香港四照花花芽分化的形态学观察

采用石蜡切片技术和形态观察对香港四照花(Dendrobenthamia hongkongensis(Hemsl.)Hutch.)花芽分化过程中花芽的形态变化进行观测,研究花芽外部形态与花芽分化之间的关系。结果显示,香港四照花的花芽分化开始于7月上旬,到9月底完成,形态分化过程可分为8个时期:未分化期、花序原基分化期、小花原基分化期、花萼原基分化期、花瓣原基分化期、雄蕊原基分化期、雌蕊原基分化期、雌蕊雄蕊形成期。与之对应的外部形态变化为:混合芽闭合,混合芽基部膨大,新叶展开露出圆形花序,花柄初现,花序膨大,花序表面小花突起,花柄伸长至4~6 mm,花序表面小花轮廓明显。香港四照花花芽外部形态能直观地反映出内部结构变化,可根据花芽外部形态特征推测花芽分化状况。研究结果可为香港四照花花期调控和栽培管理提供科学依据。

Morphological observation of flower bud differentiation of Dendrobenthamia hongkongensis (Hemsl.) Hutch.

To study the relationship between the external morphology of flower buds and flower bud differentiation, we used paraffin sectioning and morphological observation to observe changes in Dendrobenthamia hongkongensis (Hemsl.) Hutch. flower buds during differentiation.Results showed that the flower bud differentiation of D.hongkongensis began in early July and was completed by the end of September. The morphological differentiation process could be divided into eight periods:undifferentiated, inflorescence primordium differentiation, floret primordium differentiation, sepal primordium differentiation, petal primordium differentiation, stamen primordium differentiation, pistil primordium differentiation, pistil and stamen formation. The corresponding external morphological changes were as follows:mixed buds closed, bases of mixed buds expanded, new leaves unfolded and round inflorescences were revealed, peduncles appeared, inflorescences were enlarged, florets on the surface of the inflorescences bulged, peduncles extended to 4-6 mm, and outlines of florets became obvious. There was a certain correlation between the process of flower bud differentiation and external morphology, and flower bud differentiation could be inferred according to the external morphological characteristics of the flower buds. The aim of this study was to provide a scientific basis for flowering regulation and cultivation management of D.hongkongensis.