Time Course Morphological and Histological Changes in Differentiating Floral Buds of Styrax tonkinensis

摘要

This study was aimed to reveal the time dependent exact differentiation process of Styrax tonkinensis in order to demarcate appropriate stages for regulation of flower development. The external morphology and internal structure of floral buds of S. tonkinensis in different differentiation stages were observed by using stereo microscope and making paraffin sections. The method of BBCH (Biologische Bundesanstalt, Bundessortenamt and Chemische Industrie) scale was adopted to describe the external morphology of flower buds and leaves of S. tonkinensis. The flower bud differentiation of S. tonkinensis began in early March and ended in mid-to-late May. According to the anatomical observation on internal structure, the flower bud differentiation of S. tonkinensis could be divided into six stages, including the initiation of flower bud, the appearance of inflorescence primordium, the formation of sepal primordium, the formation of petal primordium, the formation of stamen primordium and pistil primordium. The apical growth point becoming flat marked the transition from vegetative growth to reproductive growth. The order of flower bud differentiation of S. tonkinensis was centripetal. The experimental results can provide references for forest managers to understand the flower bud differentiation law of S. tonkinensis and take actions to regulate it.