0023-6152

AA00697606

24387

査読無

0023-6152

AA00697606

Using two strains chosen from the cultivated rice species, Oryza sativa L. and Oryza glaberrima Steud., the potential of growth pertitioning or growth perenniality was comparatively examined based on the photosynthate partitioning in plants grown in solution culture. The root weight of O. sativa strain (S-70) Slightly increased for 28 days after heading ; however, that of O. glaberrima strain （G-174） decreased. The development of new roots was restricted at the post-heading stage in both species, but the treatment of roots excision promoted new root growth, and it was more vigorous in S-70. This specific difference was more clearly shown when plants were grown at a low nitrogen concentration. Furthermore, the results of ^<13>CO_2 feeding to plants revealed that a large amount of photosynthate was transported to stock （roots + the basal part of culm） in S-70, and the root excising treatment considerably increased the ratio of substance partitioned to stock in this species. From this evidence it may be predicted that S－70 distributes more excessive substance to roots than is required to keep their functional level during the limited maturing stage. A large accumulation of substance in stocks in S-70 may suggest that the growth perenniality has been strongly left as one of the genetic properties in O. sativa species.