野生和人工种群多枝柽柳的传粉生物学比较

Comparative pollination biology of Tamarix ramosissima in wild and managed populations

多枝柽柳是中国西北干旱地区的重要建群种,为了解其不同种群的传粉生物学特性,对该物种的开花动态、花粉活力、柱头可授性、访花者种类、坐果率及繁育系统进行观测。结果表明:1)野生和人工种群的开花高峰期和花生产期有差异,人工种群的持续时间更长。2)野生种群中,意大利蜂为主要的访花昆虫,花粉与胚珠比(P/O)为337.2;人工种群中,卡切叶蜂是最有效的访花者,花粉与胚珠比(P/O)为356.1。3)人工种群的坐果率高于野生种群。4)在2个种群中,杂交指数均为3,表明多枝柽柳以兼性异交为主,自交在繁育系统中只起辅助作用。

Tamarix ramosissima is an ecologically important species of vegetation in the arid regions of Northwest China. In order to understand its pollination biology of different populations,we investigated the following characteristics of the species： flowering dynamics,pollen viability,stigma receptivity,floral visitors,fruit set and breeding systems. We found that the species was characterized by four important reproductive characteristics. Firstly,the flowering peak and flower production period were different between wild and managed populations,being longer in the managed. Secondly,in the wild populations,Apis mellifera was the frequent pollinator,and the P / O rate was 337. 2. In the managed populations,Megachile（ Amegachile） kagiana was the most effective flower visitor,and the P / O rate was 356. 1. Thirdly,fruit set appeared to be higher in the managed populations than in the wild. Finally,outcrossing indexes of both populations were 3,and facultative outcrossing was dominant and self-pollination just played an assistant role in the breeding system of both populations.