Studies on the production and behavior of carbohydrates in rice plant : I. Changes of principal constituents in each organ accompanied with its development

Abstract

(1) Paddy rice, Norin No.8 was pot-cultured in usual method, and the principal constitiuents of its each organ were analysed. (2) Immediately after transplanting, nitrogen percentage of each organ was comparatively low, but much starch was accumulated in leaf sheath and culm. (3) At the time of vigorous tillering, nitrogen percentage was the highest in each organ and starch percentage in culm and leaf sheath was very low. (4) From the panicle primodia forming to the begining of ripening, nitrogen percentage of each organ reduced rapidly, and starch was accumulated in culm and leaf sheath. About 2weeks before heading, the panicle began its rapid development, while the nitrogen content (absolute amount) of leaf reduced. This might be caused by nitrogen translocation to panicle. (5) With the progress of ripening, perhaps by translocation to panicle starch content in culm and leaf sheath reduced. Although starch content of panicle increased rapidly, the amount of all other constituents were nearly constant at this stage. Threfore, almost all photosynthesised carbohydrates were seemed to be accumulated in panicle in the form of starch.