抄録
Paddy rice plants, var. Norin No. 29 were pot cultured under various photoperiodic conditions namely, natural day-length (N), short day (S), long day (L), 10 short days and thereafter long day (S→L)1, and short day upto heading and thereafter long day (S→L)2 (Fig. 1). The plants treated entered into reproductive phase at different time and the stage proceeded in different pace according to the condition. By means of comparing these plants with reference to dry weight and contents of chemical constituents, physiological characteristics of each stage of development were examined. In the early stage of reproductive phase the plants seemed to behave just as the plant in vegetative phase in reference to dry matter production, nitrogen absorption and content of each chemical constituents (crude protein, sugar, starch, hemicellulose and cellulose) in spite of obious difference in morphological aspects. In accordance with panicle development, sugar and starch accumulation gradually replaced the production of skelton constituents (hemicellulose, cellulose), and in ripening period, starch accumulation predominated over the production of any other constituents and productiyity of dry matter and absorbability of nitrogen declined.
