DOCTORAL DISSERTATION SERIES titlem m u m /l/tv n torn if m n MM£M£J£ IN 61/MY f i t ITS iUTHOR ££UNd RE/N STtOMML_____ u n iv e r s ity jtfcjlKsAAl STATE DEGREE f i b . COLL d a te PUBLICATION NO. i 563_ T M y UNIVERSITY UNIVtKill MICROFILMS JJ/M A IJkl A D D n D /9S! Li Ir UI ft A KJ AVAILABILITY TO PLANTS OF IRON AND MANGANESE IN GLASSY FRITS by Erling Rein Stromme A TEZSSIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science In partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Botany and Plant Pathology 1951 Acknovl edgauent It is a pleasure to e g r e s s my appreciation to Dr, F, L* ¥ynd under whose continuous encouragement and helpfull suggestions this work has heen carried out, and to whom the results are herewith dedicated* I also deeply appreciate the financial support of the JerroBnamel Corporation of Cleveland, Ohio, and the scholarship provided by Michigan State College for the past two years which made it possible for me to carry out these investigations* Xrllng Rein Stromme Michigan State College May, 1951 Brling Hein Stromme candidate for the degree of Doctor of Philosophy Pinal examination. May 18, 1951* 10:00 i,M. , Boom 450, natural Science Building Dissertation: Arailehility to Plants of Iron and Manganese in Glassy Prits Biographical Items Born, October 22, 1918, Bergen, Norway Uhdergraduate Studies, The Agricultural College of Norway, 1941-1944 Graduate Studies, Michigan State College, 1946—1947, cont, 1949-1951 Xxperienee: Besearch Assistant in Horticulture at The Agricultural Oollege of Norway, 1944-1946, Assistant Professor in Horticulture at the same institution since 1947 TABLE OF CONTENTS I. INTRODUCTION................................................ 1 II, EXPERIMENTAL METHODS AND MATERIALS........................ 9 A, Mechanical arrangement of the cultures,............ 9 B, Nutrient solutions,...................................... 11 C, Plant material,....... 14 D, Methods of chemical analysis,.......................... . 14 1, Plant material...................... .............. 14 2. Nutrient solutions,............................ 15 3, Preparation of the frits................ 16 P. Composition of the frits, 17 ..... ............... . III. EXPERIMENTAL RESULTS........................................ 20 A. Visual appearance of the plants........................ 20 1, At pH 4,0 of the nutrient solution............... 20 2, At pH 5*0 of the nutrient solution....... 21 3, At pH 6,0 of the nutrient solution.............. 22 4, At pH 7,0 of the nutrient solution..... 23 5, Summary, ••....... 2*t B. Trash veight of the plants.......... 25 0. Dry velght of the plants...... 27 D. Absorption of iron by the plants. ................ 28 1, Iron content in parts per million of the oven dry material, ................. ,.,.,29 a. At pH 4.0 of the nutrient solution,......... .29 ii b* At pH 5*0 of the nutrient solution.......... 30 c* At pH 6.0 and 7.0 of the nutrient solution** 31 2* Total absorption of iron by the plants*.••...•••• 31 a. At p H 4*0 of the nutrient solution*.....*••. 31 b. At pH 5*0 of the nutrient solution* •••• 32 e* At p H 6*0 and 7*0 of the nutrient solution** 32 3* Summary of iron absorption................... 32 33 X. Absorption of manganese by the plants.............. 1* Manganese content in parts per million of the oven dry material,..... IT. 33 a* At pH 4*0 of the nutrient solution.......... 33 b* At pH 5*0 of the nutrient solution*......... 34 c* At pH 6,0 and 7*0 of the nutrient solution*• 35 2* Total absorption of manganese by the plants....•• 35 3* Summary of manganese absorption................. • 3^ DISCTJSSIOH........................................... 38 T* SUMMARY................................................. . YI. VII. 46 LITERATURE CITED..................................... *9 AFFHTDIXXS. .ANALYTICAL PROCEDURES.......... 54 1, Determination of iron............... *. 2. Determination of manganese............................ 54 57 3* Determination of potassium and sodium in nutrient solutions by flame—photometer*....... 4* Determination of the solubility of f 39 r i t s * • 6l Till. TABLES IX. FIGURES X. PLATES I. IHTROBUCTION The results of many experiments have demonstrated the importance of minor elements in plant nutrition. Tiro of these elements* iron and manganese, have been given broad consideration because they in so many instances have been found to be limiting nutritional factors in crop production. Both elements are common in soils, and since they are needed b y plants in minute quantities, they are usually present in the soil in adequate amounts for plant growth. The reason for the occurrence of deficiencies of these elements is to be found in chemical and physio logical processes which render them unavailable to the plants or make them inactive in their physiological functions within the plant. In example of a disturbance in the iron nutrition of plants is the so-called lime Induced chlorosis which is the limiting factor in the production of certain tree fruits in several parts of the world. Bmniitt (1927) and (1929) have demonstrated that this type of chlorosis can be eliminated by sprays or by injections of iron salts. Lime induced chlorosis has been thought to be due to a high calcium carbonate content of the soil which will raise the pH value of the soil to such an extent that iron is precipitated and made un­ available to the plants. It has, however, been observed by *nd flPflfy (1944), Wallace (1928) and other workers that the concentration of iron in the dry smtter of chlorotlc leaves is not significantly different from that in comparable green leaves. Xfrgrnj ani (1944-)* on the other hand, hare found significantly higher concentrations of iron In healthy leaves than in comparable chlorotlc leaves, when the data are expressed on the basis of leaf area. The physiological distur­ bance causing the chlorosis is far from being fully understood, but it may be pointed out, as concluded by Wallace and Hewitt (1946), that the evidence suggests that the mobility of iron, both in the external medium and within the plant, plays a role in the disease* Although lime Induced chlorosis no doubt is the most Important cause r.-t iron deficiency, other causes of Iron deficiency may also be of imuortance under certain conditions* (1935) has demon- strated in solution cultures at a neutral or alkaline reaction an interrelationship between phosphorus and iron resulting in iron defi­ ciency* flhawai *-r and Scaraeth (1941) found that the application of phosphate to a slightly alkaline and to a highly calcareous clay, in both cases, produced iron chlorosis in peanuts* Similar results are reported by Slderls and gran* (1933)* HcQeorae (1923). (1924), Biuuel (1923). and Somers and JhlZS, (1942) have shown that a high manganese level in soils or in nutrient solutions will induce chlorosis In plants and that this chlorosis can be overcome by increasing the iron concentration in the nutrient solution or by sprays of iron salts* Che interrelationship thus found to exist between manganese and iron is of considerable Importance on certain soils, rich in manganese, in the ZSmallan Islands, e-pd a continuous application of iron to the plants is necessary in order to avoid chlorosis* While Iron chlorosis may "be due to a number of factorB, the occurrence of manganese deficiencies is, as pointed out by Connor (1932) and m i l l s (1932), mainly due to oxidation and precipitation of the mangan ese in the soil, the oxidised form being unavailable to the plants. ggfrrrtfiwr « i d Bnrgffft (1 9 2 7 ), and *»*»»«*>»* (1 9 3 0 ), and others have observed manganese deficiency in various crops grown on calcareous soils. (1926) and gilbert. McLean and (1926) observed the same deficiency symptoms in crops grown on heavily limed soil. The most prominent ease of manganese deficiency in crops is per­ haps the so-called "gray speck” disease of oats which is common in several parts of Europe and Australia. The Australian workers Samuel and Pfroar (1928) have proved that the disease was Identical with man­ ganese deficiency. Manganese deficiency on oats has been reported by Willie (1928) and ^ b e v t e (193*0 to occur on the eastern coastal plains in the Chi ted States and by sh*i»man and H a m e r (19*H) to occur in alka­ line organic soils of Michigan. It is now generally accepted that manganese deficiencies may occur when the soil is limed above pH — 6.5 and when the soil has strong oxidising tendencies. Che importance of iron and manganese deficiencies lies in the difficulty with which they are controlled. Soil treatments with salts of these elements, or with sulfur to make the soil more acid, are generally unsatisfactory and of limited application, since the conditions in the soil causing the original deficiencies still exist. gVHwr^f and Buprecht (1930) concluded from their experiments with truck crops on calcareous soil that much of the manganese added to the soil became Insoluble within three months, gilbert (1934) concludes that it seems necessary to apply manganese before eaeh crop under alkaline soil conditions. Wallace and Omelvle (1941) found that man­ ganese sulfate and manganese chloride used as fertilisers at a rate equivalent to 100 pounds of manganese sulfate per acre, were effective in combating manganese deficiency in globe beets oply during the early stages of their growth. Wain. Silk and Wills (1943) treated soils in the laboratory and in the field with solutions of manganese sulfate and then examined at Intervals the amounts of manganese which could be extracted with neutral 1 V ammonium acetate. They found in an experi­ ment with a highly calcareous soil that the extractable manganese down to a depth of 12 inches fell to its original level only seven days after treatment. To avoid the influence of the disturbing soil factors, resort has been made to spraying and injection of iron and manganese salts. The latter of these two alternatives can only be applied to trees, and although effective on some trees, say give rise to gumming of stone fruits (Wallace. 1929). besides being tedious to carry out. Sprays are cumbersome, and sometimes unsatisfactory since they are often damaging at effective concentrations. In case of lime induced chlorosis several applications must be made during a single season to keep the plants sufficiently well supplied with iron, because the iron in such instances is relatively immobile* In lieu of the difficulties thus encountered in maintaining a sufficient supply of available iron and manganese, the possibility of supplying the elements by adding slowly available compounds or arti­ ficially prepared physical complexes to the soil presents an intriguing approach to the problem* The material should ideally have the following properties! (l) She solubility in water should be relatively small in order to pre­ vent the elements from leaching, and also to prevent them from being rendered unavailable to the plants through chemical reactions in the soil* Bie absorption by the plant root would, therefore, necessarily have to take place directly by contact between the plant root and the material* (2 ) The material should be nontoxic to plants in high con­ centrations so that large amounts could be applied at once to furnish sui ample supply of the nutrient over a long period* (3) The rate of release of the nutrients from the material should be adequate for plant growth, but must not attain a toxic magnitude. The implication of a contact absorption does not present any serious objection to the development of such a material* in active role played by the absorbing root surfaces in releasing nutrient elements from the solid phase of the soil has already been recognized, and a mechanism of this absorption has been suggested by ♦Teaw (1938)* According to Jenny, colloidally adsorbed nutrients may be absorbed directly by the plant roots without the intervention of water solubil­ ity when there is a contact between the colloidal particles and the absorbing surface of the plant root. The reaction taking place is des­ cribed as being merely an exchange of adsorbed ions. This mechanism will, of course, not explain a possible release to the plant roots of nutrient elements held in a crystalline or amorphous matrix. There exists, however, good evidence that plant roots have the ability to break down such structures to a limited extent and to obtain nutrients during the process. In recent years, it has been observed that the highly Insoluble mineral magnetite may serve as a source of iron for plants in hydroponic cultures. Baton (1936) claims that 0.1 percent of magnetite mixed with quarts sand makes unnecessary the use of soluble iron in the culture solutions maintained on the acid side of neutrality, and that a number of crop plants obtain sufficient amounts of iron from magnetite even when the pH value is as high as 8. fib£BMR (1939) reported that Citrus seedlings grow successfully in quarts gravel containing 0.1 gram of magnetite per 100 grams of gravel flooded with a nutrient solution at p H value from 5*8 to 7.0. He found that the addition of calcium carbonate to the gravel resulted in ohlorosis unless the amount of magnetite was correspondingly In­ creased. This experiment indicates that there must be a sufficient area of contact between the magnetite and the plant roots in order to prevent chlorosis. 7 Quest ( 1 9 ^ ) used ‘bentonite and magnetite Incorporated Into quarts 8and as a solid-phase source of certain nutrients In hydroponic cul­ tures* He found that even at alkaline reactions of the nutrient soltt* tlon, chlorosis did not appear in Citrus seedlings as long as the magnetite was finely ground in order to present a large surface area. Incorporation of finely ground dolomite in the sand Induced chlorosis which he assumed was due to interference of solid dolomite particles with the contact between the roots and the magnetite particles* Che present study was carried out in order to investigate the possibility of compounding relatively insoluble glassy frits in such a manner that certain plant nutrients would be held in a relatively insoluble form, but would be released to the absorbing root surface when a contact is established between the root and the frit particle* Che material which has been studied is a product of the porcelain enamel industry* It has an amorphous structure, and its physical and chemical properties can be varied within wide limits by changing the raw composition and the manufacturing procedure. Che technical problem involved in the study is, therefore, to prepare frits in which plant nutrients are held in the amorphous matrix with sufficient forces to prevent their dissolution in water, but which are not strong enough to prevent their release and subsequent absorption by plant roots acting on the matrix* *L' nA (19^5) were the first ones to describe the possi­ bility of using especially compounded glasses as a source of plant nutrients* These authors attempted to prepare glasses of such a high solubility that the rate of disintegration in water would be sufficient to support plant growth. Studies were made on the effect of melting temperature on the solubility of the products manufactured from miXH tures of rock phosphate, potash and silica, and it was found that glasses may be prepared which are surprisingly soluble with respect to phosphorus and potassium. Che work was not extended to include other elements, nor were any nutrition experiments carried out. There is reason to bell ere that their material would hare a strong tendency to raise the pH Talus of the medium in which it was dissolved. Ho pH measurements, however, were reported* Che purpose of the present study was to explore the value of glassy frits as a source of iron and manganese for plants, and es­ pecially to determine the Importance of the pH value of the medium on the release of iron and manganese to the plant and on the release of these nutrients by aqeous solubility of the frit material* 9 . II* SCPXRIMBBTAL MBT90DS AHD MATERIALS The availability of iron and manganese in frits was studied in grerahoiufl experiments in which vbsat seedlings vere grown in hydro­ ponic pot cultures using the frit in place of gravel* A quartz culture served as control to each individual frit culture* by helng flooded repeatedly with Identical nutrient solution* in a maxmer to he described beloir* The difference in growth and chemical composition of the plants in the two cultures could he taken as a measure of the relative importance of contact ahsozptlon and absorption based on the aqueous solubllity of the frit constituents* A. Mechanical arrangement of the cultures The culture pots were one gallon* glased earthenware pots. A . hole three-quarters of an inch in diameter was located near the base of the wall of the pot* Through this hole the nutrient solution was Introduced at regular intervals by an automatic subirrigation system* The details of the automatic system employed are shown in figure 1* The oeurboy C contained 16 liters of nutrient solution* At Intervals of four hours an electric time clock turned on an electrically driven air pump for seven minutes* The air from the pump entered the main air line (S) running underneath the greenhouse table and forced the nutri­ ent solution upwards flooding the pots A and B simultaneously* Culture pot A contained the eaqperlmental frit, while pot B contained quarts gravel equal In particle size to that of the frit, A hydrostatic water column (X) was connected to the end of the main air pressure line. The maximum pressure in the line could thus he regulated by- altering the height of the column. Since the volume of the nutrient solution in the carboy greatly exceeded the volume needed to fill the two culture pots. A and B which it supplied, an accurate regulation of the air pressure was necessary in order to prevent the excess nutri­ ent solution from being forced over the rim of the culture pots. The end of the glass tubing leading the nutrient solution into the pot. was inserted into a six-inch test tube (X), the opening of which was covered with a thin layer of glass wool. Thus the material in the pot was prevented from entering the glass tube and the nutrient solu­ tion in the carboy. A total of 44 pairs of pots were arranged on two parallel, adja­ cent greenhouse tables, as shown on plates I. II. and III. One air pressure system controlled simultaneously the entry of nutrient solu­ tion in all of the cultures. When the electric time d o c k shut off the motor driven air pump, the solution in the culture pots drained back into the carboys. It is apparent that pot A and B were supplied with an identical nutrient solution. Any soluble material released from the frit in pot A would become equally distributed between pot A and its corresponding quarts control culture B. If the experimental frit released soluble nutri­ ents, both cultures would profit equally. If. on the other hand, the plants growing in the frit were able to obtain nutrients by contact . 11 absorption* the plants growing In the corresponding quartz culture would be expected to be inferior to those growing in the frit, provid­ ing the nutrient solution was deficient in one or more of the nutrients furnished by the frit* All frits were studied in duplicate, and eeush frit culture was coupled with its individual corresponding quartz culture, 3. Ifutrient Solutions As the purpose of this study was to determine the availability of Iron and manganese in frits, two types of frits were used, one contain­ ing iron but no manganese, and one containing both iron and manganese. Consequently, the nutrient solution which flooded the pots containing the iron frit was complete except that no iron was added, while the nutrient solution flooding the iron-manganese frit was complete except that neither iron nor manganese was added. A three-salt solution, similar to that of Shivs (1915), was used, amd its final composition was as follows! Salt Grams per liter SfeSOjfTHgO 3.70 0a(303)2. ^ 0 1.23 2.76 Cone eat retted stock solutions of each, salt were made up separately with the following concentrations: Salt teams per liter HgSOj^. 7 &2.0 296 Oa(H03 )2 .4lt,0 SHgPO^ 98 221 Bach carboy* containing 15 liters of distilled water* received 200 milliliters of each of these stock solutions* and then distilled water was added to bring the total volume to 16 liters* Micro-nutrients were supplied by adding 16 milliliters to each carboy of a stock solution having the following composition: Salt BiO teams per liter 2*860 3 MhSOjj* THgO 0*220 MoO^ 0*007 CuSO^.SHgO 0*080 nitration of the micro-nutrients in ■1 XLement Parts per million Boron 0.50 Zinc 0.05 Molybdenum 0.05 Copper 0*02 I . 13 To the culture solutions flooding the frits containing iron hut no mangan ese, 16 milliliters of a stock solution containing 1*538 grams of MnSO^.H^O per liter were added per carboy. The final concentration of manganese in the solution was approximately 0.5 parts per million. Absolute control cultures with quarts gravel in pot A as well as In pot B (figure l) were arranged in the same manner as described above. Iron and manganese were added to the nutrient solutions according to the following tablet Absolute control culture Mi cro-nutri ent s Barts per million of Ye Ml 1 Iron and manganese A.O °.5 2 Manganese only 0 0.5 3 Iron only A.O 0 A Ho iron and no man­ ganese 0 0 Bach culture was run in triplicate. Iron was supplied by adding ten milliliters of a stock solution made up as follows! 6.40 grams of electrolytic iron was dissolved in 12 milliliters of concentrated sulphuric acid. The solution was transferred to a 1000 milliliters volumetric flask half filled with distilled water. After cooling the solution was brought to volume with distilled water. Since the acidity of the nutrient solution may be a major factor determining the rate at which frit constituents are brought into solu­ tion, a constant pH value was maintained In the nutrient solutions throughout each experiment. The pH value of the solution in eaeh individual carboy was determined twice a week with a glass electrode and* If necessary, adjusted to the proper value by the addition of a 1 5 sulphuric acid solution or a 1 N potassium hydroxide solution* The p H values of the nutrient solutions were maintained within 0.2 pH unit from the value originally decided upon for the experiment* C. Plant Material Porty-five seeds of wheat, variety "ILLINOIS" harvested in 194-8* were planted an inch deep in the culture media* were obtained in each pot* Prom 30 to 40 plants Ho effort was made to obtain a uniform number of plants per pot since the removal of plants severely disturbed the root system of the remaining plants* The plants were harvested when they had reached the Jointing stage, and each experiment lasted for about 45 days* The roots of the plants were separated from the tops and discarded* The lower part of the stems, which had been in contact with the nutrient solution, was washed in running tap water, rinsed in distilled water* and gently wiped dry with a cheesecloth* The plants were dried in a forced-air chamber at a temperature of 60° C. D. Methods of chemical analysis 1* Plant material X one gram sample of the dry and finely ground plant material . 15 was weighed into a platinum crucible and placed in a cold electric muffle. The temperature was gradually increased until smoking began, and held constant until heavy smoke was no longer given off. The temperature was then increased to 850° C. and maintained at that level for two hours. After cooling, the ash was wetted with one milliliter of a lt4> sulphuric acid solution, about five milliliters of concentrated hydro­ fluoric a d d was added, and the crucible was then placed on a hot plate at low heat. The solution was evaporated until a viscous residue was left in the crucible. About ten milliliters of a 0,1 If nitric acid solution were added while the crucible remained on the hot plate. The dissolved residue was transferred to a 50 milliliters volumetric flask. After cooling, the solution was made to volume with 0.1 IT nitric acid. Iron in the ash solution was determined colorlmetrioally by the o—phenanthrollne method described by Hummell and Willard (1938), detailed procedure is given in appexdlx 1, The Manganese in the ash solu­ tion w a s determined oolorimetrically by the periodate method described b y Willard and Greathouse (1917), Detailed procedure is given in appendix 2 , 2 , Hutrient solutions Samples of the nutrient solutions were collected after the comple­ tion of the individual experiments. In order to obtain a representative sample, five milliliters of concentrated sulphuric acid were added to each carboy, the acidified solution was well shaken, and the sample collected while the carboy was emptied. The sample was filtered, and 500 milliliters of the solution were transferred to a 600 milliliter beaker, and evaporated on a hot plate until the volume was about 50 milliliters. solution was transferred to a 100 milliliter flask. The concentrated After cooling, the solution was made to volume with distilled water. Iron and manganese in the concentrated sample of the nutrient solution, was determined by the same method as used for the plant material (see appendix 1 and 2 ). The concentrations of potassium and sodium in the nutrient solu­ tion were determined by the Perkin-SIwer flame photometer. Model No. 520, using a n acetylene flame. A 2—milliliter aliquot of the concen­ trated nutrient solution was pipetted into a 50 milliliter volumetric flask and made to volume with distilled water. The concentration of potassium and sodium in this solution was determined according to the direct intensity method (see appendix 3 )* S. Preparation of the frits Technical grades of raw materials were used in compounding the experimental frits, such as powdered quartz, potassium carbonate, sodium carbonate, mono—calcium phosphate, etc. The well mixed eo»* ponents were melted in an electric smelter and held in the molten stage for 3.5 hours. The molten material was quenched by permitting it to flow into cold, running water* The material was fragmented into small pieces b y the rapid cooling in the water. The moist, fragmented material was cooled and dried in a commercial rotatory drying pan, and then the particles were graded for size in a series of screens. The material selected for the nutrition experiment was about oneeighth of a n inch in diameter. Before the frit was placed in the culture pots it was sieved through a 2 millimeter sieve in order to remove all finer particles* The material retained on the sieve was washed in tap water and finally rinsed thoroughly with distilled water after being placed in the pots. Two liters of frit were placed in each pot* Quarts gravel was sieved in the same manner as described for the frit in order to obtain a uniform and equal particle size in the two comparable cultures. Die quartz gravel was further spread out in a thin layer and thoroughly treated with a strong electro—magnet to re­ move any iron impurities* It was then soaked for several days in a dilute sulphuric acid solution (pH 2.5) * thoroughly washed in tap water and finally rinsed in distilled water* F* Composition of the frits The composition of the frits used in the present study were based upon results obtained in previous studies with iron-containing frits* A report on the preliminary experiments has been given by Ifrnd (1950* 1951). and his results are summarized as follows* The composition of the frits used in the preliminary experiments was based arbitrarily on the data presented by ft***™** and fiQZ (1945) and the frits thus obtained varied greatly in solubility as determined by the method given in appendix 4. The solubility of the frits was found to have a marked influence on the growth of the plants, a high solubility (above 7*0 percent) made the nutrient solutions alkaline, thus creating a toxic condition for the plants. She most successful wheat cultures, comparing favorably in growth with absolute control cultures receiving a complete nutrient solution, were obtained with frits of relatively low solubility. Chlorosis would, however, appear in the later stages of the experimental period, and in later experi­ ments the iron content of the frits was increased from 2,0 to 5*0 per­ cent *®2°3 * Some of the frits thus developed produced plants which were green and healthy throughout the experimental period and which were superior in slse to plants grown in the absolute control cultures receiving a complete nutrient solution. In table 1, the composition and the solu­ bility of the newer frits are listed. The table includes three groups of frits representing three different levels of silica content. Within each group a decrease in the percentage of OaO, KgO, Kg0, and Bs^O with a corresponding increase in the phosphorus content resulted in a de­ crease in solubility. Of the frits listed in table 1, 6238-C and 6224-C produced the best plants as judged by the fresh weight obtained, 6238— C produced slightly higher fresh weights than did 6224— C. Based on the total amount of iron absorbed per plant however, 6224— C gave a higher value 19 than 6238--C. The basic formulae represented by these two frits were, therefore, selected for the present study. Since both frits had proved successful, the Investigations had reached the point where it was appropriate to explore the effects of changes in the iron content. At this stage w angan ese was also included in the study, ani the four series of frits listed in table 2, were prepared for the present study. She 6285 and 6287 frit series in table 2 conform to the basic for^ nula represented by 6238-C in table 1, and the 6286 and 6288 series conform to the basic formula represented by 6224— 0 in table 1. She variation in iron and manganese in the new frits, as shown in table 2 , has been compensated for by a change in all the other constituents to avoid any appreciable deviation from the basic formula with subsequent change in solubility. All frits listed were studied simultaneously at various p H levels of the nutrient solution. Experiment So. The following experiments were carried outs pH of nutrient solution Experimental period Total number of days 1 6.0 June 13— July 26 43 2 7.0 Sept. 10— Oct. 24 44 3 4.0 Hov. 7— Dec. 22 45 4 5*0 Dec. 28— Feb. 14 48 III. BXFERIMUTTAL HEST7LTS A. Visual appearance of the plants 1. A t fifi ^ 0 of the nutrient solution. The experiment with the nutrient solutions at pH m 4.0 was carried out during the months of Ho t ember and December and the plants grew relatively slowly because of the low light intensity. In spite of the slow growth, pronounced differences in the else of the plants and in the color of the leaves was obserred, between the plants grown in frit and those grown in quarts. In all instances, the size of the plants in the frit cultures was larger than that of the plants in the corresponding quarts cultures. In most instances, the plants which were grown in the frits exhibited a darker green color than did those grown in the corresponding quarts cultures. It was noticeable also that the plants grown on the frits of the 6285 the 6287 series with low S102 content were larger than the plants grown on the frits of the 6286 and 6288 series with high 810^ content. Similar differences were observed between the plants grown In the respective quarts control cultures, the largest plants being associated with the largest frit-grown plants. Within the cultures of each series of frits, no visible diffsil­ ences were apparent, nils indicated that the different iron or man - ganese contents of the frits exerted no effect o n 'the plants which was visibly evident. The color of the absolute control plants grown without iron was 21 . leas green than the color of the plants supplied with complete nutrient solution. Vo deficiency symptoms were ohserred in those absolute con- trol cultures from which manganese was excluded. Although the size of the iron deficient plants was not appreciably smaller than the size of the ones receiving complete nutrient solution. It was apparent, however, that the plants receiving a -complete nutrient solution were ssw.ller than the plants grown In the frits of the 6285 and 6287 series. 2. S3i fifi SimSL Sli. aaSri.gfl* solution. out during the months of January and February. The experiment was carrie The installation of adeauate artificial light materially Improved the growth of the plants. The control plants showed signs of chlorosis early in the experi­ mental period and the growth was markedly inhibited. All of the frit grown plants, however, were still green and healthy at the end of the experimental period. Agsiin it was observed that the frit series 6285 and 6287 produced larger plants than did the 6286 and 6288 frit series, and a similar difference was again noticeable between the corresponding control plants. Therefore, the control plants corresponding to the 6285 and 6287 frit series were larger than the control plants corresponding to the 6286 and 6288 frit series. The plants grown in fTit had, in most instances, started to Joint at the time of harvest, while very few of the eoxftrol plants had reached the Jointing stage when they were harvested. Vi thin estch frit series, no narked visible differences in the plants were associated with the differences in the iron or manganese 22 content of the frits. . However, in case of the series 6287. the frit containing 2 percent of NnO^ produced definitely taller plants than did the rest of the frits * x thin this series. The corresponding coxh trol culture likewise produced definitely taller plants than did other control cultures in the series. The absolute control cultures receiving no iron in the nutrient solution produced plants which were very chlorotie and the growth was obviously inhibited, Omission of manganese from the nutrient solution resulted in a slight chlorosis of the plants. The growth, however, seemed not to have been visibly inhibited by the ehlorotlc condition. The complete nutrient solution gave rise to normal healthy plants, but in no instances did the growth of these plants compare with that of the plants grown in the frits of the 6285 and 6287 series. 3. A t a s 6.0 o£ nutrient solution. out during the months of JTune and July. The experiment was carried It was. therefore, difficult to avoid high temperatures in the greenhouse on bri^it days and injury to the plants in the form of drying of the leaf tips was encountered in some instances. The same general picture of the growth of the plants as described for the previous experiment also was apparent in this experiment. The control plants became chlorotie at an early stage of their development, and the else obtained by the control plants was markedly less than the sise obtained by the plants grown in the corresponding frit cultures. The plants grown on frit 6287-B (2.0 percent V«20^) reached an exceptional large else and the frits of the 6285 and 6287 series f l produced plants of a size superior to that of the absolute control plants receiving complete nutrient solution (Plates IT, 7, 71, and Til). Since one might expect precipitation of the Iron In the nutri­ ent solution at the high p H level used in this and the following e x ­ periment, the solutions receiving Iron were thoroughly shaken once a day prior to flooding of the culture pots. Since the plants grown In the absolute control cultures receiving complete nutrient solution app ea red green and healthy, this precaution was apparently sufficient to keep the plants supplied with iron. Still, the growth of these plants was Inferior to the growth of the best frit grown plants (Plate Till). Manganese deficiency did not occur in this or in the following experiment w h e n manganese was excluded from the nutrient solution of the absolute control cultures. Iron deficiency, on the other hand, became very prominent in the cultures not receiving iron in the nutri­ ent solution (Plate IX). h. AS. EH. 7.0 of the nutrient solution. The plants in this experi­ ment , which was carried out during the months of September and October, made a very slow growth which might be ascribed partly to low light intensity and partly to the unfavorable p H level of the nutrient solt*» tlon. The difference in growth between the plants in the frit cultures and the plants in the corresponding control cultures was here more pro­ nounced than in any of the previous experiments. The control plants reached only about half the size obtained by the corresponding frit grown plants. The control plants were in all instances very chlorotie. It was again easily observed, that the plants grown in the frits of the 6285 and 6287 series were superior in size to the plants grown in the frits of the 6286 and 6288 series* The development of the plants in the absolute control cultures was as described for the previous experiment. 5* JonftEX* T*1® visual observations made of the development of the plants, can be summarized as follows! (1) The frit cultures pro­ duced normal, green plants over a range in p H from 4.0 to 7*0 of the nutrient solution* (2 ) The corresponding control cultures of these frits produced more or less chlorotie plants whose growth was inferior to that of the corresponding frit grown plants* The degree of chlorosis and the difference in growth between the control plants and the corres­ ponding frit grown plants Increased with increase in pH of the nutri­ ent solution. (3) Frits of the series 6285 and 6287 produced at all p H levels conspicuously larger plants than the ones obtained in the absolute control cultures receiving complete nutrient solution* (4) The growth of the plants in the control cultures seemed to be related to the growth of the plants in the corresponding frit cultures in such a way that a good growth of the plants in the frit culture generally was associated with a good growth of the corresponding control plants* The visible appearances of the frit grown plants clearly showed that the favorable effect of the frits, as compared to the corresponding control cultures. Increased as the pH value of the nutrient solution increased* B. Freeh weight of the plants The fresh weights of the plants obtained in the individual cultures at the various levels of pH of the nutrient solution are listed in tables 3 «ad 4 (pH 4.0), tables 5 and 6 (pH 5.0), tables 7 and 8 (pH 6.0), and tables 9 and 10 (pH 7.0). The data show that the fresh weights obtained in the individual frit cultures are, at all pH levels, significantly larger than the fresh weights obtained in the corresponding control cultures. Farther, it will also be noticed that the fresh weight of the control plants is closely correlated with the fresh weight of the corresponding frit grown plants. Thus, a relatively large fresh weight of the plants grown in the frit was generally associated with a relatively large fresh weight of the corresponding control plants. The frits of the 6285 and the 6286 series have invariably produced larger yields of fresh weight than have the frits of the 6286 and 6288 series, and, similarly, the fresh weights obtained in the control cul­ tures corresponding to the 6285 and 6287 frit series are almost in­ variably larger than the fresh weights obtained in the control cultures corresponding to the 6286 and 6288 frit series. The relative average fresh weight obtained in the individual cultures, calculated in percent of the average fresh weight obtained in the absolute control culture receiving complete nutrient solution, is plotted againet frit composition in figures 2, 3, 4, and 5* These figures show that at all pH levels, the fresh weights obtained on the 6285 and 6287 frit cultures were significantly larger than the average fresh velght of the absolute control cultures receiving a complete nutrient solution. The same is true for the fresh velght obtained in the 6286 and 6288 frit cultures except when the nutrient solution was maintained at a pH of 5*0• In vhich case the ^plants grown in these frits obtained about the same fresh velght as the absolute control plants receiving complete nutrient solution. The figures also demonstrate that within each individual frit series there was a change in fresh velght from one frit culture to another reflected in a parallel change in the fresh weight obtained in the corresponding control cultures. The figures do, however, not indicate that the fresh weights obtained have any correlation with the amount of iron or manganese present In the frit. At p H 5*0 and 6,0 of the nutrient solution (figures 3 and k) frit Ho, 6287-B (2,0 percent MnC^) gave rise to an exceptionally large fresh velght, which would indicate that this frit represents the most favorable composition with regard to iron and manganese. The average fresh weight obtained in the control cultures within each individual frit series was calculated in percent of the average fresh weights obtained in the corresponding frit cultures, and the values obtained are plotted against p H of the nutrient solution in figure 6, The effect of raising the pH of the nutrient solution from lt,0 to 7,0 has been to Increase the difference in fresh weight between the frit grown plants and the corresponding control plants. The exceptionally low percentage value found at pH 5*0 of the nutrient solution, especially in the case of the 6288 frit series, can be explained as being due to a relatively large difference in the physio­ logical age between the frit and the control plants in this particular experiment* At the tine of harvest the frit plants had in aost cases began to Joint, while the control plants had not reached the Jointing stage* In the other eoqaerlnents the plants were harvested at a som»- what earlier stage in their development* C. Dry velght of plants The dry velght of the plants obtained in the individual cultures at different levels of pH of the nutrient solution is listed in tables 11 and 12 (pH fe*0), 13 and lb- (pH 5*0), 15 and 16 (pH 6*0) and 17 and 18 (pH 7.0). The data show that at all pH levels the dry weights obtained in the frit cultures were significantly larger than the dry weights ob­ tained in the corresponding control cultures, and that the dry weight of the control plants is closely correlated with the dry weight of the plants grown in the corresponding frit cultures* Zt is further noticed, from figures 7, 8, 9, and 10, that the frit series 6285 and 6287, at all pH levels, have produced signifi­ cantly higher yields of dry plant material than did the absolute con­ trol culture receiving complete nutrient solution* The same result is obtained with respect to the frits of the 6286 and 6288 series except at pH 5*0 of the nutrient solution* At this pH the dry weight of the plants grown in the 6286 and 6288 frits Is not signifleantly different from the fresh weight obtained In the absolute control cul­ tures receiving complete nutrient solution* The figures do not Indicate any correlation between the amount of Iron or manganese present In the frit and the dry weight of the plants produced* It ls» however, noticed that frit Vo. 6287-B (2*0 percent MnOg) has Increased the dry weight of the plants about 100 percent as compared to the dry weight obtained In the absolute control cultures receiving complete nutrient solution, and that frit Vo. 6285-C (7*5 percent Ve^O^)' on the same basis has increased the dry weight about 80 percent. The effect of pH of the nutrient solution on the relative differ­ ence in dry weight between the plants grown in frit and the ones grown In the corresponding control cultures Is demonstrated In figure 11. It will be seen that the same relative differences were obtained for dry weight as were obtained with respect to fresh weight of the plants* 3>. Absorption of Iron by the plants Surface contamination of dust may be a major source of error In Iron determinations of plant material, tfafortunately, this error was not fully recognised in thp present study until the plant material obtained from the two first experiments (pH 6.0 and 7*0) had been analysed. The inconsistencies of the analytical data pointed towards serious contaminations of the material. In an attempt to eliminate this 29 error* the plants in the third experiment (pH 4.0) were washed b y re­ peated dippings in distilled water shortly after they had been har­ vested. Somewhat more consistent results were thus obtained. A still higher degree of consistency was obtained, however, in the last experi­ ment (pH 5.0) in which the plants were dipped sereral times in a dilute hydrochloric acid solution and rinsed in distilled water before they w e r e placed in the drying oven. 1. Iron content as parts per million of dry tissue »• A t 2 & fr.O aX. the nutrient solution. The iron content expressed as parts per million of oven dry material, is listed in tables 19 and 20. The differences in iron content between the plants grown in frit and the ones grown in the corresponding control cultures are, in most instances, smaller than the differences in iron content between plants grown in duplicate cultures. There is thus no basis to conclude that the plants grown in frit contain more iron per unit dry weight than the plants g rown in the corresponding control cultures* further, the data do not indicate that the amount of iron present In the frit has had stay Influence upon the concentration of iron in the d r y material of the plants, nor is there stay Indication that the maagsunese content of the frit has had such an influence. As shown in table 20, the addition of iron to the nutrient solution has had but little influence upon the concentration of iron in the dry matter of the plants grown in the absolute control cultures. In the ease where manganese but no iron has been added to the solution a ■ light depression of the Iron concentration of the dry matter of the plants is observed. h S L SiL ShSL nutrient solution. Che iron content expressed as parts per million of the oven dry material is listed in tables 21 and 22. It will be seen from these tables, that even though there existed large differences in the data obtained from duplicate cultures, a consistently higher average value for iron content was obtained for the plants grown in frit than for those grown in the corresponding control cultures. Figure 12 demonstrates that the frit series 6285 has produced plants with a higher concentration of iron in the dry matter than has the frit series 6286. and, similarly, that the frit series 6287 has produced plants with a higher concentration of iron in the dry matter than the frit series 6 2 8 8. X close parallelism between the frit and the corresponding control cultures with res­ pect to iron concentration in the dry matter of the plants is charac­ teristic for both iron-frlt series. from figure 12 it is also seen that the addition of manganese to the frits has inersased the concentration of iron in the dry matter of the plants. This finding is not in accordance with the general belief that manganese has a depressing effect on the absorption of iron b y plants. Such a depressing effect of manganese is, however, demonstrated b y the data presented in table 22. It will be seen that w h e n both iron and manganese are added to the nutrient solution of the absolute control cultures, the concentration of iron in the d r y setter of the plants is less than when only iron is added. 31 * Similarly, w h e n only m a e a n e s e is added, the concentration of iron in the dry matter is lees than v h e n none of the two elements is added, O* £ & £*£. Z mSL s £- jtfcs, zvutrient solution. As already m e n ­ tioned, no seasures wore tahen in order to eliminate iron contamina­ tion of the material obtained in these experiments. It will be saen from tables 23, 2t, 25* and 26 that the data obtained for iron content in the dry natter are of a higher order of magnitude than the corres­ ponding data obtained in the previous experiments, and that the differ­ ences between the duplicate cultures are generally very large, Vo conclusion, therefore, can be drawn as to the relative concentration of iron in the plant material, 2, Total absorption of iron by the plants a. A t Efi &*£. J& £ aatarlwrt solution. The concentration of iro in the dry matter of the plants grown in frit and the plants grown in the corresponding control cultures did, as already pointed out, not show any significant differences. The total amount of iron absorbed is, however, larger in the frit cultures than in the corresponding control cultures as shown in table 27* The plants grown in the frits of the 6285 a nd 6287 series have absorbed more iron than the plants g rown in the frits of the 6286 and 6288 series. Further, the control plants corresponding to the 6285 and 6287 frit series have absorbed more Iren than the control plants corresponding to the 6286 and 6288 frit series. The average amount of iron absorbed by the plants grown * 32 In the absolute control cultures receiving complete nutrient solution Is in most instances lover than the amount of iron absorbed by- the frit grown plants* *>• ££. Efi 2*2. <2i the nutrient solution. At this p H of the nutrient solution it was found to b e a higher concentration of iron in the dry matter of the plants grown in frit than in the dry matter of the plants grown in the corresponding control cultures* Che total amounts of iron absorbed in the various cultures are listed in table 2 8 , and the average values are plotted against frit composition in figure 12* It will b e noticed that the plants in the frit cultures have absorbed about twice as much iron as the plants i n the corresponding control cultures* Chls is true for all four frit series* It will also be notices (table 2 8 ) that the plants grown in the frits of the 6285 and 6287 series generally have absorbed more iron than the plants gtown in the absolute control cultures reoeivlx^ a complete nutrient solution* c* A&. Sfi 6*0 and 7*0 iha. MrtrlflB* flgluUoa- Cables 29 and 30 show that, in spite of the inconsistencies of the analytical results, there is Indication of a definitely larger absorption of iron b y the plants grown in frit than b y the plants grown in the corresponding control cultures* This difference is especially noticeable when the frits series 6285 and 6287 are considered* 3* Summary of iron absorption Che data obtained for iron absorption by the plants at a p H of 5,0 of the nutrient solution are the most reliable ones, since special precautions were taken in this experiment to eliminate iron contamina­ tions of the plant material* (1) The data from this experiment showx She plants grown in the frit cultures have accumulated more iron in the tissue than the plants grown in the corresponding control cul­ tures* Shis result indicates that the frit grown plants have had a better access to available iron than the control plants* (2) She plants grown in the frits of the 6285 and 6287 frit series have ab­ sorbed more iron than the plants grown in the 6286 and 6288 frit series* which indicates that the iron present in the former frits is more available than the iron present in the latter* (3 ) She control plants corresponding to the 6285 and 6287 frit series have generally absorbed more iron than the control plants corresponding to the 6286 and 6288 frit series* which would indicate that the iron in the former frits is slightly more soluble than the iron in the latter frits* (4) There is no indication of a correlation between the amount of iron in the frit and the amount absorbed by the plants* X* Absorption of manganese by the plants 1* Manganese content as parts per million of the oven dry tissue *• A 1 22S &*£. J& & nutrient solution. Manganese content of the dry plant material is listed in tables 91 and 32* that the It is readily seen presence of manganese in the frit has had a considerable in­ fluence upon the concentration of manganese in the dry plant tissue* An increase in the manganese content of the frit from 1*0 to h*0 per­ cent *in02 has greatly Increased the concentration of manganese in the plants* It will also be noticed that the concentration of manganese in the dry matter of the control plants is of the same order of magnitude as the concentration of manganese in the corresponding frit grown plants* This is an indication of a relatively large solubility of the frit manganese* The plant8 grown in the 6287 amounts of manganese per 6288 frit series* unit dry frit seriescontain all higher weight than the plants grown inthe The solubility of the manganese in the 6287 frits* therefore* is larger apparently than that of the manganese in the 6288 frits. The absolute control plants which were supplied with a nutrient solution from which manganese was excluded did not contain any detect­ able amounts of manganese in the dry tissue* b. p g 5.0 & £ the nutrient solution* oven dry tissue is listed in tables 33 and Manganese content in the The data show the same tendency towards an increase in manganese concentration of the dry tissue following an Increase of the manganese concentration of the frit* In contrast to what was found in the previous eoqperiment* a large differ­ ence is observed between frit and corresponding control cultures with respect to manganese concentration in the dry tissue* In both iron frit series (6285 and 6286) the control plants have a higher concen­ tration of manganese than the corresponding frit grown plants* The same large)' difference in the concentration of manganese in the dry . 35 plant material is observed between frit and the corresponding control cultures of the manganese frit series 6287. Ho such difference is observed with respect to the frit series 6288. This finding, together with the relatively low manganese concentration of the plants grown in this frit, again indicates that the mamgsmese in the 6288 frit is less available to the plants than the manganese in the 6287 frit. The data also indicate that the manganese in the 6288 frit is less soluble than the manganese in the 6287 frit since the control plants associated with the latter frit contain relatively large amounts of manganese, e. A £ 12& 6.0 and 7,0 of the nutrlent solution. Manganese concen­ tration in the dry plant material is listed in tables 35. 36, 37* and 38, The data from the two experiments point out the same general re­ lationships as mentioned for the previous experiment. The observations already made regarding the relative availability of manganese in the two frit series 6287 and 6288 are confirmed in these two experiments, 2, Total absorption of manganese by the plants Total absorption of manganese by the plants, expressed as milli­ grams per ten plants, is listed in table 39 (pH h,0), table 40 (pH 5.0), table hi (pH 6,0) and table 42 (pH 7,0), The average values are plotted against frit composition in figure 13 (pH h,0), figure lh (pH 5.0), figure 15 (pH 6 ,0 ) and figure 16 (pH 7,0), The total amounts of manganese absorbed by the plants grown in the frit cultures of the iron series (6285 and 6286) is in moot cases of the same order of magnitude as the amount absorbed by the corresponding m frit grown, plants* She higher concentration of manganese observed in the control plants is thus largely compensated for by a smaller total weight of dry matter* There sure no indications in the data pre­ sented that the amount of iron present in the frit has had any influence upon the total absorption of manganese by the plants* The total amounts of manganese absorbed by the plants grown in the manganese containing frits are, in most oases, increased as the manganese concentration of the frit is increased* Bxe same relation­ ship holds true for the corresponding control plants* The most manganese has been absorbed by the plants grown in the 6287 frit series* The control plants corresponding to this frit series hare in most cases absorbed more manganese than the plants grown in the 6288 frit series* 3 * Summary of manganese absorption A review of the data pertaining to manganese in the plants points out the following! (1) The concentration of manganese in the dry matter of the control plants is of the same order of magnitude as the concentration of manganese in the dry matter of the corresponding frit grown plants when the data from the experiment at p H 4*0 of the nutrient solution are considered* In the rest of the experiments, the control plants corresponding to the frit series 6285, 6286 and 6287 contain significantly more manganese i n the dry matter than the corres­ ponding frit grown plants* The control plants corresponding to the frit series 6288 contain also In these experiments about the same amount of manganese in the dry matter as the corresponding frit grown plants. These findings seem to indicate that the control plants of the manganese frit series have had access to appreciable amounts of manganese, and that the manganese in the frits has been relatively soluble. (2) There is a strong correlation between the total amount of sutagamese absorbed by the plants and the amount of manganese present in the frit. This holds true both for the frit grown plants and the control plants, indicating that the amounts of manganese released from the frit b y the nutrient solution has Increased with increase in the amount of manganese present in the frit. (3) The large amounts of manganese absorbed b y the plants grown in the 6287 frit series as compared to the amounts absorbed by the plants in the 6288 series indicate that the manganese in the 6287 frits has been more easily available than the mangeuiese in the 6288 frits. The large amounts of manganese absorbed b y the control plants corres­ ponding to the frit series 6287 as compared to the amounts absorbed b y the control plants corresponding to the 6288 series, likewise indicate a larger solubility of the manganese in the 6287 than in the 6288 frits. IT* DISCUSSION The nost striking result of the experiments is the difference In growth between the plants in the individual control cultures and the plants in the corresponding control cultures, the frit grown plants generally being larger and having a greener and healthier appearance than the corresponding control plants. Since both the frit and the control culture received identical amounts of nutrients in the culture solution, the better growth of the plants in the frit culture must be attributed to a component of the frit only available to the plant roots upon contact w i t h the frit. Then iron containing frit was used in connection with a nutrient solution devoid in iron, the better growth of the plants grown in con­ tact with the frit as compared to that of the plants grown in the con­ trol culture must be due to a direct absorption of iron from the frit. The objection may be put forth that the iron in the frit may be soluble, but does not reach the plant roots in the control culture due to precipitation in the carboy containing the nutrient solution* In order to test this possibility, determinations were made of the amounts of iron present in the nutrient solutions at the end of the experimen­ tal periods. The results obtained in connection with the experiments carried out at pH 4.0 and pH 5*0 of the nutrient solution are listed in tables 43 and 44. It will be seen that iron was present in the nutrient solutions in negligible amounts, and that the amounts are of 39 the same order of magnitude as the amounts found In the absolute con­ trol solutions receiving no Iron. The data obtained In connection wi t h the other experiments were of the same low order of magnitude. Wie data for iron in the nutrient solutions do not Indicate any accumulation of iron with increase in the Iron content of the frits. Apparently no iron was released from the frits in amounts sufficient to support plant growth. The fact remains, however, that the control plants corresponding to the 6285 frit series made a better growth and absorbed slightly more iron than did the control plants corresponding to the 6286 frit series (see figure 12). The only explanation for this difference seems to be that the control plants corresponding to the 6285 frit series have had a slightly better access to iron than have the control plants corres­ ponding to the 6286 frit series. In spite of the negligible amounts of iron found in the nutrient solutions. It is not possible to rule out completely that a slight amount of iron may have been released by the nutrient solution flooding the 6285 frits. The amounts released has, however, not been sufficient to prevent chlorosis and stunted growth of the control plants. Another fact pointing towards a slight solubility of the frit iron is the close parallelism observed between iron absorption of the frit grown plants and the control plants. This parallelism is clearly demonstrated b y the curves for p.p.m. of iron in the dry matter of the plants grown in the 6285 frit series and corresponding control cultures « and the p.p.a. of iron in the dry matter of the plants gr own in the 6286 frit series and corresponding control cultures* In contrast to what is found for the iron present in the frit, the manganese in the frit exhibits a considerable solutlllty, as in- dieated b y the amounts of manganese absorbed by the control plants grown in connection with the manganese containing frits. The indica­ tion of a relatively large solubility of the manganese is substantiated b y chesd.eal analysis of the nutrient solutions flooding the manganese frits. Jftgure 17 demonstrates the amounts of manganese released by the various nutrient solutions. It is seen that the largest amounts of manganese are released from the 6287 frits and that the p H of the nutrient solution has haul a strong Influence upon the amounts released, ▲t p H b.O of the nutrient solution there has been released about twice as much manganese as at p H 7.0. Owing to the large solubility of the manganese in the frits there is no basis to conclude to what extent the plant roots have been able to absorb manganese from the frit by contact with the frit particles. The better growth of the plants grown in the manganese frits as com­ pared to that of the plants grown in the corresponding control cultures, must be ascribed to a n effect of the iron in the frit. It is evident from various reports in the literature that the elements iron and manganese are functionally Interrelated in their physiological effect on plants. T?1r+4T1TI’ MMI‘ and this interrelationship in nutrient cultures of wheat. (1916) studied Their data sesm to indicate that the best growth of the plants was obtained when ratio of iron to manganese in the nutrient solution was lsl* More recently Somers and Shire (1942) hare reported that the beet growth of soybeans in nutrient solution culture was obtained when the ratio of iron to manganese in the nutrient solution was within a narrow limit of 2.5> the absolute concentration of the elements being of a lesser importance than the ratio between their concentrations* Che ratio of iron to manganese in the nutrient solution flooding the manganese frits in the present experiments was apparently extremely low* especially in the ease of the 6287 frit series. It will be seen from figure 17 that at p H 4.0 of the nutrient solution* the frit 6287-’]) (4.0 percent MnO^) released mangSLnese to the solution in amounts corresponding to 10 p.p.m* of M h at the end of the experlmental period. Cable 43 shows that the iron concentration of the solution was about 5 milligrams per carboy or 0*3 p*p*m* of 7e* Chls will give a ratio of iron to manganese of about 0*03 which is far below the optimum ratios reported in the literature* Che possibility exists* therefore* that the chlorotie condition and stunted growth observed in the con­ trol cultures in certain cases may be due to manganese toxicity* If this is true, it is of Interest to notice that the plants grown in the corresponding frit cultures did not show any toxicity symptoms * although they were supplied with the same high manganese solution as the control plants* Che effect of the frit must* therefore, have been to eliminate th® uafavorabl® iroB^aaaganese ratio due to the presence of the iron In the frit. ▲seaming that the concentrations of iron and manganese in the plant tissue will be determined largely by their concentrations in the substrate* the ratio of iron to manganese in the dry matter of the plants should give an indication of the relative availability of the elements to the plant roots. This ratio is calculated for the plant material obtained In the experiment carried out at a pH of 5.0 of the nutrient solution. The data are presented in table 45. It will be noticed that the ratio of iron to manganese in the control plants is smaller than the ratio of iron to manganese in the corres­ ponding frit grown plants. This would indicate that the frit grown plants have had a better access to iron than the corresponding control plants. It is further noticed that the difference in the Iron-manganese ratio between the control plants and the corresponding frit grown plants is larger in the ease of the 6285 and 6287 frit series than in the case of the 6286 and 6288 frit series. This is another indication to the effect that the plants grown in the frits of the 6285 and 6287 series have absorbed relatively more iron than the plants grown in the 628JS and 628$ frit series. The difference in effect observed between the frits of the 6285 and 6287 series and the frits of the 6286 and 6288 series with respect to growth and chemical composition of the plants has been very pronounced, Bruch more so than the effect of changes in iron and manganese con­ centration of the frits. The main difference between the two basic formulas represented "by these frits is that the formula underlying the 6286 and 6288 frits contains about 40 percent more silica than that underlying the 6285 and 6287 frits. This difference in the basic for­ mula has been shovn to affect markedly the solubility of the frits as indicated by the data for manganese release presented in figure 17. figures 18 and 19 demonstrate the amounts of sodium released from the frits b y the nutrient solution maintained at a p H of 4.0. Again are larger amounts of the element released from the 6285 and 6287 frits than from the 6286 and 6288 frits. A correlation between the amount of sodium present in the frit and the amount released by the nutrient solution is apparent. Similar tests were made for accumulation of potassium and phosphorus in the nutrient solutions, but since these elements were added to the nutrient solution in comparatively large amounts, it was difficult to detect the small amounts which might have been derived from the frits. Che conclusion which can be drawn from the experiments is that glassy frits might be developed in which plant nutrients are held with forces strong enough to prevent their dissolution in water but which are not strong enough to prevent them from being released by the action of acid solutions or by the action of absorbing root surfaces. Since the relative difference in growth between the plants grown in frit and the plants grown in corresponding control cultures was larger at p H 7.0 than at p H 4.0 of the nutrient solution (see figures 6 and 11). one might assume that a contact absorption warn more prominent at the high, than at the low p H of the solutions* The value of using frit as a source of minor elements in large scale hydroponic gravel culture is apparent* One of the main diffi­ culties met with in this form for crop production is the maintenance of a sufficient supply of iron to the plants* Frequent applications of iron to the nutrient solution together with continuous adjustments of the pH is necessary in order to maintain a proper iron level in the solution flooding the plant roots* The results of the present experi­ ments have indicated that wheat plants can grow well* without develop­ ing chlorosis* at a pH value of 7*0 of the nutrient solution when the plant roots are in contact with iron-containing frit* In an experiment where the growth of soybean plants grown on frit was compared to that of soybean plants grown on some other materials suggested in the literature as media for gravel culture, the frit was found superior as a source of iron* The experimental procedure was identical w i th the one described for the present wheat experiments * the pH value of the iron-free nutrient solution being maintained at 7*0* The materials which were compared were: (5*0 percent Fe^O^ and 69*0 percent SlOg), (1) Frit Ho* 91**0— 1 (2) Finely ground magnetite as suggested by Baton (1936), (3) Pumice gravel as suggested by Metlln (194-2), and (4) Glass wool as suggested by Hills and Swanev (1938)* Ho quantitative measurements of the growth of the plants were made* Plate X demonstrates, however, the green and healthy appearance of the terminal leaves of the plants grown in frit as compared to the chlorotic condition of the terminal leaves of the plants grown in the *5 other media.. While the development of frits with the property of releasing iron and manganese to plant roots so far has been based mainly upon greenhouse studies, a few experiments in which the frit has been applied to soil under field conditions have been carried out. frnd and Stroasie (1951b) applied finely ground iron and manganese contain­ ing frit to a calcareous soil, and found a n increase in the yield and the manganese content of seeds and stems of bean plants, while the iron content of the same fractions was appreciably decreased. This result suggested that the ratios of iron to manganese in the frit must be carefully adjusted in order to avoid unfavorable ratios of avail­ able iron to manganese in the soil. Iftrad and Bowden (1951c) applied a finely ground iron containing frit to a fertile greenhouse soil and found Increased growth of snapdragons, which seems to indicate that iron may be a limiting factor in plant growth even though no deficiency symptoms are visible. Due to the complexity of the factors responsible for minor element deficiencies in plants, the ultimate goal of developing frits with the property of eliminating specific deficiencies when applied to the soil can only be obtained through further extensive and systematic studies. V. SUMMARY 1* The occurrence of Iron and manganese deficiencies in plants are primarily due to adverse soil conditions which render the d e m e n t s unavailable to the plants* The use of sprays or injections of salts of these elements in order to avoid the disturbing soil factors are not always applicable and do not always give satisfactory results* 2* The possibility of supplying the elements by adding slowly available compounds or artificially prepared physical complexes to the soil has been suggested and the ideal properties of such a material have been defined* It has been pointed out that the absorption of the elements will have to take place through contact between the material and the plant roots* Cases in which such contact absorption is assumed to take place have been cited* 3* The use of especially compounded glassy frits as a source of mineral elements for plants has been suggested, acid successful pre­ liminary experiments carried out in order to explore the value of frits as a source of iron to plants have been discussed* 1|>* Two frit formulas, one with UO percent of SIO2 and of and one with 59 percent of SiOg and 15 percent of 21 percent both giving good results in the preliminary experiments, formed the basis for the present study* On basis of each of the formulas, two series of frits were made up, one containing 2.5» 5«0, 7*5. ®J*d. 10*0 percent of 7e90~ and no manganese, and one containing 1*0, 2*0, 3*0, and h*0 z 3 percent of MnC^ and a constant amount of 5*0 percent of TagO^* She complete chemical compositions of all 16 frits are given* 5* Hie nutritional experiments were carried out by using the frit as a medium in hydroponic gravel culture* Che growth and chemi­ cal composition of wheat seedlings grown in a pet containing the frit was compared with the growth and chemical composition of wheat seedlings grown in a pot containing guartz gravel equal in particle size to that of the frit* Both pots were flooded at four hour Intervals with iden­ tical nutrient solution supplied from the same carboy* The nutrient solution was complete except that iron was omitted when iron was the variable factor in the frit* a n d both iron and manganese were omitted w h e n manganese was the variable factor in the frit* ▲ constant and uniform p H was maintained in the nutrient solutions, and individual experiments were carried out at pH h*0, 5*0, 6*0, and 7*0 of the nutrient solution* 6. Description of the visual appearance of the plants together with data and graphs demonstrating fresh weight, dry weight, absorp­ tion of iron and manganese are presented* 7* The frit cultures produced normal, green plants over the entire range of pH of the nutrient solution* The quartz cultures produced more or less ehlorotlc plants, and the growth, as Judged b y fresh and dry weight data, was inf erior to that of the corresponding frit grown plants* The frit series with the lowest silica content pro­ duced at all p H levels significantly larger plants than was obtained in absolute control cultures where plants grown in quartz were supplied with a complete nutrient solution containing 4.0 p.p.m. of iron 0.5 p.p.m. of manganese. 8. She data for fresh and dry weight, the data for iron absorption, together with data showing that no accumulation of iron took place in the nutrient solution, have all indicated that the plants have been able to obtain iron from the frit by contact absorption. Data for manganese absorption and manganese accumulation in the nutrient solu­ tion have indicated a relatively large release of manganese by the nutrient solution, especially at low pH values, Vo conclusion can thus be drawn as to what extent eontaqt absorption has played a role in the absorption of manganese from the frit. YT. LITERATURE CITED Albert8 , V. B* 1934* further observations on manganese deficiency In oats at Florence, South Carolina* South Carolina Agr* Hxp* Sta* 47th Ann. Rep*, p. 45* Badger, A. X* and R* H. Bray-* ser possibilities* Bennett, J* P* 1927* fruit trees* 1945* Soluble glass may offer fertili­ Chem* & Met* Xng*, 52, Bo* 112-113* fhe treatment of lime-induced chlorosis in Phytopathology, 17*745— 746. Chandler, V* 7* and G. 3>* Scarseth. 1941* Iron starvation as affected b y over-phosphating and sulfur treatment on Houston and Sumter Olay soils* Chapman, H* J. Am* Soc* Agron*, 33*93-104. D* 1931* Absorption of iron from finely ground magnetite by Citrus seedlings* Conner, S* D* soils* 1932* Soil Sei*, 48*309— 317* Factors affecting manganese availability in J. Am. Soc. Agron*, 24*726-733* Baton, F. M* 1936* Automatically operated sand— culture equipment. J. Agr. Research, 53*433-444* Bills, C. and M* V* Svaney* 1938* Soilless growth of plants* Rein­ hold Publishing Corporation, Bew York, pp. 65-68* Gilbert, B. X* manganese* 1934* Bsrmal crops and the supply of available soil Rhode Island Agr* Bsp* Sta* Bull* 246* _______________ , F. T. McLean and L* J. Hardin* 1926* of manganese and iron to a lime-induced chlorosis* 22*437-446* The relation Soil Scl*, Guest, P. 1. 1944. Boot contact phenomena in relation to iron nutri­ tion and growth of Citrus, Proc. Am. Soc. Eort, Sci., 44:43-48. Hummell, F . G. and H. H* V I H a r d , biological materials, Inskeep, G, 0, 1951* 1938, Determination of iron in Ind. Aig, Chem,, Axial, B d , , 1 0 t13-15. Prit for flowers. Ind. Sag. Chem., 43, Ho. 3, p. 17A. Jenny, H. and B. Owerstreet. roots and soil colloids. Johnson, K. 0. 1917. 1938. Contact effects between plant Proc. Hat. Acad. Sci. XT. S., 24x384— 392. Manganese as a cause of the depression of the assimilation of iron b y pineapple plants. J. Ind. Big. Chem., 9,4?-*9. Lindner, B. C. and C. P. Harley. lime-induced chlorosis. Matlin, D. B. 1942. 1944. Hutrlent interrelations in Plant Physiol., 19*420— 439. Chemical Gardening. Chemical Publishing Co., Brooklyn, H. T . , pp. 99— 104. McGeorge, V. T. 1923* The chlorosis of pineapple plants grown on iBanganlferous soils. Olsen, C. 1935. Soil Sci., 1 6 x269— 274, Iron absorption and chlorosis in green plants. Compt. rend. trar. lab. Carlsberg. Ser. Chim., 21x15— 52. Proa C. A., 29*7398 (1936). 0* Bippel, A. 1923. Uber die durch Mangan ▼erursachte Bisenchlorose bei grunen Pflanzen. Samuel. O. and C. S. Piper. disease of oats. 789-799. Bio chem, Z., 140x315— 323* 1928. Grey Speck (Manganese deficiency) J. Dept. Agr. 8. Australia, 31*696— 705 cont. Schreiner, O. and P. S. Dawson. and fertilisers. 1927* Ind. Sag. Chem., 19:400— ^0^. Sherman, 0. S. and P. M. Earner. on alkaline organic soils. Shire, J. If. 1915. Manganese deficiency in soils 1941. Manganese deficiency of oats J. -Am. Soc. Agron., 33:1080— 1092. A three-salt solution for plants. Am. J. Botany, 2:157-160. Sideris, C. P. and B. H. Kraus. 1933* The effect of sulphur and phos­ phorus on the availability of iron to pineapple and maise plants. Soil Sci., 37:85-97. Skinner, J. jr. and B. V. Buprecht. with truck crops. soil. III. 1930. fertilizer experiments Truck crops with manganese on ealcareous florida Agr. Xxp. Sta. Bull. 218, pp. 37— 65* Somer, I. I. and J. V. Shire. plant aetaholism. The iron—manganese relation in Plant Physiol., 17:582— 603. T h o m e , D. If. and A.. Wallace. of high lime soils. 19^2. 19^. Some factors affecting chlorosis 1. ferrous and ferric iron. Soil Sci.. 57:299-311. Tottingham, V. B. and A. J. Beck. 1916. 'end iron in the growth of wh^nt. Antagonism between manganese Plant World, 19:359-^70. e Wain, R. L . , B. J. Silk, and C. B. m i l s . sulfate in alkaline soils. Wallace, T. 1928. 19^3. The fate of manganese J. Agr. Sci., 33:18-22. Inrestigations on chlorosis of fruit trees. II. The composition of leaves, bark, and wood of current season's shoots in oases of lime-induced chlorosis. 7:172-183. J. Pomol. Hort. Sci. Wallace, T. 1929* Investigations on chlorosis of fruit trees* She control of lime-induced chlorosis in the field. 17* J. Porno1. Sort. Sci., 7t251-269* . and'!** Ogilvie. 19*H* tural and Horticultural crops* 194-1* Manganese deficiency of .Agricul­ Summary of investigations, season Ann. Hep. Agr. and Hort. Research Sta., Long Ashton, Bristol, 1941, POP* 45—48* . and H. J. Hewitt. crops* 1946* Studies in iron deficiency of I* Problems of iron deficiency and the interrelationships of mineral elements in iron nutrition. J. Poraol. Hort. Sci., 22*153-161. Vi H a r d . H. H. and L. H. Greathouse. 1917* The colorimetric deter­ mination of manganese b y oxidation vith periodate. Soc. J • Am. Chem* 39*2366-2377. Villls, L* S. 1928* Response of oats and some coastal plain soils. _ 1932* Ifynd. V* L* 1950* Worth Carolina Agr. Hrp. Sta. Bull* 257 The effect of liming of manganese and iron. soybeans to manganese on soils on the availability J. Am. Soc. Agron., 24*71^726. The use of iron containing frits as a new- medium for hydroponic culture. Michigan Agr* Xxp. Sta., Quart. Bull* 33# PP* 52-53* ._____ , 1951a* Availability to wheat plants of iron in very insoluble glassy frits. ___________. Cad'S:**A. Bowden. vsfjr i n s o l u b l e Lloydia, (in press)* 1951b. Responses of snapdragons to iroxr“C o n t a i n i n g f r i t * Lloydia, (in press). Vynd, F. L* and X* R. Stromme. 1951c* Absorption ot manganese and iron b y 5avy bean plants grown in a calcareous soil fertilized with a manganese—containing glassy frit* Zlmmerley, H* H* tion. 1926* Lloydia, (in press)* Soil acidity in relation to spinach, produc­ Virginia Truck Sta. Boll* 57* From Z*S.R*, 57*832 (1927)* VII, APFSHDIXBS. ANALYTICAL PROCKDORHS 1, Determination of iron BXADXBTS Acetic acid, 2 V Dilate 114 milliliters of glacial acetic acid (Sjp. dr, 1.04) to one liter with distilled water. flEHSfihlSZlSL fi£UL> iBBSBlaB filissti. 1*1 (»H^)2H06H 507 1 p.rc.5. Store in a refrigerator* Discard as soon as color derelops, gpltttjl.pp. Dissolve 1 gram of o—phenanthroline monohydrate in distilled water. Warm if necessary to effect solution, and dilute to 200 milliliters. ftodiup acetate. 2 M. Dissolve 272 grams of sodium acetate trihydrate in distilled water and dilute to one liter. Iron. Standard solution. Dissolve 1.000 gram of electrolytic iron in $0 milliliters of a ten percent sulfuric acid solution. necessary to hasten reaction. liter with distilled water. Warm if Cool, and dilute to one One milliliter contains one milligram of iron. PBOCXDOQELB Plpet an aliquot of 10 milliliters into both a 25 milliliters volumetric flaslc and a JO milliliters beaker. To the solu­ tion in the beaker add 5 drops of bromophenol blue indicator. Titrate this section with 2 M sodium acetate until the color matches that of an equal volume of a buffer solution of pH 3.5 containing the same quantity of indicator. Add 1 milli­ liter of the hydroquinone solution and 2 milliliters of the o— phenanthroline solution to the section in the volumetric flask and adjust the p H of the contents to 3*5 by adding the same volume of sodium acetate, If a turbidity develops upon adjustment of the p H of the aliquot in the beaker, add one milliliter of ammonium citrate solution to the volumetric flask before adding the sodium acetate solution. Hake to volume w i t h distilled water, mix, and let stand for one hour to assure complete color development. Measure optical density in the Coleman spectrophotometer using a PO-4 filter, a wave length of 510 mj* , and a water blank. Prepare a series of standard solutions containing 0,01 to 0,10 milligrams of iron per 25 milliliter volumetric flask. Develop color as above. centration of iron. Plot optical density against con­ 2. Determination of manganese RHAGJHTS Sodium metaperiodate. flMfPfrffrtg a d d . Sulfuric acid. Sodium fidtllft- Fine powder. 85 percent Concentrated Tine powder Potassium pgEnfifififiB&JLS.* Standard solntion containing 0.0250 milligrams of manganese per milliliter. Prepare a 0.10 V standard potassium permanganate solution. Add 22.8 milliliters of the standard solution to a 250 milliliters JSrlenmeyer flask. Add about 50 milliliters of distilled water and 1 milliliter of concentrated sulfuric acid. Heat to boiling and reduce the perman­ ganate b y adding sodium sulfite powder. excess of the sulfite. Avoid a large Boil off the excess sulfur dioxide and dilute to one liter. Thch milliliter of this solution contains 0.0250 milligram of manganese. FROCXDOKE Plpet a n aliquot of 20 milliliters into a 25 milliliter volumetric flask. Add 1 milliliter of 85 percent phosphoric acid and about 50 milligrams of the sodium periodate. place in water bath at 95° C. Mix well, and Let stand for two hours. Cool, make to volume with distilled water, mix. and measure optical density in the Coleman spectrophotometer using a PC-4 filter. a wave length, of 53Omjj and a water blank. Prepare a series of standard solutions containing 0.0125 to 0.250 milligram of manganese per 25 milliliter volumetric flask. oolor as above. of manganese. Develop Plot optical density- against concentration 3* Determination of Potassium and sodium in nutrient solutions by means of flame-photometer POTASSIUM Potassium nitrate. Standard solution containing 1000 parts per million of potassium* Dissolve 2*5859 grams of XBD^ in 1000 milliliters of dis­ tilled water* fe£kEE22n& solution* Dissolve 0*75 gram of MgSO^.THgO and 0.25 grams of Ca(S0^)2 * ^ ^ 0 in 1000 milliliters of distilled water. This solution contains magnesium and calcium in approximately the same concentration as the sample of the nutrient soltw tlon prepared for flame photometric analysis* Prggytot B y proper dilutions of the standard potassium nitrate solu­ tion with the background solution prepare a series of solutions containing 0 to 150 parts per million of potassium* Calibrate the Instrument to read 10O for the 150 parts per million solution and 0 for the 0 parts per million solution. Prepare a standard curve by- plotting the intensity reading of each solution in the series against concentration* of the unknown from the curve* Bead the concentration sodium Sodium chloride. Standard solution containing 1000 parts per million of sodium* Dissolve 2*5^16 grams of XEaCl in 1000 milliliters of dis­ tilled water* Background solution. Dissolve 0*75 gram of MgSO^.T^O, 0*25 gram of 0a(TO^)2 * and 0*55 gram of KH^PO^ in 1000 milli­ liters of distilled water* Shis solution contains magnesium, calcium, and potassium in approximately the same concentra­ tion as the sample of the nutrient solution prepared for flame photometric analysis* PrnflaAnra proper dilutions of the standard sodium chloride solution with the background solution, prepare a series of tlons containing 0 to 100 parts per s o It w million of sodium* Calibrate the instrument to read 100 for the 100 parts per million solution and 0 for the 0 parts per million solution* Prepare a standard curve by plotting the iin­ tensity reading of each solution in the series against concentration. from the curve* Read the concentration of the unknown 4. Determination of the solubility of frits The frit was finely ground in a mortar and then screened to obtain a sample of material passing a 200 mesh screen* was dried at 110° C. for thirty minutes* She screened sample A 2 gram sample was trans­ ferred to a 100 milliliter volumetric flask* and water was added to give 100 milliliters* She flask was held at 70° C* for 90 hours in a water bath, and the suspension was filtered through Ho. 42 Vhatman filter paper* The filtrate was brought to 100 milliliters and the dissolved material determined by evaporating a suitable aliquot in a platinum dish* She residue was heated to a dull red color before cooling and weighing* Solubility was calculated in percent* As basis for the evaluation of the solubilities found for the frits* determinations were made of the solubility of the glass used for an ordinary Coca Cola bottle and that used for a commercial plate glass* She solubility was in both cases found to be 1*5 percent* Table 1. Chemical composition of frits used in preliminary studies on the availability of Iron in frit to wheat plants* Oro^ 1 2 3 frit Ho. ____________ Percentage of______ OaO HgO ,e2°3 Si02 ?2°5 ¥ percent 100.0 100.0 100.1 0.8 0.6 0.3 10.0 15.0 5.6 5.3 5.0 3.8 3.5 3.3 7.4 6.9 6.6 7.4 6.9 6.6 46.0 43.7 40.4 8.4 15.8 21.8 9.4 8.4 8.6 6.1 5.5 4.8 12.5 10.9 9.6 12.5 10.9 9.6 99.9 100.2 99.8 20.0 8.0 2.0 36.4 34.3 31.7 10.1 18.6 25.3 11.3 9.9 10,0 7.2 6.5 5.6 15.0 12.9 11.2 15.0 12.9 U.2 100.0 36.0 100.1 31.0 11.0 6224-1 6224-B 6224-0 5.0 5.0 5.0 66.0 62.4 58.6 6238-1 6238-5 6238-C 5.0 5.0 5.0 62k 1-1 5.0 5.0 5.0 6241-B 6241-C *2° Solubility perci 5.0 100.0 Table 2. Chemical composition of frits used in the present study on the availability of iron and manganese in frit to wheat plants. Trlt PoreonUgo of_____________________ ** Vo__________________ « OaO KgO la20 Si<> 2 *2°3 te02 ?2°5 m w V V 2.5 6285-1 6285-B 6285-C 6285-C 5.0 7.5 10.0 6287-1 6287-B 6287-C 6287-B 5.0 5.0 5.0 5.0 6286-I 2.5 6286-7 5.0 7.5 6286-8 6286-H 6288-1 6288-7 6288-8 628ft-! 10.0 5.0 5.0 5.0 5.0 ^ percent! 0 0 0 0 8.9 8.6 8.4 8.2 5.0 4.8 4.7 4.6 9.85 9.6 9.34 9.1 9.85 9.6 9.3** 9.1 22.2 21.8 21.2 20.5 41.6 40.4 39.4 38.3 99.9 99.8 99.9 99.8 1.0 2.0 3.0 4.0 8.5 8.5 8.3 8.2 4.7 4.7 4.6 4.6 9.5 9.4 9.3 9.2 9.5 9.4 9.3 9.2 21.6 21.4 21.2 20.9 40.0 39.6 39.2 38.8 99.8 100.0 99.9 99.9 0 0 0 0 6.0 5.9 5.7 5.6 3.4 3.3 3.2 3.1 6.9 6.7 6.6 6.4 6.9 6.7 6.6 6.4 15.4 15.0 14.6 14,2 59.3 57.7 56.2 54.7 100.4 100.3 100.4 100.4 1.0 5.8 5.8 5.7 5.6 3.2 3.2 3.2 3.2 6.6 6.6 6.5 6.4 6.6 6.6 6.5 6.4 14.8 14.7 14.5 14.4 57.3 56.8 56.0 55.6 100.3 2.0 3.0 4.0 100.7 100,4 100.6 Table 3* Fresh weight, m gnuas per sen pianxs, ootBinea in i m ana q w r » control cultures supplied with nutrient solution of pH 4,0, i n V flu# « Pereant *2°3 6285-A 6285“B 6285-C 6285-D 5.0 7.5 10.0 6287-A 6287-B 6287-C 6287-D 5.0 5.0 5.0 5.0 6286-1 6286-T 2.5 5.0 7.5 6286-0 6286-H 6288-E 6288-J 6288-0 628®-?. 2.5 10.0 5.0 5.0 5.0 5.0 Culture 1 Culture 2 Average Eelative average absolute control (tle+ih) - 100 Kn02 Qnarts Prit Quarts Prit Quarts Prit Quarts Prii 0 0 0 0 10.5 9.9 11.5 8.9 13.9 10.7 15.0 14.6 10.4 11.2 9.4 9.5 14.3 13.6 12.3 13.1 10.5 10.6 10.5 9.2 14,1 12,2 13.7 13.9 115 155 116 134 115 101 151 153 1.0 2.0 12.6 10.5 10,4 10.8 13.2 13.9 14.6 13.3 11,8 10.4 9.7 10,4 12.9 13.6 12.7 12.1 12,2 13.1 13.7 13.7 12.7 134 115 111 m 151 151 116 140 0 0 0 0 8.5 8.5 8.6 7.4 11,4 10.5 10,4 9.9 8.2 7.6 9.4 11.9 12.1 13.4 92 89 99 107 130 132 115 1.0 2.0 9.2 9.3 8.8 9.1 9.9 11.4 9.3 11.1 10.4 6.1 8.4 8.9 3.0 4.0 3.0 4.0 10.5 10.1 10.6 11.8 12,0 10.6 12.3 8.4 8.1 9.0 9.7 11.7 9.8 11.3 10.9 9.8 7.7 8.6 9.0 10.8 10.6 10.5 11.1 10.3 11.0 108 85 95 99 122 119 116 113 121 Table 4. fresh weight, in grams per ten plants* obtained In absolute control cultures supplied with nutrient solution of pH 4.0. Treatment re p.p.m. Hn. p.p.m. Culture 1 Culture 2 Culture 3 pot 1 pot 2 pot 1 pot 2 pot 1 . Average Belatire pot 2 of all average pots ; 4.0 0.5 6.6 6.7 10.3 13.3 8.4 9.2 9.1 100 0 0.5 7.1 7.6 10.5 10.5 11.3 11.3 9.7 107 4.0 0 8.6 8.0 9.1 8.2 8.3 • CO 8.4 92 0 0 3.1 3.3 9.4 9.1 9.4 9.9 7.3 60 p\ vn Table 5. Presh weight, in grans per ten plants, obtained in frit and quart* control cultures supplied with nutrient solution of pH 5*0* Percent Culture 1 Culture 2 Average fTl v JlOe *2°3 **2 0 0 0 0 Quart* Prit Quarts Prit Itnrti IVit Quarts Prit 11.3 17.0 18.5 26.8 26,4 27.5 15.2 19.6 18,0 22.2 26.6 22.1 22.8 27.0 19.1 22,1 17.5 21.2 70 90 83 102 123 114 113 124 12.5 27.8 20,9 17.7 26.4 30.9 23.7 31.0 28,5 18,1 25.7 21,1 18.5 83 118 97 85 109 143 134 129 13.6 15.4 20.9 23.4 21.5 24.7 17.0 16.5 15.0 17.1 20.9 22,0 20.5 23.0 78 76 69 79 96 101 94 106 22.4 17.6 21.6 10.7 8.6 10.5 23.0 8.9 20.9 19.4 17.9 20.8 49 40 48 41 96 89 82 96 6285-A 6285-B 6285-C 6285-D 10.0 6287-A 6287-B 6287-C 62B7-B 5.0 5.0 5.0 5.0 1.0 2.0 3.0 4.0 23.7 23.5 21.2 1*;3 21.0 31.0 32.2 27.5 6286-2 *8-3 6?rr„ij 2.5 5.0 7.5 10,0 5.0 5.0 5.0 5.0 2.5 5.0 7.5 10,0 5.0 5.0 5.0 5.0 Relative average absolute control ( Pe Ito) r 100 Opart* Trit Quart* Prlt Quarts frit 0 0 0 0 1.38 2.14 2.43 3.19 3.94 3.21 3.31 3.97 2,26 2.70 3.62 1,82 2,42 2.68 3.97 3.75 3.71 2.94 3.78 3.59 3.53 3.84 82 77 100 1.0 2.0 3.0 4,0 2.81 3.17 2.74 2.1KJ 3.47 4.07 4.60 4.05 1.47 3.96 2.90 2.33 3.94 5.03 3.87 4.28 2.14 3.56 2.82 2.37 3.71 4.?o 4.24 4.17 73 121 96 81 126 160 0 0 0 0 2.39 2.00 1.43 1.91 2,68 2.65 2.56 2.74 1.69 2.00 1.89 2.15 2.79 3.U 3.15 3.25 2,04 2.00 1.66 2.03 2.74 2.88 2.86 69 68 56 69 93 98 97 102 1.0 2.0 3.0 4.0 1.67 2.59 2.71 2.07 1.80 1.50 2.20 1.59 3.15 2.53 3.41 3.17 1.74 1.48 1.00 1.54 59 50 98 89 93 99 **2 1.46 1.39 l.*9 2.63 2.08 2.26 3.00 2.87 2.62 2.74 2.90 Quarts 62 61 52 Prit 129 122 120 131 144 142 Table 14. Dry weights, in grans par tan plants, obtained In absolute control cultures supplied vlth nutrient solution of pH 5.0. Treatment Oulture 1 Te Nn p.p.*. P*P«B« *.0 0.5 2.96 0 pot 1 pot 2 Oulture 2 pot 1 pot 2 Culture 3 pot 1 pot 2 of all averag pots 3.32 2.94 1.37 1.26 2.12 1.97 1.30 1.32 2.77 2.94 100 1.59 1.40 1.58 1.42 48 2.05 1.87 2.67 2.62 2.22 76 1.20 0.97 1.86 1.79 1.41 48 2.50 3.17 0.5 1.29 4.0 0 0 0 a Table 15* Dry weights, In grans par tan plants, obtained in frit and qnarts control cultures supplied vith nutrient solution of pE 6,0. Percent Oulture 1 Culture 2 Average i n v AO# JMt 0 0 0 0 4.15 4.23 3.95 3.25 9.95 5.97 6.93 9.95 1.0 &85-A 6285-B 6285-0 6285-® 2.5 5.0 7.5 10.0 6287-A «8M 5.0 5.0 5.0 5.0 6287-0 6287-® 6286-S 6286-1 6286-0 6286-H 6283-B 62?8-F 6?6*-t 6rr8-i 2.5 5.0 7.5 10,0 5.0 5.0 5.0 5.0 frit Quarts JWt Quarts frit 3.51 3.30 2.75 9.03 5.68 5.02 5.52 5.68 3.77 3.35 3.69 5.32 5.50 6.23 5.32 110 108 96 105 153 158 179 153 3.18 9.76 3.15 3.05 5.55 8.47 5.08 4.17 3.05 3.98 3.90 3.16 9.96 7.38 5.92 9.10 88 114 98 91 143 212 156 118 4.95 4.34 4.49 4.24 3.91 2.69 2.55 2.95 9.39 9.08 9,20 3.56 98 82 73 70 126 3.86 2.77 3.09 2.89 9.99 3.52 9.05 9.19 111 80 87 83 3.0 2.92 3.19 3.ft 4.0 3.27 9.36 6.28 5.76 9.03 0 0 0 0 2.77 2.00 1.95 1.51 3.83 3.81 3.90 2.88 9.05 3.68 3.19 3.38 1.0 2.0 3.0 4.0 3.99 2.7? 9.70 r\ CM• -d- KnO 2 CO • Qnarts P.2°3 5.28 3.5? 3.55 3.99 --- — 2.90 2.84 4.54 4.83 2.0 3.17 2.93 Relative average absolute control ( Je to) - 100 - 117 121 102 143 101 116 119 Table l6. Dry weights, in graas per ten plants, obtained in absolute control cultures supplied with nutrient solution of pH 6,0, Treatment Oulture 1 Oulture 2 Oulture 3 Te p.p.B. Mn p.p.a. pot 1 pot 2 pot 1 pot 2 pot 1 pot 2 of all pots 4.0 0.5 3.1* 3.32 3.46 3.92 3.49 3.54 3.48 100 0 0.5 3.43 3.02 2.15 2.44 3.78 3.89 3.12 90 4.0 0 3.38 NO • 3.44 3.20 --- -- C" MN C • 95 0 0 2.24 2.73 3.23 3.00 2.20 2.58 2.66 76 awerage Table 17* Dry weights, in grant par tan plants, obtained In frit and quarts control cultures supplied with nutrient solution of pH 7.0. Percent Oulture 1 Oulture 2 Average Helatire average absolute control «j.iv av t .____ M l ft. v = 100 3 * * 8295-0 2.5 5.0 7.5 0 0 0 8285-9 10.0 0 8287-1 5.0 5.0 5.0 5.0 628J-1 8285-1 8M M 8287-C 6287-9 6286-1 6288-7 6288-0 62B6-H 8288-B v2 ° 0- ? *2P8-E 2.5 5.0 7.5 10,0 5.0 5.0 5.0 5.0 1.0 2.0 3.0 *.0 0 0 0 0 1.0 2.0 3.0 4.0 Quarts frit Quarts frit Quarts frit 0.78 1.03 0.95 0,80 1.83 1.81 1.69 1.56 0.89 0.73 0.79 0.97 1.79 1.77 1.17 1.66 0.84 0.83 0.87 0.89 1.81 1.79 1.43 1.61 72 71 74 76 155 153 122 138 1.18 1.10 1.05 0.98 1.95 1,88 1.49 1.73 0,86 1.00 0.95 1.14 2,16 1.86 1.84 1.74 1.02 1.05 1.00 2.06 1.87 1.67 1.74 87 90 85 91 176 0.83 1.16 0,74 0.73 0.76 1.05 O.83 0.92 0.77 0,86 1.42 1.34 1.36 1.44 0.83 O.83 0.75 0.81 1.29 1.20 71 71 64 69 110 102 110 115 0.73 0.97 0.86 0.74 1.25 1.18 C.84 0.78 0.89 0.84 1.44 1.59 0.79 0.88 0,88 0.79 1.35 68 75 75 68 115 118 121 1.22 1.26 I.23 1 . 37 1.61 1.58 1.06 1.29 1.35 1.39 1.42 1.48 Quarts frit 160 143 149 126 Sable 18, Dry weights, in grass per ten plants, obtained in absolute control cultures supolied with nutrient solution of pH 7*0. Treatment re Oulture 1 Oulture 2 pot 2 pot 1 pot 2 of all pots aven 1.36 1.28 1.17 1.17 1.17 100 0.89 0.73 0.63 1.09 1.00 0.88 75 1.38 1.26 1.05 0.98 1.58 1.64 1.31 112 0.82 0.83 0.73 0.71 1.26 1.32 0.95 81 Mn p.p.*. Pot 1 pot 2 pot 1 4.0 0.5 1.03 1.03 0 0.5 0.93 4*0 0 0 0 l>*p.a. Oulture 3 Table 19* Frit Ho. 6285-A control 6285-B control 6285-C control 6205-fi control 6287— A control 6287-B control 6287— 0 control 6287- D control 6286-B control 6286- y control 6286- O control 6286- H control 6288-1 control 6288-1 control 628^*0 control 6288- H control Iron content, expressed as parts per million of oxen dry tissue, of plants grown in frit and quartz control cultures supplied with nutrient solution of p H 4.0. r»rc.nt__________ CaltTire X______________ C n l t w 2 Mn02 Det. 1 Det. 2 Avs. Dot* 1 Set. 2 Are* 2.5 0 5.0 0 7.5 0 10.0 0 5.0 1.0 5.0 2.0 5.0 3.0 5.0 4.0 2.5 0 5.0 0 7.5 0 10.0 0 5.0 5.0 1.0 2.0 5.0 3.0 5.0 4.o of^fh cultures 151 47 119 111 91 110 87 85 151 56 107 105 107 119 83 87 151 52 113 108 99 115 85 86 79 93 79 76 79 78 67 71 80 83 83 83 87 63 71 66 75 88 81 80 83 71 69 69 113 70 97 94 91 93 77 78 78 83 109 103 91 107 79 88 75 83 102 103 89 105 85 88 77 83 106 103 90 106 82 88 75 95 79 83 73 79 95 87 92 78 99 69 78 80 88 75 94 79 91 71 79 88 88 76 89 93 97 81 93 85 88 91 14 83 112 93 95 94 95 86 14 79 99 87 90 96 94 89 14 81 106 90 93 95 95 96 83 75 87 51 76 79 81 95 87 75 88 40 79 84 87 96 85 75 88 46 78 82 84 93 85 78 97 68 86 86 90 107 111 90 72 38 92 96 103 88 83 95 116 76 62 79 62 88 87 92 88 85 94 116 76 62 80 62 98 98 92 94 57 77 88 83 107 110 90 75 43 89 97 103 112 — 68 32 95 95 103 — — —— 9k — Table 20* Iron content, expressed at parte per Million of oven dry tissue, of plants grown in absolute control cultures supplied with nutrient solution of pB 4*0, Treatsent Culture 1 Culture 2 Culture 3 pot 2 pot 1 pot 2 pot 1 pot 2 pot 1 7e Mn . t.p.n. p.p.m. Det,iDet. ire. Det..Dot. Are. Det,,Det. Are, Det,.Det. Are. Det,i Det. Are. Det,■ Det. Are. 2 2 2 2 1 2 1 2 1 1 1 1 Arei »«< 94 95 87 87 87 95 103 99 87 89 88 83 99 91 97 97 97 93 75 75 75 73 70 72 — — — 75 75 80 81 81 73 71 72 75 0 101 95 98 95 87 91 85 80 83 — — - 11* - 11* 97 - 97 97 o 110 •— 110 79 _ 79 75 7* 75 87 79 83 105 105 95 99 97 92 *.0 o,5 95 0 0.5 *.0 0 — Tto.'ble 21. Prit Ho. 6285-A control 6285-B control 6285-C control 6285-D control Iron content, expressed as parts per million of oven dry tissue, of plants grown in frit and quartz control cultures supplied with nutrient solution of p H 5.0. Percent___________Oulture 1______________Culture 2 PegO^ Mn02 Det. 1 Det. 2 Ave. Det. 1 Det. 2 Ave. 2.5 0 5.0 0 7.5 0 10.0 0 6287-A control 6287-B control 6287-0 control 6287-D control 5.0 1.0 5.0 2.0 5.0 3.0 5.0 *.0 6286-B control 6286-P control 6286-0 control 6286- H control 2.5 0 5.0 0 7.5 0 10.0 0 6288- B control 628ft-V control 62d8*»0 control 6288-H control 5.0 1.0 5.0 2.0 5.0 3.0 5.0 *.0 Average of cult tires 91 58 72 53 70 79 79 6* 76 56 74 52 71 83 78 60 84 57 73 53 71 81 79 62 80 91 76 73 119 64 79 56 81 96 75 77 111 66 74 56 81 94 76 75 115 65 77 56 83 76 75 64 93 73 78 59 108 60 89 83 95 67 90 75 108 64 95 79 95 70 83 67 108 62 82 81 95 69 87 71 89 105 110 91 ill 95 117 135 94 85 111 83 112 97 117 121 92 95 111 87 112 96 117 128 100 79 97 84 104 83 102 100 47 46 65 57 56 51 79 70 46 34 72 55 63 50 78 72 47 39 69 56 60 51 79 76 87 75 56 55 77 83 66 57 81 75 67 56 73 64 67 57 84 75 62 56 75 74 67 57 66 57 66 56 68 63 73 67 75 65 70 60 81 75 86 78 79 65 71 65 102 75 100 71 77 65 71 63 92 75 93 75 80 62 83 79 87 98 102 84 93 62 87 79 93 89 98 76 87 62 85 79 90 94 lOO 80 82 64 78 71 91 85 97 78 Table 22. Iron content, eipressed as parts per nllllon of oven dry tissue, ef plants grown In aVeolute control cultures stalled with nutrient solution of pH 5.0. Treat&ent Oulture 1 Culture 2 Culture 3 • P®t 1 P®t 2 pot 1 pot 2 pot 1 pot 2 re Nn - - p.p.m. p.p.m. Det. Det. Are. Det. Det. Are. Det. Det. Are. Dot. Det. Ave. Det. Det. Ave. Det. Det. Are. 1 2 1 2 1 2 1 2 1 2 1 2 ATiP" age 00 4.0 0.5 6? 70 69 75 75 75 86 96 91 75 75 75 71 78 75 71 71 71 76 0 0.5 75 79 77 6o 56 58 56 56 56 53 51 J2 71 75 73 6o 61 61 63 4.0 0 85 85 85 75 75 75 120 110 115 115 103 109 - 71 71 74 73 74 88 o 0 47 44 46 44 40 42 101 — 74 8? 81 74 87 81 74 101 — 91 91 u> Table 23. Iron content, expressed as parts per million of o r on dry tissue of plants grown in frit and quartz control cultures supplied with nutrient solution of p H 6.0. Percent Culture 1 OX P o 203 6285-A control 6285-3 control 6285-C control 6285-D control 6287-A control 6287-3 control 6287-C control 6287-D control 6286—H control 6286-P control 6286-8 control 6286-H control 6288-3 control 6288-3 control $2860 control S288—H control Average Culture 2 X1 1 v mU* Hn02 2.5 0 5.0 0 7.5 0 10.0 0 5.0 1.0 5.o 2.0 5.0 3.0 5.0 4.0 2.5 0 5.0 0 7.5 0 10.0 0 5.0 5.0 1.0 2.0 5.0 3.0 5.0 4.0 Dot. 1 Set. 2 Are, Det. 1 Pet. 2 A t *. culture 170 132 147 122 127 107 140 132 167 127 140 122 130 105 140 135 168 130 144 122 129 106 140 134 142 147 180 155 162 167 167 152 127 145 180 155 162 167 157 152 145 146 180 155 162 167 162 152 157 138 162 136 146 137 151 143 165 165 135 167 167 162 312 140 165 162 135 162 167 162 312 140 165 164 135 165 167 162 312 140 147 162 120 140 140 127 147 152 147 162 122 135 138 132 152 147 147 162 121 137 137 130 150 150 156 164 128 152 153 147 150 145 110 125 145 137 160 147 160 155 92 125 145 135 155 147 160 155 96 125 145 136 157 147 160 155 207 175 162 152 222 142 140 157 197 175 157 152 220 140 141 157 202 175 160 152 221 141 141 157 150 150 153 145 158 144 150 156 147 127 175 179 187 199 132 110 155 127 175 180 187 120 132 112 151 127 175 179 187 121 132 111 157 180 — 157 184 155 156 175 180 171 138 140 133 —— 155 152 147 155 187 —— — 152 155 147 155 ----- 154 154 147 155 Table 2*. Iron content, expressed as parte per Billion of orea dry tleene, of plants grown in abeolnte control cnltnres supplied with nutrient solution of pH 6.0, Treatsent Oulture 1 Culture 2 Pot 1_______ pet 2 Culture 3 pet1_______ pet 2_______ pot 1 pet 2 p,p,n, p.p.m. Pet, Pet, ire. Pet, Pet, Are, Pet, Pet, Are, Pet. Pet, Are, Pet, Pet, Ave, Pet, Pet, Are, M 0 *.0 0 0.5 0.5 0 0 1 2 1 2 1*5 1*2 1*3 155 1*7 1*8 165 162 163 155 155 155 157 157 157 182 180 181 163 167 165 123 123 123 1*7 170 158 1 2 95 1 2 95 1 2 1 2 1*0 132 136 122 127 125 125 125 125 1*0 162 162 162 167 167 167 1*0 140 1*0 160 95 177 177 177 — 132 132 132 132 132 132 115 115 115 — ------- 152 150 151 282 282 282 1*0 162 ® a Table 25. Trit He* Iron content, expressed as parts per million of oven dry tissue, of plants grown In frit and quartz control cultures supplied with nutrient solution of p H 7.0* Percent 7^03 6285- A control 6285-B control 6285-C control 6285-B control Hn02 2.5 0 5.0 0 7.5 0 10.0 0 6287—A control 6287-B control 6287-0 control 6287-B control 5.0 1.0 5.0 2.0 5.0 3.0 5.0 *.0 628^1 control 6286-P control 6286-0 control 6286- H control 2.5 0 5.0 0 7.5 0 10.0 0 6288-B control 6288-7 control 6281^0 control 6288-H control 5.0 1.0 5.0 2.0 5.0 3.0 5.0 *.0 Culture 1 Average Culture 2 Bet. 1 Bet. 2 Ave. 155 200 235 228 218 250 265 163 160 200 235 223 218 255 158 158 200 235 22 5 218 253 265 160 155 115 123 115 130 130 133 105 155 115 123 118 128 133 131 103 155 115 122 116 129 131 131 10* 156 158 179 171 173 192 198 132 163 128 123 123 113 130 133 133 168 128 123 125 113 130 133 130 165 128 123 12* 113 130 133 132 113 123 88 113 HO 105 130 133 110 123 90 113 110 105 130 133 111.5 122.5 89 112.5 110 105 130 132.5 138 125 106 118 111 118 131 132 128 153 1*5 1*5 130 168 1*0 135 132 1*7 1*5 1*5 132 167 135 135 130 150 1*5 1*5 131 167 137 135 105 272 2*7 2*2 250 230 225 132 105 272 235 2*7 250 250 225 132 105 272 2*1 2*5 250 240 225 132 118 211 193 185 191 20* 181 13* 133 128 155 200 153 163 250 133 132 127 155 197 1*7 162 250 122 132 127 155 199 150 162 250 127 115 120 105 1*7 157 125 132 215 110 120 102 1*5 162 127 130 200 112 120 10* 1*6 160 126 131 207 123 12* 130 173 155 1*5 191 168 ---- Bet. 1 Bet. 2 Ave. culture* Table 26, Iron content, expressed as parts per nlllion of oren dry tissue, of plants grovn In absolute control cultures supplied vlth nutrient solution of pH 7*0, Treatnent Oulture 2 Oulture 1 Culture 3 _ „ pot 1 pot 2 pot 1 pot 2 pot 1 pot 2 70 In -- - --- -p«p,n, p.p.a. Set, Det. Are. Det, Dot, Are, Det. Det, Are, Det, Det, Are. Det, Det, Are, Det. Det, Are, 1 2 1 2 1 2 1 2 1 2 1 2 4 .0 0.5 187 187 187 162 155 159 122 122 122 130 132 131 122 120 121 120 120 120 Arer» age 140 ® t 0 0.5 152 152 152 157 157 357 127 130 128 132 132 132 135 140 137 145 145 145 142 4.0 0 122 122 122 1*0 147 144 122 122 122 125 127 126 125 127 126 127 127 127 128 0 0 llo 1*0 140 120 120 1*7 1*9 1*0 1*0 140 155 157 156 157 157 157 1*4 120 155 88. Table 27. Total Iron absorbed, in milligrams per ten plants, by plants grows in frit, quarts control, and absolute control cultures supplied with a nutrient solution of p H 4.0. Prit Vo. Percent Mn02 T®2°3 6285-A 6285— B 6285— 6 6285-® 2.5 5.0 7.5 10.0 6287-A 628?-# 6?8?-C 6287-B 5.0 5.0 5.0 5.0 6286-1 6286-# 6?86-0 6286-H 2.5 5.0 7.5 10.0 6288-S 6?°8-P 6288-e 6?88-H 5.0 5.0 5.0 5.0 Culture 1 Prit Quarts Culture 2 Average Quarts Prit Quarts Prit 0 0 0 0 0.07 0.14 0.18 0.10 0.2 6 0.16 0.20 0.15 0.12 0.12 0.08 0.08 0.13 0.13 0.13 0.11 0.10 0.13 0.13 0.09 0.20 C.15 0.17 0.13 1.0 2.0 3.0 4.0 0.14 0.14 0.15 0.13 0.13 0.19 0.16 0.14 0.14 0.12 0.10 0.12 0.12 0.12 0.12 0.14 0.14 0.13 0.13 0.13 0.13 0.16 0.14 0.14 0 0 0 0 0.11 0.10 0.10 0.12 0.10 0.11 0.12 0.10 0.10 0.10 0.13 0.15 0.14 0.06 0.13 0.10 0.11 0.10 0.12 0.14 0.13 0.09 0.13 1.0 2.0 3.0 4.0 0.14 0.08 0.10 0.12 0.14 0.13 0.04 0.13 0.12. 0.09 0.07 0.07 0.13 0.12 0.12 0.11 0.13 0.09 0.09 0.10 0.14 0.13 0.08 0.12 Absolute control culture Mn Pe p.p.au Culture 1 Culture 2 Culture 3 pot 1 pot 2 pot 1 pot 2 pot 1 pot 2 Average 4.0 0.5 0.09 0.08 0.14 0.16 0,10 0.12 0.12 0 0.5 0.07 0.07 ----- 0.11 0.12 0.10 0.09 4.0 0 0.11 0.08 0.09 ----- 0.12 0.11 0.10 0 0 0.06 0.04 0.09 0.11 0.14 0.13 0.10 Frit • HN4Q ncM rscS «*«t •• oooo oooo • • 0 Jt H ITiCO S&88 N CM CM CM • # • « • lit OOOO oooo t 1 I 0 * M 0 h at 1 0 CM £ 0 L 08 M 0 fc o 1 0 •H H £ 0 L 8 M 0 I U VOSO N CO to 04*- r\ H rl rtJt H HSO CM H H H H H0n«M CM H0r 0l H H H H A • •• 0 0 0 H00H0• w• till oooo oo oo OOOO oooo i) f £ 0 8 * o' 8 n 0 0& v>>0 n o nos^ cm N N H W H N CM cm cm r\ri • • t • • • • • CM ••*• •••• oo o o o ooo OOOO oooo Jt3 coo rSH^ CM H CM H n N 8 r«19 H f l N N H H H H H H CM H •#•• •••• ••»• •••• oooo oooo OOOO oooo rico v\cm Q OsCsJt nri-st h ncM cm n HHHW N H H CM •• •• •• •• • ••• • • •• oooo oooo OOOO OOCC 0 CM 0 ! 1 H O U 0 0 A 0 0 s HA • 3 I 3 V CO H O O NVO OsN OsH Ntrs H Os© H OAHANAN A H0CM H H0 OrlOrl ••w0 •0 o0 ww 0 • 0 0 0 H•O•H H ooo o oooo OOOO oooo oooo o oAoOo A 0000 H CMrut o o o o trio too O O O O • •tnN • *o• sntriVMn CM H • • U^o tQO NU^NO • oooo H CM n^t 0 0 0 0 oooo tnv\tr,v\ H 0 0S 6 H £ 0 •rt h « u « u HfcOM OOOCOO) t A l 0 k 0 ftA • O o a • # o o H a• s• o o vn co N o O o H 0 8 r, l a0 V o N 0A £ Os CO H O o o H 0 9 At CM H o o - f n t ■ Pi Pi 4*op ««OP iAtr\«rit/\ CO00COCO COcoco CO CM IM CM CM .y.fjNN 8 o N o o o O CM • o 30 V o S8SS CM CMft CM CM £*O: * f A • o Os O • o CM H0 0 O CO >0 H O • • o o o Mh©M kA f t A A f t A o Os VS V> • • o a• H a • • O o i 1 * 1 1 • & 0 CM CM 0 0 & U 8 CO H I 8 M, l • ■ft CM 0 & • • | w • ri Os CM o H o H • • • • o o o c• o 'able 29* Total Iron absorbed. In milligrams per ten plants, by plants grown in frit, quartz control, and absolute control cultures supplied with a nutrient solution of p H 6,0. Percent M t Ho, Oulture 1 Oulture 2 Average Quartz Prit Qparte Trlt Qoartz Frit 0 0 0 0 0.54 0.52 0.42 0.44 0.84 0.86 0.89 0.69 0.52 0.51 0.46 0.62 0.82 0.90 0.90 0.93 0.53 0.52 0.44 0.53 0.83 0.88 0.90 0.81 1.0 2.0 3.0 4.0 0.48 0.53 0.59 0.46 0.72 0.85 0.97 1.26 0.52 0 .66 0.41 0.46 0.82 1.03 0.70 0.63 0.50 0.60 0.50 0.46 0.77 0.94 0.84 0.95 0 0 0 0 0.35 0.27 0.29 0.23 0.37 0.55 0.62 0.46 0.71 0.56 0.44 0.53 1.00 0.69 0.53 0.42 0.37 0.38 0.69 0.62 0.62 0.53 1.0 2.0 3.0 4.0 0.45 0.50 0.39 0.33 0 I71 0.62 0.67 0.46 0.78 0.62 0.50 0.42 0.39 0.77 0.62 0.69 0.59 7e203 *>°2 ■285-A 285-B 285-0 i285-X> 2.5 5.0 7.5 10,0 »287-A >28?-B >287-0 >287-l> 5.0 5.o 5.0 5.0 >286-1 >286-7 >286-0 I286- H 2.5 5.0 7.5 10,0 >288-7 >288-y >288-0 i288-H 5.0 5.0 5.0 5.0 0.60 O .83 --- 0.45 0.44 0.70 0.71 Absolute control culture 7e >.p.m. Mn DeT)els Oulture 1 Oulture 2 Oulture 3 Average « pot 1 pot 2 pot 1 pot 2 pot 1 pot 2 4.0 0.5 0.45 0.49 0.57 0.53 0.44 0,44 0.49 0 0.5 0.53 0.48 0.39 0.40 0.64 0.54 0.50 4.0 0 0.56 0.40 0.33 0.57 ----------- ----------- 0.47 0 0 0.36 O .36 0.43 0.35 0.33 0.73 0.43 91 Cable 30. Total iron absorbed, in milligrams per ten plants, by plants grown in frit, quartz control, and absolute control cultures supplied with a nutrient solution of pH 7,0* _ _ „ Prit No* — Percent Culture 1 .. Culture 2 Average ______ _________ ______________ Trit Quartz Prit Quartz Prit P.2°3 Hn02 6285-A 6285-B 6285-C 6285*1) 2.5 5.0 7.5 10.0 0 0 0 0 0.16 0.23 0.24 0.13 0.29 0.43 0.37 0.41 0.10 0.09 0.10 0.10 0.28 0.22 0.15 0.22 0.13 0.16 0.17 0.12 0.29 0.33 0.26 0.32 6287-A 6287-B 6287-C 6287-D 5.0 5.0 5.0 5.0 1.0 2.0 3.0 4.0 0.15 0.14 0.14 0.13 0.32 0.23 0.17 0.23 0.11 0.11 0.10 0.15 0.24 0.17 0.20 0.23 0.13 0.12 0.12 0.14 0.28 0.20 0.19 0.23 6286-1 6286-P 6286-0 6286- H 2.5 5.0 7.5 10.0 0 0 0 0 0.12 0.11 0.12 0.10 0.15 0.15 0.16 0.17 0.23 0.23 0.18 0.11 0.15 0.32 0.34 0.32 0.18 0.17 0.15 0.11 0.15 0.24 0.25 0.25 628&-B 6288-P 6288-0 628^—B 5.0 5.0 5.0 5.0 1.0 2.0 3.0 4.0 0.09 0.19 0.14 0.09 0.17 0.18 0.18 0.34 0.10 0.11 0.11 0.17 0.19 0.17 0.26 0.21 0.10 0.15 0.13 0.13 0.18 0.18 0.22 0.28 Quartz Absolute control culture Pe p.p.m. Nn a. Culture 1 Oulture 2 Culture 3 pot 1 pot 2 pot 1 pot 2 pot 1 pot 2 Average 4.0 0.5 0.19 0.16 0.17 0.17 0.14 0.14 0.16 0 0.5 0.14 0.15 0.09 0.09 0.15 0.15 0.13 4.0 0 0.17 0.18 0.13 0.12 0.20 0.21 0.17 0 0 0.11 0.10 0.11 0.10 0.20 0.21 0.14 92. table 31. ■rit Ho. Mangan ese content, expressed as parts per million of oven dry tissue, of plants grown in frit and quartz control cultures supplied with a nutrient solution of pH 4.0. Percent ,e2°3 285-A control >285—B control &85-0 control 5285-B control >287—A control >287—B control >287*0 control >287—B control S286-Z control 5286-F control 5286-0 eontrol 5286-H eontrol 6288-1 eontrol 6288-1 eontrol 6288-0 control 6288-I control Hn02 2.5 0 5.0 0 7.5 0 10.0 0 5.0 1.0 5.0 2.0 5.0 3.0 5i0 4.0 2.5 0 5.0 0 7.5 0 10.0 0 5.0 1.0 5.0 2.0 5.0 3.0 5.0 4.0 Oulture 1 Bet. 1 Bet. 2 Oulture 2 Ave. Bet. 1 Bet. 2 Ave. Average of both cultures 183 171 154 140 154 132 128 130 188 174 154 137 137 128 128 130 186 173 154 139 146 130 128 130 162 154 159 128 159 176 132 128 162 154 162 138 159 171 138 128 162 154 160 133 159 174 135 128 174 164 157 136 153 152 132 129 256 307 350 299 317 283 333 418 266 299 343 295 304 292 350 418 26l 303 347 297 311 288 342 418 270 324 302 315 375 418 370 398 270 316 302 308 359 415 362 410 270 320 302 312 367 417 366 404 266 312 325 305 339 353 354 411 120 133 120 135 116 126 111 124 120 136 111 137 126 136 124 111 120 3.35 116 136 121 131 118 118 121 119 121 121 145 160 121 153 126 116 120 123 138 157 120 143 124 118 121 121 142 159 121 148 122 127 119 129 132 145 120 133 154 113 227 213 243 278 196 216 158 111 227 210 244 268 196 213 156 112 227 212 244 273 196 215 191 147 213 196 251 227 256 273 196 170 194 159 213 192 250 226 265 278 175 136 220 202 247 250 231 247 --- 188 248 224 273 282 Table 32. Manganese content, expressed as parts per Billion of ot«h dry tissue, pt plants grevn in absolute eontrol cultures supplied with nutrient solution of pH 4,0, Treatment Oulture 1 Oulture 2 Culture 3 pot 2 pot 2 pot 2 pot 1 pot 1 pot 1 Mn fe ),p«n« p»p,B« Bet,, Det. Avs. Det,, Det. Are. Det,, Det. Ave. Det,, Det. Ave. Det,, Det. Ave. Det,, Det. Ave. 2 2 2 2 1 1 1 2 1 2 1 1 Aver­ age 4.0 0.5 128 136 132 130 125 128 125 126 126 138 137 138 131 0 0.5 132 143 138 142 145 144 202 188 195 212 213 213 205 212 209 190 200 195 182 4.0 0 traces* traces traces traces traces traces 0 0 traces traces traces traces traces traces traces* less than 10 p,p,n. tble 33* Manganese content, expressed as parts per million of oven dry tissue, of plants grown in frit and quarts control cultures supplied with a nutrient solution of p H 5*0. Percent Culture 1 Culture 2 •it Ho. -------------------------------------------------------- — Te^O^ MnOg Det. 1 Det. 2 Ave. Det. 1 Det. 2 Are. :85-A tontrol •85-B tontrel :85-0 tontrol 85-D tontrol 2.5 0 5.0 0 7.5 0 10.0 0 87-A tontrol 87-B entrol 87-C ontrol 87-B ontrol 5.0 1.0 5.0 2.0 5.0 3.0 5.0 4.0 86-J ontrol 86-P ontrol 86-0 ontrol 86-H ontrol 2.5 0 5.0 0 7.5 0 10.0 0 88-B ontrol 88-P ontrol 88-0 ontrol 88-H ontrol 5.0 1.0 5.0 2.0 5.0 3.0 5.0 4.0 Average of both cultures 145 244 157 211 128 210 128 210 145 251 150 208 130 217 128 200 145 248 154 210 130 214 128 205 137 222 128 202 142 213 120 213 137 210 125 205 140 222 134 --- 137 216 127 204 141 218 127 213 141 232 141 207 136 216 128 209 142 401 213 282 222 415 304 478 142 384 213 278 225 418 290 483 142 393 213 280 224 417 297 481 235 392 205 297 227 384 239 418 234 384 205 289 217 380 246 420 235 388 205 293 222 382 243 419 189 390 209 287 223 400 270 450 200 254 191 280 198 297 vm 260 171 256 191 282 188 300 186 248 186 255 191 281 193 299 113 254 219 273 213 268 205 290 196 290 217 270 213 273 196 290 193 295 218 272 213 271 201 290 195 293 202 264 202 276 297 295 189 273 116 94 145 120 113 196 237 176 116 91 147 120 120 196 241 193 116 93 146 120 117 196 239 185 85 68 111 85 171 154 207 217 85 68 111 91 183 155 202 213 85 68 111 88 177 155 205 215 101 81 128 104 147 176 222 200 Table 34. Mwganese content, eipressed as parts per Billion of oven dry tissue, of plants grown in absolute control cultures supplied with nutrient solution of pH 5*0* Treatment Culture 1 pot 1 pot 2 Culture 2 pot 1 pot 2 Culture 3 pot 1 pot 2 Te ito p.p.m. P»P*B. Det. Det. Are. Det. Det. Ave. Det. Det. Are. Det. Det. Are. Det. Det. Are. Det. Det. Are. 1 2 1 2 1 2 1 2 1 2 1 2 Aver­ age 4.0 0.5 210 213 212 210 213 212 188 193 191 196 196 196 213 213 213 198 205 201 204 0 0.5 333 299 316 324 319 322 362 354 358 347 3J1O 314 340 342 341 333 350 342 337 4.0 0 traces* traces traces traces traces traces 0 0 traces traces traces traces traces traces traces* less than 10 p.p.su Table 35. Manganese content, expressed as parts per million of oven dry tissue, of plants grovn in frit and quarts control cultures supplied vitli a nutrient solution of p H 6.0. Percent Culture 1 frit Ho. P.2Q3 S285-A control 5285-B control 5285-0 control 5285-B control 5287-A control >287— B control >287-0 control J287-B control i286-B control I286-T control 1286-0 control 286-H control 288-S control 28ft-P control 288-0 control 288-H control Mn02 2.5 0 5.0 0 7.5 0 10.0 0 5.0 1.0 5.0 2.0 5.0 3.0 5.0 4.0 2.5 0 5.0 0 7.5 0 10.0 0 5.0 5.0 1.0 2.0 5.0 3.0 5.0 4.0 Det. 1 Det. 2 Culture 2 Are. Det. 1 Det. 2 Are. Average of both culture? 75 109 58 103 66 137 76 137 79 109 59 103 68 136 79 137 78 109 59 104 68 137 78 138 75 123 81 126 78 156 95 134 75 120 81 126 81 156 92 137 75 123 81 126 80 156 94 136 77 116 70 115 74 147 86 137 146 245 194 354 208 290 222 305 146 245 194 354 208 293 222 290 146 245 194 355 209 292 223 298 180 350 163 340 194 418 217 404 180 344 163 354 194 421 217 418 180 348 163 348 194 420 217 411 163 297 179 352 202 356 220 355 151 203 178 217 156 234 122 197 149 193 177 217 149 242 122 197 150 198 178 217 153 239 122 197 113 134 117 151 99 177 127 174 109 134 120 151 99 183 127 177 112 135 120 152 99 180 128 176 131 167 148 185 126 210 125 187 113 85 151 171 202 202 217 251 109 89 149 171 198 202 219 251 112 88 151 172 201 203 219 251 83 100 ——— 84 98 --— — ----- ----- 217 220 220 254 217 220 208 254 217 220 214 254 98 93 151 172 209 212 217 253 95 Sable 36. Manganese content, expressed as parts per Billion of oven dry tissue, of plants grovn in absolute control cultures supplied vith nutrient eolutlon of pE 6,0, Treatment Culture 2 Culture 1 pot 1 pot 2 pot 1 Culture 3 pot 1 pet 2 pot 2 Mn . ye p.p.m. p.p.®. Set,,Det, Ave. Det. Bet. Ave. Det., Det. Are. Det. Det. Ave. Det., Det. Are. Det. Det. Are. 1 2 1 2 1 2 1 2 1 2 1 2 194 194 194 194 194 194 198 191 195 4.0 0 traces* traces traces traces traces 0 0 traces traces traces traces traces traces* less than 10 p. p.a. s 0.5 CO 0 S 117 123 120 132 132 132 106 106 106 117 117 117 117 117 117 127 132 130 CO 0.5 C"- 4.0 166 174 170 137 149 143 traces 14 Aver­ age 14 120 182 98 sible 37* rit Ho, 285—A sontrol 285—B sontrol >85- C sontrol >85-B sontrol >87-A sontrol >87— B sontrol >87- C sontrol >87-B sontrol >86-H sontrol >86-P sontrol >86-® sontrol ►86-H sontrol Percent Culture 1 Culture 2 Average --- --- ---- — ----------------------------------------— — .. of both HnO^ Bet. 1 Bet, 2 Ave, Bet, 1 Bet, 2 Ave, cultures 2.5 0 5.0 0 7.5 0 10.0 0 5.0 1.0 5.0 2.0 5.0 3.0 5.0 4.0 2.5 0 5.0 0 7.5 0 10.0 0 5.0 1.0 5.0 o • CM ►88-B sontrol •88-P tontrol ;88-® tontrol ;88-H sontrol Manganese content, expressed, as parts per million of oven dry tissue, of plants grown in frit and quartz control cultures supplied with a nutrient solution of p H 7*0, 5.0 3.0 5.0 4.0 39 121 67 104 142 47 53 56 38 123 66 95 137 52 52 55 39 122 66 99 139 50 52 55 83 122 89 106 99 136 92 89 83 113 92 109 99 140 92 89 83 118 91 107 99 138 92 89 61 120 79 103 119 94 72 72 138 166 163 277 177 277 227 362 134 175 163 262 174 276 227 333 136 170 163 269 176 276 227 347 166 170 163 248 190 349 203 333 166 166 163 251 190 351 205 322 166 168 163 249 190 350 204 327 151 169 163 260 183 214 216 338 135 170 146 220 118 200 104 184 134 170 149 221 112 198 103 184 134 170 147 220 115 199 103 184 100 170 156 180 134 180 134 191 100 170 151 183 134 183 137 188 100 170 154 181 134 181 136 190 118 170 151 201 125 190 120 187 114 81 129 118 175 160 211 189 113 78 136 117 174 160 20 5 185 113 79 132 117 174 160 208 185 35 35 72 66 245 85 163 208 38 35 75 66 251 85 170 218 37 35 74 66 248 85 166 213 75 58 103 92 211 128 188 200 Table 38, Ifrnganese content, expressed as parts per Billion of oyan dry tissue, of plants grown in absolute control cultures supplied with nutrient solution of pH 7,0, Treatment Oalture 1 Culture 2 Culture 3 fe Hn 5°t 1 2 p0t 1 p0t 2 pot 1 p0t 2 p.p.n, p.p.a. Det. Det, Are, Set, Det, Aye, Det, Det, Are, Det, Det, Are, Det, Det, Are, Det, Det. Are, t r 4.0 0.5 127 127 127 134 132 133 109 109 109 91 265 276 271 193 191 192 154 0 o,5 197 197 197 217 214 215 205 208 207 236 236 236 134 134 134 134 140 137 188 4,0 0 21 0 0 traces 21 21 20 traces traces* less than 10 p,p,B, 09 92 14 21 traces* traces traces 21 21 17 trace8 traces 11 100, Cable 39* Total manganese absorbed, la milligrams per ten plants, "by plants grown In frit, quarts control, and absolnte control cultures supplied with a nutrient solution of p H 4.0. Percent Frit Ho. . Culture 1 >2 Culture 2 Average Quarts 2rit Quarts Prit Quarts Prit 0 0 0 0 0.23 0.18 0.21 0.15 0.32 0.21 0.29 0.23 0.21 0.19 0.20 0.16 0.28 0.26 0.24 0.22 0.22 0.19 0.21 0.16 0.30 0.24 0.27 0.23 1.0 2.0 3.0 4.0 0.49 0.41 0.41 0.60 0.44 0.62 0.57 0.57 0.49 0.43 0.54 0.55 0.43 0.44 0.61 0.57 0.49 0.42 0.48 0.58 0.44 0.53 0.59 0.57 0 0 0 0 0.13 0.14 0.15 0.12 0.17 0.14 0.14 0.15 0.14 0.13 0.21 0.23 0.31 0.22 0.20 0.20 0.14 0.14 0.18 0.18 0.24 0.18 0.17 0.18 1.0 2.0 3.0 4.0 0.14 0.25 0.30 0.26 0.20 0.33 0.29 0.27 0.22 0.16 0.26 o.33 0.30 0.27 0.38 0.37 0.18 0.20 0.28 0.30 0.25 0.30 0.34 0.32 y «2°3 m w S285-A S285-B 5285-0 5285-D 2.5 5.0 7.5 10.0 6287-A 6287-B 6287-0 6287-2) 5.0 5.0 5.0 5.0 6286-1 6286- P 6286*0 6286-H 2.5 5.0 7.5 10.0 6288-2 6288-2 6288-0 6288- H 5.0 5.0 5.0 5.0 Absolute c ontrol culture Pe p.p.n. Ma p.p.®. Culture 1 Culture 2 pot 1 pot 2 pot 1 pot 2 4.0 0.5 0.12 0.12 0.17 0.25 0 0.5 0.13 0.15 0.28 0.30 Culture 3 pot 1 0.32 Average pot 2 ----- 0.17 0.28 0.28 1 ^ 101. Sable 40• Total manganese absorbed. In milligrams per ten plants, b y plants grown in frit, quarts control, and absolute control cultures supplied w i t h a nutrient solution of p H 5.0. Percent rrlt Ho, ■ » V > 3 >285-A 5285-B >285-0 >285—B 2.5 5.0 7.5 10.0 6287-A 6287- B 6287-0 6287- D 5.0 5.0 5.0 5.0 6286-B 6286-T 6286-O 6286-H 2.5 5.0 7.5 10.0 6288-X 6288-7 6288-0 6288-B 5.0 5.0 5.0 5.0 **02 Culture 1 Culture 2 Average Quarts Trlt Quarts Trlt Quartz Trlt 0 0 0 0 0.34 0.45 0.52 0.65 0.57 0.49 0.43 0.51 0.49 0.55 0.45 0.57 0.50 0.50 0.53 0.47 0.42 0.50 0.49 0.61 0.54 0.50 0.48 0.49 1.0 2.0 3.0 4.0 1.10 0.89 1.14 1.15 0.49 0.93 I .03 1.20 0.57 1.16 1.11 0.98 0.93 1.03 0.86 1.04 0.84 1.03 1.12 1.07 0.71 0.98 0.95 1.12 0 0 0 0 0.61 0.56 0.43 0.49 0.50 0.51 0.49 0.50 0.46 0.54 0.55 0.63 0.61 0,66 O .63 O .63 0.54 0.55 0.49 0.56 0.56 0.59 0.57 0.57 1.0 2.0 3.0 4.0 0.15 0.18 0.27 0.28 0.30 0.12 0.40 0.24 0.13 0.27 0.28 0.60 0.65 0.14 0.16 0.31 0.31 0.29 0.34 0.42 0.64 O .63 0.34 0.34 Absolute control culture Te p.p.m. Mn Culture 1 Culture 2 Culture 3 pet 1 pet 2 pot 1 pot 2 pot 1 pot 2 Average 4.0 0.5 0.63 0.53 0.61 0.65 0.63 0.56 0.60 0 0.5 0.41 0.44 0.45 0.55 0.48 0.54 0.48 102. table 4-1. Total BBOgaaese absorbed, in milligrams per ten plants, b y plants grown in frit, quarts control, and absolute control cultures supplied with a nutrient solution of p H 6.0. Percent tait Ho. '•2°3 >285— A >285-B 1285-0 1285-D 2.5 5.0 7.5 10.0 5287-A >287— B >287— 0 >287— D 5.0 5.0 5.0 5.0 >286-2 >286-1 >286-0 >286—H 2.5 5.0 7.5 10.0 ;288-X >288-2 >288-0 >288-H 5.0 5.0 5.0 5.0 Mn02 Culture 1 Culture 2 Average Quarts Frit Quarts Frit Quartz Frit 0 0 0 0 0.45 0.440.54 0.45 0.39 0.35 0.47 0.39 0.43 0.42 0.43 0.55 0.43 0.41 0.44 0.53 0.44 0.43 0.49 0.50 0.41 0.38 0.46 0.46 1.0 2.0 3.0 4.o 0.72 1.13 1.06 0.97 0.64 1.22 1.20 0.90 1.11 1.66 1.32 1.25 1.00 1.38 0.99 0.90 0.92 1.40 1.19 1.11 0.82 1.30 1.10 0.90 0 0 0 0 0.55 0.4-3 0.47 0.30 0.57 0.68 0.60 0.35 0.55 0.56 0.57 0.59 0.55 0.52 0.44 0.54 0.55 0.50 0.52 0.45 0.56 C .60 0.52 0.45 1.0 2.0 3.0 4.0 0.31 0.48 0.64 0.74 0.53 0.53 0.71 0.75 0.41 0.44 — ------- 0.36 0.48 0.64 0.73 0.49 0.53 0.85 0.89 — 0. 64 0.72 0.99 1.03 Absolute control cultures Fe Mn Dstlstts 1 Culture 1 Culture 2 Cultxire 3 pot 1 pot 2 pot 1 pot 2 pot 1 pot 2 Average 4.0 0.5 0.38 0.44 0.37 0.46 0.41 0.45 0.42 0 0.5 0.67 0.59 0.42 0.48 0.65 0.56 0.56 103 Esble 42. fotal mftnganese absorbed, In milllgrajns per ten plant s , b y plants grown In frit, quarts oontrol, and absolute control cultures supplied with a nutrient solution ot p H 7.0, Percent Culture 1 Frit Ho. '•2°3 6265-A 6285-B 6285-0 6285-B 2.5 5.0 7.5 10.0 6287-A 6287-B 6287- C 6287-D 5.0 5.0 5.0 5.0 6286-JB 6286-P 6286*»G 6286—H 2.5 5.0 7.5 10.0 6288-B 6288-P 6288—G 6288-H 5.0 5.0 5.0 5.0 *n02 Culture 2 Average Quartz Prit Quartz Prit Quartz Prit 0 0 0 0 0.10 0.10 0.05 0.04 0.07 0.12 0.23 0.08 0.11 0.08 0.11 0.09 0.15 0.16 0.18 0.15 0.11 0.09 0.08 0.07 0.11 0.14 0.21 0.12 1.0 2.0 3.0 4.0 0.20 0.30 0.30 0.34 0.27 0.31 0.26 0.39 0.14 0.16 0.18 0.23 0.36 0.30 0.35 0.36 0.17 0.23 0.24 0.29 0.32 0.31 0.30 0.38 0 0 0 0 0.14 0.16 0.15 0.14 0.16 0.15 0.14 0.13 0.14 0.17 0.14 0.16 0.14 0.21 0.18 0.20 0.14 0.17 0.15 0.15 0.15 0.18 0.16 0.17 1.0 2.0 3.0 4.0 0.06 0.11 0.14 0.14 0.14 0.03 0.16 0 .7? 0.05 0.05 0.12 0.40 0.26 0.05 0.08 0.11 0.16 0.10 0.14 0.31 0.28 0.29 0.08 0.18 Absolute control cultures Pe p.p.a. Mb p.p.®. Culture 1 Culture 2 Culture 3 pot 1 pot 2 pot 1 pot 2 pot 1 pot 2 Average 4.0 0.5 0.13 0.14 0.15 0.12 0.32 0.23 0.18 0 0.5 0.18 0.19 0.15 0.15 0.15 0.14 0.16 Table 4 3 . Milligrams of iron per carboy at the end of the experimental period at p H 4.0 of nutrient solution* Frit Ho. Oarboy Ho. 2 1 6285-A 6285-B 6285-0 6285-B 3.4 5.7 4.7 5.6 4.4 4.2 3.8 3.1 6286-JB 6286-F 6286-0 6286-H 3.8 5.7 3.4 8.4 6.3 7.8 3.6 3.6 Treatment Fe added Absolute controls Carboy Ho, 25.0 18.8 36.0 20.2 Fe not added 4.2 3.3 4.2 2.7 Table 44. Milligrams of iron per carboy at the end of the experimental period at pH 7*0 of nutrient solution Hrit Ho. Oarboy Ho. 2 1 6285-A 6285“® 6285-C 6285-1) 3.8 7.0 7.7 7.7 14.0 11.5 10.2 10.2 6286-S 6286-1* 6286-a 6286-H 7.0 8.3 8.3 8.9 7.0 6.4 4.5 2.6 Absolute controls Oarboy Ho. Treatment 1 He added He not added 56.3 7.7 2 3 — — 7.6 5.1 ■P •H 0 a N -P 1 P CM * « * § •P N P u 3 • • • * 901 3 N P h I 4 H^CO cSnrvcM •••• O O H ft o o o o Ov Q CMH • • • • oooo CMHCM V\ H CMO Ov CM r \ C M C M C •••• M •CM •CM •CM • co•Nwvrv •• • o o o o oooo OOOO m o o o o o o o o 4 C^QVO 3- rvrvcM •••• 00 HMD Ov H O H IS CMCMCMH CvOnVO W • • # • t • • • • • • • o o o o OOOO o o c o o o vjvo in3 •••« O C^CvCv vyo Hf» V cm c^rv* V04NPV •••• • • • • oooo o c o o s • • • • • • • • o o o o rv^oo o oooo VOONV> H ?SH H • • • • o o o o o o o o o o o o • • • • h cmrv-tf cmcmr\rS • t • • a• •m • • OOOO 8• m • s • • HOOO cmr\cM Pv o o o o o so • • • • o o oo v>v5a>vo • • • • CM 4* • • • o o o o o o o o H SSSfc K8»ft 3S£3 o o o o a m • • • • m s • • • • oooo oooo oooo o•o•o•o• H CMrv^ u 0 r> Ai o •N h o * H S w o w o o• o• o• o• • • •• CMV\N O w w w w H o•o•o•o• mowvo • • • • CMV\NO w w w w H oR rlflrLpl 0000€0CO 00X0 00CD N CMCMCM NON VNONNOV VO VOVCV)VO NAOtH viv/)vAvi on oo co oo MVCO MVCO M VCOMVCO ^ADR «*ow cia* ck e!> COCO 00CO cm r;cm cm VCVCVOVC 107. Figure 1.Mechanical arrangement or the cultures, (A) and (B) one— gallon glased earthenware cultjore pots. (C) carboy' containing 16 liters or nutrient solu­ tion, (D) Pipe leading compressed air to carboy. (E) Hydrostatic water column regulating the level of the nutrient solution in the culture pots, (P) Test tube and layer of glass wool covering end of glass tube leading the nutrient solution into the culture pot. 106. 160 RELATIVE WEIGHT VkQ ItO IOO 90 60 — C o n t r o l — SSffVpOl. to 4o 2 . iT s r a g a f r e s h m l ^ i t o f p la n t s i n f r i t and c a n t— r o l c u lt u r s s i c a lc u la te d in p e r c e n t o f a v e r a g e f r e s h w e ig h t o f p la n t s i n a b s o lu t e c o n t r o l c u l­ t u r e s r e c e i v i n g c o a q p le te n u t r i e n t s o l u t i o n * p l o t ­ t e d a g a in s t f r i t c o m p o s it io n . N u t r e ie n t s o lu t i o n o f pH 4 * 0 i I O' ^7. RELATIVE WEIGHT 160 tzo Io o «o 60 — 6265* — — CONTROL. 2jO — £267 — CONTROL. 6266 — 62 88 — CONTROL. — CONTROL /.o % F«„0. Flgura 2* Average fresh weight or plants in frit and con­ trol cultures, calculated in percent of average fresh weight of plants in absolute control cul­ tures receiving complete nutrient solution, plot­ ted against frit composition. Nutrient solution of pH 5*0 iso \ v \ RELATIVE WEIGHT 160 IZO 60 6040 20 — G 2SS — CONTROL. --- 6 2 9 7 — o — CONTROL 6Z8S — CONTTROU — r .s tO .o /.O — 62«a • — CONTROL 1 2.0 1______ u 3 .o <4.0 % M n O z Figure Average fresh weight of plant;s In frit and con­ trol cultures, calculated in percent of average fresh weight of plants in absolute control cul­ tures receiving cosq>lete nutrient solution, plot­ ted against frit composition* Nutrient solution of pH 6,0 //I. RELATIVE WEIGHT 160 IZO IOO 60 60 - — 6285" 2C - 2.51 — 6 2 6 7 — CONTROL — 6266 — CONTROL 5Io 75- % r e 203 /0.o — CONTROL — 6 2 as — CONTROL l.o 2.0 %MnOz Ttgnra 5* A w n g * fr«ih wai^it of plants In frit and con­ trol culturaa, calculated in porcent of ararmgo fresh weight of plants in absolute control cul— tures reeeiiing coaplete nut riant solution, plot­ ted against frit composition. Nutrient solution of pH 7*0 i / i . /oo 90 801 - PERCENT TO 60 50 40 30 So 6.0 76 Flirore 6* /Ltsnge fresh weight of control plants, c&lculated in percent of average fresh weight of corre­ sponding frit grown plants, plotted against pH of nutrient solution. RELATIVE WEIGHT / / 3. — 20 6267 — CONTROL. ROL. Figure 7» Average dry weight of plants in frit and con­ trol cultures, calculated in percent of average dry weight of plants in absolute control cul­ tures receiving complete nutrient solution, plot­ ted against frit composition. Nutrient solution of pH 4.0 RELATIVE WEIGHT O c AO ---<5285 — 20 ° - C O NTROL • — 62 87 o — CONTROL 6286 6288 — • -CONTROL 2.3* 1 5.o « T.s % Fe^Oj ■ 10.0 •CO N T R O L Lo 2.0 3.0 A.o % M nO x Figure 8. Average dry weight or plants in frit and con­ trol cultures, calculated In percent of average dry weight of plants in absolute control cul­ tures receiving complete nutrient solution, plot­ ted against frit composition. Nutrient solution of pH 5*0 / r kJ . 200 ~ 180 160 RELATIVE V EI6H T 14 0 120 IOO, 80 60 — 6285 J67 _o n t r o l . — CONTROL 20- — 6266 — -CONTROL % 7r F«*a 6266 — CONTROL /.o 3Lo Figure 2» Average dry weight of plants in frit and con­ trol cultures, calculated in percent of average dry weight of plants in absolute control cul­ tures receiving complete nutrient solution, plot­ ted against frit composition. Nutrient solution of pH 6.0 / / VJ . 180 RELATIVE WEIGHT 160 120 IOO 80 60 o — CONTROL o 62 87 o — CONTROL 6286 6288 • — CONTROL 20- • — CONTROL 2.5 S.o % 75 F e20 3 lo 2 .0 So %MnOz Figure I D , Average dry weight of plants I n frit and con­ trol cultures, calculated In percent of average dry weight of plants In absolute control cul­ tures receiving complete nutrient solution, plot­ ted against frit composition* Nutrient solution of pH 7.0 IOO 9o 80 TO LU ^60 Ul Cl. SO Figure 1 1 . Average dr y weight of control plants, calculated in percent of average dry weight of correspon­ ding frit grown plants, plotted against pH of nutrient solution. SO MILLIGRAMS 40 30 - 20h PPM. _ 10 60*- — 6 2 85 — CONTROL 20 2.5 — 6286 -CONTROL So ONTROL £o %MnO. pii«e p . Parts per million of iron in the d r y matter of the plants (lower cureves) and total absorption of iron in milligrams per ten plants (upper curves) plotted against frit composition. Nutri­ ent solution of pH 5«0 6285, control - - 6 286 , control — tg g & — m u .60 SO MILLIGRAMS .4 0 .30 .20 JO 5.o Lo 2 .0 %Mn Figure 13 « Total absorption of manganese in milligrams per ten plants plotted against frit composition Nutrient solution of pH 4*0 - ~ t.ZO - 6286 . ~ con trol - con trol c o n tr o l LOO MILLIGRAMS .80 .60 .40 .20 /d o Figure 1 4 * Total absorption of manganese In milligrams per ten plants plotted against frit composition Nutrient solution of pH 5*0 6285 , — control 628/ , control — — — 62SP , control con — 1.20 MILLIGRAMS LOO .60 .40 .20 2.5 So /O.o Lo 2.0 %MnO. jM 15 . Total absorption of manganese in milligrams per ten plants plotted against frit composition Nutrient solution of pH 6*0 MILLIGRAMS, 6255 6287 C o n tr o l — 6 SP c oZ n t r o l7 - , c o n tr o l - c o n tr o l .20 S.o 2s LO 2.o Figure 1 6 . Total absorption of manganese In milligrams per ten plants plotted against frit composition Nutrient solution of pH 7*0 / O . #60 140 6 2 88 120 MILLIGRAMS IOO so 60 HZ 20 % Mn O Figure 1 7 . Milligrams or manganese accumulated in carboy at the end of the experimental period as affec­ ted b y manganese content of the frit. MILLIGRAMS 1600 1400 1200 IOOO 600 600 200 .2. .3 .7 Figure 1 8 , Milligrams of sodium accumulated In carboy at the end of the experimental period as affected by sodium content of the frit. Frit no, 6285 and 6287, Nutrient solution of pH 4*0 r *- . § 300 6288 I O O .G Figure 1 9 . Milligrams or sodium accumulated In carboy at the end of the experimental period as affected b y sodium content of the frit. Frit no. 6236 and 6238. Nutrient solution of pH 4*0 i LEGEND TO PLATES Plate I. Detail of mechanical arrangement of the cultures showing connection between main air line (under­ neath greenhouse table) and carboy, and, connection between carboy and pair of culture pots. Pot to the left in each pair contains frit no. 6285— C and 62Q5-D respectively. Vote the chlorotic condition of. plants in^ the g o ryespondlng control pots* She plants were supplied with a nutrient solution of p 9 6*0. Plate II. Arrangement of pots on greenhouse table. Plate 111. General 'view of the arrangement of the experiments. Plate IV. Tbur weeks old plants grown in frit no. 6285-A (to the left) a n d corresponding control culture at p H 6.0 of the nutrient solution. Plate V. Pour weeks old plants grown in frit no. 6285— D (to the left) and corresponding control culture at p H 6.0 of the nutrient solution. Plate VI. Pour weeks old plants grown in frit no. 6287— A C- . / 3 *h. Plate VII. / 3 5. Plate VIII Plate IX.