Rice plants were cultured in the nutrient solution containing 0.5% NaCl by sand culture. And paper chromatography represented free amino acids and amides in the leaves, stems and grains of the rice plants, at the different stages of growth. Distribution of free amino acids and amides was shown in table 2. In the leaves and stems, asparagine, glutamine and threonine were idenified in the chloride excess culture, but absent in the control at the different stages of growth. In the grains, asparagine, glutamine and glycine were observed at the heading stage, but absent or decreased at the mature stage. Serine was identified in the control but absent in the chloride excess culture at these two stages.

View full abstract

The authors intend to clarify the relationship between morphological characteristics of rice plant and content of carbohydrates in stems. Plants supplied with different amount of nitrogen have been treated under different photoperiodic conditions in vegetative stage. The growth phase, content of carbohydrates and nitrogen of these samples are compared with plant cultured under normal condition. Results obtained are as follows : (1) Number of leaves on main stem of plant treated under short day condition is diminished and each leaf-blade is short in length. Due to the acceleration of ear formation the heading is hastened by about one month, accordingly, the active period of each leaf from sprouting to the heading is comparatively short. Content of carbohydrates in the stem of these plants is relatively small at the heading time, especially, in the plot where nitrogen is amply supplied. However, due to high nitrogen content of these plants, the assimilating activity is vigorous throughout maturity period. Therefore, content of carbohydrates in culm at maturity is larger than that at heading time in much nitrogen supplied plot. (2) Of plants treated under long day condition, the heading is delayed by about two weeks and leaf-blades on main stem and lower internodes of culm are long. In these plants content of carbohydrates in stem is remarkably large at the heading time, while content of nitrogen is small. But the amount of net assimilation product during maturity period is reduced to nearly nothing. Therefore, in these plots, it may be seen almost the whole amount of carbohydrates in ear is a translocated product stored in stem till the heading time. (3) It may be considered that the content of carbohydrates in stem is mainely affected by the area and activity of upper leaves and the active period of that leaves from sprouting to heading time.

View full abstract

In the previous report, the characteristics of nitrogen metabolism of leaves at their respcetive definite positions were studied to make clear the physiological bases of this function of leaves. The present report is concerned to the phosphorus and potassium metabolism of leaves at definite positions on the stem similar to the case of the previous report on nitrogen metabolism. The following results were obtained. (1) The content of phosphorus and potassium in each leaf increases with their growth, reaches a maximum and then decreases. The time when this maximum content is attained, occurs in sequence from lower leaves to upper leaves as in the case of nitrogen. These elements accumulate in lower leaves and then translocate to upper ones. (2) Before ear-forming period, these elements in the upper leaves are kept at a higher level than in the lower ones. After ear-initiation, that difference between the level of these elements in upper leaves and in lower leaves becomes narrower. (3) Leaves 3/0〜5/0 have direct connection with the tillering. The physiological condition under which they play their principal function, is characterized by high nitrogen and low phosphorus content. These leaves die rather at high level of mineral nutrients, so the cause of their death seems to be lack of carbohydrate as energy source. The chief function of these leaves, 3/0〜5/0,seems to be carbon assimilation to support tillering. (4) Leaves 10/0〜12/0 have intimate connection with ripening. The physiological condition under which they play their function is characterized by low nitrogen and high phosphorus level. The function of these leaves seems to be not only carbon assimilation but also the storing of nitrogen and phosphorus for ripening.

View full abstract

Experiment with rice plants was made for 30days in greenhouse under the scheme, shown in Table 1,combining several factors in different ways. The amounts of NH_3-N and iron found in drainages were discussed with a special reference to the redox condition of soil (Fig. 1). In the plot, cdC, the amount of water stable aggregates larger than 1.0mm in diameter, remained constant during the experimental period, but, in other plots decreased clearly. The most important factor for the growth of roots in these periods might not be the redox condition of soil but the amount of NH_3-N in the soil. (Fig. 2& 3) Analytical data on the ferruginous films formed around roots were discussed. (Fig. 4 & Table 3)

View full abstract

Observation of soil profiles in reference to the distributions of active and inactive oxides throughout the soil profiles of unmatured dry rice fields was made. Though many years elapsed since the cultivation of rice began in each field, the accumulation of the active iron oxides just below the furrow slice was scarcely found by the macroscopic observation. Somewhat ill drainage of the field was considered to be the principal cause of this phenomenon. The results of analyses are illustrated in Fig. 1,2,3,4,& 5,and the followings are concluded ; 1. Active oxides had been leached out, when the soils began to be used as the paddy field. 2. But in Soil A, active manganese oxides have been accumulated in the horizon below the furrow slice after using as the paddy field, and in Soil B, active manganese oxides and iron oxides have been accumulated. 3. Decreases of active alumina in the furrow slices are due to the downward movements of clay in addition to the lateral movements, though the drainages are not good.

View full abstract

The presence of asparagine in free state was investigated among various young crops as peas, root vegetables, vegetable fruits and edible herbs in soil culture. Asparagine was found freely in some young crops as peas and vegetable fruits (egg plant, tomato), and it more markedly occurred when they are subjected to darkness, while in edible herbs and root vegetables, -for example, Pak-choi, Pot herb mustard, chinese cabbage, radish and turnip as tested here-it was not found at the normal application of ammonia in light. It appeared only when they were subjected to darkness. On the contrary, glutamine of the two amides always appeared in all tested crops both in darkness and in light. Uuder darkness NH_3 required to form asparagine may be attributed to decomposition of amino acids of crops.

View full abstract

As the adsorptive ability of soil for cation was considered to be governed by two factors, i.e., its capacity and intensity, the author tried to estimate the intensity of soil to hold cation by the following two methods. A soil was equilibrated with a N- or N/10-salt solution of several cations by leaching; and then the amount of the cation adsorbed from the solution by the soil was determined. As the dilution of salt solution always decreased the amount of the adsorbed cation in widely different extent, the rate of this decrease was assumed to a index of intensity to hold the exchangeable cation against hydrolysis. Moreover, when a soil was equilibrated with several salt solutions, pH of which was 7,6,5 or 4,the decrease of pH also brought about a variable decrease of the cation adsorption. The rate of this decrease was to be a index of intensity to hold the exchangeable cation against acidification. Two soils having a remarkably different nature (table 1) were selected, and the above mentioned intensities were estimated for Ca and NH_4 ions. As shown in table 2,3,4 and 5,the intensity for Ca ion was not parallelled with that for NH_4 ion. This discrepancy was more cleary shown from the results of selective adsorption in a Ca and NH_4 mixed solution (table 6 and 7). To interpret the above facts, the author has considered as follows : The soil humus has a tendency to adsorb Ca much more strongly than NH_4 ion. It may, however, be not a special nature of humus but a common tendency shown by ion exchange substances. The mineral clay, on the other hand, has a specific property to adsorb NH_4 ion to a remarkable extent. The presence of its crystal structure is assumed to be a cause of this specificity.

View full abstract

The reciprocal offects of Mg and K or Ca on the release of these cations from Bentonite and Kaolinite by relatively small amount of H were investigated, the results being as follows : (1) Mg-K relationship When both cations were present on these clays, the percent release of Mg was decreased as the increase of K/Mg ratio, the curve of decrease being relatively sharp at the first half. But Na was more effective than K in depressing the percent rel ease of Mg. On the other hand, the percent release of K was remarkably increased as the decrease of K/Mg ratio. Thus, the distinguished reciprocal effects between Mg and K were confirmed. (2) Mg-Ca relationship The percent release of Ca was not affected by the presence of Mg as complementary ion in these clays, but the presence of Ca was accompanied by a slight increase of percent release of Mg. Consequently, the reciprocal effects were insignificant.

View full abstract