Studies on the Yield Analysis of Soybean : [I] Changes in Principal Chemical Constituents of the Soybean Plant in Relation to Its Growth

[摘要] Shirobana-sai No. 1, an early variety of soybean, was grown under usual conditions in order to be exemined for total sugars, starch, total nitrogen, phosphorus, potassium and crude ash of each organ. Samples were taken at every tenth day throughont the growing period. The results obtdined are as follows. In stages prior to the flowering, the increase of all the constituents took place very slowly. During the flowering period, there was a remarkable increase in the accumulation of carbohydrates (Sugars+Starch) and potassium in the aerial parts of the plant. This was followed by the increase in nitrogen, phosphorus and crude ash, and rapid absorption of the above mentioned constituents took place in the pod-developing stage. The phosphorus absorption was almost similar to that of nitrogen. The absorption of these elements continued strikingly upto the maturity period in order to fulfil the necessary requirement for the growth of the seeds. In the stems the leaves and the pods, all the above mentioned constituents attained to their maximum amounts between 10-20 days after the end of the flowering period. Comparing these results obtained from Shirobana-sai No. 1 with those of other varieties, no significant results have been obtained in the accumulation of nitrogen and ash. But in regard to phosphorus and potassium, chemical analysis has not been made. In all the varieties examined the leaves played an important role, with few exceptions, both in accumulation process and also in the translocation of those constituents to the seeds. Therefore, the yield analyses of these varieties may be possibly acomplished by investigating the amount of principal constituents accumulated in leaves, at the stage accomplished certain days (10-20 days in Shirobanasai No. 1) after the end of flowering, and also by observing the level of accumulation changes which may be effected by environmental conditions. In this experiment, however, the behaviour of carbohydrates seemed to be one of the varietal characteristics. therefore, these differences among the varieties should be considered before the observation is made.

[学科分类] 农业科学（综合）