Studies on the Varietal Adaptability for Heavy Manuring in Rice : 1. Varietal differences in nitrogen and carbohydrate metabolism affected by different supply of nitrogen

The accumulation process of carbohydrate in rice varieties in relation to their response to nitrogen in the tropics

“…(5) fourid 'that a high nitrogen responsive japonica variety tended to accumulate more starch at high nitrogen levels than a low nitrogen responsive indica variety. They attributed th~ lower starch content of the indica variety to ·its vigorous nitrogen uptake.…”

“…It has been mentioned that a japonica variety maintains a higher starch content at a high nitrogen level than an indica variety (5,8). This conclusion seems to have been drawn from a comparison between the improved japonica variety and the leafy indica variety; the problem does not appear to be a matter of whether the variety is an indica or a japonica, but whether it is a good or a poor plant type.…”

“…Much of the starch accumulated in the leaf sheath and culm before flowering is translocated into the grains during ripening(l,2,3). The contribution to grain carbohydrate of the carbohydrate synthesized and stored in the leaves and culms before flowering varies with variety, nitrogen application and climatic conditions (1,2,4,5,6).…”

“…The carbohydrate accumulation of the rice plant is closely associated with nitrogen nutrition (4,5,7,8,9). According to TAKAHASHI et al (5), a high nitrogen responsive variety tends to accumulate more starch before flowering, particularly when subjected to high nitrogen levels, than a low nitrogen responsive variety.…”

“…According to TAKAHASHI et al (5), a high nitrogen responsive variety tends to accumulate more starch before flowering, particularly when subjected to high nitrogen levels, than a low nitrogen responsive variety. BABA(9) also showed the relationship between starch accumulation and the response of rice varieties to nitrogen.…”