抄録
In case of Japonica paddy rice varieties, the number of aleuron cell layers averaged 4.2 on dorsal side, 1.1, 1.2 on lateral and ventral sides, respectively, and 1.0 on midway portion between lateral and ventral sides. No difference was found in the number of aleuron cell layers among the sample varieties (Table 1), among the varietal groups classified according to grain size (Table 2), and between glutinous and nonglutinous strains (Table 1). In case of Japonica upland rice varieties, the number of aleuron cell layers on dorsal and ventral sides were larger than those of the Japonica paddy varieties (Table 3). In foreign varieties, the number of aleuron cell layers on dorsal side was less than those of Japonica ones. Especially, tested varieties of Indian and Chinese varieties are less than 3 layers (Table 4). The number of aleuron cell layers on the dorsal side of incompletely developed grains was less by about one layer than that of the full-grown grains in the same panicle. Regardless of completely or poorly developed grains, at least one cell layer of aleuron was formed on the lateral and ventral sides (Table 5). In case of early season cultivation in which the ripening stage is shifted to warmer season it showed the effect of increase in the number of aleuron cell layers on the dorsal side, but almost no effect on the leteral and ventral sides. The same tendency was found also in case where the ripening stage of Indica varieties was shifted to warmer season (Table 6).
