单性木兰花部综合特征及其传粉适应性

对单性木兰花部综合特征和访花昆虫种类及访花行为进行了研究,结果表明,单性木兰花冠顶端呈半合拢状,花被片之间存在间隙,只有那些能够穿过这些间隙的昆虫才能到达花内为其采粉和授粉,对访花者的要求较为苛刻。于降雨前去掉雄花和雌花花被片,使雄花雄蕊群和雌花柱头充分暴露,另外选择雄花和雌花作对照,降雨后将花取回并测定雄花花粉生活力和雌花柱头上的花粉粒。结果表明,在雨天,单性木兰花冠顶端呈半合拢状的开放方式对雄花和雌花均起到了保护作用,这种花部结构的特化是对花期持续降雨的一种生态适应。从访花昆虫种类上看,单性木兰雄花的昆虫种类是雌花的两倍,显然雄花比雌花更能吸引昆虫。

The Floral Syndrome and Its Pollination Adaptability in Kmeria septentrionalis (Magnoliaceae)

This paper studied on the floral syndrome,species of visiting insects and their foraging behavior of Kmeria septentrionalis.The results showed that the top of corolla of Kmeria septentrionalis was half open,and there were spaces between tepals,only the insects that could go through the space were able to get to the flowers inside to collect pollens or pollinate for them.The tepals of male flowers and female flowers were cut off to show their stamens and stigmas completely before rainning,and other male flowers and female flowers were chose for comparison.After rainning,the pollen viability of male flowers was tested and pollens on stigmas of female flowers were counted.The results showed that the bloom pattern of Kmeria septentrionalis performed the function of protecting.It made pollens on male flowers refrain from being soaked by rainwater,and reserved pollens on stigmas of female flowers.This floral constructure was of ecological adaptability to continuous raining at flowering time.Species of visiting insects of male flowers was double as that of female flowers'.For insects,male flowers were more attractive than female flowers.