南京地区簸箕柳雌、雄花序建成动态观察

【目的】 柳树雌株性成熟后会产生严重的飞絮污染,阐明其性别分化的分子机制是控制飞絮污染的关键。研究柳树雌、雄花芽分化以及花序建成的关键时期,为性别分化分子调控机理研究奠定基础。【方法】 以木本植物簸箕柳(Salix suchowensis)雌株和雄株花芽及花序为材料,从当年6月至翌年2月分别在17个时间点采集样品,利用石蜡切片技术对其雌、雄花芽分化及花序建成过程进行观察,分析不同发育阶段的相关特征。【结果】 簸箕柳花序建成初期为6月中旬至7月初,小花原基分化期在7月中旬至8月下旬,雌、雄蕊分化期在9月上旬至11月初,11月中旬至翌年2月初雌雄花序进入休眠期,翌年2月中旬至3月为大小孢子发生及雌雄配子体发育期,随后雌雄花序开放。研究表明,花序外观形态变化与内部解剖结构变化之间具有一定的相关性。【结论】 簸箕柳雌、雄花均为单性花。花序生长趋势总体呈“S”形上升趋势,在整个发育过程中,雄花序比雌花序外形稍大。簸箕柳花序外观形态可以用于判断花发育的关键时期。研究结果为全面了解簸箕柳花芽分化以及花序建成的完整过程提供了详细信息,为进一步阐明不同关键发育阶段的分子调控机制奠定了基础。

The dynamic observation of male and female inflorescence establishment of Salix suchowensis in Nanjing area

【Objective】 Salix (willows) cause severe seed hair pollution when they reach sexual maturity. Elucidating the molecular mechanisms underlying sex differentiation is essential for seed hair pollution control. To clarify the molecular regulation of sexual determination, it is necessary to understand the key period of floral bud differentiation and the establishment of inflorescence. 【Method】 In this study, we studied the morphology and anatomy of Salix suchowensis floral buds and determined the period at which inflorescence is established in males and females by light microscopy and paraffin sectioning. This study was conducted within one year. 【Result】 The inflorescence primordium differentiation occurred from mid-June to July; floret primordium initiation took place from mid-July to August; gynoecium or androecium differentiation occurred from September to November; dormancy of inflorescence spanned from mid-November to February of the following year, whereas male or female gametophyte development occurred from mid-February to March, following the flush of male or female catkins. Additionally, the morphological characteristics were correlated with anatomical structure of the inflorescence. 【Conclusion】 Both male and female flowers of S. suchowensis are unisexual. The growth curve of the inflorescence exhibited a sigmoid shape, and the male inflorescence was larger than that of the female inflorescence during the entire developmental process. External morphology can be used to deduce the differentiation stages of flower buds. This study provides a panoramic view of the dynamic changes in floral bud differentiation and inflorescence establishment in S. suchowensis, which provides essential information for clarifying the molecular mechanism underlying the key developmental stages of female and male flowers.