3'.52- ^ HAWAII AGRICULTURAL EXPERIMENT STATION HONOLULU, HAWAH Under the supervision of the UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 52 MANGANESE CHLOROSIS OF PINEAPPLES: ITS CAUSE AND CONTROL BY MAXWELL O. JOHNSON, Chemist Issued July, 1924 I \*A "v^rm* WASHINGTON GOVERNMENT PRINTING OFFICE 1924 HAWAII AGRICULTURAL EXPERIMENT STATION, HONOLULU. [Under the supervision of the Office of Experiment Stations, United States Department of Agriculture. 1 E. W. Allen, Chief, Office of Experiment Stations. Walter H. Evans, Chief, Division of Insular Stations, Office of Experiment Stations. STATION STAFF. J. M. Westgate, Agronomist in Charge. W. T. Pope, Horticulturist. H. L. Chung, Specialist in Tropical Agronomy. J. C. Ripperton, Chemist. M. O. Johnson, 1 Chemist. R. A. Gofp, In Charge of Glenwood Substation and Extension Agent for Island of Hawaii. Nellie A. Russell, 2 Collaborator in Home Economics. Mabel Greene, Boys* and Girls' Club Leader. Resigned, effective Mar. 20, 1919. * Resigned, effective June 30, 1923. Bui. 52, Hawaii Agr. Expt. Station. PLATE I. Wkl*(i\> ik Main Field Experiment Showing Benefits Produced with Iron Sulphate Solution, plants on left not Sprayed, Those on Right Sprayed. HAWAII AGRICULTURAL EXPERIMENT STATION HONOLULU, HAWAII Under the supervision of the UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 52 Washington, D. C. V July, 1924 MANGANESE CHLOROSIS OF PINEAPPLES: ITS CAUSE AND CONTROL. Bv M. O. Johnson, 1 Chemist. CONTENTS. Page. Page. Yellowing of pineapples on manganese soils I Previous investigations en manganese. .. 2 Investigations on lime-induced chlorosis.. 5 Status of manganese problem when the present investigations were undertaken 6 The manganiferous soils and their effect on pineapple and other plants 7 An explanation of the physiological effects of manganese on plants.. 24 A successful treatment 27 Practical tests of the method of spraying 30 Practical advice regarding the treatment 34 Genera] summary and conclusions 35 Literature cited ■ 36 YELLOWING OF PINEAPPLES ON MANGANESE SOILS. The yellowing of pineapples grown on the manganese soils of the Hawaiian Islands was a serious problem to pineapple growers for many years. Large areas of these black or dark manganese soils are found in the chief pineapple-growing district lying on the sloping plateau between the Koolau and Waianae Mountain ranges on the island of Oahu. Such soils also occur in the very large potential pineapple areas on the islands of Molokai and Lanai, and to some extent on the islands of Kauai and Maui. None of these areas could be profitably utilized until a solution of the manganese problem was found. When pineapple plantings were first being extensively made in 1902, prospective growers eagerly sought the dark soils, being influ- enced by the color which was thought to be indicative of great fer- tility. It was soon discovered that the pineapples on these soils suffered serious injury, a trouble which locally became known as i4 pineapple yellows/' or "manganese yellows." The most pronounced characteristic by which these pineapple plants were differentiated from normal plants was a gradual fading of the leaves until the whole plant assumed a yellowish-white appear- ance. Blanching of the leaves occurred at any period of growth, but usually started in three to six months after the time of planting. i The writer wishes to thank J. M. Westgate, agronomist in charge of the Hawaii Agricultural Experiment Station, for heartiest support and encouragement in this investigation, and J. T. Whitmore, S. T. Hoyt, and H. Blomfield Brown, of the Hawaiian Pineapple Co., for their generous cooperation and help. 2 BULLETIN 52, HAWAII EXPERIMENT STATION. In many cases the plant ceased growth and began to die back from the tips of the leaves. During the earlier stages of development the fruit was reddish-pink in color instead of deep green, and in the ripened stage the flesh was not only hard and white instead of straw- colored, but it also lacked flavor and contained considerable acid. Many of the fruits cracked open and decayed before ripening. Preliminary reports (24, 25, 26) 2 of the writer's investigations on the manganese problem were published in order to make available as quickly as possible information concerning the simple remedy dis- covered for the " manganese yellows." This remedy, consisting of in- expensive sprayings with solutions of iron sulphate, met with immediate success and is now being used on thousands of acres of Hawaiian pineapples. Considerably over half of Hawaii's production of canned pineapples is borne by sprayed plants. This bulletin gives a rather detailed account of the results obtained and also of the manner in which manganese induces chlorosis. REVIEW OF PREVIOUS INVESTIGATIONS ON MANGANESE. Manganese is found in small quantities in most soils and in many plants. Certain forest trees, notably the conifers, contain rather large amounts of manganese. Schroeder (40, 41) reported in 1878 the occurrence of 35.53 per cent Mn 3 4 in the ash of pine needles and of 41.23 per cent in the ash of pine bark. Many experiments have been made with manganese in different forms as a fertilizer. Kelley (32) and Skinner and Sullivan (43) give extensive reviews of these experiments. It is not necessary to refer to these in detail, as they were carried on in connection with crop production, and the results obtained do not show that manganese is valuable as a fertilizer. Some investigators have found a stimulation of growth from the application of small quantities of various manganese com- pounds, while others have found no effects and even a retardation of growth. It appears generally that the application of large amounts of manganese produces a toxic effect. The chemical similarity of manganese and iron has suggested a number of interesting experiments dealing with the physiological effects of manganese. Unsuccessful attempts were made by Sachs (38) , Birner and Lucanus (7) , and Wagner (45) to substitute manga- nese for iron in the production of chlorophyll, and an injurious effect was noted when manganous and manganic phosphates were sus- pended in culture solutions. Since the discovery by Bertrand (5, 6) that manganese occurs in the ash of oxidizing enzyms, the physiological effects of manganese on plants have been generally attributed to some influence of the manganese on these enzyms. Loew and Sawa (33) in 1902 observed a yellowing of pea plants, barley, and soy beans in water-culture experiments with solutions to which small amounts of manganese sulphate had been added. The addition of manganese sulphate to the usual iron-containing nutrient solution caused an increased growth in which yellowing later took place. This yellowing is thought to have been due to the increased activity of the oxidizing enzyms. They conclude that " manganese exerts in moderate quantity an injurious action on plants, consisting 2 Reference is made by number (italic) to "Literature cited," p. 36. MANGANESE CHLOROSIS OF PINEAPPLE. 3 in the bleaching out of the chlorophyll. The juices of such plants show more intense reactions for oxidase and peroxidase than the healthy control plants." Aso (1) in similar water cultures with young radish, barley, and wheat plants observed a yellowing with solutions containing (a) 0.02 percent MnS0 4 + trace of FeS0 4 , (b) 0.02 per cent MnSO 4 + 0.02 per cent FeS0 4 in comparison with (c) 0.02 per cent FeS0 4 and in these three solutions diluted with 10 times their volume of water. The ordinary mineral constituents were supplied. When the solu- tion containing manganese sulphate and only a trace of ferrous sul- phate was diluted 10 times the yellowing suggested a lack of iron. JPea shoots grown during the first stage of development in solutions containing no mineral salts and only 0.002 per cent ferrous sulphate and manganous sulphate singly and in combination found the great- est stimulation with the manganous sulphate. No yellowing was observed during this first stage of development. Aso concludes that: (1) Manganese salts exert on the one hand an injurious action and on the other a stimulant influence on plants; with increased dilution the former dimin- ishes while the latter increases. Thus a dilution can be reached in which only the favorable action of manganese becomes obvious. (2) Manganous sulphate added in a dilution of 0.002 per cent to culture solu- tions exerted a stimulant action upon radish, barley, wheat, and pea. Iron seems to counteract to a certain degree the action of the manganese. (3) The intensity of the color reactions of the oxidizing enzyms of the man- ganese plants exceeds that of the control plants. That the injurious effects of manganese may be due to a depressed assimilation of iron does not appear to be suspected in the later work of Aso (2, 3) and other investigators. Katayama (27) found an increase in yield of barley when small amounts of manganous sulphate were used. Large amounts of man- ganese retarded growth. In 1907 Salomone (39) published the results of an extensive inves- tigation with various salts and oxids of manganese. A slight yellow- ing was observed in wheat in field experiments when small quantities of the oxids were used, but the final yield was increased. Serious injury was observed when manganese as manganous sulphate was applied at a rate greater than 50 kilograms per hectare, and the plants died when still larger quantities were used. The toxic effects, due to manganese, seem to be similar to those which the pineapple plant suffers on manganiferous soil, i. e., a yellowing, disorganization of the chlorophyll bodies, and other physiological derangements. The crop was injured also when these plats were planted to wheat for the second time. It is significant that lime and basic slag appli- cations did not diminish this toxic effect as was also the case in the liming experiments on the manganiferous soils of Oahu. Salomone also found that fcpavy applications of various manganese compounds caused the death of bean plants which were grown in boxes and that the toxicity of manganese was greater where manga- nese functioned as an electronegative element. Hall (21) thinks that in field experiments the stimulating action of manganese is due to some indirect effect on the dormant bases of the soil rather than to a direct effect of the manganese. He does not, however, consider this point established. 4 BULLETIN 52, HAWAII EXPERIMENT STATION. Bernardini (4) in 1910 concluded from a series of experiments that manganese has a catalytic effect on soils, increasing their oxygen- absorbing power and possibly influencing the soil bacteria. Juclging from the results of various experiments in which solutions of manga- nous chloric! effected replacement of large amounts of lime and mag- nesia in certain silicates, he thinks that the stimulating effect of applied manganese may be due to some indirect effect of replacement rather than to any physiological action. Brenchley (8) in water cultures of barley found a stimulating effect with very small amounts of manganous sulphate, but noted that the plants turned brown and died with large quantities. Kelley (28, 29, 30, 31 ) was the first to publish results showing that there is a close correlation between the yellowing of pineapples in Hawaii and an abnormal amount of manganese in the soil. Wilcox and Kelley (Jfi) found, in their study of the effects of man- ganese on pineapple plants and the ripening of the fruits, that sec- tions showed under the microscope a fading of the chlorophyll and a destruction of the organized structure of the chloroplasts. In 1912 Kelley (32) published the results of an extensive investiga- tion of the effects of these manganiferous soils of Oahu on the pine- apple and other plants. Notes were made comparing the appear- ance and growth of field plants in manganiferous soil with plants in normal soil, and likewise of plants in pots of manganese soil with those in pots of normal soil. From this investigation Kelley concluded that — Various plants when grown on manganiferous soil are affected differently. Some species are stunted in growth -and die back from the tips of the leaves, which turn yellow or brown and frequently fall off, and a general unhealthy appearance results. Other species appear to be unaffected and so far as can be judged vegetate normally in the presence of manganese. Microscopic investi- gations have shown that in certain instances the protoplasm undergoes changes. Occasionally it draws away from the cell walls, the nuclei become brown, and plasmolysis takes place. * * * From the ash analysis it was found that manganese was absorbed in consider- able quantities, and in nearly every instance was greater in the plants from manganiferous soil. The ash analysis also shows that a disturbance of the mineral balance takes place. The percentage of lime is increased, while the absorption of magnesia and phosphoric acid is decreased. * * * From these evidences we may believe that the effects of manganese are largely indirect and are to be explained on the basis of its bringing about a modification in the osmotic absorption of lime and magnesia, and that the toxic effects are chiefly brought about through this modification, rather than as a direct effect of the manganese itself. In 1914 Skinner and Sullivan et al. (43) published results of pot and field experiments in which compounds of manganese were applied as fertilizers. Changes were observed in the oxidative power of the soils as a result of the manganese. Manganese in small quantities had a stimulating effect in pot experiments with an unpro- ductive soil, but resulted in no increase in growth with a productive soil. A five-year field test with an acid soil to which manganous sulphate was added at the rate of 50 pounds per acre showed a harmful effect on each of the crops grown. In regard to the toxic effects of large amounts of manganese, Skinner and Sullivan made the following statement : Where manganese has been of little value or has given decreased yields, con- ditions were such that stimulating actions on plant and microorganisms did not come into play, or, on account of the acid reaction of the soil, the effect of the MANGANESE CHLOROSIS OF PINEAPPLE. O stimulation led to reduction processes being predominant. Large applications of manganese have been found injurious, undoubtedly because of excessive stimulation and excessive oxidation in microorganisms and in the plant, with a resulting change in the biochemical activities of plant and microorganisms and in the conditions of inorganic and organic soil constituents, the ultimate result of which change is injurious to the growing crop. Later in 1916, Skinner and Reid (J$) found that the productivity of the soil was increased by manganese when the plats on which the experiments were conducted were limed. They state that — The action of manganese in the acid soil was probably to stimulate the life processes in the soil, acting on the organic matter in such a way as to produce changes which resulted in a lessened crop-producing power, while its action in the neutralized soil was such as to stimulate oxidation and other biological processes, acting on the organic soil constituents and producing changes favor- able to the growing plants. Pugliese {37) from water-culture experiments similar to those of Loew and Sawa suspected an antagonism between iron and man- ganese anil stated that there was an optimum ratio which he gave as 1 : 2..J. McCool {36) found that- Pure solutions of manganese salts are extremely poisonous to pea and wheat seedlings. The degree of toxicity is greatly reduced by full nutrient solutions and by soil cultures. The injurious action of the manganese ion is manifested mainly toward the tops of plants. Chlorosis of the leaves is the first indication of an overdose of manganese. Manganese is less injurious to plants grown in the dark than to those grown in the light. Calcium, potassium, sodium, and magnesium ions are each effective in counteracting the poisonous action of manganese. Mutual antagonism exists between the manganese ion and each of the following: Potassium, sodium, and magnesium. Tottingham and Beck (4-0 suspected an antagonism toward iron similar to those stated above for potassium, sodium, and magnesium. Brown and Minges (9) in 1916 believed that the effects of manga- nese applications to the soil may be ascribed to their effect on ammo- nification and nitrification. Funchess (IS) found that the nitrification of dried blood on certain Alabama soils produced soluble manganese salts which were toxic in effect. Deatrick {12) found in high concentrations that manganese salts exerted a toxic effect, and in lower concentrations marked stimulation. "The toxic influence results in the browning of the roots and the bleaching of the leaves." PREVIOUS INVESTIGATIONS ON LIME-INDUCED CHLOROSIS. It has been known for many years that some plants become affected with chlorosis or bleaching when they are grown on soils containing very large amounts of carbonate of lime. Some species of grape- vines which grow on certain highly calcareous soils of France are probably the best-known examples of chlorosis. This bleaching has been attributed by some investigators to lack of potash in the soil or to the physical condition of the soil, but the general conclusion seems to be that the condition is brought about by lack of iron in the plants, due to excessive amounts of carbonate of lime in the soil. Manganese has not been associated with this condition. Gile and Ageton {16) have probably made the latest and most thorough investigation of such highly calcareous soils. In 1911 Gile 6 BULLETIN 52, HAWAII EXPERIMENT STATION. (IS) found chlorosis to occur on certain areas of Porto Rican soils and attributed it to an excessive amount of carbonate of lime in the soil. In this connection Gile notes that — Chlorosis (sometimes called icterus, bleaching, or Gelbsucht) is the term applied to that condition assumed by the leaves of plants when they fail to develop the normal amount of chlorophyll, or green coloring matter, i. e., when they are yellowish or white instead of a normal green. Chlorosis, then, does not denote a specific disease, but merely a general condition. This condition of chlorosis, however, is the result or outward sign of a disease or disturbance in the physiology of the plant. To say that a plant is chlorotic or affected with chlorosis means merely that its leaves are lacking in chlorophyll; but the chloro- sis may have resulted from a bacterial disease, poor drainage, lack of nutriment, or some other cause. Bleaching was found to occur on soils very high in calcium car- bonate while healthy plants were found on a soil containing 1.14 per cent calcium carbonate and a total lime content of 1.92 per cent. Manganese is not associated by Gile with this chlorosis as no man- ganese is reported as present in the soils or in the plants. Bleach- ing in this case appeared to be somewhat different from the yellowing of pineapples which occurs on manganiferous soils. Although a few cases of yellowing are noted, the typical appearance described is that of "waxy white" or " ivory white." No mention is made of the very characteristic red fruit which appears on manganiferous soils. The application of stable manure was found to be ineffective on these calcareous soils. In this, as in previous cases of chlorosis which were induced by lack of iron in plants growing on highly calcareous soils, Gile founcl that the plants were benefited when the leaves were brushed with iron salts in solution, but that the treatment was impracticable for Porto Rican conditions. Gile (Id, p. 34) states that — It is very doubtful if treatment with iron salts would render pineapple growing on calcareous soils commercially successful, as the repeated treatments with iron would be expensive and the crop would not be equal to that secured from soils naturally adapted to pineapples. STATUS OF THE MANGANESE PROBLEM WHEN THE PRESENT INVESTIGATIONS WERE UNDERTAKEN. From a review of the literature on manganese, it appears that the results and conclusions concerning the effect of this element on plants are very contradictory. Manganese is commonly thought to exert a stimulating action, but there seems to be no positive proof that such stimulation is due primarily to manganese. The experiments in soil culture are so contradictory that the stimulative effects found may be considered due to the effect of the anion, usually the sul- phate, which is known to cause decided stimulation, particularly on alkaline soils. The possibility of manganese being a necessary ele- ment is sometimes discussed because of its occurrence in the ash of plants. Aluminum also is found in the ash of plants, but aluminum is not considered a necessary component; in fact, under some condi- tions there is ground for suspicion that aluminum salts are toxic. Results obtained from most of the experiments in nutrient solutions, intended to illustrate the stimulating effect of manganese, are of very doubtful value since increase in height of a plant during a short period of growth is usually the only measurement used to determine stimulation. The conclusion seems to be fairly general among most MANGANESE CHLOROSIS OF PINEAPPLE. 7 investigators, however, that manganese in higher concentrations causes a bleaching or yellowing of the leaves and a depression in growth. In connection directly with the manganese problem in Hawaii, Kelley (28, 29, 30, 31, 32), as already mentioned, had made a very thorough investigation of the manganese problem. He had estab- lished the correlation between yellowing of pineapples and an abnor- mal amount of manganese in the soil. The very valuable data obtained by him in his extensive series of soil and plant analyses should be consulted in conjunction with this publication as his investigations are complementary to the writer's. The toxic effects of manganese were attributed by Kelley to modification in the osmotic absorption of lime and magnesia. At the time the writer attacked the manganese problem, the injurious effects of manganese on plants were attributed by practi- cally all scientific investigators to an indefinite " toxic effect" and to 11 manganese poisoning." A large amount of literature on lime- induced chlorosis has been available for many years, and it has been known that plants on highly calcareous soils become ehlorotic, and that spraying with solutions of iron sulphate overcame this chlorosis. No proof, however, had been presented to show that the indefinite "toxic effects" of manganese are in any way similar to lime-induced chlorosis, nor that manganese causes a deficiency of iron in the plant nor that spraying with solution of iron sulphate will cure " manganese poisoning." In Hawaii, pineapple plants were dying on hundreds of acres of manganese soil. No remedy having been found for this condition, except, possibly, heavy applications of stable manure, which was expensive, only temporarily beneficial, and limited in supply, many thousands of acres have been abandoned or left uncultivated. So little understood was the real nature of the manganese problem that experiments were being carried on with coral sand on the manganese soils. Had the "toxic effect" of manganese been known to be due to a depressed assimilation of iron by the plant, calcium carbonate, in the form of coral sand, would not have been added to depress the assimilation of iron still further. THE MANGANIFEROUS SOILS AND THEIR EFFECT ON PINEAPPLE AND OTHER PLANTS. COMPOSITION OF THE MANGANIFEROUS SOILS. The chief difference in chemical composition noticed by Kelley between the black soils where ''pineapple yellows" occurred, and the normal soils where the plants were healthy, was in the high content of manganese of the former. Kelley (32) gives the composi- tion of these soils in the accompanying analyses. BULLETIN 52, HAWAII EXPERIMENT STATION. Table 1. — Composition of manganiferous and normal soils of Oahu. Constituents. Insoluble matter Potash (KaO) .: Soda(Na 2 0) Lime (CaO) Magnesia (MgO) Manganese oxid (Mn(304)-. Ferric oxid (Fe203) Alumina (AI2O3) Phosphorus pentoxid (P2O5) Sulphur trioxid (SO3) Titanic dioxid (Ti02) Loss on ignition Total Nitrogen (N) Manganiferous soils. Soil. No. P.ct. 33. 46 .83 .40 1.39 .55 9.74 19.65 15.50 .21 .16 .73 17.73 100. 35 .39 Sub- soil. No. 10. P. ct. 36.06 .74 .42 .86 .43 8.76 21.51 15.74 .16 .09 1.09 14.45 100.31 .23 Soil. No. 11. P.ct. 39.02 .78 .36 .64 .41 4.80 18.24 15.40 .36 .23 .40 19.71 Sub- soil. No. 12. P.ct. 42.60 .81 .44 .60 .39 3.50 20. 52 16.89 .13 .05 .58 13. 72 100.35 1 100. 23 . 45 ! . 19 Soil. No. 15. P. ct. 33.73 .99 .21 .49 .52 4.01 26.03 15. 82 .35 .17 .85 16.68 ). 85 .35 Sub- soil. No. 16. P. ct. 34.53 1.07 .38 .37 .41 2.43 26.85 18.98 .21 .05 1.58 12.83 Soil. No. 27. P.ct. 42.08 .65 .32 .19 .35 4.14 22. 05 16.01 .13 .37 0) 14.02 99.69 : 100. 31 .20 .27 ton Soil - No" No. 28. 5L P.ct. 42.78 .64 .37 .21 .28 3.59 21.36 19.51 .11 .30 (■) 11.31 P.ct. 38.78 .83 .34 .24 .64 4.32- 20.40 19. 35 .11 .29 0) 15. 29 100.46 100.59 :24 Sub- soil. No. 52. P.ct. 39.74 .76 .47 .26 .49 4.24 25. 38 16.14 .14 .28 0) 12.45 100.35 .13 Constituents. Insoluble matter Potash (K2O) . Soda (Na 2 0) Lime (CaO) Magnesia (MgO) Manganese oxid (MmO-i).-- Ferric oxid (Fe203) Alumina (AI2O3) Phosphorus pentoxid (P2O5) Sulphur trioxid (SO3)- Titanic dioxid (Ti0 2 ) Loss on ignition Total.. Nitrogen (N) Normal soils. Soil. No. 7. Sub- soil. No. P.ct. 40.89 .51 .21 .51 .37 .22 35.72 3.58 .07 .09 3.83 14.22 100. 22 P.ct. 39.25 33.28 .07 2.74 13.99 100. 09 .25 Soil. No. 13. Sub- soil. No. 14. P. ct. \ 46. 52 .50 .31 .32 .40 .33 24.37 9.15 .09 .11 2.20 15.98 P. ct. 46. 37 .57 .13 .31 .42 .35 24.49 12.02 .13 .12 2.05 13. 17 100. 28 i 100. 13 . 38 I .25 ! Soil. No. 31. Sub- soil. No. 32. P. ct. 41.73 .53 .20 .22 .36 .22 23.29 16.02 .08 .46 0) 17.22 100.33 .29 P.ct. 37.16 .57 .37 .15 .30 .39 24.13 20.87 .12 .33 0) 16.38 100.77 .20 Soil. No. 49. P.ct. 42.36 .65 .46 .23 .47 1.17 20.36 20.37 .10 .23 0) 13.22 99.62 .27 Sub- soil. No. 50. P.ct. 39.82 .48 .20 .12 .44 .36 25. 87 19.42 .10 .42 (>) 13.33 100.56 .14 Soil. No. 19. P. ct. 44.00 .59 .?9 .24 .42 .16 27.94 11.91 .04 .11 .28 13.95 99.93 .29 1 Titanium was not separated from alumina. These analyses show that the manganiferous soils are well supplied with nitrogen, phosphoric acid, and potash, usually considered the three most important plant foods, and that they even surpass the normal soils in their supply of these constituents. Kelley showed that the black soils are superior to the average soils in physical properties, and that nitrification, one of the principal bacteriological factors affecting soil fertility, takes place more rapidly in the man- ganiferous soils than in the nonmanganiferous soils. Comparative solubilities in water and dilute organic acids showed little differences except in the much greater quantities of the manganese which were dissolved from the black soils. Table 2 gives some analyses of soils on which yellowing of pine- apples occurred. MANGANESE CHLOROSIS OF PINEAPPLE. Table 2. — Analyses of manganiferous soils. 1 Constituents. Soil laboratory numbers. 635 636 637 638 639 640 641 Manganese oxid (M113O4) Insoluble matter .. .. , Per cent. 0.31 29.43 .21 .83 .39 .43 15. 50 30.79 .51 .36 19.76 1.74 Per cent. 4.80 39. 99 .21 .87 .39 .61 13.23 22.78 .55 .42 15.63 .62 Per cent. 5.19 38.28 .34 .56 .42 .57 12.26 25. 05 .51 .34 15.71 .72 Per cent. 5.12 39.28 .33 .62 .44 .47 12.27 24.62 .50 .32 15. 50 •H Per cent. 2.51 39.79 .38 .92 .35 .43 10.42 25.70 .56 .48 18.06 .73 Per cent. 5.58 38.08 .40 .65 .43 .40 10.95 25.33 .61 .31 16.89 .53 Per cent. 2.85 39.63 Potash (K2O) .34 Soda (NaaO) Lime (CaO) .60 .36 Magnesia fllgO) . .51 Ferric oxid (Fe203) . 13.44 Alumina (AI2O3) 23.37 Phosphorus pent oxid (P2O5) Sulphur trioxid (SO3)--- - .53 .36 Volatile matter 17.23 Titanic dioxid (TiO) . .83 1 These soils will be referred to later in the text. These analyses are similar to those of Keller in that they show a high content of manganese where the yellowing occurred, with the exception of soil No. 635, which was obtained from Kunia, Oahu. The plants on this soil were yellow and produced characteristic red fruit. This soil, according to the analysis, contained only 0.31 per cent of manganese calculated as the mangano-manganic oxid. That this manganese is actually present as the dioxid will be shown, while the manganese in normal soils is probably in the silicate form. FORM IN WHICH MANGANESE OCCURS IN THE SOIL. Kelley, in his analyses, reported the manganese calculated as the mangano-manganic oxid (Mn 3 4 ), but concluded from his investiga- tions that at least part of the manganese is present as higher oxids, since there is a liberation of chlorin gas with acids and a change in appearance during ignition. To determine the form in which manganese was present in the soil, the writer distilled the samples according to the Bunsen method for available oxygen in pyrolusite. Table 3 compares the manganese dioxid, calculated from these results, with the total manganese pres- ent, calculated to the same form. Table 3. — Comparison of total manganese with manganese dioxid in the manganif- erous soils. Laboratory soil number. Total manganese dioxid by official method. Manganese dioxid according to the Bunsen distillation method. Laboratory soil number. Total Manganese official the Bunsen mShod d^tmation method. ( method 635 Per cent. 0.35 5.48 5.92 5.86 Per cent. 0.35 4.85 5.20 5.15 639 Per cent. Per cent. 2. 86 ', 2. 66 636 640 6 36 K fi7 637 641 3.25 1.92 638 Since the distillation method probably gives low results owing to the presence of organic matter, it is safe to conclude that nearly all the manganese present is in the form of dioxid. This assumption is 86067— 24f 2 10 BULLETIN 52, HAWAII EXPERIMENT STATION. based on the fact that the usual manganese ore is the dioxid (pyro- lusite), and that solutions of manganese in the carbonate form" in which form it is probable that the manganese is leached out of the original lava, 3 soon precipitate manganese dioxid because of their strong hydrolysis and oxidation by the air. IRON IN THE MANGANIFEROUS SOILS. Kelley (32) reported the presence of 18.24 to 26.85 per cent of iron as ferric oxid, while the writer found a variation of 10.42 to 15.5 per cent in the soil samples he analyzed. Hawaiian soils 4 contain an abundance of iron, having several times the quantity found in ordinary soils of the mainland or pineapple soils of other countries. Kelley (28) determined the solubility of the manganese and iron with a 1 per cent solution of citric acid. In this determination he gives the average amount of iron soluble as 0.243 per cent ferric oxid, or about 8,500 pounds per acre-foot. It is a striking peculiarity that, notwithstanding the presence in these manganiferous soils of an immense quantity of total iron and of citric acid soluble iron, the pineapple plants seemed unable to assimilate the iron but showed a pronounced change after they had been sprayed with 30 to 40 pounds of iron sulphate per acre. The failure of the plants to absorb iron, notwithstanding the large amount soluble in citric acid, seems to constitute a serious criticism of the general applicabilit} r of the citric-acid method for determining the available constituents of the soil. REACTION OF THE MANGANIFEROUS SOILS. The manganiferous soils when tested with litmus show an acid reaction. Kelley (28) examined a large number of these black soils and found most of them slightly acid and few neutral. In order to determine more exactly the acidity of these manganese soils, the hydrogen-ion concentrations were determined electrically. The hydrogen-ion concentrations, expressed in pH values, are given in Table 4. Table 4. — Hydrogen-ion concentrations (expressed in pH values) of the mangani- ferous soils. Laboratory soil number. Manganese oxid (M113O4). pH value. ; i Laboratory soil number. Manganese oxid pH value. (Mn 3 4 ). 9 Per cent. 9.74 4.80 4.01 4.14 4.32 t 6.5 6.4 7.0 | 5.7 j 5.9 636 __ Per cent. 4. 80 6. 1 11 638 5. 12 6. 3 15 639 . 2. 51 6. 27 641 2.85 6.0 51 The table indicates that the manganese soils in nearly every instance are fairly acid, since soils having a pH value lower than 7, the neutral point of pure water, are acid. That these soils are lacking in car- bonate of lime is proved by the fact that calcareous soils would have * Lava is the original material from which nearly all the upland soils of the island are derived. 4 Iron is one of the most abundant elements of Hawaiian soils. MANGANESE CHLOROSIS OF PINEAPPLE. 11 an alkaline reaction and a pH value approximately 8.2-8.4 (that of carbonate of lime in water). AMOUNT AND FORM OF LIME IN THE MANGANIFEROUS SOILS. The amount of lime that is contained in manganiferous soils is of interest in connection with the reaction of these soils. Kelley reported manganiferous soils containing as low as 0.19 and 0.24 per cent of lime, and his iigures average about 0.05 per cent of lime. (See Table 1.) Soils analyzed by the writer .averaged about 0.4 per cent of lime. (See Table 2.) An attempt was made to determine the presence of carbonate- in the manganiferous soils by the methods of Maclntire and Willis (34, 35) of treating the soils with 1-15 H 3 P0 4 , and by their later method with 1-15 HC1. Table 5 gives the results. Table 5. — Carbon dioxid content of the manganiferous soils by the method of • Maclntire and Willis. Laboratory soil number. Carbon Carbon , dioxid (1/15 dioxid (1/15 H3PO4). HC1). Laborat ory soil number. Carbon dioxid (1 ,15 EUPO4). Carbon dioxid (1 15 HC1). 635. 636 Per cent. 0.03 .04 .02 .03 Per cent. 0.04 .07 .06 .06 639 640 641 Percent. 0.04 .03 • . 03 Per cent. 0.03 .05 637 638 .06 The quantity of carbon dioxid found in these soils was negligible and indicated the practical absence of carbonates, as soils that are known to be free from carbon dioxid produce considerable amounts of CO, owing to the action of acids on the soil organic matter. The values which were found for the hydrogen-ion concentrations of these soils proved the absence from them of calcium carbonate. The small quantity of lime in the soils is, therefore, probably present in the form of silicate and not as carbonate. Some of it may be present as a mangariite, as James (23) suggests. It will be shown later that the injurious effects of the manganiferous soils are due to deficiencies of iron in the plant and not to toxic effects of calcium manganite, as James further suggests. EFFECTS OF MANGANESE ON RICE. It has already been explained that the toxic effects of manganif- erous soils on pineapple plants are characterized by yellowing of the leaves, cracking open and decaying of immature fruit, which is stunted and red or pink instead of normal size and green, and by a general unhealthy appearance of the plants. The injurious effects of manganese are verv completelv described by Wilcox and Kellev (46) and by Kelley {28, 29, 30. 31, 3.2). 6 Constituents other than lime do not appear of significance since they show little variation from the normal. 12 BULLETIN 52, HAWAII EXPERIMENT STATION. Growth of Rice in Nutrient Solutions. In order to investigate the influence of manganese more fully and without the complication of soil phenomena, various experiments wore conducted in nutrient solutions with the addition of manganese sulphate and manganese dioxid. Rice, which is similar to the pine- apple in its susceptibility to chlorosis, was used in these experiments because it is more convenient of culture in nutrient solutions and furnishes results more quickly than the pineapple plant. Experiment I. — This experiment was divided into two series of nine tests each, using the nutrient solutions shown in Table 6. Table 6. — Nutrient solutions used. Series I.— Loew and Sawa's (-33) nutri- ent solution. Calcium nitrate Magnesium sulphate Potassium nitrate Monopotassium phosphate Ammonium sulphate Ferrous sulphate Quantity. Series II.— Gile and Carrero's (17) acid nutrient solution. Per cent. 0.04 .01 .03 .02 .01 .01 Weight. Grams. Potassium nitrate... 0. 1017 Monobasic potassium phosphate . 0714 Sodium nitrate . 2143 Sodium sulphate .0315 Calcium chlorid . 05 Magnesium chlorid . .05 Ferric chlorid .0041 Sulphuric acid c.c. X/m__ . 5 Distilled water c.c. 1.000 The manganese dioxid used in all the experiments was prepared by Merck and marked "artificial," and "pure," and contained about 90 per cent MnO,. Ten grams of this manganese dioxid in 200 cubic centimeters of pure water gave, on 18 and 42 hours' contact, a pH value of about 6.6, or a faintly acid reaction. Coral sand and calcium carbonate under the same conditions gave a pH value of about 8.4 or a distinctly alkaline reaction. Rice seedlings were germinated in distilled water and transferred to the various nutrient solutions when the plumules were about 2 inches long. Four plants each were grown in large flasks. Dupli- cate tests of each trial were made. Transpired water was replaced with distilled water daily and the solutions were changed every fourth day. The solutions were freshly made 18 hours before chang- ing and the flasks and roots were rinsed with a little of the fresh solution when the changes were made. The plants were grown for 40 days. The plants were harvested on the fortieth day and the green and dry weights of the stalks and leaves and of the roots were determined. The results are given in Tables 7 and 8. MANGANESE CHLOROSIS OF PINEAPPLE. 13 Table 7. — Weight and condition of rice grown in Loew and Sawa's nutrient solution to which manganous sulphate, manganese dioxid, and calcium carbonate were added. ries. Culture solutions with amount Flask of added material per liter. No. Mn from Fe omitted, gm. Fe from gm. Mn Check; sol.+0.037 gm. Fe from FeS04. Sol. +0.037 gm. Fe from FeSOH-0.072 gm. Mn | from MnS0 4 . Sol. +0.072 gm, MnS0 4 Sol.+0.U3 FeSO 4+0.036 from MnS0 4 . Sol. +0.037 gm FeSO 4 +0.018 from MnS04. Sol. +0.037 gm FeSO4+0.004 from MnS04. Sol. +0.037 gm. Fe from FeSO4+0.4 gm. Mn0 2 . Sol. +0.037 gm. Fe from FeSO 4 +0.4 gm. MnO* +0.4 gm. CaC0 3 . Sol. +0.037 gm. Fe from FeSO 4 +0.4gm. CaC0 3 . Fe gm. Fe gm. from Mn from Mn Green Oven- weight A 4g ht of stalks and of stalks and leaves. leaves. Grams. Grams. 2. 86 0. 58 3. 70 . 66 3.04 3.59 2.66 2.67 3.44 4.15 4.63 4.60 4.59 4.58 5.42 6.74 .48 .48 .04 .05 .58 .59 ,61 Oven- dry weight of roots. Grams. 0.17 .21 .14 .15 .03 .04 .18 .19 Average oven- dry weight. Sta] , ks Whole le a avl *■*■ Grams. Grams. 0.62 0.81 .48 .63 .05 .08 .59 .77 .54 .75 .67 .80 .84 1.08 .73 .96 .98 Condition of plant j-Green; healthy. {Green; older leaves spotted with brown. JDead. {Green; older leaves spotted with brown. >Green; healthy. | Do. } Do. } Do. } Do. Table 8. — Weight and condition of rice grown in Gile and Carrero's nutrient solu- tion to which manganous sulphate, manganese dioxid, and calcium carbonate were added. Se- Culture solutions with amount Flask of added material per liter. No Cheek; sol. +0.0014 gm. Fe from FeCh. Sol. +0.0014 gm. Fe from FeCl 3 +0.072 gm. Mn from MnSOi. Sol. +0.072 gm. Mn from MnSO«; Fe omitted. Sol. +0.0014 gm. Fe FeCl 3 +0.036 gm. from MnS0 4 . Sol. +0.0014 gm. Fe FeCh+0.018 gm. from MnS0 4 . Sol. +0.0014 gm. Fe FeCls+0.004 gm. from MnS0 4 . Sol. +0.0014 gm. Fe from FeCh+0.4 gm. MnOi. Sol. +0.0014 gm. Fe from FeCh+0.4 gm. Mn from MnSO 4 +0.4gm. CaCOs. SoL+0.0014 gm. Fe from FeCh+O.l gm. CaC0 3 . from Mn from Mn from Mn *>$*\ weight Grams. 3.01 2.71 .20 .25 .13 .07 .65 1.11 .58 2.16 1.08 Grams. 0.52 Oven- dry weight of roots. Grams. 0.23 .19 .04 .04 .04 .04 .05 .07 .07 .04 .13 .08 .04 .04 .04 .05 .04 .05 Average oven- dry weight. Stalks and leaves. Grams. 0.49 Whole plant. Condition of plant Grams. 0.70 .21 22 |. us |Green; healthy. Leaves shriveled; brown; nearly dead. •Dead. Leaves brown spotted with dark brown. Leaves yellow and brownish. Lower leaves spotted with brown. X e a r 1 y d e a d ; light brownish white color. Bleaehed:yellow ish- white; stunted. Do. 14 BULLETIN 52, HAWAII EXPERIMENT STATION. With Loew and Sawa's nutrient solution, manganous sulphate did not cause chlorosis but a decrease in the dry weights of the plants, except in the smallest amount used. On the other hand, manganese dioxid and calcium carbonate, singly and in combination, caused a tremendous increase in the growth of the plants. Evidently, then, this solution contained an excessive amount of iron, and the increase in growth was due to manganese dioxid and calcium carbonate depressing the assimilation of some of this harmful iron. This nutri- ent solution is the one with which Loew and Sawa obtained results which they claimed proved the supposedly stimulating effect of manganese. The stimulating effect of manganese in this nutrient solution is doubtless due to its depressing effect on the assimilation of the excessive amounts of iron in the solution. With Gile and Carrero's acid nutrient solution, an amount as small as 4 milligrams per liter of manganese from manganous sulphate (0.001 per cent of manganous sulphate) was sufficient to cause brown spotting of the leaves and a decided decrease in rate of growth. Practically no growth was made in the presence of manganese dioxid or calcium carbonate and the plants were strongly chlorotic. The greatly different effects of manganese in these two nutrient solutions seemed to be due either to the form or to the amounts of iron supplied. A second experiment was therefore undertaken in which different forms of iron were used in the same solution. Experiment II. — In order to obtain results comparable with those recorded by Gile and Carrero (18), it was decided to use their neutral nutrient solution in all the later experiments. This solution had the composition shown in Table 9. Table 9. — Gile and Carrero's neutral nutrient solution. Composition. Weight. Composition. Weight. Grams. 10.71 3.57 3.57 21.43 Sodium sulphate Grams. 3.15 Monobasic potassium phosphate C alcium chlorid 2.00 Magnesium chlorid 2.00 Distilled water 100,000 This experiment was similar to Experiment I. Twelve tests were made. On the fortieth day the plants were harvested and the weights determined. The results are given in Table 10. MANGANESE CHLOROSIS OF PINEAPPLE. 15 Table 10. — Comparative weights of rice plants which were grown in nutrient solu- tions containing manganous sulphate and manganese dioxid solutions, to which iron as ferrous sulphate, ferric chlorid, and ferric citrate was added. Se- ries. Culture solutions with amount of added material per liter. Check; sol. +0.008 gm from FeS0 4 . Sol. +0.008 gm. FeSO 4 +0.072 from MnS0 4 . Sol. +0.008 gm. FeSC-4+0.007 from MnS04. Fe gm. Fe gm. Fe from Mn from Mn Flask No. Sol. +0.008 gm. Fe from FeSO 4 +0.4 gm. Mn0 2 . Sol.+0.008 FeCl 3 . gm. Fe from ' 1 Ba B, C C 2 C 3 Sol. +0.008 gm. Fe from FeCls+0.007 gm. MnS0 4 . Fe from MnO,. Fe from Fe Sol. +0.008 gm. FeCh+0.4 gm Sol. +0.008 gm. Fe2(C 6 H 5 07)2. Sol. +0.008 gm. Fe 2 (C6H 5 O-)j+0.072 Mn from MnS0 4 . Sol. +0.008 gm. Fe Fe2(C6H 5 O7) 2 +0.007 Mnfrom MnS0 4 . Sol. +0.008 gm. Fe 2 (C 6 H 5 07) 2 +0.4 gm. Mn0 2 . from gm. from gm. Bj Sol.+O.OOS gm. Fe from j 11 FeCh+0.072 gm. MnS0 4 . \ 12 ™f ht wSt Ieaves - lelvl Grams, 5.77 6.01 .80 .72 3.18 2.38 5.04 4.66 .23 .27 1.91 1.42 .15 .20 3.40 4.94 .11 .08 .25 .29 Grams. 1.04 1.03 .20 .20 .65 .07 23 I .49 24 | .49 .87 .85 .38 .04 .06 .56 .79 .04 .03 .06 .10 .12 Oven- dry weight of roots. Grams. 0.39 .37 .07 .06 .22 ' .19 .04 .05 .31 .25 .04 .04 .15 .14 .04 .04 .20 .31 .04 .04 .04 .04 05 Average oven- dry weight. S and S Whole lelves. P lant - Grams. Grams. 1.04 1.42 .20 .27 .61 . 81 .07 .11 .86 1.14 .08 .12 .42 .57 .05 .09 .68 .93 .04 .08 .06 .10 .11 .17 Condition of plants , Green; healthy. Stunted; light-col- ored, spotted with brown. \Somewhat stunt- 81 / ed; light-colored. "Very stunted; yel- low and bleached; spotted with brown. Green; healthy. Extremely stunt- ed; leaves with- ered; practically dead. IStunted; light-col- / ored. ery stunted ; leaves almost white. [Green; healthy. W i t h e r e d and dead. Very pale greenish- yellow; leaves withered. Leaves yellow , spotted with brown. The form in which iron was supplied did not seem to change the effects of the manganese. As small an amount as 7 milligrams per liter of manganese as manganous sulphate (0.002 per cent of man- ganous sulphate) caused chlorosis and a very striking decrease in weight of plants. Manganese dioxid produced a similar effect. Fer- rous sulphate appeared to be the best source of iron supply, with ferric chlorid next, and ferric citrate last. Experiment III. — It was decided to investigate more thoroughly the effects of varying amounts of iron, because the effects of man- ganese seemed to depend largely on the iron content in the nutrient solution. Tests with nutrient solution which had been used in Ex- periment II were repeated. Two plants were grown in each flask, two flasks were taken as a unit, and the units were triplicated for each variable. Eighteen tests were made. The leaves of the plants in series A 4 , B 41 and C 4 were dipped in a 0.5 per cent solution of ferrous sulphate several hours before the nutrient solutions were changed so as to minimize chances of the dipping solution getting into the nutrient solution. Representative plants of each trial were photographed on the for- tieth day just before harvesting. The weights of the harvested plants are given in Table 11 and graphically in Figure 1. lb BULLETIN 52, HAWAII EXPERIMENT STATION. Table 11. — Comparative weights of rice plants which were grown in manganous sulphate and manganese dioxid solutions to which were added various amounts of iron as ferrous sulphate. Se- ries. Culture solutions with amount of added ma- terial per liter. Flask No. Green weight of stalks and leaves. Oven- dry weight Oven- dry weight of roots. Average oven- dry weight. 1 of stalks and leaves. Stalks and leaves. Whole plant. Condition of plants. A, Sol. +0.005 gm. Fe from FeSo 4 . Sol. +0.005 gm. Fe from FeSO 4 +0.4 gm. Mn0 2 . Sol. +0.005 gm. Fe from FeS O4+O.OI8 gm. Mn from MnS0 4 . Sol. +0.005 gm. Fe from FeSOi+0.4 gm. Mn0 2 ; leaves dipped in 0.5 per cent FeSO\ solution. Sol. +0.010 gm. Fe from FeS0 4 . Sol. +0.010 gm. Fe from FeSO4+0.400gm. Mn0 2 . Sol. +0.010 gm. Fe from FeSO 4 +0.018 gm. Mn from MnS04. Sol. +0.010 gm. Fe from FeSCn— 0.4 gm. MnG 2 ; leaves dipped in 0.5 per cent FeS0 4 solution. Sol. +0.020 gm. Fe from FeS0 4 . f ! " 2 3-4 I 5-6 1 7-8 \ 9-10 I 11-12 ( 13-14 \ 15-16 I 17-18 I 19-20 \ 21-22 Grams. 15.05 15. 48 15. 71 .29 .29 .32 .67 .62 .64 2.15 2. 15 Grams. 2.41 2.53 2.48 .08 .07 .08 .16 .14 .15 .43 .42 .44 2.56 2.56 2.65 .10 .10 .09 1.28 1.33 1.29 .37 Grams. 1.05 1.07 1.00 .06 .06 .06 .06 .06 .06 .17 .22 .18 1.06 Grams. '"2.4 Grams. ""%.l\~ •Fine; green. Leaves white, spot- A 2 1 ted with brown; A3 .08 .14 shriveled and stunted: dead. Light yellowish- green, spotted with brown; A 4 .15 .21 older leaves very chlorotic, shriv- eled,and stunted. Great improve- ment over Aa; light green: spot- ted with dark green where iron penetrated: few brown spots on leave?. j 23-24 2.17 15.21 \ 27-28 15.17 I 29-30 15.47 f 31-32 . 32 .43 .62 Bi 1.07 /Fine: green. 1.01 .06 .07 .05 .39 .41 .40 .13 . 12 2.59 3.64 (Bleached; spotted J with brown; B 2 \ 33-34 ( 35-36 37-38 39-40 41-42 43-44 • 45-46 ) 47-48 1 49-50 { 51-52 I 53-54 f 55-56 .35 .27 5.91 5. 95 6.13 1. 55 B 3 .10 .16 slightly better I than A 2 . 1 Light green spotted / with brown; still 1 stunted. | About same as A4; > decided improve- Bi 1.30 1.70 1. 50 . 37 1.67 .40 13.69 2.26 13. 64 Q . 2i .16 .90 .99 .16 .19 .38 .52 1 ment over B2. Ci >Fine; green. 2.25 2.76 2.51 6.93 6.61 2.48 2.63 2.66 13.56 12.78 13.24 12.44 12.45 12.23 11.70 2.51 .50 .60 .56 .1.43 1.48 1.40 .58 .62 - 2.41 2.17 2.30 2.33 2.30 2.30 1.95 2.03 2.06 1.51 1.48 1.41 1.73 1.69 1. 73 1.38 1.42 1.40 2.33 3.23 Somewhatstunted; light green spot- ted with some brown. Dark green; infe- rior in size to O; C 2 Sol. +0.020 gm. Fe from 1 C 3 Fe.^Oi— 0.4 gm. Mn0 2 . Sol. +0.020 gm. Fe from FeSO 4 +0.018 gm. Mn from MnSO*. • Sol. +0.020 gm. Fe from I 59-60 f 61-62 \ 63-64 I 65-66 ) 67-68 \ 69-70 } 71-72 f 73-74 \ 7.5-76 I 77-78 f 79-80 \ 81-82 [ 83-84 f 85-86 .18 .41 .48 .47 .20 .23 .26 .55 .73 . older leaves c t 1.44 1.89 shriveled, but showed scarcely a trace of brown. About same as B<; dark greei where iron 1 ene- trated. j-i -.-'j;— u.4 gm. mduj; leaves dipped in 0.5 per cent FeSO* solution. '"".hi ""."84" Di Sol. +0.040 gm. Fe from .79 .85 | .70 .71 .64 .58 .85 .86 .84 .59 .62 .62 >Dark green. FeS0 4 . 2.29 3.09 I Do Sol. +0.040 gm. Fe from f Do. F^O 4 +0.4 gm. MnG 2 . D3 Sol. +0.040 gm. Fe from FeSO«+0.018 gm. Mn from MnSO«. 2.31 3.04 \ 87-88 12.06 1 89-90 1 12. 05 91-92 7. *y \ 93-94 I 95-96 7. 2S \ 99-100 9.44 [101-102 9. 77 103-104 •{105-106 7 sa \ Do. 2.01 2.71 Ei Sol. +0.080 gm. Fe from [ Do. FeS0 4 . 1.47 2.08 E- Sol.— 0.080 gm. Fe from \ Do. F. SO4+O.4 gm. Mn0 2 . E Sol.— 0.080 gm. Fe from F^n.-Ufimfc ptti \Tn 1.72 2.57 1 Do. from MnS04. 1107-108 " 1.40 2.01 MAXGANESE CHLOROSIS OF PINEAPPLE. 17 The text to Figure 1 and Table 11 show that chlorosis and severe depression in growth were caused by manganese dioxid, with 5, 10\ or 20 milligrams per liter of iron supplied from ferrous sulphate, and also by 18 milligrams per liter of manganese from manganous sulphate (0.005 per cent manganous sulphate). When the leaves were dipped in iron solution chlorosis was overcome, but full normal growth was & SO 20 40 80 Fig. 1.— (Results of Experiment III.) Effect of manganous sulphate and manganese dioxid on the growth of rice in nutrient solutions with various amounts of iron supplied from ferrous sulphate. not induced. The writer found it very difficult to supply iron to the leaves of the rice plant because they seem adapted for shedding solu- tions. Where the iron penetrated the leaves, very dark green spots appeared. When the amount of iron in the solution was increased excessively, the chlorotic effect of manganese was completely over- come. In fact, apparently, because of its removal of some of the excessive iron, manganese dioxid gave slightly better results than the check. 86067— 2-it 3 18 BULLETIN 52, HAWAII EXPERIMENT STATION. Experiment IV. — Experiment III was repeated, using a different form of iron. The different variables were the same as in Experiment III except that ferric chlorid was the source of iron, and the plants 30 31- 32 <[ 33- 34 [ 35- 36 ( 37- 38 \ 39- 40 : I 41- 42 Grams. 20.50 20.34 19.89 .25 .28 .28 1.15 1.14 1.16 .85 .93 .92 20.52 20.48 19.97 2.37 1.87 I 2.16 | 3.92 | 3.79 4.13 Sol. +0.020 gm. Fe from FeClj. Sol.+0.02C gm. Fe from 0.4 gm. Mn0 2 . Sol. +0.020 gm. Fe from FeCl 3 +0.01S gm. Mn from MnSO<. Sol. +0.020 gm. Fe from FeCh; leaves dipped in 0.5 per cent FeCU solu- tion. Sol. +0.040 gm. Fe from FeCU. Sol. +0.040 gm. Fe from FeCh+0.4 gm. Mn0 2 . Sol. +0.040 gm. Fe from FeCh-i-0. 01s gm. Mn from MnSOi. Sol. +0.080 gm. Fe from FeCl 3 . Sol. +0.080 gm. Fe from FeCh+0.4 gm. MnOj. Sol. +0.080 gm. Fe from FeCh+0.018 gm. Mn from MnS0 4 . f 49- 1 51 " l 53- (55- l 59- f 61- \ 63- l 65- 67- Vh 71- 79- 80 81- 82 83- 84 85- 86 87- 88 89- 90 91- 92 93- 94 95- 96 97- 98 99-100 101-102 103-104 105-106 107-108 15.58 16.83 15.38 I Grams. 3.33 3.39 3.33 .09 .09 .09 .30 .30 .31 3.60 3.46 .50 .43 .48 .92 .91 .95 1.16 1.13 1.11 2.60 2.89 2.61 56 5S 60 10.72 10.70 1.17 1.83 1.87 2.00 62 64 66 6.56 7.16 6.26 1.56 1.53 1.43 9.58 10.15 10.70 3.17 3.58 3.06 4.58 4.96 4.70 2.98 2.85 2.96 .42 .67 .42 1.16 1.18 1.30 .66 .64 .59 1.83 1.91 1.86 .91 .78 1.09 1.18 1.12 .75 .67 .72 .14 .20 .12 .30 .31 .36 .19 .18 .17 Grams. 1.30 1.34 1.30 .06 .06 .08 .08 .08 .11 .11 .10 1.34 1.23 1.16 .16 .14 .18 .20 .17 .21 .45 .46 .44 .78 .94 .78 .61 .65 .67 .38 Grams. Grams. 3.35 09 30 .24 3.57 .47 93 1.13 2.70 1.90 ^4 1.13 .15 38 35 4.81 -,3 IVery fine; green; healthy. '(Bleached white; I withered; very j stunted; practi- l cally dead. {Very stunted; yel- lowish; lower leaves withered and spotted with brown. Decided improve- ment over A 2 ; yellowish-green, showing dark green spots where iron pene- trated. Green; healthy. Stunted; yellow- ish-green spotted with brown. 1.12 3.53 2.54 1. 87 2. 60 1.55 71 .99 15 . 23 32 . 42 .18 29 Light green; lower leaves withered. Decided improve- ment over B 2 ; light-green spot- ted with dark green where iron penetrated. Green; healthy. Leaves rather light green, showing only few brown spots. Few brown spots on lower leaves. •About same as C2. Much smaller than Ai; dark green; roots formed fuz- zy ball but ap- parently were unable to enter the solution. Slightly larger than Di; dark green. Dark green. Very stunted; leaves withered; only a few strug- gling roots with brown iron de- posit. Larger than E j with better roots. About same as Ei. 20 BULLETIN 52, HAWAII EXPERIMENT STATION. The results of Experiment IV are similar to those of Experiment III. Manganese dioxid with 5, 10, or 20 milligrams per liter of iron supplied as ferric chlorid and 18 milligrams per liter of manganese as manganous sulphate (0.005 per cent manganous sulphate) caused chlorosis and a severe depression in growth. When the leaves were dipped in iron solution the chlorosis was largely overcome but normal frowth was not fully induced. Very dark green spots formed on the ipped leaves where the iron penetrated. The chlorotic effects of & /O 20 40 SO M/LUG#tfMf OF '//eO/V P£% Z/7Z/P &//>/*./&? TO TH£ Fig. 3.— (Results of Experiment V.) Effect of manganous sulphate and maganese dioxid on the growth of rice in nutrient solutions supplied with various amounts of iron from ferric citrate. manganese were completely overcome when the amount of iron in the solution was increased to 40 and 80 milligrams per liter, but the checks were injured by this amount of iron from ferric chlorid. Manganese dioxid, by its removal of some of this excessive iron, gave slightly better results than the check. Experiment V. — This was a repetition of Experiment III. The different variables were the same as in Experiment III except that MANGANESE CHLOROSIS OF PINEAPPLE. 21 ferric citrate was substituted for ferrous sulphate as the source of iron and the plants in series A 4? B 4 , and C 4 were dipped in a 0.5 per cent solution of ferric citrate instead of ferrous sulphate. The weights of the plants on the fortieth day are given in Table 13 and graphically in Figure 3. Table 13. — Comparative weights of rice plants which were grown in manganous sulphate and manganese dioxid solutions to which were added various amounts of iron as ferric citrate. Se- ries. Culture solution with amount of added ma- terial per liter. Flask No. Green weight of stalks and leaves. Oven- dry weight of stalks and leaves. Oven- dry weight of roots. Average oven- dry weight. Stalks and leaves. Whole plant. Condition of plants. Aj Sol. +0.005 gm. Fe from Fej (CeHsOr)*. Aj Sol. +0.005 gm. Fe from Fe 2 (C 6 HsO7)2+0.4 gm. MnOj. 1- 2 3- 4 5- 6 7- 8 9- 10 11- 12 Aj i Sol. +0.005 gm. Fe from 1 13- 14 Fe2(C6H 5 O:)2+0.018gm.|> 15- 16 MnfromMnSOi. |J 17- 18 A< Sol. +0.005 gm. Fe from Fes (C 6 H 5 O-)2+0.4 gm. MnOs; leaves dipped in a 0.5 per cent Fe2 (C 6 H 5 0;)2 solution. jj Bi I Sol. +0.010 gm. Fe from Fe 2 (C6H s 07)2. B: Sol. +0.010 gm. Fe from 1 Fe2(C6H 5 O:)2+0.4 gm. MnOi. B3 Sol. +0.010 gm. Fe from I Fe 2 (C 6 H 5 O-)2+0.018 |] gm. Mn from MnSOi. Bi Sol. +0.010 gm. Fe from Fe2(C 6 H 5 O:)2+0.4 gm. MnOif, leaves dipped in a 0.5 per cent Fe2 (C6H 5 0r)2 solution. Ci Sol. +0.020 gm. Fe from Fe2(C6H 5 0:)2. C; Sol. +0.020 gm. Fe from Fe2(C6H 5 O:)2+0.4 gm. Mn0 2 . C3 Sol. +0.020 gm. Fe from Fei(CeH|0 7 ) 2+0.018 gm. Mn from MnS04. C 4 Sol. +0.020 gm. Fe from Fe2(C 6 H 5 O7)2+0.4 gm. MnO:; leaves dipped in a 0.5 per cent Fe2 (C6Hs07)2 solution. Di Sol. +0.040 gm. Fe from Fe2(CeH 5 07)2. D 2 Sol. +0.040 gm. Fe from Fe2(C 6 H 5 O7)2+0.4 gm. MnO a . D3 Sol. +0.040 gm. Fe from Fe2(C 6 H 5 07) 2+O.OI8 gm. Mn from MnS04. Ei Sol. +0.080 gm. Fe from Fe2(C 6 H 5 0;)2. E2 Sol. +0.080 gm. Fe from Fe2(C 6 H 5 O7)2+0.4 gm. MnOj. E 3 . Sol. +0.080 gm. Fe from Fe2(C 6 H 5 O : )i + 018 gm. Mn from MnS04. 19- 20 21- 22 23- 24 25- 26 27- 28 29- 30 31- 32 33- 34 35- 36 37- 38 39- 40 41- 42 43- 44 45- 46 47- 48 49- 50 51- 52 53- 54 55- 56 57- 58 59- 60 61- 62 63- 64 65- 66 69- 70 71- 72 73- 74 7.5- 76 77- 7^ 79- 80 81- 82 83- 84 85- 86 87- 88 89- 90 91- 92 93- 94 95- 96 97- 98 99-100 101-102 103-104 •105-106 107-108 ! Grams. Grams. 15.61 2.41 14. 16 2. 29 15. 98 2. 56 .59 .85 .61 .16 .15 .16 1.60 1.62 1.20 16.85 17.44 17.14 .63 .53 .55 .12 .13 .17 .97 1.05 .91 IS. 33 18.47 18.39 .79 .95 1.09 1.68 •1.59 1.44 3.40 3.22 3.88 17.90 18.96 19.40 5.27 6.79 5.67 9.01 9.44 8.78 15. 27 16.06 16.57 6.47 6.53 6.68 9.84 9.80 9.78 .11 .18 .13 .07 .07 .07 .32 .25 .30 2.99 3.06 3.19 .14 .13 .13 .05 .23 .24 .21 3.43 3.34 3.52 .20 .23 .26 .42 .41 .35 .73 .74 .74 3.07 3.40 3.66 1.04 1.25 1.08 1.81 1.95 1.82 2.95 2.86 3.03 1.34 1.36 1.41 2.21 2.08 2.18 Grams 1.00 .85 1.06 .08 .11 .07 .04 .04 .04 .19 .14 .17 1.00 1.04 1.10 .08 .07 .07 .04 .04 .05 .10 .09 .13 1.17 .95 1.08 .11 .11 .12 .18 .17 .14 .37 .37 .37 1.22 1.31 1.10 .56 .64 .59 .59 .61 .65 1.45 1.53 1.69 .65 .67 .60 1.01 .92 .98 Grams. Grams. 2.42 .14 .07 .29 .23 3.43 .23 .74 3.38 1.12 2.95 1.37 2.16 3.39 23 .46 4.13 20 .10 34 34 1.11 4.59 1.72 ~2.~48~ 4.51 2."6i" 3.~l3~ Fine, green plants. Very stunted; yel- lowish-white spotted with brown. Withered; brown; practically dead. Decided improve- ment over Aj; light green spot- ted with dark green where iron penetrated. Fine, dark green plants. Same as A 2; leaves bleached. Same as A3. Decided improve- ment over B2; light green spot- ted with dark green where iron penetrated. Fine, green plants. Yellowish -white; stunted; spotted with brown. About same as Cj. 'Good, dark green, spotted with very little brown. Fine, green plants. Light green; good plants spotted with little brown Same as Da. Fine, green plants. Light green; very few brown spots; fairly good plants. Light green; no brown spots; fairly good plants. 22 BULLETIN 52, HAWAII EXPERIMENT STATION. Manganese dioxid with 5, 10, and 20 milligrams of iron per liter from ferric citrate and 18 milligrams per liter of manganese from manganous sulphate (0.005 per cent manganous sulphate) caused a strong chlorosis and a severe depression in growth. Chlorosis was overcome and growth increased as a result of dipping the leaves in solutions of ferric citrate. The chlorotic effect of manganese was overcome and the weights approached those of the checks when the supply of iron in the solution was increased to 40 and 80 milli- FlG. 4. & JO 20 40 &O (Results of Experiment VI.) Effect of calcium carbonate and manganese dioxid on the growth of rice in nutrient solutions supplied with various amounts of iron from ferrous sulphate. grams. Here, where there were no harmful effects due to the pres- ence of excessive iron in the solutions, increased growth was not made, because of the presence of manganese dioxid. Experiment VI. — Since the action of manganese in causing chlo- rosis is similar to that of calcium carbonate, this experiment was made to determine the effects of the latter. The weights of the plants on the fortieth day are given in Table 14 and graphically in Figure 4. MANGANESE CHLOROSIS OF PINEAPPLE. 23 Table 14. — Comparative weights of rice plants which were grown in manganese dioxid and calcium carbonate and in calcium carbonate solutions alone, to which were added various amounts of iron as ferrous sulphate. Culture solutions with amount of added mate- rial per liter. Flask No. Green weight of stalks and leaves. Oven- dry weight of stalks and leaves. Oven- dry weight of roots. Average oven- dry weight. Stalks Whole kavt.le'-t- Condition of plants. Ai * M A 3 Aj C 2 C 3 C t T>i D 2 Dj Ei E 2 Sol. +0.005 gm. Fe from FeSO*. Sol.+0.005 gm. Fe from FeSO 4 +0.4 gm. Mn0 2 + 0.4 gm. CaC0 3 . Sol.+0.005 gm. Fe from FeSO4+0.4gm. CaCOs, Sol.+0.005 gm. Fe from FeSO 4 +0.4gm. Mn0 2 + 0.4 gm. CaCOs; leaves dipped in 0.5 per cent FeS04 solution. Sol. +0.010 gm. Fe from FeS0 4 . Sol.+O.OlO gm. Fe from FeSO4+0.4gm.MnO 2 -f 0.4 gm. CaC0 3 . Sol.+O.OlO gm. Fe from FeSO4+0.4gm. CaC0 3 . Sol.+O.OlO gm. Fe from FeSO 4 +0.4 gm. Mn0 2 + 0.4 gm. CaCOs; leaves dipped in 0.5 per cent FeS04 solution. Sol. +0.020 gm. Fe from FeS04. Sol.+0.020 gm. Fe from FeSO 4 +0.4gm.MnO 2 + 0.4 gm. CaC0 3 . Sol. +0.020 gm. Fe from FeSO4+0.4gm.CaCO 3 . Sol. +0.020 gm. Fe from FeSO4+0.4gin.MnO 2 + 0.4 gm. CaC0 3 ; leaves dipped in 0.5 per cent FeS04 solution. Sol. +0.040 gm. Fe from FeS0 4 . Sol. +0.040 gm. Fe from FeSO 4 +0.4 gm. Mn0 2 + 0.4 gm. CaC0 3 . Sol. +0.040 gm. Fe from FeSO4+0.4gm. CaC0 3 . S0I.+O.O8O gm. Fe from FeSO«. Sol. +0.080 gm. Fe from FeSO 4 +0.4 gm.Mn0 2 + 0.4 CaC0 3 . Sol. +0.080 gm. Fe from FeSO4+0.4 gm. CaC0 3 . 1- 2 3- 4 5- 6 7- 8 9-10 11-12 13-14 15-16 17-18 19-20 21-22 23-24 25-26 27-28 29-30 31-32 33-34 35-36 37-38 39-40 41-42 43-44 45-46 47-48 49-50 51-52 53-54 55-56 57-58 59-60 61-62 63-64 65-66 67-68 69-70 71-72 73-74 75-76 77-78 79-80 81-82 83-84 85-86 87-88 Grams. 13.07 13.48 12.98 .27 .26 .28 .85 .82 .74 91-92 93-94 95-96 97-98 99-100 [101-102 103-104 105-106 107-108 Grams. 2. 73 2.66 .10 .10 .10 .21 .20 .17 4.29 4.30 4.43 12.38 14.86 12.97 .22 .18 .23 .62 .81 .83 3.14 3.66 3.51 14.11 13.37 15.15 .20 .21 .24 5.00 4.58 5. It) 1.22 1.47 1.24 11.82 12.17 12.74 .47 .52 .64 10.68 11.55 11.59 5.97 7.24 5.78 5.13 4.50 5.32 11.61 12.58 11.25 2.62 2.76 2.75 .08 .06 .09 .16 .20 .21 .71 .71 2.71 2.64 2.73 .07 .07 .97 .97 .27 .34 .30 2.60 2.97 2.74 .15 .15 .19 2.14 2.31 2.29 1.52 1.64 1.45 1.05 1.12 1.22 2.20 2.52 2.31 Grams. 0.75 .77 .77 .07 .07 .07 .11 .82 .88 .05 .05 .06 .36 .34 .35 .13 .13 .16 .87 1.02 .11 .12 .67 .67 .79 .51 .56 .50 .35 .34 .42 .73 .72 .72 Grams. 2.69 2.71 Grams. 1.01 .30 2.77 2.25 1.54 1.13 "2.~34 3.45 .30 1.20 3.55 Fine,green,healthy . 1 Bleached white; spotted with brown; stunted. Yellowish-w h i t e; faint, green, brown spots; lit- tle better than A 2 . Green and healthy; dark green spots where iron pene- trated. Green; healthy. .28 1.00 3.55 .13 "l."36 .44 with- 2.96 2.06 T50" "3.~06" Same as A 2 ; ered. Same as A 3 . Same as A 4 . •Green; healthy. •Same as Bi. Light yellowish- green; somewhat stunted. •Same as A4. Green; healthy. Yellowish -green spotted with brown; stunted. Somewhat light in color. Green; healthy; roots injured by excessive iron. Light green; rather stunted. Fine, dark-green plants. Calcium carbonate with 5 and 10 milligrams per liter of iron supplied from ferrous sulphate caused a strongly chlorotic condition and severe depression in growth. Chlorosis almost disappeared with 20 milligrams and did not occur at all with 40 and 80 milligrams. In fact, with 80 milligrams calcium carbonate caused a decided 24 BULLETIN 52, HAWAII EXPERIMENT STATION. increase in growth due to its removal of some of the excessive iron present. Manganese dioxid and calcium carbonate combined with 5, 10, 20, and 40 milligrams per liter of iron caused a strong chlorosis and a severe depression in growth. The chlorosis was overcome when the leaves were dipped in iron or when the iron supply was increased to 80 milligrams. Experiments III and VI may be considered together since the plants were grown in each for the same length of time with the same solutions and each had approximately the same check. This has been done in Figure 4. A study of Tables 3 and 6 and Figure 4 indicates that calcium carbonate and manganese dioxid have the same effects. Although the above-mentioned results were obtained when calcium carbonate and manganese dioxid were used singly in excessive amounts, the chlorosis was very greatly increased when the two were used in combination. Manganese dioxid and calcium carbonate each appears to possess its own peculiar chlorotic effect and to exert an additive chlorotic effect in the presence of the other. Discussion of Results. The results obtained show that manganous sulphate and manga- nese dioxid cause a strong chlorosis and a severe depression in the growth of the plant. This chlorosis is overcome when the leaves are dipped in iron solutions or when the amount of iron in the nutrient solution is excessively increased. Manganese thus apparently causes a depression in the assimilation of iron by the plant or a deficiency of iron in the plant. This confirms the results with pine- apples previously obtained by the writer. Many investigators have found that manganese, especially in large amounts, causes chlorosis, but none has offered proof to show that manganese-induced chlorosis is due to a depression in the assimilation of iron or to a deficiency of iron in the plant. Manganese-induced chlorosis occurs in acid solution and is alto- gether distinct from lime-induced chlorosis which is caused by calcium carbonate. In the latter instance the availability of the iron is reduced by the alkalinity of the solution. Manganese and calcium carbonate can each exert an additive chlorotic effect in the presence of the other. Since chlorosis is produced by manganese in acid solutions with no excess of lime, it is proved conclusively that chlorosis in general is not due to the alkalinity of the solutions or to excess of lime, but simply to deficiency in iron. Manganese is commonly referred to as a plant stimulant. In these experiments manganese has been found to cause increased growth only when the solution contained a large excess of iron, some of which the manganese dioxid removed. AN EXPLANATION OF THE PHYSIOLOGICAL EFFECTS OF MANGANESE ON PLANTS. Pugliese (37) and Tottingham and Beck (44) have suspected an antagonism between manganese and iron. In the writer's opinion, however, the physiological effect of manganese, at least the effect of the manganiferous soils, can be explained on purety chemical grounds. Hildebrand (22) gives a titration curve for ferrous sulphate in which .MANGANESE CHLOEOSIS OF PINEAPPLE. 25 the hydrogen-ion concentration of the solution is determined at various stages of titration with sodium hydroxid. Ferrous hydroxid was not precipitated until the solution was made quite alkaline. Ferric salts could not be investigated with the hydrogen electrode, but Hildebrand predicts "that they would behave very much like aluminum salts/' which are precipitated while the solution is still /.O 2.0 &o 4.0 ^ 7.0 8.0 9.0 /ao MO TO /=>£J?NT