Tomato plants (TVR-2), collected at the beginning of fruit harvest period, were separated into root, stem, petiole, lamina, fruit petiole, and fruit. These organs, except root, were further fractionated on the basis of node orders. Each fraction was subjected to chemical analysis with regard to 15 main nutrient elements. The amounts of uptake for major essential elements were proportional to their standard concentration in culture solution. No such relationship was found for minor essential elements. Elements such as N, Ca, S, B, Zn, and Cu are the highest in concentration at lamina ; elements such as NO_3-N, P, K, Mg, Sr, and Cl, at petiole ; elements such as Fe, Mn, and Na, at root ; and an element C, at fruit. It is notable that NO_3-N and Mg concentrations at petiole were much higher than those at lamina. The concentrations of NO_3-N, P, S, Mg, Mn, Zn, and Cu at the lower part of leaves (lamina and/or petiole) were much higher than those at the upper part of leaves. These elements may be excessively absorbed and accumulated at the lower part of leaves.

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Objectives of the present experiment were to confirm the inhibitory effect of volatile fatty acids (VFA) on denitrification found by previous experiments and to clarify its mechanisms. Formic and acetic acids were examined for their effects on denitrification and anaerobic decomposition of organic substrates (these organic acids themselves, easily decomposable soil organic carbon and glucose) in two soils : Konosu soil (Grey lowland soil, Aquept) and Tanashi soil (Black volcanic ash soil, Andept). The organic acids were confirmed to inhibit decomposition of the organic substrates (direct effect) even in the absence of nitrate. In addition, denitrification in the presence of organic acids was found to strengthen the inhibition effect on the microbial decomposition of the organic substrates (indirect effect). This was caused by formation and accumulation of nitrite and was enhanced by both the increased reaction rate of denitrification and by the increased concentration of the added organic acids. Konosu soil was more vulnerable to the direct effect than Tanashi soil. However, these two soils were rather similar in regard to the indirect effect. The added formic acid appeared more inhibitory than acetic acid if their amounts were calculated by the amount of organic carbon but rather similar if their amounts were calculated by the number molecule.

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Plantlets of Spathiphyllum were cultured photoautotrophically in vessels under a photosynthetic photon flux at 26μmol/m^2・s. The effect of nutrient composition, especially the ratio of NH_4-N to NO_3-N in the medium, on growth, and utilization of NH_4-N and NO_3-N were investigated. 1) There was not difference in the growth of plantlet among MS, Noji Shikenjo, WHITE, KNUDSON C and Enshi medium. 2) In plantlets cultured in the media with NH_4-N:NO_3-N ratios of 0 : 17 to 5 : 12, the growth and nitrogen contents were higher than those of 8.5 : 8.5 and 12 : 5. The analysis of ^<15>N in plantlets fed ^<15>NH_4NO_3, K^<15>NO_3 or NH_4^<15>NO_3 showed that absorbed and utilized nitrogen contents in plantlet cultured in the media with NH_4-N:NO_3-N ratios of 0 : 17 and 5 : 12 were higher than those of 8.5 : 8.5.3) There was a rise in pH in the media with NH_4-N:NO_3-N ratios of 0 : 17 to 8.5 : 8.5.

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Dilute, 6.17mM, HCl as added to three soil differing in ion-exchanger composition at a soil : solution ratio of 1 : 8 and the change in both the solution and exchangeable cation composition was traced over a period of 240h. Common to all soil samples were that the pH of the reacting solutions rose from about 2.2 to 4 within 1h and that the exchangeable base content decreased. The cation concentration in the reacting solution increased for all the soil samples. However, the total normality of the cations in the reacting solution, including H^+ and Al^<3+>, was kept almost constant during the reaction period for a soil dominated by smectite, while it decreased by about 30 and 70% for soils dominated by Al-humus complexes and allophane-imogolite, respectively. These observations and the fact that the exchangeable Al content did not increase significantly indicate that the cation exchange was the major process responsible for the acid neutralization in the smectitic soil and that the breakdown of the clay lattice due to the attack by the adsorbed hydrogen ion did not proceed to a significant extent in the reaction period. On the other hand, the major process was the acid adsorption, i.e., the protonation of inorganic hydroxyl groups and the subsequent anion adsorption, in the allophanic soil. In the soil dominated by Al-humus complexes, both cation exchange and acid adsorption contributed to the acid neutralization.

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Water retention and ion exchange of a synthetic vinyl alcohol-sodium acrylate co-polymer, in aqueous salt solution, were investigated. The water retention of the polymer decreased with decreasing pH of the ambient solutions, due probably to suppression of the dissociation of H^+ from carboxyl group. It also decreased as the concentration of salts and the valency of cations in the solutions increased. For example, the amount of water held by unit weight (g) of the dry polymer in deionized water was 434g, and those held in 17 and 170 meq/g NaCl solutions were 113 and 62g, whereas the corresponding values in CaCl_2 or MgCl_2 were 70 and 21g, respectively. The suppressed water retention of CaCl_2-treated polymer was recovered by washing with NaCl solution or deionized water. The carboxyls in the polymer participated all in cation exchange, with CEC of 5-6 meq/g, and they repelled anions electrostatically, resulting in negative adsorption.

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A nitrification inhibitor and dolomite were applied to two kinds of soils to clarify their effects on growth of tea plant and content of cellular constituents in the new shoots. The total leaf yield in 6 years was greater in sandy loam than that in loam. It decreased by application of dolomite at more than 200kg per 10a. The effect of nitrification inhibitor on leaf yield was not recognized. Amount of total nitrogen and amino acid contents in new shoots were higher in the new shoots grown in sandy loam compared to those grown in loam. And, they trended to be higher by application of nitrification inhibitor into the soil .They, however, became lower when dolomite was not applied. Total amount of amino acids in new shoots yielded from the field supplied with 100kg per 10a was highest in this experiment. Rate of nitrification in sandy loam was lower than that in loam. The application of dolomite accelerated the nitrification. From these results, it was concluded that amino acid content in the tea leaves, which affects the tea quality, was significantly increased by application of nitrification inhibitor and dolomite (100kg per 10a in a year).

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The rice variety `Koshihikari' was cultivated as the early-season culture in Kyushu (west-southern district in Japan) from 1976 to 1978. The experiments were conducted at 19 plots which had different nitrogenous fertilization in all 3 years. 1) The brown rice productions were about 6t/ha in each year. But the efficiency of absorbed nitrogen on the rice grain varied with the cultivated year and the nitrogen supplied. When the efficiency of absorbed nitrogen was low, rice plant had many ears and abortive grain. 2) Strong negative correlation was observed between the efficiency of absorbed nitrogen on the rice grain and the number of ears. 3) Positive correlation was observed between iron-manganese ratio in the stem and leaf at the early stage and the efficiency of absorbed nitrogen on the rice grain, also the number of grains per head. But the number of ears, nitrogen % in the stem and leaf at heading time and the amounts of nitrogen uptake at maturing stage had negative correlation with iron-manganese ratio. 4) In the high-yielding culture of `Koshihikari,' it was a very useful method that gives priority to the increase of the number of grains per head over the increase of the number of ears. 5) I supposed the relation between the efficiency of absorbed nitrogen on the rice grain yield and the uptake of iron and manganese in the early stage was affected by the soil condition, the character of seedlings and the physiological activity of rice plant's roots.

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Quantitative analysis was undertaken for the interaction of calcium and magnesium in uptake by tomato seedling leaves. Tomato seedings were raised by aerated solution culture technique with nutrient solution added 5, 10, 15, 20, 25 meq/l of calcium chloride or magnesium chloride. The culture solution for calcium or magnesium series contained magnesium or calcium of 12 meq/l, respectively. At 2nd and 4th weeks, Ca, Mg, and K concentrations (meq/100g dry weight) in the leaves of each treatment were determined. Potassium and magnesium concentrations of the leaves were decreased by the addition of calcium to the nutrient solution. Calcium concentration was reduced by the addition of magnesium but K concentration was not affected much. Ratios between the decrement of Mg (ΔMg, meq/100g dry weight) and the increment of Ca concentration (ΔCa, meq/100g dry weight), ΔMg/ΔCa, were calculated for each treatment, ΔK/ΔCa, ΔCa/ΔMg, and ΔK/ΔMg were also calculated. Repression values were obtained as an average of the values for 10, 15, 20, 25 meq/l treatments of each element. The higher the value had risen, the stronger the repression of the uptake. At 2nd week of the culture, repression values of Ca for Mg and K were 0.47 and 0.76, and the values of Mg for Ca and K were 10.69 and 0.34, respectively. The repression value of Mg for Ca uptake was the highest. Though the values changed according to the age of the plants, the highest value was obtained with Mg for Ca uptake at 4th week of the culture.

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An efficient and easy water culture was examined with pot. The plant growth could be cultivated with no use of aeration system and no renewal of nutrient solution. This method was named the storage nutrient culture method (SNC method). The plant growth in this method was compared with the custom method, and development of SNC method was tried. As the comparison of SNC and custom method was carried out with the spinach, the concentration of nutrient solution varied by plant growth. However, serious difference in the yields and nutrient conditions was not observed in the plant growth process. Fourty-four species of plants were grown by the SNC method with pot. These cultivations all succeeded well. And the scale of SNC method was expanded. Spinach was grown for one month in 76l container. Tomato was grown for 3 months in the 355l container. Cucumber was grown for 6 months in the 560l container. The yields of these plants were the same as the custom method. The penetration test of SNC method was carried out with the following method used as a cultivation tank of the 76l container. A detector of nutrient solution level was adopted as a simple control system of medium. As the nutrient solution reached a significant lower level, it was replenished up to the first level. Cucumber was grown from the first 10 days of August to the last 10 days of November with this system. The aerial parts and roots of cucumber plants all grew normally.

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Rapid and accurate method for analysis of major elements in soils by Lithium Metaborate Fusion ICP-AES was studied. The procedure established is summarized as follows. Mix 50 mg of finely powdered soil sampled and 100 mg of lithium metaborate in platinum crucible. Fuse the mixture in muffle furnace at 1,000℃ for 10 min. After cooling, transfer the crucible into a 30 ml tall beaker, and add a Teflon-coated stirring bar and 10 ml of 1 M nitric acid. Stir gently for dissolution of the melt in water bath with magnetic stirring unit at 60℃ for 10 min. Quantitatively transfer the dissolved melt to a 100 ml volumetric flask, and dilute to volume by water after cooling to room temperature. prepare blank and standard solutions form standard rock such as JG-1 or JB-1 in the same way as the sample, and analyze Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, and P by ICP-AES. The total time of analysis was about 30 min for dissolution and about 5 min for ICP-AES measurement. The accuracy of this method was confirmed by analysis of reference standard soils (SO-1〜4).

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[in Japanese]

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