Abstract
The seedlings of lowland rice, variety. Aichi Asahi, grown under three kinds of seeding spaces, that is, 4.5cm×4cm as a thin rate, 3cm×1.5cm as an intermediate one and 1.5cm×1.5cm as a thick one were sampled at every leaf stage from 2nd to 8th, at which each leaf had completely emerged, thereafter the differentiation of primordia of leaves and tillers and the development of tillering buds were studied by using scales, calipers and microscopes. When the nth leaf has emerged, i.e. at nth stage, the (n+4)th leaf of a main stem has differentiated, simultaneously the primordia of (n+2)th and (n+1)th tillers are found as merely a swelling in appearance at the axis of(n+2)th and (n+1)th leaf, respectively. The nth tiller, which was a swelling primordium at (n-2)th and (n-1)th leaf stages, begins to develope and grow as tillering bud differentiating one or two leaf primodia at nth stage, and thereafter it continues to grow if the environmental factors are suitable. In thick rate seedlings, the growth of each tiller is supressed as compared with thin rate seedlings, the inhibiting effct of thick rate seeding, however, on the growth of nth tiller can hardly be seen before the nth leaf stage, at which the tiller beginS to differentiate leaves and to grow rapidly
