荒漠生境罗布麻(Apocynum venetum)传粉生物学比较

Comparative pollination biology of Apocynum venetum at different desert landscapes

罗布麻(Apocynum venetum)是中国西北干旱地区的重要优势植物种,为了解其在荒漠生境的传粉生物学特性,对开花物候、花粉活力、柱头可授性、访花者种类、座果率及繁育系统进行观测。结果表明:(1)在荒漠-绿洲过渡带和荒漠边缘种群中,罗布麻的开花高峰期和花粉活力有差异,荒漠-绿洲过渡带种群的持续时间更长。(2)在过渡带种群中,姬蜂(Ichneumonsp.)是最有效的访花昆虫;在荒漠边缘种群中,意大利蜂(Apis mellifera)是主要的访花者。(3)过渡带上罗布麻种群的坐果率高于荒漠边缘。(4)在2个生境下,罗布麻杂交指数均为2,表明其繁育系统以兼性自交为主,异交在繁育系统中只起辅助作用。

Apocynum venetum is an ecologically important species of vegetation in the arid regions of Northwest China.In order to understand its pollination biology at different desert habitats,we investigated the characteristics for this species：phenology,pollen viability,stigma receptivity,pollinators,P/O rate,fruit set and breeding system.We found that the species showed four reproductive characteristics.First,the flowering peak and pollen viability were different between desert-oasis eco-tone and desert edge populations,longer in desert-oasis eco-tone populations.Second,in the desert-oasis ecotone,Ichneumonsp.was found to be the most effective flower visitor;in the desert edge,Apis mellifera was the frequent pollinators.Third,fruit set appeared to be higher in desert-oasis eco-tone populations than in desert edge.Finally,both outcrossing index were 2,we found that facultative autogamy was dominant and that out-crossing just played an assistant role in the breeding system.