甘藷の生理的特性に関する研究 : XII. 塊根形成に伴う根の生理的変化について

抄録

So far as the writers are aware, few accounts seem to have been given to the physiological behavior of sweet potato roots by the root tuber formation. The present investigation was undertaken to see whether the carbohydrate contents, amylase and phosphorylase activities in the sweet potato roots may relate to the differentiation of root tuber and to the determination of the thickened part of tuberous roots. Sweet potato of the variety "Okinawa No. 100" was used as material. The experimental results obtained may be summarized as follows: 1. By the 10 day after planting, the carbohydrate contents in the tuberous roots showed no remarkable difference from those in the fibrous roots. While by the 20 day after planting, the accumulations of non-reducing sugar and starch were observed in the slightly thickened part of tuberous roots. By the 30 day after planting, it was recognized that the contents of reducing and non-reducing sugars and starch were high in the distinctly thickened part of tuberous roots and also that the non-reducing sugar and starch contents were pretty abundant in the upper part of tuberous roots. Judging from these results, the carbohydrate contents in the tuberous roots may-be assumed to proceed parallel to the progress of root tuber formation. 2. As the characteristic features of the root tuber formation throughout the whole stage, the carbohydrate contents in the lower part of tuberous roots were almost similar to those in the fibrous roots, and the interrelation of carbohydrate contents between the thickened, upper and lower parts of tuberous roots added further confirmatory support to the previous results (1958, a). 3. Concomitant with the behavior of carbohydrate contents, the amylase and phosphorylase activities in the tuberous and fibrous roots differed from each other. Moreover, the variations of these enzyme activities in the tuberous roots were closely related to the root tuber formation.