MORPHOLOGICAL-STUDIES ON THE REGULARITY O F SHOOT DEVELOPMENT IN RICEPLANTS .6. THE REGULAR RELATIONSHIP BETWEEN LEAF PRIMORDIA DEVELOPMENTS IN THE MAIN SHOOT AND PRIMARY TILLER BUDS

Rice cv. Koshihikari was seeded and grown for three years. Seedlings w ere dissected under a stereoscopic microscope for anatomical studies a t the following stages;in n.1 age when the (n+1)-th lamina of the main shoot emerges from the n-th leaf sheath of the same main shoot, and i n the middle of n.1 age and (n+1). 1 age through the vegetative phase. Appearance of a protuberance at the peripheral zone of the shoot apex was used as the sign of differentiation of a leaf primordium. Through 1.1 age to 10.1 age, the main shoot of the plant at n.1 age developed at the axil of its (n+1) leaf a hemisphere primordium which evolves i nto a primary tiller bud. This relationship was true for the developme nt of the 2nd to 9th primary tiller buds. During the phyllochron (leaf emergence interval) of the (n+1) leaf, two leaf primordia for the pro phyll and the Ist leaf were formed on the above tiller apex. During th e three successive phyllochrons, the number of leaf primordia formed o n the tiller apex was two, one and two, respectively. When the above l ast leaf primordium corresponding to the 6th leaf of the tiller differ entiates in the third phyllochrons, the 2nd lamina of the tiller start s to emerge from its Ist leaf sheath. Generally, the 2nd to 9th tiller buds evolved into tillers.