Abstract
Fagus crenata produce intermittently large numbers of seeds or flowers, not annual reproduction. Several hypotheses have been developed to explain the mechanism of intermittent reproduction; i.e. internal resources, climate cues. These proximate factors assume that the plant sets flowers as a result of that these factors induce differentiation of floral meristem as a starting signal. However, there are no direct evidences about whether these factors function as a signal of floral initiation, because it cannot be detected when the first switch of flowering on. In order to explore these factors on floral initiation, we quantified expression level of flower identity gene; LEAFY homolog (FcLFY) as well as process of flower bud differentiation using mature F. crenata. We measured seasonal pattern of FcLFY expression in bud using real-time quantitative PCR. In addition, we observed the relationship between FcLFY expression in bud and process of flower bud differentiation. We also analyzed relationship between FcLFY expression and internal resources. This approach could allow us to evaluate which proximate factor works as a signal of floral initiation in F. crenata.
