外来物种黄顶菊花器官分化的初步研究

The Observation on Floral Organ Differentiation of an Alien Species,Flaveria bidentis (L.) Kuntze

利用扫描电镜(SEM)观察了黄顶菊(Flaveria bidentis(L.)Kuntz)花序发育过程中蝎尾状聚伞花序、头状花序和小花的形成。黄顶菊的花序由主轴及一至三级分枝组成,各级分枝交互对生,形成方式相同。植株主轴和侧枝顶端的每个花序由3～6个蝎尾状聚伞花序密集而成;每一蝎尾状聚伞花序由5～15个头状花序组成;每一头状花序中有4～11枚小花。小花分化顺序为5个花冠原基、5个雄蕊原基和2个心皮原基。2007年,天津地区黄顶菊的花期是7月下旬到9月下旬。7月中旬,花序和花器官原基不断形成并分化,至花器官成熟经历的时间约15d。

The formation of scorpioid cyme, capitulum and floret of Flaveria bidentis （L.） Kuntze was observed under scanning electron microscopy. The inflorescence of F. bidentis was composed of the main axis with three orders branches in a decussate arrangement. Scorpioid cymes （3 - 6） were developed at the apex of the main inflorescence axis as well as lateral axes. Each scorpioid cyme had 5 - 15 capitulums which was consist of 4 - 11 florets. For the floral development process, five petal primordia arose firstly, then five stamen primordia appeared, followed by two carpel primordia. In 2007, florescence of F. bidentis was from late July to late September in Tianjin. In Mid July, the inflorescence primordia and floret primordia were formed and differentiated continually, and approximately 15 days after the initiation of flower bud differentiation, individual floret was well formed.