XVI International Botanical Congess

Apical dominance is a phenomenon in which a terminal bud grows predominantly and the growth of axillary buds is suppressed. We analyze the molecular mechanisms of apical dominance from the point of view of cell cycle control in axillary buds. We showed that most cells in dormant buds are arrested at the G1 phase, and that pea RB-related protein may play an important role in the suppressive control of the cell cycle during dormancy. Using the specific antibodies, we found that the complex containing PCNA and cyclinD is formed during dormancy, and it is dissociated after decapitation. We try to identify CDK-inhibitors in the PCNA-cyclinD complex by the yeast two-hybrid system. We will discuss the possibility that the cell cycle in dormant buds is controlled by mechanisms similar to those operating in animals.