Studies on the production and behavior of carbohydrates in rice plant : II. On the accumulation and distribution of starches in the organs of rice plant with its development of growth

Abstract

The process of accumulation and distribution of starch in the organs of rice plant, with its development of growth, was observed chiefly microscopically using 0.1% J-KJ solution. As the parts which accumulated much starch were both the base of leaf-sheath and the interode of culm, the authors estimated the relative amount of starch accumulated there, by the methods illustrated in Fig.1 and Fig.2 respectively. The results observed were as follows : (1) A 1arge number of minute starch-grains accumulated in all young organs before elongation, but theydisappeared during elongating period being probably consumed for enlargement of cells. When the elongation ceased accumulation of starch took place again and increased thereafter in amount. (2) The behavior of starch in the leaf-sheath of the locus lower than the 12th was different from that of higher one : In the formers starch disappeared thoroughly before the development of young culm and panicle and the leaves soon died, but in the latters it attained maximum in amount about lO days before and decreased just before heading date, again increasing till the beginning of translocation of it to kermels and decreased gradually thereafter (Fig.3, upper). (3) In the lower internodes (8-9∼10-11) starch decreased in amount in tillering stage, but later, amount of it in all internodes increased and attained its maximum lO days after heading when fruiting began, then decreased with the progress of translocation. At maturity, the lowdr internodes restored considerable amount of starch, but in rachis and peduncle it was lost thoroughly (Fig.3, lower).