the controls serving as a basis for comparison. These results furnish more trustworthv data as to the relative merits of the different localities as places for storing seeds. Likewise the per- centages of deterioration between the time of the first and the second tests are shown in Table IV. Table IV. — Average percentages of germination of all seeds kept at the various places, their deviations from the controls, and iJie increased percentages of loss in the second series of tests. Place of storage. Average germina- tion of all seeds used in experi- ments. Deterioration in vitality as com- pared with con- trols. First test. Second test. First test. Second test. Per cent. Per cent. Per cent. Per cent. 87.79 53.59 86. 77 24. 31 38.95 71.98 ...| 08. 21 '< 45. 18 1 ''H 21.39 (' 47. 93 80.48 50.86 8.32 41.39 85.57 .52. 42 2. .52 39.58 85.70 57.34 2.38 33.91 83.00 61. 27 5. 45 29. 38 82.12 02. 11 0. 45 28. 41 S6. 23 84. .58 1.77 2.52 Deterio- ration in vitality between first and second tests. Control Mobile, Ala. San Juan, P. R . Baton Rouge, La , Durham, N. H Auburn, Ala Lake City, Fla.... Wagoner, Ind. T . Ann Arbor, Mich. Per cent. 1.10 54.61 9.20 39.86 36.81 38.74 33.10 26.18 24.37 1.91 a Calculated results. EFFECT OF CLIMATIC CONDITIONS. 19 In Table IV the results are arranged in the order of the loss in vital- ity as shown by the second tests. However, a few words of explana- tion will be necessary, especially concerning the loss at San Juan. In the first place, the seeds were kept at San Juan onlj^ 131 davs" during the earl}' part of the summer, while during the most critical period, June 20 to November 6, they were in the botanical laboratory of the University of Michigan. Those marked Mobile, Ala., were, during the entire time, 262 days, under the influence of the warm, moist cli- mate of the Gulf of Mexico. The seeds kept at other places can well be compared with those from Mobile, the time being approximately the same. The average loss as shown b}^ the second tests was 3.35 times greater than the loss in the first test, which by calculation would bring San Juan next below Mobile, with a loss of vital energy in the seeds equal to -IT. 93 per cent. But more data are necessary before such a gradation of injurious climatic influences can be established. Table IV, however, brings out another interesting point, as shown by comparing the results of the first and second tests at San Juan and Mobile. In the first test the loss in vitality of the seeds from Mobile was 38.95 per cent, while the seeds returned from San Juan showed a loss of only 14.31 per cent as compared with 71.98 and 21.39 per cent, respectively, as shown in Table II. The degree to which the seeds were injured while they were stored in San Juan was such that they continued to deteriorate much more rapidly than the control sample. This deterioration was most marked in the case of the pansy seed, the germination of the first test being 20 per cent and that of the second test only 6.5 per cent, showing a loss in vitality of 68.2 per cent and 87.7 per cent, respectively. Thus when seeds are once placed in con- ditions unfavorable for the preservation of their vitality for a sufficient length of time to cause some injurj^, this injury will always be mani- fest and cause a premature death of the seeds even though they after- wards be removed to more favorable conditions. Seeds of strong vitality can withstand greater changes in conditions than seeds of low vitality without any marked deterioration. Through- out these experiments a wide difference has been observed between the "A" sweet corn and the "B" sweet corn. The original tests made January 30, 1900, at the time the seeds were received, showed a germination of 94 per cent for the "A" sample and 88 per cent for the "B" sample of corn. The control tests, made in November, 1900, showed a germination 0.5 per cent higher in each case; but the average loss in vitality of the two samples of seed kept at the various places was 12.17 per cent for the "A" sample and 26.10 per cent for the "B" sample. As with the pansy and the phlox these samples showed that « The number of days here given for San Juan is not absohitely correct. The time was reckoned from the date the seeds were sent from the laboratory until they were received in return. 20 THE VITALITY AND GERMINATION OF SEEDS. the stronger the vitality of the original sample of seed the more harsh treatment (;an be undergone witliout being- injured. Strong A'itality implies long life as well as vigorous seedlings. Another very important factor to be considered in the handling of seeds is the relative resistance of seeds of various species to adverse conditions. Certain seeds under one set of conditions may retain their vitality exceedingly well, while seeds of other species of plants under identical (,'onditions may he killed in a comparatively short time. For this reason no general rule can be laid down for the preservation of seeds. Table V shows the varying degrees of deterioration of the different species of seeds used in the experiments. Table V. — Differed degrees of deter ior(Uio)i. of various kinds of seeds. Kind of seed. Tomato Pea Corn, sweet, "A" . . Watermelon Lettuce Radish Corn, sweet, "B" . Bean Cabbage Carrot Onion Pansy Phlox drumiiiondii First test. Germi- nation of control. Per cent. 95. 5 95. 3 95.9 98.3 81.6 83.6 89.3 98.7 92.7 83.3 95.8 63.0 69.0 Average germi- nation from the various places. Per cent. 93. 06 91. 56 94. 75 97. 75 SO. 00 74. 38 78. 10 93. 00 86. 00 75. 16 82.18 38. 87 44. 87 Deterio- ration in vitality as com- pared Avith the control samples. Per cent. 2.55 3.92 1.20 .57 1.96 11.02 12. 47 5. 76 7.22 9.77 15. 26 38.33 34. 97 Second test. Germi- nation of control. Average germi- nation from the various places. Per cent. Per cent. 97.5 92. 43 95.7 84. 80 94.5 83.00 99.0 86.62 92.3 77.75 78.8 60.93 ,S8. 5 65. 40 98.7 69. 50 92.4 52. 15 82. 37. 81 97.0 25. 12 53.0 8.00 53.9 7.62 Deterio- ration in vitality as com- pared with the control samples. Per cent. 5. 20 11.39 12. 17 12.51 15. 77 22.67 26. 10 29. 58 43.56 53. 89 74.10 84.90 85. 85 In the above table the list of seeds is arranged in the order of their power to withstand the action of diverse climatic conditions, as shown by the results of the second test, given in Table II. Tomato seeds were found to be the most resistant, the control sample germinating 97.5 per cent. The average germination of the samples of tomato seed kept at the various places was 92.43 per cent, or a loss in vitality of only 5.20 per cent. The seed showing the next least injury was the peas, with a deterioration of 11.39 per cent. The phlox, which was the most affected by the unfavorable conditions, germinated only 7.(52 per cent, thus showing a loss in vitality of 85.85 per cent. It is also interesting to note that the order, as shown by the second series of tests, is quite different from that of the first. This lack of uniformity increases the dilficulties that must be overcome before the causes of the loss of vitality in seeds can be fully comprehended. Were all seeds affected in the same way when subjected to identical con- EFFECT OF CLIMATIC CONDITIONS. 21 ditlons, the ordei- sliould have ivinained the .same throuo-hout, but the wide variation in atnio.s[)iieric changes ati'ects diU'erent seeds so very differently that no uniformity of results can be secured. For example, the conditions prevailing- from February until June were much more disastrous to the vitality of the tomato and pea than to the "A" sweet corn, watermelon, and lettuce, while the conditions existing from June to November were more injurious to the "A" sweet corn, watermelon, and lettuce. An examination of the table will show other results of a similar nature. During the earlier stages of devitalization seeds undergo a gradual deterioration in vitality, but after reaching a cer- tain stage in their decline there is a comparatively sudden falling off, and seeds, except perhaps a few of the most persistent, soon cease to show any power of germination. Such factors as these must be taken into account in determining the relative length of time that different kinds of seed will retain their vitality. But as yet sufficient informa- tion is lacking in order to make any trustworthy attempt to classify seeds in respect to their viable periods when subjected to different con- ditions. Numerous experiments are now under way, with the hope of furnishing a basis for such a classification. In order to obtain more data as to the influence of climate upon vitality additional samples of seed were sent to Mobile and Baton Rouge, where they were stored under the same trade conditions as for the former experiment. For these tests only cabbage, lettuce, and onion seeds, put up in envelopes, as for the previous tests, were used. The different packages of seed, placed in paper boxes from which they were not removed, were sent from the laboratorj^ on May 20, 1901, and were returned November 26, 1901, the total time of storage being 190 days. The results of these tests are shown in Table VI, and are even more striking than those of the former tests shown in Tables I and II. Tahle VI. — ■Relative merits of Mobile, Ala., Baton Rouge, La., and Ann Arbor, Mich. as places for storing seeds. [Period, 190 days.] Cabbage. Lettuce. Onion. Seeds subjected to "Trade condi- tions." Percentage of seeds germinated at the end of— Percentage of seeds germinated at the end of— • Percentage of seeds germinated at the end of— 36 hours. 60 hours. 14 days. 36 hours. 60 hours. 11 days. 60 hours. 84 hours. 108 hours. 14 days. Mobile, Ala Baton Rouge, La . . Ann Arbor, Mich.. 0.0 0.0 10.0 0.0 0.0 04.5 8.5 •22. 5 86.6 0.0 2.h 07.0 14.0 3.".. r, 82.5 64.0 74.0 96.5 0.0 0.0 3.0 0.0 0.0 10.0 0.0 - 0.0 43.0 0.0 0.0 93.0 Table VI shows quite clearly the deleterious action of the warm, moist climate of the Gulf of Mexico on the life of seeds. The onion seed which was stored at Mobile and Baton Kouge did not germinate, 22 THE VITALITY AND GERMINATION OF SEEDS. while .seed from tlu' ,samc lot stored at Ann Arbor g-erniin:ited !)3 per cent. The cabbage seed was injured nearly as much as the onion, the sample from Mobile germinating- only 8.5 per cent. The conditions at Baton Rouge were slightl}^ more favorable to the preservation of vitalit}'. The cabbage seed stored at the latter place germinated 22.5 per cent, while a like sample of seed stored at Ann Arbor germinated 86.5 per cent. The lettuce was nmch more resistant than either the cabbage or the onion seed, but here, too, the injury was quite marked, especially as shown l)y the retardation in germination. The conditions at Mobile were also the most disastrous for the lettuce seed. During the first 36 hours that the tests were in the germinating chamber none of the lettuce seed from Mobile germinated, while the seed from the corresponding sample from Ann Arbor germinated 67 per cent. The final percentages of germination were 64 and 96.5 per cent, respectively, for the seed from Mobile and Ann Arbor, showing a loss in vitality of 33.68 per cent in the seed stored at Mobile. Here it will be seen, as in Table V, that the onion seed was most sensitive and the lettuce seed most resistant to the unfavorable conditions. In the first tests shown in Table V the average loss in vitality of the lettuce, caljliage, and onion was 15.77, 43.56, and 74.10 per cent, respectively, while for the last tests, as shown in the foregoing table, the losses in vitality of similar samples of seed kept at Mo])ile were 33.68, 91.29, and 100 per cent, respectively. The ratio is practically the same in both cases, the loss in the cabbage seed being 2.7 times greater than that of the lettuce. The foregoing data are sufficient to indicate that climatic influences pla}' a very important part in the life of seeds, and that the degree of injury varies greatly indifferent places and likewise in different seeds. Some seeds were practically worthless after an exposure of four or five months in such places as Mobile, Baton Rouge, or San Juan, as shown in Table 1. After longer exposures, six or nine months, similar results were obtained from all of the places to which seeds were sent. Many of the seeds were killed, as shown in Table II. The conditions at Mobile were fatal to all of the seeds; that is, the seeds were worthless so far as the gardener is concerned. CAUSES OF THE LOSSES IN VITALITY IN DIFFERENT CLIMATES. Having shown that seeds lose their vitality nuich sooner in some localities than in others, the question naturally arises, ''Why this loss in vitality ? " Unfortunately only two of the places where seeds were stored. Mobile and San Juan, have Weather Bureau stations which are e({uipped for making complete observations of the meteorological conditions. It has l)ccn observed, however, that there is a very close relationship between the precipitation and the loss in vitality in seeds; that is to say, in a measure the loss in vitality is directly proportional to the amount of rainfall. This deterioration is more apparent as the CAUSER OF LOSSES IN VITALITY. 28 tempcvature increases, hut the injnry due to the increase in tempera- ture is dependent on the amount of moisture present. The following table has been compiled in order to show the ratio between the loss in vitalit}^ and the precipitation and temperature. The loss in vitality, as given in the second column of Table VII, rep- resents the average losses in percentages, calculated from the results of the germination tests of the 13 different samples of seeds, as shown in Table II. " The third column shows the annual precipitation in inches. The aniuial precipitation has been taken, because in some instances heavy rainfalls occurred just previous to the time that the seeds were put into storage. Then, too, the annual precipitation furnishes more accu- rate data for a basis of comparison. The mean temperatures, as given in column 4, are not the mean annual temperatures, but the averages covering the time during which the seeds were stored. The mean annual temperatures were not taken, chiefly for the reason that the critical period, in so far as temperature is concerned, is during the summer months. Table VII.- — lialio hehreen vildlit}/, precipitation, and temperatxire. ^ Place whore seeds were stored. Mobile, Ala Baton Rouge, La. Durham, N. H . . . Auburn, Ala Lake City, Fla . . . Wagoner, Ind. T . Ann Arbor, Mich Average loss in vi- tality of the 13 dif- ferent sam- ples of seeds. Pcv cent. 71.98 41.39 39. .'■)8 33. 91 29. 38 28.41 Annual precipita- tion. Indies. 91.18 C6.37 48.20 (!2. 61 49. 76 42.40 28. 58 Temperature. Mean Fahr. Degrees. 7L4 72.2 52.3 64.4 73.3 67.1 49. 12 Maximum Fahr. Degrees. 96.0 98.0 98.0 98.0 103.0 107.0 98.0 I' These seeds were sent out in Fel)ruary, 1900, and were returned to the liotanical lal)oratory and tested in October and November, 1900. The average time that the seeds were kept at the various places was 252 days. ''The results of the San Juan tests have been omitted from this table because, as has been previously stated, all of the seeds were returned from San Juan on June 20, 1900, when the first tests were made. The second .series of tests was made in October, 1900. During the time intervening between the first and second tests the San Juan samples were kept in the botanical laboratory at the University of Michigan. According to the table the seeds kept at Mobile suffered the greatest loss in vitality. However, it is quite probable that the greatest loss would have been from the seeds stored at San Juan had the time of storage been the same for the two places, so that the results of the San Juan tests could have been included in the table. This conclusion is based on the following facts: Normally, the number of rainy days at San Juan far exceeds those at Mobile. In 1900 there were 211 days on which rain fell in liun Juan, while the records for Mobile show only 140. Likewise the average temperature of the dew-point Tor San Juan was 71° F. and only 59° F. for Mobile, which, when expressed in terms of absolute moisture, gives 8.240 and 5. .5.55 grains of water per cubic foot at the time of saturation. On the other hand, the relative humidity of San Juan was 78.5 per cent, or slightly lower than that of Mobile, the latter having a relative humidity of 80.5 per cent. However, the mean annual temperatures were 77.6° and 71.4° F., respectively, hence a mean absolute humidity of 7.099 grains of aqueous vapor for San Juan and only 0.718 grains per cubic foot for Mobile. 24 THE VITALITY AND GERMINATION OF SEEDS. From the forco-oino- table it will be seen that precipitation is a factor of much greater importance than temperature. In order to show the real value which- the amount of precipitation furnishes as a basis for judging the length of time that seeds will retain their vitality when stored in localities having a marked difference in the amount of rain- fall, the results set forth in the above table are represented diagram- matically as follows: Effect of jyrecipUation on vitolify. Place. Percentage of loss in vitality. Inches of precipitation. IMobilc 71.98 91. IS Baton Rouge 41. 39 GC. 37 Durhiiiii 39. r,,s 48. 20 Auburn 33.91 G2.61 Lake City 29. 3S •->s. II 49. 71 i Wagoner 42.4(1 Ann Arljor 2. .'i2 28. TiS " A discrepancy is ver}" marked for Durham, N. H., which may be partially explained ))v considering again the conditions under which the seeds were stored. It will be remembered that these samples of seeds were stored in a hall which opened directly into a chemical labora- tory. It is quite probable that the low percentages of germination were due to the injurious action of gases emanating from the labora- tory. Of these gases, ammonia probabl}^ plaj^ed a very important part, as it is well known that seeds are very readily injured when subjected to the action of ammonia. It is to be understood that the above comparisons are somewhat indefinite. If the amount of rainfall were equally distributed through- out the year a definite ratio could, in all probability, ])e established; but in the majority of places there are alternating wet and dry seasons, whicli make such a comparison very difiicult and unsatisfactory. Yet for ordinary considei-ations it is sufficient to say that seeds will retain their vitality much ])etter in places having a small amount of rainfall. For more exact comparison other factors nnist l)e taken into account, especially the relati^'e hmuidity, mean temperature, and temperature of the dew-point, which ultimately resolves itself into the absolute amount of moisture present in the atmosphere. EFFECT OF MOISTURE AND TEMPERATURE UPON VITALITY. From tlic foregoing experiments it is quite evident tliat moisture plays an important part in bringing about the premature death of seeds and that the detrimental action of moisture is more marked as EFFECT OF MOISTURE AND TEMPERATURE. 25 tho temperature increases. Formerly the general consensus of opinion has been to make this statement in the reverse order — that is, that temperature exerts a very harmful action on seeds if much moisture be present. For comparatively high temperatures the latter statement would probably suffice — at least it is not misleading, and in a certain measure it is true; but at the lowest known temperatures, as well as at ordinar}' temperatures, moisture is the controlling- factor, and in order to be consistent it should likewise be so considered for higher temperatures — that is, within reasonable limits. That temperature is only of secondar}' importance is brought out in the results obtained by a number of investigators. It has been well established by Sachs," Haberlandt,* Just,'' Krasau,'' Isidore-Pierre,^ Jodin,-^', Dixon, s' and others that most seeds, if dr}", are capable of germination after being- subjected to relatively high temperatures for periods of short duration. The maximum for most seeds is a tempera- ture of 100° C. for one hour; but if the seeds contain comparatively large quantities of moisture they are killed at much lower tempera- tures. It has been reported that lettuce seed will lose its vitalit}^ in two weeks in some of the tropical climates where moisture is abundant. Dixon has shown that if lettuce seed be dr}?^ it will not all be killed until the temperature has been raised to 114° C. In case of low temperatures the factor of moisture is of less impor- tance; yet even under such conditions the moisture must not be exces- sive or the injury will be quite apparent. But if seeds are well dried it can safely be said that they will not be killed as a result of short exposures to the lowest temperatures which have thus far been produced. Our knowledge of the resistance of seeds to extremel}" low temperatures is based on the experiments of Edwards and Colin, ^'^ Wartmann,' C. De Candolle and Pictet,-' Dewar and McKendrick,^" Pictet,^ C. De Candolle,'" Brown and Escombe,".Selby,^' and Thiselton- «Handbuch d. Exp. Phys. d. Pflanzen, Leipzig, 1865, p. 66. ftPflanzenbau I, 1875, pp. 109-117; Abs. in Bot. Jahresbr., 1875, p. 777. cBot. Zeit., 33, Jahrg. 1875, p. 52; Cohn's Beitriige zur Biol, der Pflanzen, 1877, 2: 311-348. ''Sitzungsbr. d. Wiener Akad. d. Wiss., 1873, 48: 195-208. I. Abth. ''Ann. Agron., 1876, 2: 177-181; Abs. in Bot. .Tahresbr., 1876, II. Abtb., 4: 880. /Compt. Eend., 1899, 129: 893-894. f/ Nature, 1901, 64: 256-257; notes from the Botanical .School of Trinity College, Dublin, August, 1902, pp. 176-186. /'Ann. sci. nat. bot., ser. 2, 1834, 1: 257-270. « Arch. d. sci. phys. etnat., Geneve, 1860, 8: 277-279; ibid., ser. 3, 1881, 5: 340-344. ilbid., ser. 3, 1879, 2: 629-6.32; ibid., ser. 3, 1884, 11: 325-327. ^Proc. Eoy. Inst., 1892, 12: 699. ^ Arch. d. sci. phj-s. etnat., Geneve, ser. 4, 1893, 30: 293-314. '"Ibid., ser. 4, 1895, 33: 497-512. «Proc. Roy. Soc, 1897-8, 62: 160-165. ^'Bul. Torr. Bot. Club., 1901, 28: 675-679. 2(l THE VITALITY AND GERMINATION OF SEEDS. Dyer." la the experiments of the last-named investigator seeds were subjected to the temperature of liquid hydrogen (—250- to — 252'-'C.) for six hours, and when tested for vitality the germination was perfect and complete. '' Much more might be said on the effect of high and low temperatures on vitality. But for the commercial handling of seeds the extremes of temperature are of secondai-y importance and need not be further discussed at this time. In the present work the purpose has been to show the effect of moisture on the vitality of seeds when subjected to such temperatures as are usually met with in the storing of seeds. SEEDS TACKED IN ICE. On February 6, 1900, samples of each of thirteen kinds of seed were put up in duplicate, both in manila coin envelopes and in small bottles. The bottles were closed with carefully selected cork stoppers. These two sets of duplicate samples were then divided into two lots. Each lot contained one of each of the packages and one of each of the bottles of seeds. The samples thus prepared were carefully packed with excelsior in wooden boxes, the boxes l)eing then wrapped with heavy manila paper. In one of the boxes was also placed a Sixes' self-registering thermometer, so that the minimum temperature could be ascertained. These boxes were stored in a large ice house near Ann Arbor, being securely packed in with the ice at the time the house was being tilled. The first box was taken out with the ice on June 12, 1900, after a lapse of 126 days; The thermometer in this box registered a minimum of —3.6° C. It is safe to assume that this temperature was uniform, at least up to within a few days of the time when the seeds were taken out. Unfortunately, absence from the university at this particular time delayed an examination of the seeds until June 20. During the eight intervening days the box of seeds was kept in the laboratory and there many of the seeds in the packages molded, so that they were unfit for germination tests. In fact, the results of the tests from the paclcages are of little value within themsehes; but in comparison with the \'italit3' tests of the seeds kept in the bottles some important facts are l)rought out, and it has been deemed advisable to tabulate these results with those of the second series. The second box of seeds was packed approximately in the center of a large ice house (100 by 60 by 20 feet) and was taken out with the ice on July 21, 1900, after having been 167 days in cold storage. The «Proc. Roy. Soc, 1899, 65: 361-368. b Bra ssica alba (oily), Pisnm sativum (nitrogenout^), CucHrhiUi pepo (oily), Triticnm safivniit. (farinaceous), and Ilordeum vulgare (farinaceous). EFFECT OF MOISTURE AND TEMPERATURE. 27 box was broug-ht directly to the laboratory and tlie seeds were exam- ined at once. Those contained in the paper packages had absorl)ed a considerable quantity of moisture and were much softened. In all of the packages except those containing the onion and watermelon seeds some mold had developed; but in the seeds used for the germination tests care was taken to avoid using those that showed any trace of a mycelium, thereby reducing the injury due to fungous growth to a minimum, even though subsequent experiments have shown that such injuiy is practically negligible. An interesting point concerning the germination of some of the seeds at this low temperature may be stated in this connection. Eight of the peas, or i per cent, had already germinated, the radicles vary- ing in length from 1 to 2.5 cm., thus corroborating Uloth's results in germinating peas at or slightly below the temperature of melting ice.^' Table VIII. — The tntalily of seeds kept in an ice house in envelopes and bottles, and like- nise the vitality of the controls. First test, after 126 days. Second test, after 167 days. Germination. Differ- ence be- tween envel- ope and control sam- ples. Differ- ence be- tween envel- ope and bottled sam- ples. Germination. Differ- encebe- tween envel- ope and control sam- ples. Differ- ence be- tween envel- ope and bottled sam- ples. Kind of seed. Con- trol. Envel- ope. Bottle. Con- trol. Envel- ope. Bottle. Corn "A" Per ct. 96.0 90.0 95.0 93.5 88.5 79.5 92.0 100.0 .52. 5 74.0 18. 80.0 Per ct. 36.0 60.0 92.5 89.0 5.0 73.0 90.0 Per ct. 94.0 96.0 96.5 94.0 81.5 80.0 88.0 100.0 65.5 "16.5 93.5 100.0 66.0 Per ct. 00.0 30.0 2.5 4.5 Per cf. .58. 30. 4.0 5.0 Per ct. 92.0 92.0 9.5.0 92.0 80. 5 73.6 94.7 100.0 52.0 .54.0 96.5 100.0 81.5 Per cl. 86.0 74.0 94.5 90.0 74.0 52.0 90.0 0.0 2.6 11.0 51.5 90.0 66.0 Per ct. 96.0 94.0 95. 94.0 89.0 75. 5 90.0 98.0 05.5 08.5 96.0 100.0 71.0 Per ct. 6.0 18.0 0.5 2.0 6.6 21.6 4.7 100.0 49.5 43.0 45. 4.0 15.5 Per ct. 10.0 20 Corn "B" Onion 5 Cabbage Radish 4.0 15.0 Carrot 23 5 Pea 6 Bean 98 Pansy 47.5 60.5 63 Phlox 57. 5 Tomato 22. 5 8.0 20. 5 10.0 44 5 Watermelon Lettuce 4.0 5.0 Average 87.3 63.6 87.9 25.0 27.7 84.9 02.1 87.6 24.3 27.0 '« In making up the averages the result of the germination of the phlox was omitted because a sub- sequent examination showed that the bottle containing this sample of seed was broken at the bottom, thus admitting sufficient moisture to destroy vitality, as is borne out by the second test. The above table shows, as previously stated, that the results of the first tests are incomplete and not very satisfactory, owing to the fact that the germination tests were unavoidabl}^ delayed for eight days after the seeds were taken from the ice house; but with the second set a Flora, 1875, pp. 266-268. 28 THE VITALITY AND GERMINATION OP SEEDS. of samples the counts for the vitality tests were beouii within an hour from the tiiue the seeds were removed from the ice house. Thus, the conclusions for these experiments must be drawn chief!}' from the sec- ond series of tests. However, comparisons wnll be made Avith the first where such seem justifiable. It will at once be seen that the seeds which were in paper packages gave a much lower percentage of germination than either the control samples or those kept in bottles. The average germination of the controls was S-t.O per cent, and the average germination of the seeds kept in bottles was 87.6 per cent, while onl}' 02. 1 percent of the seeds kept in paper packages germinated. This is equivalent to a loss in vitalit}' of 24.3 and 27 per cent, respectively, as compared with the vitality of the control samples and the samples from the bottles. The results of the first tests are practically the same, save that the difl'er- ences l)etween the control and the bottle samples are less marked. In the second case the a\'erage vitality of the seeds kept in envelopes was much reduced 1)}" the complete failure to germinate in the case of the ))eans, which are most susceptible to the deleterious action of moisture at the given low temperature. One of the most important points brought out b}' these experiments is the result ol)tuined with onion, cabbage, and w atermelon seeds. In both the first and the second tests the germination varied but little throughout. However, in all cases the seeds in the paper packages were slightly injured by the action of the moisture. This factor is of much importance, especially in the case of the onion seed, which, when kept in a moist atmosphere at normal temperatures, soon loses its vitality', })ut when maintained at temperatures slightly below freezing it becomes very resistant to the action of moisture. The beans, on the other hand, were all killed, although they are ordinarily much more hardy than onion seed. It is quite probable, however, that the death of the l)eans may be attributed to the reduction in tem- perature. Containing as they do large quantities of starch, they absorl) more water than less starchy or more oily seeds. This factor, together with the large embryo, renders them much more susceptible to the injurious action of freezing temperatures. Another im])ortant feature brought out by these experiments was the better germination of the seeds which had been stored in bottles in the ice house. The average germination of these samples was 2.7 per cent higher than that of the control. In a measure this may be included within the limits of variation; but when it is considered that all of the bottle samples except the beans, tomato, and lettuce showed a vitality equal to or greater than the control, it can hardl}' be considered as a normal variation, especially since only the lettuce gave an}^ marked variation in favor of the control. Likewise, the average percentages EFFECT OF MOISTURE AND TEMPERATURE. 29 of the first series of tests show a slight increase in favor of the seeds kept in the bottles, though the increase is not so well marked and is less uniform than in those of the second series. Aside from the final germination there is still another factor that nuist be taken into consideration as bearing evidence of the advantage of keeping seeds at low temperatures, provided that they are kept dry. All of the samples that were stored in the ice house in ])ottles showed a marked acceleration in germination. It is quite evident that tlie res- piratory activities and accompanying chemical transformations were much reduced by the reduction in temperature, and the vital energy was thus conserved; but when the conditions were favorable for germination the greater amount of reserve energy in these seeds gave rise to a more vigorous activity within the cells and a corresponding acceleration in germination. Numerous other experiments showing the effect of moisture on tlie vitality of seeds were made. In contrast to those just given, the injurious action of moisture at higher temperatures, yet temperatures well within the limits of those ordinarily met with in the handling of seeds, will be next considered. EFFECT OF MOISTURE ON VITALITY AT HIGHER TEMPERATURES. This set of experiments was undertaken particularly to furnish con- ditions somewhat similar to those existing in the States bordering on the Gulf of Mexico, or, in fact, all places having a relatively high degree of humidity and a temperature ranging from 30^ to 37^ C. (SQ"^ to 98.6"^ F.) during the summer months. In order to secure the desired degrees of temperature two incubators were utilized, one being maintained at a temperature varying from 30° to 32° C, the other from 36° to 37"^ C. The thermo-regulators were so adjusted as to admit of a possible variation of nearly two degrees in each case. Beans, cabbage, carrot, lettuce, and onion were used for these tests. In each of the incubators the seeds were subjected to four different methods of treatment: 1. In a moist atmosphere, in free communica- tion with the outside air. 2. In a moist atmosphere, but not in con- tact with fresh air, the seeds being in sealed bottles of 250 cc. capacity. 3. In a dry atmosphere, in free communication with the outside air. 4. Air-dried seeds in sealed bottles. In order to obtain the conditions requisite for the first method of treatment, an apparatus was used as shown in figure 1. The seeds were put up in small packages and then placed in a 250 cc. bottle. The bottle containing the packages of seeds was placed withiii a specimen jar which was partially filled with water. This jar was then closed with a large cork stopper which carried two glass tubes, each of 1 cm. })ore. These tubes extended 25 cm. above the top of the jar and out through 30 THE VITALITY AND GEEMINATION OF SEEDS. ^P the opening in tlie top of the ineulcitor. The primaiy object of the tub(^s was to prevent any water vapor from escaping within the incu- bator and thereby doing damage to the seeds that were to be kept dry in the same inculiator. For the same reason the cork in the jar was well coated with paraf- fin. Approximately the same volume of water was maintained in the jar throughout the ex- periment, more water being added through tube (U as occasion demanded, to replace the loss by evaporation. The chief advantage in having two tubes was the comparative ease with which the air within could be displaced by a fresh supply by forcing a current of fresh air through one or the other of the tubes. Two such preparations were made, one being left in the oven maintained at a temperature varying from 30^^ to 32^ C. , the other in the oven maintained at a tempera ture varying from 36° to 37"^ C. In both cases the bottles contained five packages of each of the live samples of seed, thus making provisions for testing at ditferent intervals. In order to supply the conditions for the second method of treatment, similar packages from the same samples of seeds were put into 8-ounce bottles, which were then kept for five days in a moist chamber. The in- crease in weight due to the absorption of water within the five da,ys was as follows: Beans, 3.03 per cent; cabbage, 8.09 per cent; carrot, 8.26 per cent; lettuce, 7A5 per cent, and onion 8.43 per cent. This increase, with the water alread}' present in the air-dried seeds, gave a water con- tent of 13.23 per cent for the beans, 13.99 per cent for the cabbage, 13.60 per cent for the carrot, 12.45 per cent for the lettuce, and 14.84 per cent for the onion. The bottles were then corked and sealed with paraffin, ))ut were so Fig. 1. — Apparatus used to de- termine the effect of moisture and temperature on the vitality of seeds in communication witli free air. Fig. 2.— Apparatus u.scd to determine the effect of mois- ture and temperature on the vitality of seeds not in com- munication with free air. EFFECT OF MOISTURE AND TEMPERATURE. 31 constructed that the relative humidity of the inclosed air could be increased without the admission of more free air. The detailed con- struction of this apparatus is shown in fig. 2." The seeds continued to absorb moisture to a limited extent. In order that the inclosed air might l)e maintained at approximatel}' the same degree of saturation, a crude hygroscope was attached on the inside of each bottle. These hj^groscopes were made from awns of Stqm caplllata L., the tip of the awns being removed and a short piece of fine copper wire used as an indicator. These hygroscopes were suspended from the under side of the cork, as shown at /;, and by the side of each was suspended a fine fiber of silk, which, being carried around by the indicator, recorded the number of turns made by the awn. Five such preparations were made for each of the two sets, so as to furnish seeds for a series of tests. One set was kept at a temperature of 30^ to 32° C, the other at 36° to 37° C. The seed from one of the bottles, at each of the temperatures, was weighed after eighty-one days, at the time the germination tests were made. These weighings showed that at the lower temperatures the average increase in weight for all the seeds was 8.6 per cent, and at the higher temperatures, 6.3 per cent. The increase in the case of the beans was quite marked at this time, being 13.3 per cent for those maintained at a temperature ranging from SO-* to 32° C, and 9.8 per cent for those maintained at 36° to 37° C. The third set of conditions consisted simph" of packages of the air- dried seeds kept in open boxes in each of the incubators. This series of tests was made especially for the purpose of determining the effect of dry heat on the vitality of seeds when maintained at the tempera- tures above given for some considerable time. For the fourth series small packages of the seeds were put into 2-ounce bottles, which were then corked and sealed with paraflin. Five of these bottles were kept in each of the ovens and germination tests were made at irregular intervals. The results of these tests furnish a « The wide-mouth bottle (5) contains the packages of seed (s). Through an open- ing in the cork is inserted a short piece of soft glass tubing, being first fused at the lower end and having a slight constriction drawn at c. At a distance of 1 cm. above the constriction is blown a small opening, as shown at o. A short piece of heavy rubber tubing if), cemented on a piece of heavy brass wire (tr), serves as a stopper. This stopper, which must fit closely within the glass tube, is operated by means of the heavy wire. When drawn up, the water in the tube may give off aqueous vapor, which can escape through the small opening (o) into the bottle. When suflicient moisture is present the supply is shut off by pushing the stopper down firmly against the constriction. The stopper must be well coated with vas- eline to prevent its sticking to the sides of the glass tube. To make the apparatus more secure against the entrance of fresh air, a second piece of rubber tubing ()■) is placed in the upper part of the glass tube, the top of whicli is then filled with oil. 32 THE VITALITY AND GERMINATION OF SEEDS. basis for comparing the relative merits of keeping- seeds in open vessels and in sealed bottles. Table IX will show the eft'ect of the various methods of treatment on the vitality of the seeds. Tahle IX. — Vitality of needs xvlien suhjected to the action of a dry and a moist atmosphere, both when exposed to free air and when confined in glass bottles, at relatively hiyli temperatures. « Kind of seed. Begin- niiiK of I'Xperi- merit. Bean Mar. Do do. Do do. Do ...do. Cabbage .do . Do I. ..do. Do I... do. Do ...do . Carrot. . Do . Do . Do . Lettuce Do . Do . Do . Onion . . Do . Do . Do . .do . .do. .do. -do . .do . .do. .do . .do. .do. .do. -do. .do. End of experi- ment and date of germina- tion tests. Apr. 4 May 12 May 24 July 22 Apr. 4 May 12 May 24 Julv 22 Dura- tion of ex- peri- ment. In open bot- tles, at tem- peratures varying from — 30° to 36° to 30° to 36° to 32°. 37°. 32°. 37°. Apr. May May July Apr. May May July Apr. May May July Days. 31 69 81 140 31 69 81 110 31 69 81 140 31 69 81 140 31 69 81 140 Vitality of seeds when kept in a moist at- mosphere. In sealed bottles, at tempera- tures vary- ing from — P. cl. 100.0 97.5 94. 2.3 87.8 71.6 80.0 0.0 83.5 69. 5 48. 0.5 92.5 38.0 55. 5 0.0 95.5 68.0 59.5 0.0 P.ct. 100.0 0.0 90.5 0.0 77.5 0.0 90.5 0.0 89.0 0.0 P.ct. 78.0 75.0 0.0 0.0 73.0 30.0 1.0 0.0 54. 5 22. 5 2.5 0.5 78.0 44.5 1.0 1.5 64.5 2.5 0.0 0.0 30° to 36° to 32°. 37°. P.ct. 44.0 0.0 0.0 0.0 72.5 0.0 0.0 0.0 29. 5 0.5 0.0 0.0 58.0 2.0 0.0 0.0 45.0 0.0 0.0 0.0 Vitality of seeds when kept in a dry atmos- phere. In open boxes, at tempera- tures vary- ing from — P.ct. 86.0 100.0 98.0 100.0 86.5 67.5 89.0 84.0 84.5 82.0 44.5 81.0 91. 42.0 6.5.0 82.0 95.5 97.0 95.5 90.0 P.ct. 84.0 90.0 90.0 94.0 84.0 87.9 92.0 83.0 88.0 85.0 50.0 81.2 86.5 38.5 58.5 87.0 93.0 95.0 94.0 92.0 In sealed bottles, at tempera- tures vary- ing from — 30° to 36° to 32°. 37°. P.ct. 98.0 92. 5 98.0 98.0 83.5 79.0 92. 5 88.5 89.5 83.5 50.0 78. 5 91.5 38.5 62.5 81.5 96.0 97. 5 99.0 97.5 P.ct. 98.0 95.0 100.0 96.0 86.9 78.5 92.0 86.7 89.0 82.5 48.0 83.1 90.0 51.5 67.0 88.0 97.5 93.0 95.0 94.7 Ger- mina- tion of con- trol sam- ples. P.ct. 94.0 98.7 98.0 99.4 91.0 83.0 92.5 93.1 92.5 78.0 64.5 83.1 90.0 31.5 53.5 79.9 96.0 98.5 96.5 95.4 a A study of the table will show that the lettuce and carrot seed germinated very poorly at the end of 69 .ind 81 days. This, however, was not due to any inherent quality of the seed, but to an excess- ive temperature at the time the tests were made. Both of these seeds require a comparatively low temperature for tlieir suect'ssful germination, lettuce germinating best at 20° C, and carrot at an alternating temperature of from 20° to 30° C. The amount of moisture absorbed or expelled under the ditt'erent methods of treatment has an important bearing on the duration of vitality and will be considered briefly at this time. Only the g"cneral results will be disc-"s.sed in this connection, inasmuch as later experi- ments, carried out in a similar manner, show the detailed results to much better advantage. Nevertheless, it requires only a glance at the above table to show the marked difterence in the germinative power of seeds which have been stored in moist and in dry conditions. The seeds which were exposed in a moist atmosphere to the higher EB^FECT OF MOISTUKE AND TKMrEUATUKE. 83 tenipciaturcs (36^ to 37'^ C) were killed much cai-lier than those subjected to the moist atmosphere at the lower temperatures — 30*^ to 32^ C. — in both the open and the closed bottles, A weighing" at the end of 31 days showed that the average increase in weight of the seeds kept in the open, moist chamber, due to the absorption of moisture, was 6 per cent at a temperature of 30 to 32"^' C, and 5 per cent at a temperature of Si}'^ to 37° C. For the seeds kept in the oven, maintained at the temperature of 30° to 32*-^ C, another weighing was made at the end of IS-i days, at wliich time the average increase in the water content had risen to 8.07 per cent. Unfortunately the seeds from the second oven, maintained at the higher temperature, had })ecome badl}^ molded in 09 da3^s, so that only the one weighing was made. Vitality tests made at this time, 69 days, showed that all of the seeds from the open, moist chamber, at the higher temperatures, had been previously killed as a result of the drastic treatment; conse- quently no future germination tests were made. Those maintained at the lower temperatures were almost entirely free from mold at the expiration of the experiment, only an occasional seed showing an}^ trace of fungous growth. Nevertheless, germination tests showed that the vitality had been destroyed in the cabl)age, lettuce, and onion. Beans and carrot were most resistant, the former having germinated 2.3 per cent and the latter 0.5 per cent. All of the seeds had become very nuich softened. The beans and the lettuce had changed very materially in color, the beans (Early Kidney Wax Six Weeks) having become much darker and the lettuce (Black-Seeded Simpson) ahnost a lemon color. AVith the seeds constituting the second series, i. e. , in a tnolut atmos- phere Ijiit in sealed hottlea^ the injur}^ was much more severe. Here, as with the open chambers, the seeds sul)jected to the higher temperatures were killed tirst, even though the amount of moisture actually absor])ed was less, as was also true with the other series. A weighing made at the end of 81 da3"s gave an increase of 8.6 per cent for those from the oven maintained at a temperature of 30° to 32° C. , and 6.3 per cent at the higher temperature. Likewise, in this series, the seeds had become very much softened and a verj^ disagreeable odor had developed as a result of the putrefaction of their nitrogenous constituents. A close examination made at the end of 81 days revealed slight traces of fun- gous growth, but there is no reason to believe that these plaj'ed any part in the destruction of vitalit3^ However, in making counts for germination tests all molded seeds were carefully discarded. The results of the germination tests showed that the vitality of the seeds kept at the lower temperatures had been practically destroyed at this time. The beans and onions failed to germinate, while the 25037— No. 58—04 3 34 thp: vitality and okkmination of seeds. cabbtio'c, carrot, and lettuce germinated only i, li.5, and i per cent, respectively. During- the succeeding (JO days much mold had developed, and at the expiration of the experiment, 140 days,- only the carrot and the lettuce gave any indications of vitality. It is especially interesting to note with what rapidity the deterioration took place ])etween the sixt}'- ninth and the eighty-first days, showing that when vitality reaches a certain point in its decline there follows a comparativel}' sudden death. This same fact is also shown in the case of those seeds in this same series kept at the higher temperature. After 31 days' treatment the}^ all failed to germinate, except 0.5 per cent in carrot and 2 per cent in lettuce seeds. In the two series of experiments just considered there was an increase in water content as a result of the humidity of the air in wliich the seeds wore kept. But the third series, ^ O -f' O :c -o" OC' cc" -I* O CC "^ -I' 00 :o -^^ -1^ cc* O O 00 CS (^ 'san^oq III pasopTit ojaAv spaas 8[iqM^qi?ioAVuiosiJ3jo ■ap JO asvajatn jo aSinuaojafi • <£>ocC'io-t-OTHCi-^cat^ 'imii^ ^-OiOOOOiOiOiOiOiOiOOOiOOOOOiCOOiCOiOOiCiO i^t^':di^-^r^c4»c-^cO':ooicO'^o6iC'^r-ioic'ico>cur:!C'it~-cccocc •sjnoii ZL J*^ P'!'"* '"^m IV OiOiOiCiCOiOOOiOiOiCOiOiOiCiOOOOOOiCOOOiCiO l^ !>. i^ l^ i^ 1^ i-O i^ l^ O !>■ '~D -^ X"Xl 00 I"- '^ CO X' 00 X' t^ iC X OC t— "sa^noq III paso[.iui aiaAV spaas ajuiAV j"ii:^'taAv HI os'i?aja -ap JO asi^ijoiii JO a^ri'iniiaojOfX • •-HOJOC^i— I r-1— i'y2^"^cC'CO'-H-rc^t^-^i>0OTrco •OOOOOOc-ir-Jr-JrHrHrHCCCOCCC-ic^C^lClC-^ : ^ XOiCOOiOiCiOOOiOiOOiCOOiOOOiCOOOOOiCOO rHi>-iJ?o'a6i>to^ica^u:>co'^r^'Xo6o^oow':D-^i>^--i^ccoi^i^c^ •sjooq 0?.I JO pna ain IV »OOOOiOLO>OiOiOi/;>OOiOiOOOiOiCiCOiCiCO>OOiCOO 050cocio6l0^^c^"^^^^^t^05OiOiOOOOOiO H CO (M C^ :M rH C^ItMrHi-H •san^oq til pasoiaiii ajaAv spaas a^iqAv iq^iaAv tit asTtajaiii jb aSTrjiiaojaC5O^OsOiO^C>O50^O^OiCC00CaClO5X'XiCCiO^Oi •sjnoq 98 Jo ptia aqi ^ v l>iCiOiCiCOO»COiCiaOiOOOinOiOOOOOiCOOiOOiC X ^- X X X X X l^ X t^ X I> O l^ 1^- 00 00 l^ (M X t-* l-^ l^ lO X 00 l^ 'sat^^oq lit pasopui ajaAV spaas aiu{A'v it[i?iaAv tit ast?ajO[it JO aSt^uaojaj ' OJOO'^OCOi-HOi-^rH-t^'t^O'^COtCOl'^CO-^'MtH • grH(N,-(,-(rHX'-f<'^0-T<(MCCOI:^COC^COCO(Mt^ iOoOOOOT-HrHrHr-H,-Ht-HOOc6cic^C'ioilOir?^ •imttji XHCiOiOOiCOOOOiCiCOOiOiCvCiCiOOiOiCOiOOOOiO C4 rH a> OS 't' CO ai OS O r-i O rH x' O C^i O -T' '^* C4 IC X r-J C^i .-^ rH OiOiOOXa5CJ5'XXOiCniOiaiXCiCT)05QiaOXiOiX'C^O^Xi— (OSOOS •sjitoix 9j; JO ptia ot{; ly COOiCOOOOiCOOOOOOOOiOiOOO»OiOO»COOiC>0 i-^-jDcdccooio-*^r^r-5c>ix"oiO''^c^"as--i^'^oocorHOicooc^r^ iC lO lO lO O lO lO lO CD iC lO iC :^ O 'O lO lO tM !■- lO iC <:£> to CD C^ 'san^))(l lit pas(i[oui ajaAV spaas aiu[Av ^qi^taAV tii asTtajaui jb ai^tmiaajarX • 'iO CC 1-i -JD t^ lO l~ f< X C-1 CO '£) -ti Oi C ^ CDiCcOOOCT) 'OOi— irHi-IO-f*i-OCOO'^'MOl--X-1 tn 2i XCO'MOiMOOOCOC^OOlOXCO'MOfNOGCCOC^lO'MOCOCOOJ rH-MCOCO-t* i-HC^COCO-r i-H CI CO CO -Tf* rHOJCOCO-t rH C-l I I I I 1 I I I I I 1 I I I I I I I I I -HOOOOr^r-«OOOOr-,-.OOOOI--rHOOOOI:^i-tOO I i-H CO CO Ol r-( (N :: :|gg-"-J :Sga^. -SBa^j. :Sa3-J^ ^^g C -f' >f^ ^ I^ ^ OS 00 O^ O rH C-l CO C^l CO ^ lO -O l-^ -f* iC O I^ 'If . Oi O i-l c^ O CO CQ CO CO CO CO OJ CJ CO CO CO CO O) iM (M C iC lO lO iC >0 lO IC lO lO lO iC lO lO lO lO lO lO »0 lO to iC lO tO lO »C If5 EFFECT OF DEFINITE QUANTITIES OF MOISTURE. 39 ooooooooo o '*' o to o o:* Gc -i5 o ' ' ' ' '• '' '' OO OVCDXiX) ooooooooo I ! i I I i I 00 O O '^ O X X* o o Oico aioxcc 1-- O ■M C-l CO CO X' Oi C-1 • • • • • I • .-I lO Oi Ol t^ CO r-t I"- l> l^t^OrMO^OrHOO 'OiCOOOOiC>0 0»OOOiCiOiOiC v: I •- c^ c-i 'C ■^ CO -p o C'i ci ^ t^ lO vo "^ :7ii— 03 cj OiOiCOOiCO»COiOiCO rtJx'oooi-Ht^iCOcoic-tx'oJir^cc Xi-H I-^001>!Ci c^i-i>:oocoi> '^^oool^oco O -M O iC io»o-i^co:dcoocoLc"ooooooi-i I I looooimcu^ooioioiooicoo iooo-H-^r^i^oooiai«di>i-ot>^r^ GO Oi Oi CC rH Ci Oi 05 0> O^ 05 O^ OOOOuDO»000»0>CO»CiOOO •^*OOOc4 CO t- 05 00 Ci Ci O CO CI icooiCioo^ooooiCiOvnmo 'M"oooi'i*-t^oioocsodi-I*i^ai'^':i« !•- Ir-COlCiC I>I>COXI>l>GC iCO^iH-MOCOCOOCOOO OJ^-'M'M OC0C0t^'©O^oOO0o OiCOOOiCiOOOu^-OOvOOOO cocoocioicoi^ooGooi'M'oai— -co CO oicocor- cooiosjsX'OiCs lOOOOiCOOOOiOiCiCOOOiO cdooc'ioi'M'^oot-^c^cooooco CI iCiOC^rH lOiC^OiClOiOiC COi-IC^OOI>CftTHOiCOOOO'M oj <3^0 OOt^^OiOiOCOiOiCOOCOi— (r-tO pH p^O iOiO'^'t>I>?Ot>t^<©*000020o !g!g ooooooooo c4c^oioococccococot) o o u « o ^ OC-IOODCOCMOiMOXeOtNOCNOO COCO-^ rHC^COCO-f i-H (M CO CO "^ CO I I I I I 1 I I I I I t 00l>r^0000t>•1-l0000^-0 i-ICOCOdrHIMTHCOCO'MrH'Mi-HCOCO.-H SCO 'S "S "S o o CO -t< lO CO r— x> Oi o >-< o i-H (M CO -r *c f^o rHi-irH.-ir-'i-i.— l'^^c■I-t■-f-r-f-f'^-^ lC >o ic lO lO ic »i^ lO lO lo »o lO ic ic If? "ft 40 THE VITALITY AND GERMINATION OF SEEDS. The fovoooiiio- tiiblo, showino- the conditions nndor which the seeds were kept, has been made quite complete. Aside from the linal per- centages of germination, the percentages of germination after a defi- nite numl)er of hours have likewise been given, the latter being better expressed as germinative energy. The germinative energy, as has been previously stated, is an important factor in determining the potential energy of a seed. This is quite clearly shown in many of the germi- nation tests recorded in the above table. The preliminary results show a marked contrast as a result of the different kinds of treatment, while the final I'esults reveal nothing more than the regular degree of varia- tion usuall}^ met with in testing seeds. Of the five species of seeds, the onion has yielded the most striking variations in the earlier stages of germination. Take, for example. No. 1535, the sample that was kept in an open bottle in the fruit cellar. The moisture absorbed was suffi- cient to cause a chemical transformation, which injured the vitalitv of the seed and consequently caused a retardation in germination. No. 1539, the onion seed from the incubator maintained at a temperature of 37° to 40° C, germinated only 16.5 per cent in 77 hours, while the final percentage of germination was 95.5 per cent. Onion seeds Nos. 1532 and 1533 germinated in 77 hours 18.5 and 2.5 per cent respectively, while the final germination of the former was 93.5 per cent and of the latter 96 per cent. All of these tests gave final per- centag-es of germination somewhat higher than the mean of the control samples. But the germination was considerably retarded, the control samples having germinated 29.5 per cent during the first 77 hours. These retardations in germination must be due to a lowering of vitalit}^, as a more careful study of the table will show, and not to any excessive drying that ma}^ have taken place during the time of treatment. Numerous other examples are to be found in the ta]>le, some even more striking than those mentioned, but it is not deemed necessar}^ that they all be pointed out and discussed here. The table also shows the results of the various weighings made of all of the difl'erent samples which were kept in closed Ijottles. With but very few exceptions there was an increase in weight, which increase was quite marked in all cases where free water was introduced. The air- dried seeds that were sealed in bottles without the introduction of free water all increased slightlj^ in weight, with the exception of the peas, which showed a slight decrease in weight. It has been observed that the absolute loss in the weight of the peas was slightly greater than the total gain in the four other samples of seed. This, however, is not of sufficient uniformity throughout to fully justify the conclusion that cabbage, lettuce, onion, and tomato seed have a greater affinity for water than peas, and that the former ro))bed the latter of a portion of their water content. Yet a portion of the increased weight of the cabbage, lettuce, onion, and tomato seed is ])r()])ab1v b(>st accounted EFFECT OF DEFINITE QUANTITIES OF MOISTURE. 41 for in that way. On the other hand, it is quite prol»al)U^ tiiat a ]K)r- tion of the increase in weight was due to the results of intraniolecuhir transformations and to the coexistent respiratory activities of tlie seed. The means of making these determinations are far from easy. Van Tieghem and G. Bonnier have shown" that seeds kept in sealed tubes in atmospheric air increased in weight during two years, but the increase was very small. In their experiments the peas which were in sealed tubes increased tjI^ of their original weight, A corresponding sample kept in the open air increased ,V of its original weight. Nos. 1510 to 1515 in Table X show an increased weight in seeds when sealed in bottles for TO days. These seeds were previously dried for 30 days at a temperature of 30° to 32° 0. Disregarding the increase in weights as aliove given and the factors to which such increase may be attributed, it is quite evident that in all cases where water was added the increase in weight was due chiefly to the absorp- tion of the water. The absolute increase was approximately the same as the w^eight of the water added. The amount of water absorbed by different seeds varies greatly under identical conditions, depending largely upon the nature of the seed coats and the composition of the seed. The average increase in weight of the seeds used in these experiments was as follows: Onion, 6.27 per cent; pea, 5.51 per cent; cabbage, 4.12 percent; lettuce, 3.99 per cent; tomato, 3.99 per cent. The loss in vitality of the corre- sponding samples was 28, 12, 23.7, 18.5, and 11.7 per cent, respec- tively. The relationship here is quite close, the amount of water absorbed being roughly proportional to the loss in vitalit3^ The peas, however, afford an exception to this general statement. But it must be remembered that peas require a much larger percentage of moisture to start germination and are likewise capa])le of undergoing much wider variations than the other seeds in question. However, before a definite ratio can be established between the al)Sorption of water and the loss in vitality, many other factors nmst be taken into consideration, such as the composition, water content, and duration of vitality of the seed under natural conditions. Another interesting factor is shown in No. 1516 of Table X. These seeds were dried for 30 days at a temperature of 30° to 32° C, after which they were kept in an open bottle in the laboratory for 10 days. During the 30 days' drying the ca])bage lost 2.41 percent, lettuce 2.59 per cent, tomato 2.71 per cent, and the onion 3.47 per cent of moisture. These same seeds when exposed to the free air of the laborator}^ for 40 days never regained their original weight, the increase being as follows: Cal)])age, 0.6 per cent; lettuce, 0.58 per cent; tomato, 1.56 per cent; onion, 0.89 per cent. The average quantity of water expelled was 2.79 «Bul. 8oc. bot. France, 29: 25-29, 149-158, 1882. 42 THE VITALITY AND OERMTNATION OF SEEDS. per cent in 30 da3's, while the average increase in weight during- the 40 days was onl}^ 0.91 per cent. These results show that if seeds are once carefully and thoroughly dried, they will remain so; that is, if kept in a comparatively dry room. This is an important factor in the preser- vation of vitality, as is l)orne out in the results of the germination tests. Later experiments were made wdth ver}' similar results, and an analogous method of treatment promises to be of much value as a preliminary handling of seeds. It is not definitely known to what this stronger vitalit}' is due, whether it be simply to the effect of the dry- ing or to some process of chemical transformation which makes the seeds more viable. These results are now under consideration and will be reported at some future time. The table also shows in a very striking degree the decrease in the numl)er of germinable seeds with an increase in the moisture and temperature. The amount of moisture absorbed by the seeds, with a limited amount present in the bottles, was inversely proportional to the temperature. At the higher temperatures the inclosed aii- held a larger portion as water vapor; however, there was a greater deterioration in vitality. Where the seeds were kept outdoors at the low" temperatures (—21.6° to 8.9° C.) of the winter months, no injury was apparent except where 3 cc. of water was added, and then onl}^ the onion seed was affected. This sample of seed had absorbed a quantit}" of water ecjual to 10.38 per cent of the original weight, which together with the original water content (6.41 per cent of the original sample) made IY.88 per cent of moisture in the seed. Practically the same results were obtained with the seeds kept in a fruit cellar at a temperature of 10° to 13° C. The samples of this series, in the open l)ottles, were also injured, as has been pointed out. With the samples that were stored in the dark room and in the herbarium room, the injury was more marked as a result of the higher ten>perature; })ut even here the seeds in the bottles which contained 0.5 cc. of free water deteriorated very little. The injury was confined to the onion seed, which showed a slight retardation in germination. Where 1 cc. , 2 cc. , and 3 cc. of water were added, vitality in some instances was likewise remarkably well preserved. The lettuce, tomato, and peas gave no indications of any deterioration save in the bottles containing 3 cc. of water. Here the lettuce and peas were permanently injured, while the tomato seeds sufi'ered only sufficiently to cause a delay in the rapidit}' with which they germinated. The calibage seed was retarded with 2 cc. and a lowering of the final percentage of germination with 3 cc. of water. The onion seed, being very sensitive to these unfavoi'able conditions, deteriorated very greatly, being practically worthless where 3 cc. of water were added. A brief study of the table will readily show that many seeds were killed at the still higher temperatures of 30° to 32° C. and 37 to 40° C The onion seed was slightly injured even where EFFECT OF DEFINITE QUANTITIES OF MOISTURE. 43 no water was added. However, a temperature of 40^^ C. is sunici(Mit to injure many seeds, even thoug-h the lil)erated water be permitted to escape, as is shown in the tests of the onion, No. 1539 of the talde. The greatest injiuy when air-dried seeds are sealed in bottles and tlien subjected to a higher temperature is due to the increased humidity of the confined air, as a result of the water liberated from the seeds. At first glance some of the conditions given in the above tal)le may seem to be extreme and far beyond any normal conditions that would be encountered in the ordinary handling' of seeds. This may seem to be especially true with the seeds kept in the bottles with 3 cc. of water where the additional amount of moisture absorbed gave rise, in some of the seeds, to a water content of approximateh^ 20 per cent. Yet this need not be thought of as an exception, for such extreme cases are often encountered in the commercial handling of seeds. During the process of curing' even more drastic treatment is not infrequently met with. Pieters and Brown ^' have shown that the common methods emploj^ed in the harvesting and curing of Poa pra- tensis L. were such that the interior of the ricks reached a tempera- ture of 130° to 140° F. (.54.4° to 60° C.) in less than sixteen hours, at which temperature the vitalit}^ of the seed is greatly damag'ed and frequently entirely destroyed. The interior of one rick reached a temperature of 148° F. (64.4° C.) in twent}^ hours, and the vitality had decreased from 91 per cent to 3 per cent, as shown l)y the ger- mination of samples taken simultaneously from the top and from the inside of the same rick. On the other hand, the extreme cases need not ))e considered. Take, for example, the onion seed that was sealed in a ])ottle with 1 cc. of water and maintained at a temperature of 37° to 40'^ C. Tlie increase in weight due to the water absorbed was 3.91 per cent, thus giving a moisture content of 11.2 per cent and a complete destruction of vitalit}". The cabbage seed, kept in the same bottle, had absorbed a quantity of water equivalent to 2.35 per cent of its original weight, which, with the 5.90 per cent contained in the original sample, gav^e 8.25 per cent of water. This sample of seed germinated only 11 per cent, having thus no economic value. In neither of these samples was the amount of water present in the seeds greater than that ordi- narily found in commercial samples. Moreover, the temperature was much below that frequently met with in places where seeds are offered for sale and likewise well within the limits of the maximum temperature of our summer months, especially in the Southern States. Take, by way of comparison, the maximum temperatures of some of the places at which seeds were stored to determine the effect of climate on vitality, as shown in another part of this paper. During « Bulletin 19, Bureau of Plant Industry, U. 8. Department of Agriculture, 1902. 44 THE VITALITY AND GERMINATION OF SEEDS. the summer of 1900 the maximum temperature at Wag-oner, Ind. T., was 107° F. (41.1° C), while that of Lake City, Fla., was 103° F. (39.5° C). If these points are kept in mind, it is not at all surpris- ing to find that seeds lose their vitality within a few weeks or months in warm, moist climates. In order to make the abov^e facts more clear the preceding table has been summarized and is presented in the following condensed form, showing the relation of the water content of the seed to vitalit}^: Table XI. — Marled dek'r I oration in vitality with an increase in the qiinntity of the imler content of seeds. How preparations were made. Amount of water introiliicecl inli) the l»ottk-s. Average in- erease in weight as a rt'sult of the greater water content. Average moisture in .seeds at the time germi- nation tests were made. Average germina- tion. Control sample cr. Per cent. Per crnt. 6.07 '1 2. 77 G. .55 8.31 9.91 12.75 1.5. 10 Per cent. 93.3 Closed bottles, sealed with paraffin Do Water expelled. None. 0.5 1.0 2.0 3.0 0. 06 .08 1.75 3.24 .5.91 8.13 a 93. 9 94.0 Do Do 91.7 83.3 Do Do 67. 5 ,58. 6 a Peas not included in this set. Numerous other results of a similar character might be cited, l)ut it hardly seems necessary at this time, since there can be no doubt that moisture is the prime factor in causing the premature destruction of vitality in seeds in the usual conditions of storage. Wh}' they lose their vitality as a result of the unfavorable conditions is quite a differ- ent question, and has to do wnth the very complex composition of the seed. A COMPARISON OF METHODS OF STORING AND SHIPPING SEEDS IN ORDER TO PROTECT THEM FROM MOISTURE AND CONSE- QUENTLY TO INSURE A BETTER PRESERVATION OF VITALITY. SUGGESTIONS OF EARLIER INVESTKJATORS. As early as 1S32, Aug. Pyr. De Candolle" wrote a chapter on the conservation of seeds, in which he said that if seeds be protected from moisture, heat, and oxygen, which are necessarv for germination, their vitality \\\\\ be nnich prolonged; moreover, that if seeds are buried sufficiently deep in the soil, so that they are protected at all times from the very great influence of oxygen and moisture, their vitality will be preserved for a much longer period. "Physiologie Vegetale, Paris, 1832, Tome II, p. 618. COMPARISON OF METHODS OF STORING AND SHIPPING. 45 Gii;lioU" goes so far as to say: There is no reason for denying the possibility of tlie retention of vitality in seeds preserved during many centuries, such as the Mummy wheat and seeds from Pompeii and llerculaneum, provided that these seeds have been preserved from the begin- ning in conditions unfavorable to chemical change. * * * The original dryness of the seeds and their preservation from moisture or moist air must be the very first (conditions for a latent secular vitality. Some of the earliest suggestions for storing seeds in quantity were made })y Clement and Fazy-Pasteur, and were reported by Aug. IVr. De Candolle in his Physiologie Vegetale. Clement suggested the use of large cast-iron i-eceptacles, made impervious to air and water, the well-dried seeds to ])e poured in through an opening at the top, after which the opening should be hermeticall}' sealed and the seeds with- drawn through an iron pipe and stopcock at the bottom of the tank. The scheme of Faz3^-Pasteiu' was to store seeds in wooden boxes well covered with tar. This method was especially applicable to small ([uantities of seeds, and was used to a limited extent at that time, but, so far as has been ascertained, it has long since been discarded. The keeping of seeds in large iron tanks, as suggested by Clement, has never l>een practiced to any extent. It seems quite possible, however, that the present "tank" grain elevator, now so itniversally used, might readily l)e modified in such a way as to make the method suggested ])y Clement quite practicable. THE NECESSITY FOR THOROUGHLY CURING AND DRYING SEEDS. In addition to being well matured and carefully harvested, seeds should be thoroughly cured and dried before being put into the stor- age bins. Much better results would be obtained if .such seeds were artilicially dried for several days in a current of dry air at a tempera- ture not to exceed 35*^ C. With this method of drying, from 2 to 4 per cent of the moisture usually present in air-dried seeds is expelled. The accompanying contraction of the seed coats makes them more impervious to the action of moisture, and consequently the seeds are better prepared for storing and shipping. Experiments made with cabbage, lettuce, onion, and tomato seeds gave results as follows: The average loss in weight of the air-dried seeds, after an additional dry- ing of 30 days at a temperature of 30"-^ to 32° C. was 2.79 per cent. Yet these same seeds, when kept for 40 days in the laborator}^ reab- sorbed only an average of 0.91 per cent of moisture. Like quantities from the original sample gave onl}^ the slight variations ordinarily met with, due to the humidity of the atmosphere. Thus seeds, when once carefully and thoroughly dried, will not regain their original weight, provided they be kept in a dry room. a Nature, 1895, 52: 544-515. 46 THE VITALITY AND GERMINATION OF SEEDS. CIIAKACTEli OF THE SKEU WAREHOUSE OK STOKAtiE ROOM. Another important factor in the .storing- of seeds is the character of the seed warehouse or storage room. The first point to be considered is dryness. Such houses should be kept as dry as possible, which can be accomplished either by means of artificial heat or by the use of strong drying agents, or better still, by l)oth. True, if the seed ware- house be located in a section having a dr}' climate, this ditiiculty is at once largely overcome. But in man 3^ cases such a location is imprac- ticable or even impossible, and other means must be resorted to. As a matter of fact, most large seed warehouses are not heated and a great loss in vitality inevitably folloAvs; but each seedsman nmst determine for himself whether or not this loss is sufficiently great to justify the expense of heating- such a storage room. Experiments carried on during- the progress of this work have shown some very marked differences in favor of seeds stored in rooms artificiall}' heated. The averages of the thirteen samples of seeds from the eight places at which they were stored show a difi'erence in the loss of vitality of 9.87 per cent. Those kept in rooms that were arti- ficially heated during- a greater portion of the time deteriorated 25.91 per cent, while those stored in rooms not so heated deteriorated 35.78 per cent. The loss here given for seeds stored in dry rooms is greater than such conditions warrant, owing to the very unfavorable condi- tions at Mobile, Ala,, and Baton Kouge, La. At Lake City, Fla., the relative percentages of deterioration Avere 29.42 and 16.27 for the unheated and heated rooms, respectively; at Auburn, Ala., 33.90 and 10.31 per cent, and at Durham, N. H., 39.58 and 3.57 per cent, respec- tively. Unfortunately these experiments were not made with this definite point in view, and the results are not entirely satisfactory, as no records were made of the temperatures and humidities. THE VALUE OF GOOD SEED TO THE MARKET GARDENER. This work was undertaken chiefl}^ for the purpose of finding some improved methods of shipping and storing seeds in small packages, wherein their vitality might be better preserved. The rapid deterio- ration in vitality causes great losses to gardeners living in districts where the climatic conditions bring about the premature destruction of vitality in seeds. In many cases the seeds are practically worthless or altogether fail to germinate after a few weeks' exposure. The loss in such cases is not in the greater quantity of seed reqviired, but the retardation or complete failure of the germination often means delay, making the difference between success and failure in the desired crop. Seed of low vitality is even worse than dead seed. With the latter the difficulty is soon discovered, while with the former, although the seed will germinate, the seedlings are not sufficiently vigorous to develop COMPARISON OK METHODS OF STORING AND SIIIITINO. 47 into strono- and heiilthy plants. True, most enterprising gardeners usually have vitality tests made inmiediately preparatory to planting, but this is not always convenient, and they rely on the results of tests made at some earlier date. In such cases it quite frequently hai)pcns that they accept the results of tests made several weeks earlier. With many seeds this will suffice, yet there are many others that will dete- riorate very materially w ithin a few weeks or even within a few days in such unfavorable climates as exist, for example, near the Gulf of Mexico. In a letter dated January 15, 1903, Mr. J. Stecklcr, of New Orleans, La., wrote as follows concerning the vitality of seeds: Some seeds are not worth being planted after being here three months. This is especially true of eaulitlower seed. We have made repeated tests and this seed after remaining here 90 days was worthless and had to be thrown away. SHIPPING SEEDS IN CIIAKCOAL, MOSS, ETC. Bornemann" made some experiments with seeds of Vtctorui n'(/!a and Enryale fcrox, in which he found that when packed in powderi^l charcoal they soon lost their vitality, but Avhen packed in powdered chalk slightl}^ better results were obtained. On the other hand, Dammer* recommends powdered charcoal as a method of packing for seeds that lose their vitality during shipment, especially the seeds of palms and a number of the conifers. Charcoal is undoubtedly much better than moist earth or moss, which are frequently used, the latter ali'ording abundant opportunities for the development of molds and bacteria during transit. Some such method as moist charcoal is necessary in case of seeds which lose their vitality on becoming dry. Numerous other reports have been published from time to time concerning the shipping of seeds of aquatic plants, as well as those of low vitalit}^, but they need not be discussed further at this time. NATURE OF THE EXPERI3IENTS. Aside from some popular accounts and miscellaneous suggestions, but little has been done toward finding improved methods of shipping and storing seeds of our common plants of the garden and field. Accordingly, in February, 1900, a series of experiments was under- taken to determine some of these factors, in which three questions were considered: (1) How ma}^ small quantities of seeds be put up so as to retain a maximum germiuative energy for the greatest length of time? (2) What immediate external conditions are best suited for the longevity of seeds? (3) What part do climatic conditions pkw in affecting the life of seeds ? « Gartenflora, 35. Jahrg., 1886, pp. 532-534. &Ztschr. trop. Landw., Bd. I, 1897, No. 2. 48 THE VITALITY AND GERMINATION OF SEEDS. In order to answer the tirst question, duplicate samples of the various kinds of seeds were put up in double manila coin envelopes, as described on page 1-i. Likewise, duplicate samples were put up in small bottles, the bottles being closed with good cork stoppers. Some of the bottles were filled with seed, while others were only partl}^ full. In some cases there was a surplus air space five times as great as the volume of the inclosed seeds. This space, however, had no bearing on the vitality of the seeds as far as could l)e determined. In order to determine what immediate external conditions play an important part in the destruction of vitality, samples of seed, ])repared as above described, were stored in difl'erent places." At each place they were subjected to three dift'erent conditions of storage, which, for convenience, have been designated as "trade conditions,'" "dry room," and " basement," as described on page 14. In addition to these three methods of storage, numerous other conditions were tried in and near the laboratory; such as in incubators at increased temperatures and with var3dng degrees of moisture, in cold storage, in greenhouses, and in various gases, in vacuo, in liquids, etc. The third question, " What part do climatic conditions play in aifect- ing the life of seeds F' has been answered for the most part in a dis- cussion on the efl^ect of climate on vitality, page 13. In fact, the seeds in the envelopes kept under trade conditions were the same in both cases, being used here simply as a means for comparing the vitality of seeds when stored in paper packages and in bottles, as well as to show the relative merits of trade conditions, dry rooms, and basements as storage places for seeds. DISPOSITION OF THE SAMPLES.* A more definite description of the treatment given the seeds in the various places may be summed up as follows: San Juan, P. R. — The seeds were sent to San Juan on February 9, 1000, and were returned on June 20, 1900, after a lapse of 131 days.^ At San Juan the seeds were stored under trade conditions only, and the various packages were not removed from the original box in which they were sent. While in San Juan the box containing the seeds was kept in a room well exposed to climatic influences, being protected only from the direct rays of the sun and from rain. « San Juan, P. R. ; Lake City, Fla. ; Mobile, Ala. ; Auburn, Ala. ; Baton Eouge, La. ; Wagoner, Ind. T. ; Durham, N. H., and Ann Arbor, Mich. '' The places of storage represented by trade conditions have already been described for each of the localities, but it seems advisable to rewrite the descriptions here so that they may be more readily compared with the dry room and ])asement conditions. t-'The exact time that the seeds remained at San Juan was much less than 131 days, the time of transportation being included, as has l)een done for the other places. COMPAKISON OF METHODS OF STORING AND SHIPPING. 49 Lahe C'dy^ Fla. — The .seeds were sent to Lake City on February 9, 19U0. The first complete set was returned on June 18, after 129 days. The second complete set was returned October 1, after 234 days. The "trade conditions" at Lake City were supplied by keepino- the seeds in a small, one-story frame building, the doors of which were open the greater part of the time. This building was not heated, and the seeds were stored approximately 5 feet from the ground. "Dry room" conditions were those of a storage room on the fourth tloor of the main building of the Florida Agricultural College. The third set was kept in a small bulletin room in the basement of the same building. 2Iohlle, Ala. — The seeds were sent to Mobile on February 17, 19U0. One set was received in return on July 7, after 180 days. The other set was received on November 6, after 262 days. The "trade condi- tions " in this case consisted of a comparatively open attic in a one-story frame dwelling. The set in a "dry room" was kept in a kitchen on a shelf 5 feet from the floor, and not more than 6 feet distant from the stove. Here they were subjected to the action of artilicial heat through- out the entire period. '^ The seeds under "basement" conditions were kept in a small collar, which during the season of 1900 was very moist. Auhurn, Ala. — The seeds were sent to Auburn on February 17, 1900. The first complete set was received in return on May 30, the second on November 19 of the same year, or after 1()2 and 275 days, respectivel3\ " Trade conditions " consisted of an office room connected with a greenhouse, with the doors frequently standing open; "dry room" conditions w^ere obtained in the culture room of the biological laboratory on the third floor of the main building of the Alabama Polytechnic Institute, " })asement" conditions being found in the base- ment of the same building, a comparatively cool situation, yet with a relatively high degree of humidity. Baton Rouge., La. — The seeds were sent to Baton Rouge on February 17, 1900. ' On June 18 the first complete set was received in return. The second set remained until Octol^er 22, making the time of absence 121 days for the first and 247 for the second set. "Trade conditions" at Baton Rouge were furnished by keeping the seeds throughout the entire time of the experiment on shelves in a grocery store, the doors of which were not closed except at night. These conditions were thus identical with those to which seeds are subjected when placed on sale in small stores. The "dry room" was a class room on the second floor in one of the college buildings. A storeroom in the basement of a private residence, having two sides walled with brick, furnished ' ' basement " conditions. « Presumably these were in a dry place, but further evidence showed that the pre- sumption was erroneous. The vapors arising while cooking was being done on the stove gave rise to conditions very detrimental to a prolonged life of the seeds. 25037— No. 58—04 4 50 THE VITALITY AND GEKMINATION OF SEEDB. W(i(/onet\ hid. T. — The seeds were sent to Wa<^oner on February 17, 1900. The lirst series was received in return on June 2o, after 126 days; the second set was returned after 238 daj^s, on October 13, I'JOO. The sets for "trade conditions " were kept in a drug- store, on a counter near an open door. The "dry room" was a sleeping- room on the iirst floor of the same building, while "basement" conditions were supplied by keeping the seeds in a large depository vault in a bank. Darhmn, W. II. — The two sets of seeds were sent to Durham on February 17, 1900, and were returned on July 14 and October 20, after 117 and 231 days, respectively. The seeds under "trade conditions" were kept over a door at the entrance of one of the college buildings. The door opened into a hall, which led into office rooms, the chemical laboratory, and the basement. An office room on the first floor of the same building- supplied "dry room" conditions. The seeds were located well toward the top of the room, which was heated with steam and remained quite dry at all times. The "])asement" conditions were found in a storage room in one corner of the basement of the same building. Ann ArJ}(>i\ Midi. — The set of samples placed under "trade condi- tions" was kept in the botanical laboratory, being moved about from time to time in order to supply the necessary variations to an herbarium room, to an open window, and to an attic. From February IS, 1900, until May 12, 1900, the set of seeds under " dry room" conditions was stored in a furnace room. The seeds were only a few feet from the furnace and were always quite dry and warm: The maximum tem- perature recorded was 43 - C, with a mean of 38^ during cold weather, and of 30^ C. during milder weather. On May 12 this set of seeds was transferred to the her})arium room on the fourth floor of the botanical laboratory, where they remained until vitality tests were made. " Basement" conditions were found in a fruit cellar, having two outside walls and a temperature fluctuating ])etween 10'^ and Vo^ C. These packages and bottles were all securely packed in new cedar l)oxes from which they were not removed until after their return to the laboratory. RESULTS OF THE GERMINATION TESTS. After receipt of the seeds, germination tests were made as rapidly as possible, the results of which are given in the tabulations which follow. Likewise, in each case is shown the vitality of the control sample. Furthermore, a sunnnaiy of each table is given, showing the average percentages of germination of the seed from the various places for the first and second tests, respectively. From these results the average percentage of loss in vitality has ])cen calculated, reckoning the germination of the control sanq^le as a standard. It is thus a very simple matter to compare the relative merits of the ditierent methods of storing and the role they play in pronioting the longevity of seeds. COMPARISON OF METHODS OF STORING AND SHIITINO. 51 Taisle XII. — Percentage of (jermlnaiiun of beans subjected to various conditions of storage ill, different localities. [tiermination of control sample: First test, ' )8.7 per cent; second test 98.7 i>er cent.] Order of tests. Num- ber of days in storage. Percentage of germination. I'lace of storage. Trade con- ditions. Dry rooms. Basements. Envel- opes. Bottles. Envel- opes. Bottles. Envel- opes. Bottles. Lake City, Fla Do Fir.st Second . First.... Second . First Second . First.... Second . First Second . lLi9 23-1 102 275 140 202 121 247 131 98 84 98 5G 58 96 60 100 90 96 82 100 78 98 100 98 98 97. 5 98 96 90 100 96 100 98 90 100 100 . 96 84 100 98 90 100 94 82 92 28 98 98 100 98 100 98 100 100 86 97. 9 0(i 54 98 100 Auliurn, Ala Do 97. 5 100 Mobile, Ala 100 Do 98 98 Do 98 Do Wagoner, Ind. T First.... Second . First.... Second . First... 120 238 147 251 98 100 98 98 100 100 100 98 100 84 100 98 Do 98 Durham, N. H 100 Do 90 92 98 84 91. 5 98 92 92 Do Second . 100 [First.... jsecond . [First.... jSecond . Average percentage of ger- mination. 128 251 93 69.50 96.44 97 95.43 69.33 97. 14 97. 36 60. 99 55. 66 97. (!4 98. 86 Average percentage of gain or loss in vitality. 128 251 5.78 29. 59 2.29 1.72 3.31 29. 76 1.58 1.36 32.13 43.61 1.06 -t-0.10 The beans at Mobile were seriously affected under all conditions except when put up in bottles and thus protected from the moist atmosphere. Those kept in bottles under "trade conditions" deteri- orated to 90 per cent, but the result of the first test of the same series indicates that some moisture passed through the cork and that the seeds were injured in that way. At Baton Rouge the beans retained their vitality somewhat better; but even here all those from the envelopes were practically worthless after 247 days, for beans that germinate only 60 per cent are of no value for planting. The "trade conditions" at Auburn, Ala., and Durham, N. H., were also very unfavorable to the prolonged vitality of the beans. At Wagoner, Ind. T., San Juan, P. R., and Lake City, Fla., there was a marked deterioration, yet not sufficiently great during the time g^ivcn to render them worthless for planting. However, it is quite evident that beans subjected to such conditions of storage would not be fit for planting the second season. A summary of the table shows that the vitality of the beans when kept in bottles and subjected to either of the three conditions was not interfered with. The averages .show a variation of less than 2 per cent. With those kept in paper packages the results were quite dif- ferent, the advantage being slightly in favor of the "trade condi- tions." The loss in vitality was 29.59, 29.76, and 43.61 per cent, respectively, for "trade conditions," "dry rooms," and "basements." r^9 THE VITALITY AND GERMINATION OF SEEDS. Tablk XIII. — FcrcentcKje of gi'i-miiKiHon of peas subjected t.v various comlitioiis of storage in different localities. [(icrminiUicin of coiitrul sample: First test, 95.3 per cent; second test, 95. 7 per cent.] Ortler of tests. Num- ber of days in storage. Percentage of germin ition. Place of storage. Trade condi- tions. Dry rooms. Basements. . Envel- opes. Bottles. Envel- opes. Bottles. Envel- opes. Bottles. First Second . First.... Second . First Second . First.... Second . First.... Second . First. . . . Second . First.... Second . First 129 234 102 275 140 262 121 217 131 126 238 147 251 9() 86 93.3 97.9 69. 2 44 94 80 94 98 98 80 98 94 90 98 97.9 98 94 94 92 100 92 88 100 98 90 92 94 98 94 94 94 92 87.8 90 88 42 94 70 94 92 97.8 96 96 96 90 98 90 6 93.9 86 10.2 90 98 Do 98 Auburn, Ala Do 94 98 98 Do 98 98 Do 98 Do 96 100 94.7 94 94 92 96 98 96 72 92 90 88 94 98 96 86 88 Do 92 Durham, N. H 98 Do 90 94 Do Second . f First.... (Second . 1 First {second . 100 Average jiercentage of ger- mination. 128 251 91.56 84.74 94.24 96.25 93.4 80. 45 91.41 95.14 81.44 60.66 96.43 96.28 Average percentage of gain or loss in vitality. 128 251 3.92 11.45 1.12 0.47 1.99 15. 94 4.08 0.58 14. 55 36. 62 +0.U -1-0.60 The peas retained their vitality much better than the beans. How- ever, the greatest loss in both peas and beans was in the envelopes at Mobile and Baton Rouge. Some of the samples from the envelopes germinated fully as well or even better than the control, but the gen- eral averages of the second tests for all of the localities show a loss of 11.45 per cent in ''trade conditions," 15.91 per cent in "dry rooms," and 36.63 per cent in "basements." The beans under identical condi- tions lost 29.59, 29.76, and 13.61 per cent, respectively. The seeds kept in bottles deviated but very little from the standard of the control. COMPAJIISON OF METHODS OF STORING ATSTB SHIPPING. 58 Table XIV. — Prrcrnfngr of germmatinn of cabhage aubjcrted to various cDinlilioiis of storage in different londities. [Germination of control sample: First test, 92.7 per cent; second test, 92.4 per cent.] Place of storage. Lake City, Fla Do Anburn, Ala Do Mobile, Ala Do Baton Rouge, La Do San Juan, P. R Do Wagoner, Ind. T Do Durham, N. H Do Ann Arbor, Mich Do Average percentage of ger- mination. Average percentage of gain or loss in vitality. Order of tests. First.... Second . First.... Second . First.... Second . First.... Second . First.... Second , Finst..., Second . First..., Second First..., Second , First... Second JFirst... [Second Num- ber of days in storage. 129 234 102 275 140 262 121 247 126 238 147 251 128 251 128 251 Percentage of germination. Trade condi- tions. Envel- 89.5 63.5 91 61.5 64.5 17 88.5 25.5 82 76.2 83.5 70.5 93 12 96 91 86 52. 15 7.23 43.56 Bottles. 92.5 89.5 90.5 90 93.5 87. 5 93 90.5 95. 5 89 93 91.5 97.5 92.6 92 94 93.47 90. 56 -1-0.83 1.94 Dry rooms. Envel- opes. 89.5 81.5 89.5 90 90.5 11.5 94 86.43 61.5 6.77 33. 44 Bottles. 95.5 92.5 96 95.5 90.5 82 92 89.93 0.86 2.67 Basements. Envel- opes. 86.5 14. 5 92 60 5.8.5 79. 5 0.5 Bottles. 88.5 76.5 95.5 92. 5 89. 5 76 84.29 53.33 9.07 42. 29 90. 6 91. 5 91 85. 5 92. 5 94 94 90. 5 97. 5 89 94.5 96. 5 94.5 95. 5 93. 5 92. 21 -fO.86 0.22 Table XIV shows that the cabbage, like the peas, was injured to a less deg-ree at Mobile and Baton Rouge than the beans, but even the cabbage seed kept in the paper packages in these cities were all but killed. The average degree of injurj^ however, was greater in the cabbage than in the beans. In a majority of cases there was more or less deterioration in the case of this seed kept in the envelopes. Aside from those alread}" mentioned, the trade conditions at Durham, N. H., and the basement at Lake City, Fla., should bo expressly noted. The seeds kept in the bottles deviated but little from the control, while those kept in paper packages germinated only 62.15, 61.50, and 53.33 per cent for the trade conditions, dry room, and basement — equivalent to a loss in vitality of 43.56, 33.44, and 42.29 per cent, respectively. 54 THE VITALITY AND OERMINATION OF SEEDS. Tahle XV. — Prrccnhujc <•/ i/rniiination of radish subjected to rorloiis rondif ions of storage in different localities. [Germination of control sam7)le: First test, S3.C per cent; second test, 7S.8 per cent.] Order of tests. Num- ber of days in storage. Percentage o germin xtion. Place ol" storage. Trade condi- tions. Dry rooms. Basements. Envel- opes. Bottles. Envel- opes. Bottles. Envel- opes. Bottles. Lake City, Fla . . . First.... Second . First.... Second . First Second . First.... Second . First.... Second . First Second . First.... Second . First 129 234 102 27ri 140 202 121 247 131 120 238 147 251 79 58. 5 7-5. 5 03 58. 5 51 77. 5 55.5 04 62 77.5 00. 5 80.0 69.5 82.5 77.5 78. 5 04 85 72. 5 8] 71.5 85. 5 09. 5 81.5 73.5 80.5 75.5 75.5 81.5 85 80. 5 84. 5 07.5 85. 5 00 .50. 5 49 73.5 49. 5 75 71.5 80.5 73. 5 81 70 78. 5 74.5 66 48. 5 86. 5 00. 5 61.5 51.5 83 Do 67 Aiibnrn, Ala 8,5.5 Do 70. 5 Mobile, Ala 76 Do ... ... 72 78 5 Do San .Tnan, P. R Do 79 76.5 74.5 82. 5 79.5 84 77 85 85 79.5 .57. 5 80. 5 63 81 0)8 78 62. 5 86.5 Do 70 5 74 Do 79 Ann Arbor, Midi 82 9 Do Second . [First.... jsecond . P^ir.st.... Second . 78. 5 Average i)erccntage of ger- mination. 12S 251 74.39 60.94 81. 50 73. 50 70. SO 64. 33 80. 5 72.71 75. 5 59 80. 91 74.07 Average percentage of loss in vitality. 128 251 11. 02 22.67 2.44 6.65 8.07 18.37 3.71 7.73 9.67 25. 13 3.22 6 The results of the tests of the radish seed are very similar to those of the (•al)))ao-e; the latter, however, showed a g-reater loss in vitality. As shown l)y the second tests, the average percentages of deterioration of the cal)l)age seed which was kept in the envelopes were as follows: Trade conditions, 43.56 per cent; dry room, 33.44 per cent; basement, 42.29 per cent, while the loss in vitality of the radish was only 22.67, 18.37, and 25.13 per cent, respectively. COMPARISON OF METHODS OF STORING AND SHIPPING. 55 Taumo XVI. — J'rrrnit(t(jr (if f/i'niil)uitlon of carrot subjcctid la vdj'invs conditions of Ktor(i(/e in different localitiest. [Germination of control sample: First test, S3.3 per cent; second test, S'i per cent.] Order of tests. Num- ber of days in storage. Percentage of germination. Place of storage. Trade condi- tions. Dry rooms. Basements. Envel- opes. Bottles. Envel- opes. Bottles. Envel- opes. Bottles. First Second . First.... Second . First Second . First.... Second . First.... Second . 129 234 102 275 140 2G2 121 247 131 76.5 43.5 84.5 30 59 8.5 74.3 25 71.5 48.5 81.5 49 78 2 76 86 83 80.5 82 76.5 87.5 86 82.3 72.6 82.5 86.5 82 81. 5 82. 5 85. 5 79 78 78 67.5 83 72.5 . 51. 5 .5 75.1 16.5 78.5 78.5 86 76. 5 83.5 69 86.8 52. 5 73 3 86.5 47. 5 20.5 57.3 Do SI. 5 Do Mobile, Ala... 87 Do Do 39 Sixn .Tnan, P. R Do First.... Second . First.... Second . First 12C 23S 147 251 77.5 84 87. 5 S3 78.5 81 81 85.5 85.5 75. 5 80 77.5 45.5 83. 5 72 78 87 5 Do Durham, N. 11 Do Ann Arbor, Mich 84 82. 5 87. 5 .1^3 r-i Do 58 5 1 71 jFirst.... [Second . jFirst.... jsecond . Average percentage of ger- mination. 128 251 75.16 37.31 82.6 80.87 76. 01 53. 83 82.4 74.71 68.04 37. 75 83.83 75.21 Average percentage of gain or loss in vitality. 128 251 9.72 54.5 0.84 1.38 8.75 34.35 1.08 8.89 18. 32 -1-0. 63 53. 96 9. 5 Talile XVI shows results veiy similar to those of Table XV, except that the carrot was affected slightly more than the cabbage. There was also a greater falling off in the case of the seeds kept in the bottles in diy rooms and ))asements. The reason for this is not very clear. Apparently it was due to some local conditions, inasmuch as it was confined chiefly to the Ijottles kept at Mobile and Baton Rouge. The average results of the germination tests of the seeds kept in packages are quite low for the carrots. Seed from trade conditions germinated 37.31 per cent, from basements 37.67 per cent, and from dry rooms 63,83 per cent, with a loss in vitalit}" of 54.5, S-i.OO, and 34.36 per cent, respectively. Under similar conditions the cabbage lost in vital ity 43.56, 42.28, and 33.45 per cent, respectively. 56 THE VITALITY AND OKRMINATION OF SEEDS. Table XyU.—rermitaye of grrminaiion of "A" Rweet corn mhjecied to various condi- tions of storage in different localities. [Germination of control sample: First test, 92.7 per cent; second test, 92.4 per cent.] Order of tests. Num- ber of days in storage. Percentage of germination. Place of storage. Trade condi- tions. Dry rooms. Basements. Envel- opes. Bottles. Envel- opes. Bottles. Envel- opes. Bottles. First Second . First Second . First.... Second . Fir.st.... Second . First 129 234 102 275 140 2i;2 121 247 131 94 92 96 88 SO 20 90 88 90 92 90 90 100 90 100 98 96 100 98 98 100 90 94 90 94 94 98 90 92 96 SO 98 94 96 94 94 80 20 9f; 88 92 90 98 90 90 100 88 90 88 54. 5 100 80 94.1 86 14 98 j)o 100 Auburn, Ala Do Mobile, Ala Do 92 100 96 96 100 Do San Jnan, P. R Do 100 First.... St'cond . 120 238 147 261 94 95. 9 90 94 100 90 90 90 90 89 96 90 92 TOO 100 100 92 96 Do 94 Durham N H First.... Second . First 96 Do 98 96 Do Second . 98 [First.... {second . (First.... [Second . Average percentage of ger- mination. 12.S 251 94. 75 83 94. 75 96. 75 92.56 83.33 94.14 94.86 94.87 72.08 96.29 98 Average percentage of gain or loss in vitality. 128 251 +2. 21 10.11 +2. 21 -f4.71 0.15 9.81 -t-O.Ol +2.66 +2.34 22 +3.87 +6.06 Table XVIII. — Perccntnge of germination of "J?" siveet corn sidijecfrd to various condi lions of storage in different localities. [Germination of control sample: First test, 89.3 per cent; second test, 88.5 per cent.] Order of tests. Num- ber of days in storage. Percentage of germination. Place of storage. Trade condi- tions. Dry rooms. Basements. Envel- opes. Bottles. Envel- opes. Bottles. Envel- opes. Bottles. Lake City, Fla First Second . First.... Second . First.... Second . First Second . First Second . 129 234 102 275 140 202 121 247 131 86 77.] 88 62 48 12 SO 54. 2 72 78 70 78 89. 3 82 92 80 60 2 92 50 81.2 52 82 30 72 71.7 82 70 69. 5 91.8 88 92 90 04 80 82 00 10 81 60 38 86 38 87. 5 54 94 40 76 30 SO 82 75 01 4.5 46 Do 84 Do 89. 6 Mobile, Ala 86 Do 70 88 Do 01.2 Do First.... Second . First.... Second . First 120 238 147 251 90 84. 2 81 88 86 88 88 S3. 6 88 48 22 84 88 80 76 S8 82 84 Do 70 Durham, N. H SO Do 88 96 Do 88 (First.... [Second . fFir.st.... {second . Average percentage of ger- mination. 128 251 78.16 65. 41 78. 31 59.70 83. 17 66.33 75. 01 48 79 60.41 80. 55 68.40 Average percentage of loss in vitality. 128 251 12. 47 26. 09 12. 31 32. 55 6.87 25. 06 16 45. 76 11.54 31.7) 9.80 22. 71 COMPART^iOlSr OF METHODS OF STOKING AND SHTPPTN(}. 57 Tables XVII and XVIll have been considered together, since both have to do with the same variet}^ of sweet corn. The difference in the (juality of these two samples was quite marked when the seed was received. Germination tests were made January 30, 1900, and showed 94 per cent for the "A" and 88 per cent for the "B" corn. In November, 1900, samples of seed from the same original packages were tested, giving a germination of 92.4 per cent and 88.5 per cent for the " A '' and " B " samples, respectively, as shown in the controls of the above tal)les. Thus, when two grades of corn are subjected to favorable conditions of storage, both are well preserved; but when subjected to unfavorable conditions, the one of poorer quality is much more susceptible to injury. The "A" sample which was stored in envelopes in trade conditions lost 10.11 per cent, as compared with 20.9 per cent for the "B" sample. The "A" sample which was stored in dr}^ rooms lost only 9.81 per cent, while the "B" sample lost 2.5.00 per cent. In basements, the "A" sample lost 23 per cent and the " B" sample 31.74 per cent. In both samples the corn in the packages stored in the basement at Mobile was so badly molded at the time the second tests were made that they have lieen omitted from the table. The most interesting feature in comparing the results of these two samples is found in the seed which was stored in the bottles. The average results of the "A" samples show a much higher percentage of germination for those from the bottles than the control, while the averages for the " B" sample were nuich lower than the correspond- ing controls. The average germination of the "B" sample from the bottles was 59.7 per cent for the trade conditions, 48 per cent for dry rooms, and 68.4 per cent for basements, or a loss in vitality of 32.55, 45.76, and 22.71 per cent, respectively. This difference was due to two causes, first, a difference in the quality of the seed at the begin- ning of the experiment, and, secondly, the larger amount of water in the second sample, "B." The greater quantity of water present in the seed gave rise to a more humid atmosphere after the seeds were put into the bottles, especiall}' when sul^jocted to higher temperatures than those in which the seeds had been previously stored. This is an important factor always to be borne in mind when seeds are put up in closed receptacles; they must be well dried if vitality is to be preserved. 58 THE VITALITY AND TERMINATION OE SEEDS. Taiu.r XIX. — Perccntagr of germinatloi) of Irfliire .vilijrctrd lo vdrU/UK (■(ni)Iillniit< of Rhirage in diflWmt localiticft. [termination of control sample: First test, Sl.fi jtcr cent: second test, 92.3 percent.] Order of tests. Num- ber of days in .storage. I'ercentage o germ in ation. Place of storage. Trade conditions. Dry rooms. Basements. Envel- opes. Bottles. Envel- opes. Bottles. Envel- opes. Bottles. Lake City, Fla First Second . First.... Second . First Second . Fir.st 129 234 102 275 140 2G2 121 247 131 87 85 80. 5 85 (v:, 20 82.5 84.5 79 83.5 78 82 82.5 88. 5 82 92.5 84 92 85.5 90. 5 78 88. 5 81.5 93.5 87. 5 89 76 92. 5 80.25 93 68. 5 90 81 92.5 88. 5 90.5 .58 31 79 74.5 76. 5 90 .84. 5 91 87. 5 90.5 78. 5 87. 5 68 43. 5 .84. 5 83. 5 1.5 70. 5 77 Do 95. 5 88. 5 Do 90 S3 Do 91. 5 76 Do 92. 5 First.... Do ' Wagoner Ind . T First.... Secoml . First 126 23S 147 2.'S1 80 83. 25 92 84.5 89. 5 82 94 77.5 93 81.5 90.5 81 87.5 80 90. 5 78. 5 88 70. 5 Do 89 Durham, N. H Do 90. 5 First 72 1)0 . Second . jFirst.... (Second . JFirst.... [Second . 91.5 Average percentage of ger- mination. 128 251 80.06 77.75 80. 15 91.12 79. 18 78.33 81.14 90.93 66. 28 65. .58 78.31 90.78 Average percentage of loss in vitality. 128 251 1.89 1.5.76 1.77 1.29 2.97 15. 14 . 56 1.49 18.78 28. 95 4.03 1. 05 The lettuce has shown no vei\y marked deviation from the controls, save the seeds from the packages kept at Mobile, and those which were stored in l)asements in envelopes at Baton Rouge and Lake City. The average results of the second series of tests show a similar losss in vi tality of all of the seeds from the envelopes. The samples of seed from the bottles germinated practically as well as the controls. The results of the first series of tests are not entirely satisfactory, none of the tests having gone to standard. The low germination of the lettuce in this series was due to inability to properly control the temperature in the germinating pans. The proper temperature for the successful germination of lettuce seed is 20'^ C, while in this lirst series the ger- mination tests were unavoidalily made at 26 " to 27.5'' C. Neverthe- less, this seeming objection is of little consequence, since all of the results are directly comparable with the control. COMPARISON OF METHODS OF STORTNC} AND SnTlMM>f(l. 59 Tahi.e XX. — Pcrcnttagr of germination of onion Hubjected lo rariouft ro)i(Iilions or, Mich Do Average percentage of ger- mination. Average percentage of gain or loss in vitality. Order of tests. Num- ber of days in storage. Fir.st.... Second . First Second . First.... Second . First Second . First.... Second . First.... Second . First Second . First Second . [First ISecond . I First.... [Second . 129 234 102 275 140 262 121 247 12f) 238 147 251 128 251 128 251 Percentage of germination. Trade condi- tions. Envel- opes. 95 16.5 96 12 7 90 0.5 84.5 50 93.5 24.6 96. 5 95 97.5 Bottles. 82. 19 25. 12 14. 20 74.11 95 95. 5 96. 5 96 94.5 94.5 93 97.5 98 96.5 97.5 95 9G 97.5 96 97.5 Dry rooms. Envel- opes. 95. 5 79 96 96 11.5 94 95. 5 95. 81 96. 25 -fO.Ol 1.20 94. 5 96 99. 5 95 S3. 79 61 12. 53 37.12 Bottles. 95 9(! 98. 5 98 91"). 5 96. 5 Basements. Envel- opes. 97 97.5 96 97 97 96. 5 96. 21 92.36 -f- 0.43 4.80 80 97 23.5 75. 5 «0 81.36 33. 08 15. 07 65. 90 Bottles. 97.5 97.0 97.5 99 99 97.5 96.6 48.5 94. 5 97.5 94.5 98 9(i. 64 90.86 +0.87 6.33 fiThis test has not been included in making up the averages inasmuch as the seeds were badly molded when put in test. The onion seeds which were stored in the envelopes were very seri- ously affected in many of the places. Those from the basement at Lake City, froni all of the conditions at Mobile, and from the dry room and basement at Baton Rouge were entirely killed. The seed from trade conditions at liaton Rouge germinated only 0.5 per cent. In man}' other cases the samples from the envelopes had become practical!}^ worthless. In only two instances was there any loss in vitality wdiere the seeds were stored in bottles, viz, the second tests from the dry rooms and basement at Baton Rouge. These two tests have lowered the average results quite materially. If they were not included the averages would be raised to 96.91 and 97.90 per cent, respectively, instead of 92.36 and 90.86 per cent, as given in the table. The average percentages of germination of the seeds from the envelopes were very low in the second test, and were as follows: Trade conditions, 25.12 per cent; dry rooms, 61 per cent, and basements, 33.8 per cent. This represents a loss in vitality of 74.11, 37.12, and 65.9 per cent, respec- tively. Onion seed is relatively short lived, and very easily affected by unfavorable external conditions. For this reason onion seed should be handled with the greatest care if vitality is to be preserved for a maximum period. This may be done successfully by keeping the dry seed in well-corked bottles, or in any good moisture-proof ptickage. (•)() thp: vitality and oermination ok seeds. T.\BLE XXI. ^ — Prrrerittiijr of i/mniiuilion of pdri.fi/ ftii]>jrrir(l in varimis rnnditions of storage in different localities. [Germination of control sample: First test, 63 per cent; second test, ."is per cent.] Order of tests. Num- ber of days in storage. Percentage of germination. Place of stf)rage. Trade conditions. Dry rooms. Basements. Envel- opes. Bottles. Envel- opes. Bottles. P^nvel- opes. Bottles. First.... Second . First.... Second . First.... Second . First.... Second . First Second . First 129 234 102 275 140 2G2 121 247 131 120 238 147 251 44. 5 1.5 57. 5 2 3 28.5 20 6.5 48.5 7. 5 55. 5 53.5 46.5 63 .54 68 20.5 57. 5 20. 5 53 34 60.5 .58.5 01.5 65 06.5 60. 5 51 45 45 22. 5 60. 5 28 •2 38 .58. 5 47 62 27. 5 01 25. 5 44 17 10. 5 00 1 4.5 . 02.5 Do 57.6 59.5 Do .. 33.5 59 Do 2.5 54 Do 2.5 Do Wagoner, Did. T 50. 5 49.5 44 69.5 52 02. 5 .59. 5 63. 5 60. 5 40 48.5 40 .S.5 ■19 36. 5 .50 3.5 .59 Do .52. 5 Durham, N. II "First.... Second . First.... 03. 5 Do 60 Ann Arbor Mich 53 Do 60. 5 [First Isecond . JFirst.... {Second . Average percentage of ger- mination. 128 251 38. 87 8 60.12 44.75 44.43 24.41 55. 93 40.80 31.. 57 8.08 5S. 64 38. 43 Average percentage of loss in vitality. 128 2.51 38.3 84.91 4.57 1.5.60 29. 48 .53. 97 11.23 23.02 49.89 84.70 6. 92 27. 49 T;\KLE XXII. — Percentage of germination of phlox drummondii sidrjected to variotis con- ditionti of storage in different localities. [Oermination of control sample: First test, 69 per cent; .second test, ,53.9 per cent.] Order of tests. Num- ber of days in storage. Percentage of germination. Place of storage. Trade condi- tions. Dry rooms. Basements. Envel- opes. Bottles. Envel- opes. Bottles. Envel- opes. Bottles. Lake <;ilv, Fla First Second . First Second . First.... 129 234 102 275 140 202 121 247 131 41.5 2.5 61.5 1 0.5 47. 5 23. 5 11.5 .50. 5 5.5 67 0.5 67 40 78 .57 72.5 .50. 5 55 .51.5 02. 5 58 05 01. 5 73. 5 00 71 02. 5 66 64 02 02 13.5 0.5 43. 5 02 25. 5 63 59 74. 5 58. 5 .58. 5 58. 5 20.5 05. 5 1 0. 5 2 77.5 Do 63 Auburn, Ala 67.5 Do 65 Mobile, Ala .58. 5 Do 48 5 First.... Second . Fir.st Second . 70 5 Do 61.5 San .Juan, P. R Do Wagoner, I nd. T First.... Second . First Second . First 126 238 147 2.51 01 02. 5 33 75. 5 55 70 57 4.5. 5 30. 5 69. 5 .58. 5 05 9.5 09. 5 4.5. 5 04. 5 10.5 75 Do 47.6 Durham, N. 11 71.5 Do 70 Ann Arbor, Midi Do Second . 61 (First.... (Second . [First (Second . Average percentage of ger- mination. 128 251 44.87 7.62 68.31 58. 37 .52. 70 17.91 63. 28 49. 64 41.07 11. 08 70. 35 69.5 Average percentage of gain or loss in vitality. 128 251 34.97 85. 80 1 -1-8.27 28. .54 00. 78 8.29 7.91 40. 49 79.45 + 2.01 4-10.39 COMPARISON OF METHODS OF STORING AND SHIPPING. 61 Pansy and phlox have been considered together, since their behav- ior was ahnost the same. Both of the controls deteriorated to a con- siderable degree during the 123 days which elapsed between the time of the lirst and the second test, pansy losing 15.87 per cent and phlox 21. SS per cent. In both cases the mean loss in vitality of the seeds in the envelopes was very great. The results of the second tests show a loss of 81.91 per cent for pansy, and 85.86 per cent for phlox where stored under trade conditions. In dry rooms there was a mean loss of 53.57 per cent for pansy and 66.78 per cent for phlox, and in base- ments a loss of 81.76 per cent for the pansy and 79.15 per cent for the phlox. These results are obtained by considering the second test of the control as a standard, the depreciation of the control being dis- regarded. Some samples were dead and many more were of no eco- nomic value. It is especially interesting to note how quickly the seeds died at Mobile, Ala., there being only a few germinable seeds at the end of 110 days. The behavior of the seeds in the bottles was more or less variable. Some of the pansy seeds showed a higher vitality than the control, but the averages were somewhat lower, the mean loss ranging from 15.60 per cent under trade conditions to 27.19 per cent in basements, while with the phlox the means for trade conditions and for basements were higher than the control by 8.27 and 10.39 per cent, respectively. Table XXIII. — Percentages of germination of tomato subjected to various conditions of storage in different localities. [Germination of control sample: First test, 95.6 per cent; second test, 97.5 per cent.] Place of storage. Lake City, Fla . Do Auburn, Ala ... Do Mobile, Ala Do Baton Rouge, La. Do San Juan, P. R. Do Wagoner, Ind. T. Do Durham, N. H . Do Ann Arbor, Mich Do , Average percentage of ger- mination. Average percentage of loss in vitality. Order of tests. First..., Second , First..., Second , First Second First..., Second , First..., Second , First..., Second , First..., Second , First..., Second First... Second [First... [Second Num- ber of days in storage. 129 234 102 275 140 262 121 247 Percentage of germination. Trade condi- tions. Envel- opes. 126 147 147 251 128 251 128 251 94 94 95 94 90 79.6 91.5 96 94 96.5 96.5 94 94.5 87 89 98.5 93.06 92.44 2. 56 6.20 Bottles, 94.5 98.5 94.5 97. 6 95 96. 5 94.5 94 5 97 98 95 98 94 98 94.81 97.31 0.72 0.20 Dry rooms. Envel- opes. 94 94 93.5 97 91.5 87 91 93 1.57 3.29 Bottles. 96. 5 97.5 97.5 94.5 96.5 95.5 96 98 96. 6 97.5 94 99 91.5 97.5 95. 21 97.07 0.30 0.44 Envel- opes. 88.6 77 96 98 64. 5 19.6 83. 6 39.6 98.6 98.5 97.6 97.6 89 95 88.21 84.25 7.64 13.63 Bottles. 94 97.5 94.5 96.5 93.5 98 95 96 96 93.5 96.5 97 92.5 98 94.57 97.21 0.98 0.30 G2 THE VITALITY AND GERMINATION OF SEEDS. The tomato .scud, as .shown in Tables V and XXV, was the most resistant to the unfavoraV^le conditions of storage. The .seed in the bottles was not injured at an}^ of the places. The lowest germination was 91.5 per cent from the seed kept in a dry room at Ann Arl)or, Mich. The seed in the envelopes gave a much wider variation, falling quite low in some of the samples which were stored in the basements. The average losses in vitality for the entire series of the second set of seeds which were kept in envelopes were as follows: Trade conditions, 5.20 per cent; dry rooms, 3.29 per cent; basements, 13.03 per cent. The average percentage of germination of the seed which was kept in the ))ottles ditl'ered from the control less than one-half of 1 per cent. Taisle XXIV. — Fcrceyilitge of (jcrtnination of watermelon subjecled to vuriuus condltmis of storage in differeyit localities. [Uoruiinatioii of control .sampk': Fir.st test, 95.5 per cent; second test, "JS) per cent.] Place of storage. Lake City, Fla . Do Auburn, Ala ... Do Mobile Alii Do Baton Rohrc, La. Do San Juan, P. R Do Wagoner, Ind. T. Do Durliaru, N. H Do Ann Arbor, Mich . Do Average percentage of ger- mination. Average peccntage of loss in vitality. Order of tests. First... Second First..., Second , First..., Second , First..., Second , First... Second , First..., Second , First..., Second , First Second , (First..., Isecond . [First.... Isecond . Num- ber of days in storage. 129 234 102 275 140 262 121 247 126 238 147 251 128 251 128 251 Percentage of germination. Trade condi- tions. Envel- opes. 100 92 96 88 98 94 98 82 100 96 Bottles. 97.75 86.75 0.56 12. 37 98 96. 2 94 100 98 96 98 98 100 100 98 98 98 96 100 100 98 98.02 0.31 0.99 Dry rooms. Envel- 100 98 96.86 88.67 1.47 10.44 Bottles. 98 98 98 98 100 96 100 100 100 96 98 92 94 92 98.29 96 Basements. Envel- opes. 96 88 98 94.1 98 100 95.29 77.70 0.01 3.03 3.06 21.52 Bottles. 100 94 100 96 100 100 98 100 98. 29 97.43 0.01 1.59 What has been said of the tomato seed is practically true for the watermelon, .save that there was a greater loss in vitality in the latter, when seed;j were kept in envelopes. The average percentage of ger- mination of the second tests was 86.75 per cent for trade conditions; 88.67 per cent for dry rooms; and 77.7 per cent for basements, or a lo.ss in vitality of 12.37, 10.44 and 21.52 percent, respectively, as com- pared Avith the vitality of the control sample, which germinated 99 per cent. An examination of the foregoing set of tables will show that in mo.st cases the deteriortition was comparatively slight during the first 128 days. Yet even during this short period the losses in vitality were very marked in some of the more critical localities, particularly COMPARISON OK METHODS OF STOKTNO AND SHIIMTNG. 08 lit Mobile. However, the j^Tcatest lo.ss, a.s shown ))y the o-eniiination tests, was during the 1'2'd daj^s immediately followino-. While seeds, like other living things, are capable of withstanding ([uite unfavorable conditions for a considerable time without showing any appreciable deterioration in vitalit}^ still the forces destroying \itality are at work. When the turning point is once reached and can be detected by germination tests, the decline is more noticeable and death soon follows. The preceding tables show that the loss in vitality was very differ- ent in the different places. The conditions at Mo1)ile, Ala., proved to be the most injurious, while those at Ann Arbor, Mich., were the most conducive to longevity. These results, however, are given in anotlier part of this paper dealing with the effect of climate on the vitality of seeds. The results are tabulated on pages 18 and 23 and represented diagrammatically on page 24c, so that any further discus- sion at this time is unnecessary. Likewise each table has been summarized, giving the average per- centages of germination and the average percentages of the loss in vitality of each sample of seed for both the first and second tests. These averages include those of the three conditions of storage — trade conditions, dry rooms, and basements— in both envelopes and bottles. Naturally, the results of the second tests are of the greater impor- tance, and, in order that the results may be readily compared and more critically examined, they have been collected and tabulated herewith: Taule XXV. — Airnuje percentage of germination and average percentages of loss in vitality of the different kinds of seeds when kept under different conditions. 1 c o a .2 3 ^^ a a o Trade conditions. Dry rooms. Basements. Envelopes. Bottles. Envelopes. Bottles. Envelopes. Bottles. Kind of set'd. o a a o (3 O a a 1 o 1-1 S a a o a o B O 'S 1 o 2 o S a 0) O o 3 a § iJ 97.5 92.4 92.44 83 5.20 10.11 97.31 90. 75 0.20 +4.71 94.33 83.33 3.29 9.81 97.07 94.86 0.44 +2.66 84.25 73.08 13.63 22 97.21 98 0.30 SWL-ct com, "A" .. + 6.00 IViis 95.7 84.74 11.45 95.25 .47 80.45 15.94 95.14 .58 60.66 3(;. 62 90. 28 + .60 WatcruiL'loii 99 ' 86. 75 12. 37 98. 02 .99 88. 67 10.44 96 3.03 77.70 21. 52 97. 43 1.59 Lettuce 92.3 77.75 15.70 91. 12 1. 29 78.33 15.14 90.93 1.49 65.58 28.95 90. 78 1.05 Kiidisli 78. S 60.94 22.67 73.56 6.65 64.33 18.37 72. 71 7.73 69 25.13 74.07 6 Sweet corn, "B" .. 88.5 C5.41 26.09 59.70 32.55 66.33 25.06 48 45.76 60.41 31.74 68. 40 22. 71 Bean 98.7 69.50 29.59 97 1.72 69.33 29.76 97.36 1.36 55.66 43. 61 98. 86 + .10 Cabbage 92.4 52. 15 43.56| 90.56 1.94 61.50 33.44 89.93 2.67 53.33 42.29 92.21 .22 Carrot 82 37.31 54.50 80.87 1.38 53.83 34.35 74.71 8.89 37.75 53. 96 7.5.21 9. 50 Onion 97 53 25. 12 8 74.11 84.91 90.25 44. 75 1.20 15.60 61 24. 41 37.12 53.97 92.36 40.80 4.80 23.02 38.08 8.08 65.90 84.76 90. 86 38. 43 C. 33 I'ansy 27. 49 Phlox 53. 9 7.62 85.80 58. 37 +8.27 17.91 60.78 49.64 7.91 11.08 79.45 59. 50 + 10.39 Average loss in vitality . 36. 63 3.92 21.19 8.08 42. 28 4.51 64 THE VITALITY AND OERMINATION (»K SEEDS. In comparing the average results shown in Tul)le XXV, it will be seen that different seeds behave very differently under practically iden- tical conditions. The list of seeds has been arranged according to their loss of vitality as represented by those kept in envelopes under trade conditions, as shown in the fourth column. The tomato seed gave a loss in vitality of 5.20 per cent, being the most resistant to the unfavorable climatic conditions. Phlox, on the other hand, germinated only 7.62 per cent, representing a loss in vitality of 85. SB per cent. Likewise the same seeds behave very differently under slightly different conditions, as will be seen by comparing the percentages of deterioration in the case of seeds kept in envelopes luider trade condi- tions, in dry rooms, and in basements. In dry rooms the order, except the peas, is the same as for trade conditions. The loss of vitality in the seeds stored in the dry rooms was uniforndy less than for those stored under trade conditions, excepting for the peas and beans; but in the series from the basements there was great irregularity. The loss in vitality for the most part was uniforndy greater than imder trade conditions or in dry rooms save in the last ffve — cabbage, carrot, onion, pansy, and phlox — where the loss Avas less in the case of those kept in the basements. This indicates that these live species of seed are less susceptible to the evil effects of a moist atmosphere when the temperature is relativelj^ low. The relative value of these three conditions for storing seeds in paper packets is best obtained l)y a comparison of the general averages. The average losses in vitally for the thirteen different samples of seed which were kept at the eight different stations were as follows: Trade conditions, 36.03 per cent; dry rooms, 21.10 per cent; basements, 42.28 per cent. From these results it is quite clear that seeds put up in paper packages will retain their vitality nuich better if kept in dry, artificially heated rooms than if they are subjected to trade conditions or stored in basements. But another comparison needs yet to be made, and is the most impor- tant of the series, i. e., the vitality of seeds when kept in closely corked bottles. In the majority of cases there was but little deviati<^n from the control samples, and many of the samples germinated even better where the seeds were kept in bottles. The "A" sweet corn offers the best illustration of the increased germination. At the same time the "" B" sample of sweet corn was very much injured. Here are two samples of the same variety of corn behaving very differently when kept in bottles. This difference in vitality is directly attributed to the greater ([uantity of water in sample "B," showing the necessity of thoroughl}^ drying seeds if the}^ are to be put up in closed vessels. A comparison of the general averages of the bottle samples and of those kept in envelopes indicates that the former is far superior to the latter as a method for preserving the vitality of seeds. Under trade conditions the loss in vitality was 36.63 per cent in envelopes and EXPERIMENTS IN KEEPING AND SHIIM'ING. 05 3.03 per cent in bottles; in dry rooms, '21.1d percent in envelopes unci 8, OS per cent in bottles; in basements, 42.28 per cent in envelopes iind 4.51 per cent in bottles. The necessary precautions to be taken, if seeds are to be stored in bottles, are (1) a well-dried sample, preferably artificially dried seed, and (2) a cool place for storing-, at least a place in which the tempera- ture will not be higher than the temperature at which the seeds were orig'inall}' dried. If the above precautions are taken at least two beneficial results will follow: First, protection against moisture, which is of considerable importance, as many seeds are soon destroyed in that way when kept in paper packages. Secondl}^, vitality will be preserved for a longer period and consequently there will be a more vigorous germination, a l)etter growth of seedlings, and a greater uniformity in the resulting crop. Having thus shown that seeds retain their vitality in warm, moist climates much better when kept in bottles than Avhen kept in paper packages, the necessity of finding a more suitable method for sending small quantities of seed to such places at once presents itself. EXPERIMENTS IN KEEPING AND SHIPPING SEEDS IN • SPECIAL PACKAGES. At present the greatest disadvantages in sending out seeds in bottles are the inconvenience and expense involved by this method of putting up seeds. The increased cost of bottles, as compared with the paper packets now so universally emplo3'ed, the additional labor and expense necessary to put up the seeds, the greater cost in handling and pack- ing the bottles to insure against losses by breakage, and the increased cost of transportation, arc all matters of vital importance. Seedsmen claim that the existing conditions of the trade will not admit of their raising the price of seeds sufliciently high to justify the increased expense of glass containers. Although to the seedsmen the preserva- tion or the prolongation of vitality is an important factor, yet the demand is for an inexpensive and at the same time a neat and service- able package. Accordingly, duplicate samples of the following-named seeds were put up in special packages, one set being sent to Mobile, Ala., and the other kept at Ann Arbor, Mich. The seeds used for these experi- ments were beans, peas, cabbage, lettuce, onion, pansy, and phlox. « «The lettuce, onion, pansy, and phlox were from the same bulk samples of seeds as those used in the earlier experiments; but the beans, peas, and (^ahbage used for these tests were from samples received at the laboratory on February 4, 1901. How- ever, the latter three were from the same general stock of seed, differing from those used in experiments already given only in that they were stored during the interval in the warehouse of D. M. Ferry & Co., Detroit, Mich., instead of in the botanical laboratory at the university. 25037— No. 58—04 5 66 thp: vitality and germination of seeds. All of these samples were tirst dried for ten days in an incubator main- tained at a temperature of from oi) to 32'- C. The amount of mois- ture in the samples ))efore and after dr3^ing-, as well as the moisture expelled during the drying process, was as follows: Iloisliirc test of nccih in special jxiclcages. Kind of seed. Beans Peas . . Cabbuj Lettiic Onion Pansy Plilox "it'dried" Moisture samples! remaining. Per cent. 10.32 9.70 4. .S9 5.33 ().<18 4.82 5. 82 Per cent. 4.90 6.00 3. 47 3. 80 4.47 3.13 4. 30 Moisture liberated. Per cent. .5.42 3.70 1.42 1.53 •2.01 1.69 1.52 These well-dried seeds were then put up in seven different kinds of packages : (1) Doul)le coin envelopes, of much the same qualit}^ as those in which seeds are commonly sold. (2) Bottles of 120 cc. capacity, closed with firm cork stoppers. ! (3) Bottles of 120 cc. capacity, corked and sealed with paraffin. (4) Tin cans having closely fitting lids, the whole being then care- fully dipped in paraffin. (6) Double coin envelopes, as for No. 1, the packets })eing then dipped in melted paraffin. (()) Double coin envelopes, the inner one paraffined, the outer envel- ope l)eing used simply to protect the paraffin and to facilitate ease of handling. (7) Doul)le coin envelopes, with both the inner and the outer coated with paraffin. On Fel)ruary 15, llX »1, one of each of the above preparations was sent to Mo])ile, Ala., and stored in a cellar approximately -lOO feet l)ack from the ba3^ After the lapse of 108 days, i. e., on June 3, these samples were received in return, at which time germination tests were made. The other complete set, retained in the botanical laboratory at Ann Ar])or, was subjected to a very moist atmosphere. The samples were kept in a damp chamber made by taking two battery jars of different sizes, the smaller containing the seeds being placed within the larger, which was lined with filter paper and then partiall}^ filled with water. The whole was covered with a glass plate, and the atmosphere within was always on the verge of saturation. A third and an extreme set of conditions was established b}^ keeping some of the paraffined packages immersed in water for twenty-seven EXPERIM.ENTS TN KEEPIJfG AND SHI1MMN(}. 07 days. At the end of that time (March 14) the .seeds wei-e tested for germination, as were also those from the unprotected envelo]:)es in the moist chamber. The seeds that were kept under water in the paraffined packages germinated readily and normally, showing no deterioration in vitalit}^ ; but the seeds from the packages not paraffined, which were kept in the moist chamljer, had been injured to an appre- ciable extent, there being a marked retardation in the germination of all of the species of seed. The cabbage at the end of thirtj^-six hours had germinated only 11 per cent, as compared with 57.5 per cent for seed from the immersed paraffined package. The relative merits of the two conditions as affecting onion seed may be expressed by a germination of 13.5 per cent and 89 per cent, respectively, after sixty- one and one-half hours. Not only was there a marked retardation, but likewise a reduction in the final percentage of germination, with the single exception of the cabbage. These results can be more care- fully studied in Table XXVI. (Termination tests were made of all of the other samples on June 3, IDUl, the date when the seeds were returned from Mobile. At this time the seeds in the unprotected envelopes in the moist chamber were so badly moMed that no germination tests were made. The samples from Mobile, which were directly comparable with the above, except that they had been stored in a basement, were greatly injured. The beans had deteriorated to 88 per cent, the onion to 27 per cent, the pansy to 8 per cent, while the phlox was dead. However, seed of the other species — cabbage, lettuce, and peas — gave final percentages of germi- nation varying but little from the control, but the slowing down in the rapidity of germination was sufficiently marked to show a corre- sponding loss in vitality. With the samples which were put up in bottles, tin cans, and paraffined packages the results were quite different from those given above. In no case was there any marked deviation beyond that which might be justly attriV)uted to ordinarj^ variation, except in the phlox from a tin can which had been stored in the moist chaml)er in the laboratory. This sample of phlox germinated only 3.5 per cent. Unfortunately, both the pansy and the phlox seeds used for these experiments were not very satisfactory. These samples were at this time nearly two years old and consequently of a low vitality. The tabulated results of the foregoing experiment follow. 68 THE VITALITY AND GEKMINATION OF SEEDS. Taulk XXVI. — MtaUtij of seeds pretferved in different kiitds of jxtckages. Trcatuit'iit of .'ahje of different packages as a means of putting up seeds. In Table XXVII it will he observed that the results obtained from the waterpi'oof and parchment paper envelopes have been omitted. These omissions have been made ])ecause the results were practically identical with those of the ordinary seedsmen's packets; but the com- parisons to be made ])etween the ordinary paper packets and the paratlincd packages are w^orthy of consideration. Tlie envelopes that were paraffined after being" filled with seed gave the best results. This difference, however, was due not to the special treatment but to the higher melting- point of the paraffin. The average percentages of germination of the three samples of seed kept under trade con- ditions in the three localities were 59.39 per cent for the envelopes previously paraffined, 62.9-1 per cent for the envelopes dipped in paraffin after being filled with seed, and -idA-i: per cent for the seeds- men's envelopes. In dry rooms the results were 61.11, 65.66, and 49.22 per cent, respective^. These averages were somewhat higher than the true conditions of Baton Iloug-e and Mobile warrant, as the results of the germination tests from all of the packages retained at Ann Arbor showed but little variation. Taking the three samples of seed which were stored under trade conditions in Mobile, the average percentage of germination was 21.2 for the seed from the nonparaftined package and 45. 5 per cent for the seed from the paraffined package, show- ing a loss in vitality of 77.3 and 49.5 per cent, respectively, considering- the germ ination of the Ann Arbor sample as a standard. At Baton Kouge the results were slightly better; the average percentages of germination were 32.2 for the seeds from the nonparaffined and 53.5 per cent for the seeds from the paraffined packages, representing- a loss in vitality of 65 and 40.5 per cent, respectively. While in either case the loss was very great, still the advantages of the paraffined packages are worthy of consideration for the reason that a prolongation of life for only a few weeks is frequently of the greatest importance, particularly in districts where much fall planting is done. In this connection ma}^ l)e given the results of some other tests, which really were a part of this same experiment, but included onl}^ onion seed. This seed was put up in seedsmen's envelopes and in paraffined envelopes like those previously described. In addition, seed was also put up in small bottles, which were corked. These packages were kept in a small box within a. suit case carried on two trips across the Atlantic and on a tour tlirough Central Europe, thus subjecting them to very varia])le conditions. Germination tests gave the following results: Seed from the ordinary packages, 77 per cent; paraffined envelopes, 90 per cent; l)ottles, 91 per cent. To test more thoroughly the keeping (qualities of seeds in paraffined packages and in ])ottles, anotlier series of experiments was begun on December 20, 1901. For these tests onlv cabbaa'e and onion seeds EXPERIMENTS IN KEEPING AND SHIPPING. 71 were used, but each with three dift'e rent deo-rees of moisture: (1) Seed from the original packages, i. e. , air-dried samples, the cabbage hav- ing a water content of 5.80 per cent, and the onion 6.48 per cent. (2) Air-dried sampk's were exposed in a moist atmosphere under a bell jar for two da3's, during which time the cabbage absorbed 1.83 per cent of water and the onion 2.41 per cent, thus raising the water con- tent to 7.63 and 8.89 per cent, respectivel3^ (3) Air-dried seeds which were dried in an incul)ator for eight days at a temperature vary- ing from 27 ' C. to 39° C. During this interval 2.05 per cent of water was expelled from the cabbage and 3.11 per cent from the onion seed, leaving a water content of only 3.75 per cent in the former and 3.37 per cent in the latter. Each of the samples, treated as just described, was put up in three different kinds of packages: (1) Seedsmen's regular seed envelopes. (2) Similar envelopes which were paraffined, after being filled with seed, at a temperature of from 70" to 75° C. The melting point of the paraffin was 53° C. (3) In bottles which were closed with firm cork stoppers. One of each of the above packages was then stored at Mobile under trade conditions and in a basement; likewise at Ann Arbor in the herbarium room of the botanical laboratory, in a greenhouse, and in an incubator maintained at 40° C. The duration of this experiment was 131 days, from December 20, 1901, to April 30, 1902. The results of the germination tests are given in Table XXVIII. Two percentages have been given for the control sample, one for Ann Arbor and the other for Mobile. This was necessary since the two series were tested at different times and comparisons can not be made interchangeably between the two. Table X^X^VIII.— Vitality of cabbage and onion seed as preserved in various kinds of packages and sidjected to different conditions of storage. [Germination of control samples — Ann Arbor: Cabbage, 81.7 per cent; onion, 74 per cent. Mobile: Cabbage, 88 per cent; onion, 8-1.5 per cent.] Special treat- ment of package. Percent- age of water content of seed. Percentage of germination. Ann Arbor, Mich. Mobile, Ala. package. Botan- ical labo- ratory. Trade condi- tions. Green- house. Incuba- tor at 40° C. Trade condi- tions. Base- ment. Cabbage: None 5.80 5.80 5.80 7.63 7.63 7.G3 3.75 3.75 3.75 81. 80.0 79.5 85.5 80.5 80.5 76.0 80. 83.0 81.0 79.0 85.0 80.5 82.0 85.0 85.5 8J.0 8-1.0 68.0 85.5 85.0 65. 5 83.5 86.5 67.0 76.0 74.0 72.5 62.0 68.5 74.5 69.5 48.0 73.0 71.0 64.5 60.0 87.5 84.0 64.5 86.5 82.0 64.0 82.5 82.5 10.0 Do Paraffin Corked None 52.5 Bottle 84.0 Envelope 15.5 Do Paraffin Corked None Paraffin Corked 46.5 Bottle 91.5 Envelope Do 9.0 78.0 Bottle 85.0 72 THE VITALITY AND GERMINATION OF SEEDS. Table XXVIII. — Vita/ili/ ofcahiHigr and onion seed as preserved in various kinds of packages and snhjecied to different kinds of storage — Continued. Special treat- ment of package. Percent- age of water content of seed. Percentage of germinatien. Ann Arbor, Mich. Mobile, Ala. package. Botan- ical labo- ratory. Trade condi- tions. Green- house. Incuba- tor at 40° C. Trade condi- tions. Base- ment. Onion: None (!. 48 G.4S 0. 4.S S. S9 8. 89 8. 89 3..S- 3.37 3.37 78.5 76.5 73.5 74.5 74.5 78.0 (>1.5 75.5 69.5 66.5 71.5 60.0 66. OS. 63. 5 7'i. 5 71.0 3.5 67.0 60. 11.5 .56.0 67.5 8.5 .58. 77.0 47.0 4.5 64.0 •28.0 9.0 3.0 ? 6.0 ? 9.0 59. 5 19.5 83.0 86.0 21.0 74.5 77.5 17.0 77.0 84.5 10.0 Do Paraffin Corked None 27.0 Bottle 82.5 2.5 Do Paraffin Corked None 21.0 Bottle 78. 5 6.0 Do Paraffin Corked 60.5 Bottle 81.5 Manj^ of the points brought out b}" this table are vcr}' similar to those of the preceding- one, yet the differences are sufficientl>' marked to justify its being given in this connection. The seeds stored in the botanical laboratory and those subjected to trade conditions at Ann Ar))or have germinated practically the same, the cabbage slightly favoring trade conditions and the onion being better preserved in the laboratory. But a comparison of the trade conditions at Ann Arbor and Mobile in the unprotected packages shows the same wide variation that has been already pointed out. The advantage of drying is not very clearly )>rought out in this table; in many cases there seems to have been a slight injurj'^ as a result of the high temperature at which the drying was done. Una- voidably the temperature at that time reached 39° C, which, as has already been stated, is slightly above the maximum to which seeds can be subjected for any considerable time without injury. The injury due to heat is ver}^ evident in the samples stored in the incu- bator maintained at 40" C, this injury being more apparent with the increased moisture, especially in the paraffined package and in the bottle. However, on the whole the percentages of germination are higher for the dried seed than for the seed which had absorbed an - additional quantity of moisture; and, indeed, tlie comparison should properly be made with these two, for seeds as they are usually stored contain even higher percentages of moisture than either the cabbage or lettuce after they had absorbed the additional amount of water. But the chief purpose of the present experiments was to determine the relative advantages of envelopes, paraffined packages, and bottles as methods of putting up seed in order that vitality might l)e pre- served for a longer time. This comparison is best made by consider- experimp:nts in keeping and shipping. 75 ino- the vitality of the ,seod stored in the greenhouse at Ann Arbor and under trade conditions at Mobile. It will be readily seen that the vitality of the seed from the unprotected packages was greatly reduced, while those from the parafhned envelopes and from the bottles germi- nated nearl}' as well as the controls. These differences are better rep- resented diagrammatically, as follows: Bkujram represent ing ilie jwrcentarjes of gerwination of cabbage seed irhen treated as described. Kind of package. Special treat- ment of package. Percent- age of water content of seeds. Ann Arbor, Mich., green- house. Mobile, Ala., trade conditions. Envelope 5.80 5.80 5.80 7.63 7. (13 7. (53 3.75 3.75 3.75 5. SO 73.3 60 Do Paraffined ( ;orked 92.1 87.5 Bottle 91.5 .S-1 Envelofn' 70. 5 64. 5 Do Paraffined Corked 89.9 ,8C). 5 Bottle 93.1 82 Envelope 72.1 64 Paraffined Corked Original pack- age. Do 81.. s 82 5 Bottle 79.7 ,H2. 5 Control sample . 8.S 8,S Diagram represenling the percenlages of germination (f onion seed ivhen treated as described. Kind of package. Special treat- ment of package. Percent- age of water content of .seeds. Ann Arbor, Mich., green- house. Mobile, Ala., trade conditions. 6.48 6.48 6.48 8.89 8.89 8.89 3.37 3.37 3.37 6.48 4 76. 6 19.5 Do Paraffined Corked 83 Bottle 68. 6 .86 Envelope 13.2 64 21 Do Paraffined Corked 74.5 Bottle 77.3 77.5 Envelope 66.3 17 Do Paraffined Corked Original pack- age. 77 Bottle 8,s .84.5 Control sample.. .S4.."i .S4. 5 The percentages for Ann Arbor shown in the graphic representations are not the same as those given in the foregoing table. In the diagram they are directl}^ comparable with the results from the Mobile series, 74 THE VITALITY AND GERMINATION OF SEEDS. all being* based on the vitalit}^ of the controls, as shown l)y the tests made at that time, the standard ])eino- ss per cent for the cabbage and 84.5 per cent for the onion. A discussion here hardl}' seems necessary, as there can he no douljt that seeds retain their vitality much l)etter in moist climates if pro- tected from the action of the atmosphere. This ma}" ])e accomplislied by dipping- the packages in paraffin or ])y putting the seed in bottles. Disregarding the expense, V)ottles surpass paraffined envelopes as a means for the preservation of vitality, and also in tlie ease with which the seed can be put up. The results are more certain if care is exer- cised in selecting good corks. RESPIRATION OF SEEDS. From a practical point of view it lias been conclusivel}^ shown that moisture is the controlling factor in seed life. Seeds stored in a humid atmosphere soon lose their vitality, luit if carefulb,- dried and protected from moisture life is greatly prolonged. The question at once presents itself: In wliat way does the presence of increased quantities of moisture cause a premature death of the seed, or why is vitality prolonged if the water content of the seed be reduced? In a measure, the answer to this question is respiration. Seeds as we commonly know them absorb oxygen and give off carbon dioxid; that is, respire." During their respiratory activities the energy stored within the seed is readily evolved, the vital processes are destro3"ed, and life l)ecomes extinct. The intensity with which respi- ration takes place is largel}^ dependent upon the humidity of the sur- rounding atmosphere, which ultimately resolves itself into the amount of water in the seed. The respiratory activity is directly propor- tional to the quantit}^ of moisture al)sorbed l)y the seed up to a certain point, attaining its maximum during the process of germination. It has been found that a decrease in the water content results in a cor- responding dimiimtion in the intensity of respiration and consequently in a prolongation of the life of the seed as such. Bonnier and Mangin'' ^vere the first to show that respiration in liv- ing plants increases with an increase in the humidity in the surround- ing air. As this is true for growing plants, it is even more marked in stored seeds. Maquenne '" suggested that a reduction in moisture is accompanied by a reduction in respiration, l)ut at that time no experiments had been made to show that such was actuall}^ the case. aKolkwitz (Ber. d. dentsch. But. Ges., 19: 285-287, 1901) reports resxuratiou in recently gi-ound seeds. 6 Ann. sc. nat. hot., ser. 7, 2: 365-380, 1885. cAnn. Agron., 26: 321-332, 1900. I RESPIRATION OF SEEDS. 75 In 1832, Aug. P^-r. De Candolle wrote in the second volume of hi.s Physiologic Vegetale that the vitality of seeds would bo prolonged if they were i)uried sufficiently deep in the soil to protect them from oxygen (or air) and moisture. Unfortunately, De Candolle did not discover the true cause of this prolonged life, for nowhere did he make any reference to respiration. Nevertheless his general conclu- sions were properly drawn. De Candolle also stated that light acceler- ates evaporation in seeds and thus causes a premature death. Here, however, his results were wrongfully interpreted. These conclusions arc applica])le only in case of seeds that die if allowed to become dry. The real effect of light is to cause a slightly accelerated respiration and consequently a greater deterioration in vitalit3^ Jodin^' states that light accelerates respiration to a marked degree. His experi- ments were with peas which contained 10 to 12 per cent of moisture. Two samples of peas were placed, each under a bell jar, over mer- cury. One sample was kept in the light and the other in the dark. At the end of ■! years 6 months and 11: daj^s an analysis of the con- lined air from the sample kept in the light gave the following results: Peas, 3.452 grams, in air, in light: Percent. Oxygen 19.1 Nitrogen 78. 6 Carbon dioxid 1.2 At the end of -1 years 7 months and 11 days an analysis of a sam- ple of air taken from the other chamber was as follows: Peas, 3.580 grams, in air, in dark: Percent. Oxygen 20. 8 Nitrogen 79. 1 Carbon dioxid 1 The 3.152 grams of peas that were subjected to the influence of the action of light had absorbed, in the given time, 2.4 cc. of oxygen and produced 1.8 cc. of carbon dioxid. The seed kept in the dark showed but little signs of respiratory activity. Germination tests of the former showed the peas to be dead, while five peas from the sample kept in the dark germinated perfectly. While there is no question that light exerts some influence on respi- ration, still the above results do not furnish sufficient data to establish the fact that respiration practically ceases in the absence of light. In fact, experiments have shown that respiration is also quite marked in case of seeds stored in the dark, and the difl['erence is very slight if the same temperature be maintained. Van Tieghem and Bonnier, in their "Recherches sur la vie latente des graines,"* demonstrated that 7.976 grams of peas, sealed, in air, «Ann. Agron., 23: 433-471, 1897. 6 Bui. See. bot. France, 29: 25-29, 1882. 76 THE VITALITY AND GERMINATION OF SEEDS. in !i tiil>e, respired quite freely. Aftei' the hipsc of two yeai's an analysis of the confined air i^ave the following- rosidts: I'er cent. Oxygen 14. 44 Nitrogen 81. 74 Carl)on dioxid 3. 82 These same seeds g-erminated 45 per cent and had increased ^-J-y of their original weight. In the experiments of the writer it was found that 40.11.50 grams of air-dried beans liberated 7.7 cc. of carbon dioxid in 370 days. The concentration of the carbon dioxid in the flask at the time the gas was drawn for analysis Avas 1.54 per cent. This sample of seed germinated 97 per cent, and there was only a very slight retardation in germina- tion, which Indicated that the vitalit}' had not been materiall}" reduced. During this time there was a slight decrease in the weight of the seed — 0.10 per cent. At the same time two check bottles were set up, one containing 40.1184 grams of beans known to be dead, and the other bottle containing nothing except air. Analyses of the air from these two bottles gave the same results as samples of air drawn from the laborator}. These preparations were kept in subdued light through- out the experiment. That respiration may take place in the dark, that it is ^ery intense if much moisture be present, and that intensive respiration is accom- panied b}^ a rapid loss in vitality is shown In' the following experi- ments. On April 3, 1900, samples of beans, ca])bage, carrot, lettuce, and onion were sealed, each in bottles of 250 cc. capacity, and were stored in a dark room which was maintained at a temperature of from 20^ to 25° C. These samples were first carefully weighed and then placed in a damp chamber for 175 hours, so that an additional quantity of moisture could ])e absorbed. Control samples of air-dried seeds were also kept in sealed bottles and subjected to the same subsequent treatment. After the lapse of one 3'ear analyses of the confined gases and germination tests of the seeds were made, the results of which are given with the general details. Beans. — Of beans, 24.9994 grams absorbed 4.70 per cent of water while in the damp chamber. The respiration during the year was equivalent to 2.5 cc. of carbon dioxid. The loss in weight was only 0.05 per cent, but the vitality had fallen from 100 to 86 per cent, as shown by the control. Cnhhage. — Of cabl)age seed, 10 grams, with an additional 9.79 per cent of water, were used for this test. During the 3'ear this sample of cabbage seed had given off 24 cc. of carbon dioxid, an equivalent of 2.4 cc. of carbon dioxid per gram of seed per j^ear. The control sample germinated S9 per cent, Init this seed was dead. RESPIRATION OF SEEDS. 77 Carrot. — Of carrot seed, 10 j>-rams were allowed to absorb during 175 hours an additional 10.25 per cent of water. In one year 27 cc. of carbon dioxid were produced, giving a concentration of carbon dioxid of nearly 12 per cent. The deterioration in. vitality was from 84 to per cent, as compared with the control. Lettuce.— Oi air-dried lettuce seed, 10 grams were allowed to absorb an additional 8.87 per cent of water. During the experiment 19.5 cc. of carbon dioxid were formed, an equivalent of approximatel}^ 10 per cent of the original volume of the inclosed air. These seeds were all killed. The control sample germinated 94 per cent. Onion. — Of air-dried onion seed, 10 grams were allowed to absorb an additional 10.11 per cent of water. The seed gave off 26.5 cc. of carbon dioxid during the experiment and deteriorated in vitality from 97 to per cent. A bottle containing 4 cc. of water was also sealed at the same time and served as a check for the other analyses. A sample of air taken from this bottle gave the same results as the original air sample. It is a matter of much regret that no analyses could be made of the air from the bottles which contained the check samples. These bottles contained the same weight of air-dried seeds as was used for the experiments. Unfortunately the seals on these bottles had become dry and admitted of an exchange of gases, so that the results were not reliable. Another series of experiments consisted in keeping onion seeds in sealed bottles for 1 year and 13 days, with the following results: {a) Fifty grams of air-dried seed were sealed, in air, in a bottle of 500 cc. capacity. There was an increase in the weight of the seeds of 0.1091 gram — slightly more than 0.2 per cent. An analysis of the inclosed gas gave: Per cent. Oxygen 12. 27 Nitrogen 85. 87 Carbon dioxid 1. 86 {1)) Fiiiy grams of air-dried seed were sealed, in air, in a 500 cc. bottle, with 4 cc. of water in a small test tube at the bottom of the bottle. Nearly all of the water was absorbed by the seeds, there being an increase in weight of 3.6475 grams, or 7.3 per cent. The composition of the inclosed air was: Per cent. Oxygen None Nitrogen 86. 65 Carbon dioxid 13. 35 The oxygen had all been consumed and the seeds were all dead. {c) Fifty grams of onion seed were sealed in a 500 cc. bottle, in a Lorc. 78 THE VITALITY AND GJ:RMINATI0N" OF SEEDS. mixture of illuniiiiatino' gas and air. The increase in weight was only 0.01 per cent. An analysis of the inclosed gas was as follows: Per eeiit. Oxygen : 3. 23 Carbon dioxid 1. 21 Methane and nitrogen 95. 96 {d) Another 50-grani sample of onion seed, belonging to a different series, was sealed in a bottle of 300 cc. capacity, and showed the following composition of the inclosed air: Per cent. Oxygen 8.02 Nitrogen 85. 17 Carbon dioxid 6. 81 In only one case was there an}^ deterioration in vitality, namely, where the large (juantity of moisture was present. The other samples germinated normally. The seed kept in the illuminating gas germi- nated even better than the control. In all of the bottles there was a marked decrease in pressure, show- ing that the volume of oxygen al)sorbed was much greater than the volume of the carbon dioxid given off. During respiration certain chemical changes must be taking place which exert a marked influence on the vitalit}^ of seeds. What these changes are is a (juestion 3^et to l)e solved. The protoplasts of the individual cells gradually but surely ])ecome disorganized. C. De Candolle" takes the view, in discussing the experiments of Van Tieg- hem and Bonnier, that during respiration life is simply subdued. But the period of suljdued activity, he says, is comparatively short, for respiration soon ceases and life becomes wholly latent. As a result of his own experimiMits in storing seeds at low temperatures he con- cludes that seeds cease to respire and l)ecome completely inert; in which case they can suffer any degree of reduction in temperature without ])eing killed. The killing of the seeds experimented with (lobelia) he attributes to the fact that the protoplasm had not l)ecome inert, l^ut simply sul)dued, and the seeds were thus affected ])y the low temperature. As a result of later experiments C. Do Candolle,^ in keeping some seeds inidcr mercury to exclude air, concludes that *■' seeds can contimie to subsist in a condition of complete vital inertia, from Avhich they recover whenever the conditions of the surrounding medium permits their 'encu-gids,' or living masses of their cells, to respire and assim- ilate." He compares the protoplasm in latent life to an explosive mixture, having the faculty of reviving whenever the conditions are favorable. This comparison seems rather an unfortunate one; yet, within a certain measure it is probabl}^ true. « Revue Sdentifi(iue, ser. 4, 4: 321-326, 1895. ^Pop. Sci. Montlily, 51: 106-111, 1897. RESPIEATION OF SEEDS. 79 It is now quite generally accepted that respiration is not absolutely necessary for t^ie maintenance of seed life, notwithstandino- the fact that Gray contended that seeds would die of suffocation if air were excluded/' The experiments of Giglioli'' in keeping seeds of Medicago sativa immersed in various liquids for approximately sixteen years, after which many responded to germination tests, has done nnich toward demonstrating the fact that seeds can live for a considerable time in conditions prohibiting respiration. Kochs'" succeeded in keeping seeds for many months in the vacuum of a Geissler tube without being able to detect the presence of any carbon dioxid, and consequently he concluded that there was no gas given off l>y intramolecidar respiration. Romanes <^ kept various seeds in vacuum in glass tubes for 15 months and the seeds were not killed. However, his vitality tests can not be considered as entirely satisfactory. In the first place, the number of seeds used (ten) was too small; secondl}^, the variations in the results, even in the controls, indicate that the samples were not of very good quality. In the experiments of the writer cabbage and onion seed were kept in a vacuum over sulphuric acid for 182 days. During this time all of the free Avater had ])een extracted from the seed. When again con- nected with a vacuum gauge the dial showed that there was not the slightest change in pressure, and that consequcntl}- no evolution of gases had taken place. The cabbage germinated 75 per cent and the onion 73 per cent as compared with 81 and 71 per cent, respectively, for the controls. The results of the various experiments above given demonstrate quite full}^ that the vitality of seeds, as we commonly know them, is not interfered with if they are kept in conditions prohibiting respira- tion. Brown and Escombe'' hold that all chemical action ceases at temperatures of liquid air. They accordingly conclude that " any considerable internal chemical changes in the protoplasts are rendered impossible at temperatures of —180° to —190° C, and that we must consequentl}^ regard the protoplasm in resting seeds as existing in an absolutely inert state, devoid of any trace of metabolic activit}^ and yet conserving the potentialit}' of life * * * And since at such low temperatures metabolic activity is inconceivable an immortality of the individual protoplasts is conceivable providing that the low tempera- tures be maintained." «Amer. Jour, of Sci., 3cl series, 24: 297, 1882. «> Nature, 52: 544, 1895. cBiol. Centrbl., 10: 673-686, 1890. f^Proc. Roy. Soc, 54: 33.5-337, 1893. sibid., 62: 160-165, 1897-98. 80 THE VITALITY AND GERMINATION OF SEEDS. Giglioli" arrived at practically the same conclusion.s when he said: It is a coniinon notion that life, or capacity for life, is always connected with con- tinuous chemical and i)hysical change * * * The very existence of living matter is supposed to imply change. There is now reason for believing that living matter may exist, in a completely passive state, without any chemii'al change whatever, and may therefore maintain its special jiroperties for an indefinite time, as is the case with mineral and all lifeless matter. Chemical change in living matter means active life, the wear and tear of which necessarily leads to death. Latent life, when completely passive in a chemical sense, ought to be life without death. But even thouo-h ordinary respirator}^ exchanges are not necessary for the maintenance of vitalit}^, and granting that intramolecular respiration does not occur in the resting protoplasts, there is no exper- imental evidence pointing to the fact that all chemical action ceases, although some writers, as has already been shown, maintain the view that living matter ma}^ exist in a completely passive state. If "com- pletely passive" meant devoid of respirator}- activities none would dare dissent; l)ut that seeds are entirely quiescent under an}- known con- ditions has not been proved. To conceive of all activity ceasing within the seed under certain conditions, and that with such cessation of activity an inunortality of the seed is possible, i. e., if such con- ditions continue to exist, is, from our present knowledge of the chem- istry and behavior of the living cell, impossil)le. In Giglioli's experi- ments respiration w^as undoubtedly prevented, and, according to his own conchisions, vitality sliould have been preserved, for he says "in the al)sence of any chemical change the special properties ma}' lie main- tained indefinitely.'' But, in his own experiments, the special prop- erties were not maintained, foi- all of the seeds with which he experi- mented deteriorated very much, and many died. Granting that those which suffered the greatest loss in vitality were injured by the pres- ence of the particular gas or li(iuid used there remain no means of accounting for the deterioration in those giving the highest percentages of germination. His experiments were made for the most part with Medicago sativa^ which, under ordinary conditions of storage, is espe- cially long lived. Samek '' has shown that seed of Medicago satioa 11 years old was capai)le of germinating 51 per cent. Giglioli succeeded in getting a germination of only 56.56 per cent after a little more than 16 years in hydrogen, and 81.20 per cent when they had l)een kept in carbon monoxid. Jodin ^" kept peas immersed in mercury for 1^ years and they germinated 80 per cent. After 10 years the vitality had fallen to 41 per cent. Nobbe obtained a germination of 33 per cent in peas 10 years old which had been stored under normal conditions. Likewise the experiments of Brown and Escoml)e do not justify the « Nature, 52: 544-545, 1895. ''Tirol, landw. Bliitter, 13: lHl-162, 1894. cAnn. Agron., 23: 433-471, 1897. RESri RATION OF SEEDS. 81 coiu'lusioiis which they have dniwn. It is now definitely known that all chcuiical actions do not cease at the temperature of li(iuid air. Thus it can not ])e o-ranted that the protoplasm becomes inert as a result of the reduction in temperature. Maquenne " more nearl}'^ expressed the true conditions applicable to low temperatures when he wrote that with dessication, at low temperatures, seeds are transformed from a condition of diminished activity into a state of suspended life. But tliere are still other factors to be considered. The vegetative functions may cease, metabolic processes may be at a standstill, intramolecular respiration need not exist, yet vitality is not, nor ever has been, pre- served; sooner or later life becomes extinct. What does this signify? The gradual process of devitalization means chemical change, and chemical change means activity within the cells. We nuist not forget the great complexity of the composition of the protoplasmic bodies which go to make up a seed. The chemistry of the living cell is still surrounded bj^ many difficulties and is likewise tilled with many sur- prises, and before the question of the vitality of seeds can l)e under- stood a more comprehensive knowledge of both the functions and composition of the cell contents is necessary. It is well known that all organic compounds are made up of a very few elementary substances, but the numerous and obscure ways in which they are put together furnish questions of the greatest per- plexity. Substances having the same elements may difl'er widely as to their properties. Moreover, isomeric substances — i. e., those hav- ing the same elements in the same proportions, giving an equivalent molecular weight — are usually very different in their chemical reac- tions and physiological functions. As yet this intramolecular atomic rearrangement is but vaguely understood, and the writer ventures to suggest that with a more comprehensive knowledge of the chemistry of the living cell some such chemical activity will be discovered. With these discoveries will come, perhaps, an understanding of the devitalization of seeds, and with it the theory of the immortality of seeds will vanish. SUMMARY. (1) Seeds, like other living organisms, respire when subjected to normal conditions of storage. (2) Respiration means a transformation of energy, and consequently a premature death of the seed. (3) Within certain limits respiration is directly proportional to the amount of water present in the seeds and to the temperature at which they are stored. (4) By decreasing the watei- content of seeds respiration is reduced and vitality greatly prolonged. «Compt. Rend., 134: 1243-1246, 1902. 25037— No. 58—04 6 82 THE VITALITY AND GERMINATION OK WEEDS. (5) In most seeds the (Quantity of oxyj^-eii a])Sorb(Hl o-roatly exceeds the ([uaiitity of carbon dioxid evolved. (()) Respiration is nearl}^ as active in the dai-k as in the lioht. (7) Respiration apparently is not necessary for the maintenance of seed life. (8) A cessation of respiration does not mean a cessation of chemical activities. ENZYMES IN SEEDS AND THE PART THEY PLAY IN THE PRESERVATION OF VITALITY. During the past decade the so-called unorganized ferments have taken an important place among the subjects of biological research. Our knowledge of their wide distribution has increased many fold. The part they play in both ana])olism and catabolism has furnished us many surprises, but with all of the work that has been done our knowl- edge of these most complex compounds is very limited. The part that enzymes pla}^ in the processes of germination is of the utmost importtmce. It is now quite well understood that they are developed as germination progresses. They act on the most complex reserve food products, converting them into simpler substances that can be more readily utilized by the growing seedling. However, even in this connection there is a great diversity of opinion, especially as to their distribution and enzymic action within the endo- sperm itself. Puriewitsch," Griiss,'' and Ilansteen '^ are cited by Brown and Escombe'' as holding the view that the amyliferous cells of the endosperm of the grasses can digest their reserve materials independ- ently of any action of the embryo — i. e., the starch -bearing cells are living cells and secrete enzjnnes in the grasses as well as in the coty- ledonous cells of Zv/pinus, PJiaseohts, and Btcin us. In 1890, Brown and Morris' did not find such to be the case; but the results of Furie- witsch, Griiss, and Ilansteen led to a duplication of the experiments by Brown and Escombe in 1898. At this time they demonstrated that the amyliferous cells play no part in the chemical changes which take place during the process of germination, but on the contrary that the enzymic action in the endosperm of the grasses is confined to the aleuron layer. But the purpose of the present paper is not to consider the localiza- tion of the particular enzyme, and much less the action of enzymes during germination. At this time quite another question is to be f'Pringsheims Jahrb., 31: 1, 1897. J'Landw. Jahr1)iicher, 1896, p. 385. <^ Flora, 79: 419, 1894. f^Proc. Roy. Soc, 63: 3-25, 1898. «Jour. Chem. Soc, London, 57: 458-528, 1890. ENZYMES IN 8EEDS. 83 considered, viz, In what way do enzymes function in the presei'vation of vital it}'? Maquenne" points to the view tliat the vitality of seeds is dependent on the sta])ility of the particular ferment present. He attributes the prolongation of vitality in seeds that are kept dry to the l)etter preser- vation of the enzymes. This view has been largely strengthened as a result of the investigations made ])y Thompson,^ Waugh,'' Sharpe,'' and others, in which they have show'n that the artiticial use of enzymes may greatly increase the percentage of germination in some old seeds. By the use of diastase the percentage of germination of 12-year-old tomato seed has l)een increased more than 600 per cent. If the suggestions made by Maquenne were true in ever}"^ sense, then dead seeds should be awakened into activity b}^ artificially supplying the necessary enz3mies; but this can not be, or never has been, accom- plished. True, many experiments have been recorded in which a greater percentage of seed has been induced to germinate by the judi- cious use of commercial enz3'mes than by the ordinary methods of germination; but this treatment is applicable only where the vital energy is simply at a low el^b and does not in any way affect dead seeds. The experiments of the writer with naked radicles from the embryos of living and dead beans have shown the presence of enzymes in both. The carefully excised radicles were ground and macerated in water for one hour. The filtrate was then added to dilute solutions of starch paste. The solutions from the living embryos gave rise to an energetic hydrolytic action. In all cases hydrolysis was sufficiently advanced to give a clear reaction with Fehling's solution. The solu- tions extracted from the radicles from the dead beans also gave reac- tions sufficiently clear to indicate that there was still some ferment present. '^ However, the hydrolysis was scarcely more than begun, giving only a brown color with iodin, but not reacting with Fehling's solution. Results of a similar character were obtained from portions of the seed «Ann. Agron. 26: 321-332, 1900; Compt. Rend., 134: 1243-1246, 1902. &Gartenflora, 45: 344, 1896. c Mm. Report, Vt. Agr. Exp. Sta., 1896-97, and Science, N. S., 6: 950-952, 1897. <' Thirteenth Annual Report, Mass. Hatch Exp. Sta., Jan., 1901, i^p. 74-83. «' This was a sample of "Valentine" l)eans grown in 1897. The same year thej'^ tested 97.3 per cent. In March, 1898, the same sample tested 87 per cent. At this time they were sent to Orlando, Fla., where they remained until May 8, 1899, approximately fourteen months. The beans were then returned and numerous germination tests were made at irregular intervals, but in no case was there any indi- cation of vitality. Several samples were also treated with "Taka" diastase (solu- tions varying in strength from 2 to 10 per cent), but none was stimulated into germination. The radicles were tested for enzymes in the spring of 1902, nearly three years after the beans lirst failed to germinate, at which time they were nearly 6 years old. 84 THE VITALITY AND GP]RM1NATK)N OF SEEDS. taken from the point of luiion of the axis and the cot^dedons. These possessed stronger hydrolytic powers, the preparations from the livinj^ and dead l)eans each giving' clear reactions with Fehling\s sohition. A third series of tests was made b}^ stopping the germination of beans when the radicles were from 1 to 1.5 cm. long. These were tlien kept quite dry for nearl}- seven months, after which the dessicated radicles were broken o& and macerated like the above. This solution was then allowed to act on starch paste, and the transformations were almost as rapid and complete as when a 1 per cent solution of commercial '* Taka" diastase was used. These results lead one to believe that the loss of vitality in seeds is not due to the disorganization of the enzymes present. There is some- thing more fundamental and probably more complex to which we nuist look for this life-giving principle. True, as Maquenne has suggested, there is a close relationship between the loss of vitalit}^ in seeds and the decomposition of enzymes. In order to determine what such a relationship might signify, the following series of experiments were made: Beans, peas, cabbage, lettuce, onion, phlox, and pansj^ seed, with definite quantities of good commercial " Taka " diastase, were put up in bottles of 120 cc. capacity, as follows: (1) In bottle closed with cork stopper. (2) In bottle closed with cork sto]:)per and paraifined. (3) 0.5 cc. of water in the bottle with the seeds and the diastase, the bottle sealed with paraffin. (•1) 1 cc. of water in the bottle with the seeds and the diastase, the bottle sealed with paraffin. (5) 2 cc. of water in the bottle with the seeds and the diastase, the bottle sealed with paraffin. (6) 3 cc. of water in the bottle with the seeds and the diastase, the bottle sealed with paraffin. (7) i cc. of water in the bottle with the seeds and the diastase, the bottle sealed with paraffin. The water in each case was carefully added on small strips of filter paper and never were the seeds or the diastase wet, only becoming gradually moist as the water was absorbed. These different preparations, each containing one of each of the sam- ples of seeds and a definite quantity of the dry powdered diastase, were then maintained at the temperature of the laboratory for a period of 85 days. At the end of that time the vitality of the seeds was deter- mined and simultaneously the h3'drol3^tic power of the diastase was ascertained. The results of the germination tests are given in Table XXIX. The effect of the increased (|uantity of moisture on the diastase is given in the discussion following the table. ENZYMES IN SEEDS. 85 Tahle XXIX. — Lous in, vitality of seeds with varying degrees of moisture when kept at ordinary room teitiperature. [Duration of experiment, S5 days.] Labor- Preparation of sami)le. Amount of water added. Percentage of germination. atory num- ber. Beans. Peas. Cabbage. Onion. Phlox. Pansy. Average of all samples. 1547 1548 1549 1550 1551 1652 1553 Control" ... Corked Paraffined.. do do do do do cc. None . . . None . . . None . . . 0.5 1.0 2.0 3.0 4.0 9(;. 98.0 9C). 96.0 96.0 96. 94.0 90.0 90.0 96. 92. 92.0 88. 86. 94.0 81.6 91.5 91.0 91.5 89.0 89.0 78.0 65.0 54.5 95.0 92. 5 93.0 88.8 64.0 13.0 2.5 .0 41. 25 52.0 39.5 . 28.5 12. 5 .5 .5 .0 46.0 32.0 31.0 25. 5 18.0 2.5 .5 .0 76. 6 76.9 73.8 69. 9 01. 2 46.0 46.1 37.6 a The samples prepared, excepting the control, were in bottles of 120 cc. capacity. The above table shows that there was a gradual deterioration in vitality as the quantity of water was increased. All stages of injury were manifested, but it is not necessary to enter into a discussion of the table at this time, inasmuch as similar tabulations, showing the injurious effects of varying quantities of moisure on the seeds, have alread}' l)een given on page 38. This table is inserted here in order that a comparison can he made with the decomposition of the com- mercial diastase used and the loss in vitality of the seeds. For a determination of the diastasic activity various quantities of 1 per cent " Taka" diastase solutions were allowed to act on definite quan- tities of a 1 per cent solution of starch paste, the whole being maintained at a temperature of from 45° to 48° C. Ten cubic centimeters of the starch solution were taken for each determination, and the amount of the diastase solution varied from one-half to 1, 2, 3, and 5 cc. In the control sample, consisting of diastase from the original bottle as it was kept in the laboratoiy, 2 cc. of the 1 per cent solution were sufficient to cause a complete hydrolysis of the 10 cc. of 1 per cent starch solution. In Nos. 1547, 1548, and 1549 the samples from the control bottle, the paraffined bottle, and the paraffined bottle containing 0.5 cc. of water, respectively, 3 cc. of the diastase solution were necessaiy for a com- plete hydrolysis. In Nos. 1550, 1551, and 1552 — that is, the samples from the bottles which contained 1, 2, and 3 cc. of water, respectively — the diastase was very much injured as a result of the increased quan- tit}^ of water in the bottle and 5 cc. of the diastase solution were required to h3'drol3'ze the 10 cc. of the 1 per cent starch paste. No. 1553 — the sample from the bottle which contained the 4 cc. of water — showed that the diastase had been almost completely disorganized, inasmuch as the greatest quantity used (5 cc. of the 1 per cent diastase .solution) was only sufficient to cause a slight hydrolytic action. When 86 THE VITALITY AND GERMINATION OF SEEDS. tested with iodine there was still a deep, purplish-hlue color. In this last case the average percentage of germination had decreased to 37.6 per cent, as compared with 70.6 per cent for the control samples. Moreover, in the latter case, the onion, phlox, and pans}' seeds were killed. These results show that there is a remarkable uniformity between the loss in vitalit}' of seeds and the loss in the enzymic action of the "Taka'' diastase under similar conditions, but it does not furnish con- clusive evidence that the loss in vitality of the seeds is in any way governed b}' the particular enzymes present. In fact, the evidence at hand Ijetter suljstantiates the opposite view. In the first place dead seeds may still contain active ferments. Secondl}^ the prolonged sub- jection of seeds to the action of ether and chloroform is generally accompanied by a premature death, and if the seeds are moist the loss in vitality is nuich more marked. On the other hand, it is generally accepted that either of these gases exerts no injurious effect on the hj^drolytic action of the various ferments. Townsend « has shown that the action of diastase on starch paste is even more energetic in the presence than in the absence of ether, but in germination ether usually has a retarding influence. In some cases, however, growth is stimu- lated by the use of ether. In the third place enzymes can not })o the chief factors controlling the vitality of a seed, because the more sensitive growing point of the radicle suffers injury much in advance of the other portions of the seed. Not infrequently in making germination tests do we find that the growing tip of the embryo is dead, while other portions of the seed may still he living and capal)le of carrying on all normal met- abolic processes. The bean is one of the best examples for demon- strating this fact. Here the radicle may be entirely dead, yet the cotyledons may still be able to make some growth; but in all seeds where the growing tip is dead the remaining portion of the radicle may l>e li^'ing, in which case adventitious roots may be formed and growth may continue for a considerable time, though ver}^ rarely will a healthy seedling be developed. It thus seems quite clear that the real vital elements are closely associated with the growing point, and when this portion of the emlnyo is once dead the vital energy in the other parts of the seed is not of such a nature as to enable growth to con- tinue for any length of time. Even though the reserve food products are digested they can not be assimilated by the growing radicle, which should be the case were enzymes the chief elements to which the preservation of vitality is attributed. Enzymes play an important part in the vitality of seeds, and are undoubtedly necessarj^ for the normal development of a seedling, but the points above given show that the life of a seed is not entirely «Bot. Gaz., 1S9V), 27: 458-466. SUMMARY. 87 dependent on the stability of the particular ferment or ferments present. There is something- more remote, possibly of a simpler but probably of a more complex composition, to which we must attribute the awakening of the metal )olic processes. Reference is not made here to the zymogenic substances which develop into the particidar ferment, for what has been said of the latter applies equally well to the former. If the zymog-ens were perfect!}' preserved the resulting- ferments would be developed normally and germination would continue in the usual manner. In conclusion, it ma^^ well be emphasized that no single element or compound can be isolated as the sole source of vitality in seeds. There must be a combination of factors, each of which plaj-s an important role in the preservation of vitality. The destruction of any one of these factors may upset the principles governing- the life of a seed, and consequently cause a premature death. It is quite probable that the nucleus is one of the most important organs governing vitality, for unless it continues to function no other growth can take place. Other parts of the cell, however, may be of equal importance. At all events all hope of future gain must come from more critical studies of the cell contents to know their chemical composition and possible reactions. A correct solution of these perplex- ing questions is nothing less than a determination of the fundamental principles of life. What will be the ultimate results no one is prepared to say. SUMMARY. (1) A seed is a living organism, and must l)e dealt with as such if good results are expected when put under favorable conditions for germination. (2) The first factoi-s determining the vitalit}" of a seed are maturity, weather conditions at the time of harvesting, and methods of harvest- ing and curing. (3) Immature seeds sown soon after gathering usuall}' genninate readily, but if stored they soon lose their vitality. On the other hand, well-matured seeds, harvested under favoral)le conditions, are com- paratively long lived when properly handled. (4) Seed harvested in damp, rainy weather is much weaker in vital- ity than seed harvested under more favorable conditions. Likewise, seed once injured will never regain its full vigor. (5) The curing of the various seeds is of the utmost importance, and great care should be taken to prevent excessive heating, otherwise the vitality will be greatly lowered. (6) The life period of any species of seed, granting that it has been thoroughly matured and properly harvested and cured, is largely dependent on environment. 88 THE VITALITY AND GERMINATION OF SEEDS. (7) The average life of seeds, a.s of plants, varies greatly with difl'er- ent families, genera, or species, but there is no relation between the longevity of plants and the viable period of the seeds they bear. The seeds of some plants lose their vitality in a few weeks or months, while others remain viable for a number of 3'ears. (S) With special precautions and treatment there is no question that the life of seeds maj he. greatly prolonged beyond that which we know at present, though ne^er for centuries, as is frequently stated. Cases so reported can not be taken as evidence of the longevity of seeds. (9) It is known that seeds retain their vitality much better in some sections of the country than in others. Tlie part which climatic influ- ences play in the vitality of seeds is of much more importance than is generally supposed. (10) Experiments have shown that moisture is the chief factor in determining the longevity of seeds as they are commercially handled. Seeds stored in dry climates retain their vitality much ])etter than when stored in places having a humid atmosphere. (11) The deleterious action of moisture is gi-eatl}^ augmented if the temperature be increased. Not infrequentl}^ is vitality destroyed within a few weeks or montlis when the seeds are stored in warm, moist climates. If stored in a dry climate, the question of temper- ature within the normal range is of little moment. (12) The storage room for seeds as they are ordinarily handled should alwa3\s l)e dry. If seeds could l)e kept dry and at the same time cool, the conditions would be almost ideal for the preservation of vitality; but the difficulties to be overcome in order to secure a dry and cool storage room render this method impracticable. (13) The most feasible method for keeping seeds dry and thus insur- ing strong vitality is to store them in well ventilated rooms kept dry by artiiicial heat. This method of treatment requires that the seeds be well cured and well dried before storing. (14) If seeds are not well dried A'itality is best preserved at tempera- tures just above freezing^ provided that the temperature is maintained uniformly. (15) In no case must the temperature of the storage liouse be increased unless the seed is amply ventilated so that the moisture lib- erated from the seed can be carried off readily by the currents of warm air. If this precaution is not taken the increased humidity of the air confined between the seeds will cause a marked injur}-. For this same reason seeds kept at low temperatures during the winter will deterior- ate in the warm weather of spring, especially if they contain much moisture. (16) Most seeds, if first carefully dried, can withstand long expos- ures to a temperature of 37° C. (98.6° F.) without injur}^ but long exposures to a temperature of from 39° to 40° C. (102.2° to 104° F.) SUMMARY. 89 will cause premature death. If the seeds are kept in a moist atmos- phere a temperature of even 30" C. {SQ'^ F.) will soon cause a marked injury. (17) Seeds can endure any degree of drjdng Avithout injury; that is, by drjnng in a vacuum over sulphuric acid. It is believed that such a reduction in the water content is necessar}" if vitalit}" is to bo pre- served for a long period of years. However, with such treatment the seed coats become very firm, and there usually follows a retardation in germination as a result of the inability of the seeds to absorb water rapidh' enough to bring about the necessary phj-sical and chemical transformations for the earlier stages of germination. (18) Seeds that are to be sent to countries having moist climates should be put up in air-tight packages. Experiments have shown that by the judicious use of bottles and paraffined packages seeds can be preserved practicalh' as well in one climate as in another. (19) It is of the utmost importance that the seeds be drj^ before being sealed in bottles or paraffined packages. A drying of ten daJ^s at a temperature of from 30" to 35" C. (86° to 95" F.) will usually be sufficient. However, a better method to follow is to dry until no more moisture is given off at a temperature equivalent to the maxi- mum of the region in which the seeds are to be distributed. If this is not done, the subsequent increase in temperature will liberate an additional quantity of moisture, which being confined in the package will, leave the seeds in a humid atmosphere and a rapid deterioration in vitality will follow. (20) Experiments in storing seeds in open and sealed bottles and in packages with definite c^uantities of moisture and at various known temperatures have shown a very close relationship between the loss in vitality and the increase in water content, the deterioration likewise increasing with the temperature. (21) Of a series of experiments the average loss in vitality of seeds kept in envelopes in a "dr}^ room" w^as 21.19 per cent, "trade condi- tions" 30.63 per cent, "basement" -12.28 percent, while the loss in the case of seeds stored in bottles was only 8.08, 3.92, and 4.51 per cent, respectively. (See Table XXV.) (22) Seeds under ordinary conditions of storage respire quite freel}^, and respiration is nmch more rapid if much moisture is present. Within certain limits respiration is directly proportional to the amount of moisture present in the seed and inversely proportional to the duration of vitality. (23) Respiration is not necessary to the life of seeds, as they can be kept in conditions unfavorable for respiratory activity and still retain their vitality even better than under normal conditions of storage. Even though respiration l)c entirely prevented seeds will continue to deteriorate, and sooner or later lose their vitality. 90 THE VITALITY AND GERMHSTATION OF REEDS. (24) The continued deterioration in the vitality of a seed after res- piration has ceased indicates a chemical activity within the cells, giving rise to a transformation of energy which sooner or later leads to the death of the seed, (25) Respiration is almost as active in the dark as in the light, pro- vided that the temperature and humidity remain the same. (26) Ferments and seeds lose all power of activity under similar conditions of moisture, and the former are undoubtedh" of the utmost importance in metabolic activity, but the evidence at hand goes to show that the life of a seed is not dependent on the preservation of the particular ferment involved or on the zymogenic substances giving rise to the enzyme. (27) The life of a seed is undoubtedl}" dependent on many factors, but the one important factor governing the longevity of good seed is dry7iess. LITERATURE CITED. Bonnier, G., et Mangin, Louis. La fonetion respiratoire chez les veg6tanx. Ann. sc. nat. hot., s^r. 7, 2: 365-380, 1885. BoENEMANN, 6. Versuche iiber Erhaltung der Keimfiihigkeit bei importirten Samen von Wasserpflanzen wiihrend des Transportes. Gartenflora, 35: 532-534, 1886. Also abstract in Bot. Jahresber., Jahrg. XIV, Abt. I, p. 132, 1886. Brown, Horace T., and Escombe, F. Note on the inflnence of very low tempera- tures on the germinative power of seeds. Proc. Roy. Soc. London, 62: 160-165, 1897-08. ■ • On the depletion (A the endosperm of Ilordeum vulgare during germination. Proc. Roy. Soc. London, 63: 3-25, 1898. • and Morris, M. Germination of some of tlie Clramivav. Jour. Chem. Soc. London, 57: 458-528, 1890. Dammer, U. Verpackung und Versandt von Samen, welche ihre Keimkraft schnell verlieren. Zeitschr. f. trop. Landw., Bd. 1, No. 2, 1897. Abstract in Bot. Centralbl., 70: 196-197, 1897. De Candolle, Aug. Pvr. Physiologie v^getale (Conservation des graines), v. 2, p. 618, Paris, 1832. De Candolle, C. Sur la vie latente des graines. Arch, des sci. phys. et nat., ser. 4, 33: 497-512, 1895. Abstract in Amer. Gard., 18: 339, 1897. La vie latente des graines. Revue scientifique, ser. 4, 4: 321-326, 1895. The latent vitality of seeds. Pop. Sci. Monthly, 51: 106-111, 1897. et PiCTET, R. Recherches concernant Faction des basses temfx^ratures sur la faculty germinative des graines. Arch, des sci. phys. et nat., s6r. 3, 2: 629-632, 1879. Abstract in Just's Botan. Jahreslier., Jahrg. VII, Abt. 1, p. 253, 1879. Action d'un grand froid prolonge sur des graines. Arch, des sci. phys. et nat., ser. 3, 11: 325-327, 1884. Abstract in Just's Bot. Jahresber., Jahrg. XII, Abt. 1, p. 26, 1884. Detmer, W. Vergleichende Physiologie des Keimungsprocesses der Samen, Jena, 1880. Dewar and McKendrick. On li(inid air. Proc. Roy. Inst., 12: 699, 1892. Dixon, 1L H. Vitality of seeds. Nature, 64: 256-257, 1901. LITERATURE CITED. 91 Dixon, H. H. On the germination of seeds after exposure to high temperatures. Notes from the Botanical School of Trinity College, Dublin, pp. 176-186, August, 1902. Edwards et Colin. De I'influence de la temperature sur la germination. Ann. des sci. nat. bot., ser. 2, 1: 257-270,1834. GiGLioLi, Italio. Sulla resistenza di alcuni semi all' azione prolungata di agenti chimici gassosi e liquid. Annuario della R. Scuola Superiore d'Agriccjltura in Portici, V. 2, 1880, Napoli, 1881, 51 p. Abstract in Nature, 25: 328, 1882. Latent vitality in seeds. Nature, 52: 544-545, 1895. Gray, A. Latent vitality of seeds. Ainer. Jour. Sci., 3d ser., 24: 297,.1882. GRtJss, J. BeitriigezurPhysiologiederKeimung. Landw. Jahrbiicher, p. 385, 1896. Haberlandt, F. Ueber die nntere Grenze der Keiinungstemperature der Samen unserer Getreidepflanzen. PHanzenbau I, pp. 109-117, 1875. Abstract in Bot. Jahresber., p. 777, 1875. Hansteen, B. Ueber die Ursachen der Entleerung der Reservestoffe aus Samen. Flora, 79: 419, 1894. IsiDORE-PiERRE, J. Uebcr den Einfiuss der Wiirme und des Beizens mit Kalk und Kupfervitriol auf die Keimfiihigkeit des Weizens. Ann. Agron., 2: 177-181, 1876. Abstract in Bot. Jahresber., 4, Abt. 2, p. 880, 1876. JoDiN, Victor. Recherches sur la germination. Ann. Agron., 23: 433-471, 1897. Sur le resistance des graines aux temperatures eiev^es. Compt. Rend., 129: 893-894, 1899. et Gantier, a. La vie latente des graines. Compt. Rend., 122: 1349-1352, 1896. JisT, L. Ueber die Wirkung hoherer Temperaturen auf die Keimfiihigkeit der Samen von Trifolium pratense. Bot. Zeit., 33 Jahrg., p. 52, 1875. Ueber die Einwirkung hoherer Temperaturen auf die Erhaltung der Keim- fiihigkeit der Samen. Cohn's Beitriige zur Biol, der Pflanzen, 2: 311-348, 1877. KocHS, W. Kann die Kontinuitiit der Lebensvorgiiuge zeitweilig voUig unterljrochen werden? Biol. Centralbl., 10: 673-686, 1890. KoLKwiTz, R. Ueber die Athmung ruhenden Samen. Ber.d. dent. bot. Ges., 19: 285-287, 1901. Krasau, F. Welche Wiirmegrade kann der Weizensame ertragen, ohne die Keim- fiihigkeit zu verlieren? Sitznngsber. d. Wiener Akad. d. Wiss., Abt. I., 48: 195- 208, 1873. Maquenne, L. Sur I'liygrometricite des graines. Compt. Rend., 129: 773-775, 1899. Recherches sur la germination. Ann. agron., 26: 321-332, 1900. Contributions ii 1' etude de la vie ralentie chez les graines. Compt. Rend., 134: 1243-1246, 1902. PicTET, R. De I'emploi methodique des basses temperatures en biologie. Arch, sci phys. et nat., Geneve, 30: 293-314, 18,-?3. PiETERS, A. J., and Brown, E. Kentucky Bluegrass seed — harvesting, curing, and cleaning. Bui. 19, Bureau of Plant Industry, U. S. Dept. of Agriculture, 1902. Romanes, C. J. Experiments in germination. Proc. Roy. Soc, 54: 335-337, 1893. Sachs, Julius. Beschiidigung und Todtung durch zu hohe Temperatur. Handbuch d. exp. Phys. d. Pflanzen, Leipzig, 1865, p. 63. Samek, J. Duration of the vitality of some agricultural seeds. Tirol, landw. Bliitter, 13: 161-162, 1894. Abstract in Exp. Sta. Rec, 6: 429, 1894-95. ScHMiD, B. Ueber die Einwirkung von Chluroformdiimpfen auf ruhende Samen, Ber. d. dent. bot. Ges., 19: 71-76, 1901. Selby, a. D. Germination of the seeds of some common cultivated plants after pro- longed immersion in liquid air. Bui. Torr. Bot. Club, 28: 675-679, 1901. Sharpe, Ji. H. Influence of chemical solutions upon the germination of seeds. Thirteenth Annual Report, INIass. Hatch Agr. Exp. Sta., jip. 74-83, 1901. 92 THE VITALITY AND GERMINATION OF SEEDS. Thiselton-Dyer, Wm. T. Influence of the temperature of liquid hydrogen on the germinative power of seeds. Proc. Roy. Soc, 65: 361-368, 1899. Thompson, A. Zum Verhalten alter Samen gegen Fermentlusungen. (iartenflora, Jahrg. 45, p. 344, 1896. TowNSEND, C. O. The effect of ether upon the germination of seeds and spores. Bot. Gaz., 27: 458-466, 1899. Tkeviranus, Ludolph C. Physiologie der Gewiichse. Vol.11, p. 578, section- 637, 1838. [Vitality of seeds as affected l)y age, heat, and moisture.] Uloth, W. Ueber die Keimung von Pflanzensamen in Eis. Flora, n. s.,Jahrg. .33, pp. 266-268, 1875. Van Tieghem et Bonnier, G. Recherches sur la vie latente des graines. Bui. Soc. Bot. France, 29: 25-29, 149-153, 1882. Wartmann, E. L'influence de froids excessifs sur les graines. Arch, des sci. phys. etnat., Geneve, 8: 277-279, 1860. Recherches sur la v^g^tation (section 3 — Role de froids excessifs). Arch, des sci. phys. etnat., Geneve, ser. 3, 5: 340-344, 1881. Waugh, Frank A. The enzymic ferments in plant physiology. Science, n. s., 6: 950-952, 1897. Also Tenth Annual Report Vermont Agr. Exp. Sta., 1896-97. INDEX. Page. Agriculture, Department, Seed Laboratory, relation to present work 10 Alabama, Auburn, seed-storing experiment 49 Allium cepa, selection for experiment 10 Amyliferous cells, relation to germination of seeds, note 82 Angaria citrulltis, selection for experiment 10 Ann Arbor, Mich. , seed-storing experiment 50 testing experiment 14-22 Apiacex, Daucus carota, selection for experiment 10 Apparatus for tests of effect of moisture on vitality of seed 30, 31 seed testing, description and use 11-12 Asferacea', Lactuca sativa, selection for experiment 10 Auburn, Ala. , place for seed-testing experiments 14-22 Baton Rouge, La., comparison with Ann Arbor and Mobile for seed storing .. 21-22 seed-storing experiment 49 testing experiments 14-22 Bean seed, ice-house storage, effect 28 selection for experiment 10 Beans, germination tests, results fur various storage conditions 51, 63-65 seed, respiration experiment, results 76 " Valentine," tests _ 83 Bluegrass, Kentucky, Foa ijralends, heating in curing, effect on seed 43 Bonnier and Mangin, plant respiration, conclusion 74 Van Tieghem, tests of respiration of seeds, results 75 Brassicacex, Brassica oleracea and Raphanus sativus, selection for experiment. . 10 Brown and Escombe, seed germination experiment 80 views as to chemical action at liquid-air temperature 79 Brown and Morris, and Escombe, experiments as to enzymes in germination. 82 Cabbage, germination tests, results for various storage conditions 53, 63-65 seed, comparison of storaee in three climates 21-22 ice-house storage, effect 28 moisture and temperature tests of vitality 36 respiration experiment, results 76 vitality in different packages in varying storage 71-74 selection for experiment 10 Carbon dioxid, result of respiration of beans, etc 76, 77, 78 Carrot seed, germination tests, results for various storage conditions ... ... 55, 63-65 respiration experiments, results 77 selection for experiment 10 Cauliflower seeds, keejiing in moist climate, note 13 Charcoal, moss, etc. , shipping seed in packing 47 Chemical activity, relation to latent life 80 Clement, suggestion for storage of seed 45 Climates, different, causes of loss of vitality in .seeds, discussion 22-24 Climatic conditions, effect on vitality of seeds, discussion 13-22 Corn, sweet, germination tests, results for various storage conditions. . . 56-57, 63-65 selection for experiment 10 Coville, Frederick V. , preface on purpose and scope of present study 5 Cucvrbitacex, Anguria citrullus, selection for experiment 10 Curing and (trying of seeds, necessity for thoroughness 45 of seed, importance 87 De Candolle, Aug. Pyr., remarks on conservation of seeds 44 suggestion regarding vitality of seeds 75 C. , views on respiration of seeds 78 Diastase, use in experiments on vitality of seeds 85 Dry atmosphere in open bottles, effect on vitality of seeds 34 sealed bottles, effect on vitality of seed 34 heat, effect on vitality of seed, note -- 31 Drying and curing of seeds, necessity of thoroughness 45 93 94 INDEX. Page. Dryness, most iiiiiiortant factor in prolonged vitality of seud 90 relation to preservation of vitality of seed 87, 88, 89, 90 Endosperm of grasses, relation to germination, notes 82 Enzymes in seeds, part in preserving vitality 82-87 Escombe and Brown, experiments as to enzymes in germination 82 seed -germination experiment 80 views as to chemical action at liquid-air temperature ... 79 Fabacew, Pisit7n satinmi and Phaseolus vulgaris, selection for experiment 10 Fazy-Pasteur, suggestion for storage of seed 45 Ferments, relation to vitality of seeds 90 unorganized, relation to vitality of seeds 82-87 Ferry Botanical Fellowship, seed study, relation to present work 10 Ferry, D. M. , & Co. , seed for exi:»eriments 10, 15 Florida, Lake City, seed-storing experiment 49 testing experiment 14-22 Gardener, market, value of good seed 46-47 Gardeners, complaints of seeds, note 13 "Geneva tester" for germination of seeds, moditications and use 11-12 Germination and vitality of seeds, conclusion from present study 87-90 of seeds at low temj^eratures 26-27 in ice house, effect of package 27, 28 various seeds, percentage under differing storage 63-65 part of enzymes 82 tests and apparatus, discussion 11-13 results '. 50-65 Germinator, seed testing, metliod of use 12 Giglioli, conclusion as to chemical activity in latent life 80 experiments with seed of Medicago sativa 79 remarks on vitality of seeds 45 Grasses, endosperm, relation to germination 82 Gray, contention as to suffocation of seeds 79 Griiss, citation as to grass endosperm 82 Gulf of Mexico, effect of moisture on seeds 13 Hansteen, citation as to grass endosperm 82 Harvesting, relation to vitality of seeds 87 Heating, excessive, danger in curing seed 87 Hygroscope, crude, imj^rovisation from awns in seed testing 31 Hydrolysis, presence in experiments on enzymes in seeds, notes 83, 84, 85, 86 Ice, packing of seeds, effect on vitality, remarks 26-29 Incubator, seed, test for effect of moisture on vitality 29 Indian Territory, Wagoner, place for seed-testing experiments 14-22 seed-storing experiment 50 Jodin, seed-germination experiment, note 80 statement as to respiration of seeds 75 Keeping seeds, discussion {see also Storage) 65-74 Kochs, seed-resjiiration experiment 79 Lacluca sativa, selection for experiment 10 Latent life, relation of chemical activity 80 Lettuce, comparison of storage in three climates 21-22 germination tests, results for various storage conditions 58, 63-65 seed, ice-house storage, effect 28 loss of vitality in tropical climate, note 25 moisture and temperature test of vitality 36 respiration experiment, results 77 selection for experiment 10 Liliacere, Allium cepa, selection for experiment 10 Longevity of seed, dryness most imjiortant factor 90 Lycoj)ersicon lycopersicum, selection for experiment 10 Maquenne, statement as to seeds in low temperatures, note 81 suggestion as to respiration of seeds 74 suggestions as to vitality of seeds 83 INDEX. 95 Page. Market gardener, value of good seed, remarks 46-47 Maturity, relation to vitality of seeds 87 Mangin and Bonnier, plant respiration, conclusion 74 Medicago saliva, seed, experiments of Giglioli 79 Giglioli and Samek 80 Michigan, Ann Arbor, seed-storing experiments 50 University, seed study, relation to present work 10 Mobile, Ala., comparison with Baton Rouge and Ann Arbor for storing seed.. 21-22 place for seed-testing experiments l^t-22 seed-storing experiment 49 Moist atmosphere in sealed bottles, severe injury to seeds 33 Moisture and temperature, effect upon vitality of seeds, discussion 24-36 summary of results . . 35 relation to vitality of seed, tables and comment. . . 38-44 effect on vitality of seeds at high temperatures, remarks 29 in iixed temperatures, discussion 36-44 hindrance in keeping seeds, provision 13 relation to endurance of heat by seed 25 longevity of seey methods of storing and ship[)ing 44-65 relation of moisture and temperature, tal)les and conunent 38-44 storage in different kinds of packages, results 68 Warehotise, seed, storage, character, remarks 46 AVater content of seeds, increase, effect on vitality 44 Watermelon, gemination tests, results for various storage conditions 62, 63-65 seed, ice-house stoi-age, effect 28 selection for experiment 10 Waugh, citation as to enzymes 83 Zea mays, selection for experiment, note 10 o LIBRARY OF CONGRESS SS I iiiiiii i iininiHi A 000 933 705 2 ^