Brunet Johanne, Charlesworth Deborah
Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, 97331-2902.
Rocky Mountain Biological Laboratory, Crested Butte, Colorado, 81224.
Evolution. 1995 Feb;49(1):70-79. doi: 10.1111/j.1558-5646.1995.tb05959.x.
In plants whose flowers develop in a sequence, different flowers may exhibit temporal variation in pollen donation and receipt such that the fitness contributions through male and female functions can vary among flowers. Dichogamy, or directional pollinator movements within inflorescences, can create situations where flowers in different stages in the sequence may differ in the numbers of flowers in the female stage available as potential mates. We present an evolutionarily stable strategy (ESS) analysis of the resource allocations expected in different flowers in hermaphroditic plants when the mating environments vary among flowers. This introduces a modular element into sex-allocation models. Our analysis shows that such variation in the mating environments of flowers can select for differences in sex allocation between flowers. When male and female fertilities are nonlinear functions of the allocations, variation in resource availability can also select for variation in sex allocation among flowers. The influence of dichogamy and pollinator directionality on floral sex allocation is discussed, and the empirical evidence supporting the predictions derived from the model is briefly reviewed. The implications of our results for the evolution of andromonoecy and monoecy are discussed.
在花朵按顺序发育的植物中，不同的花朵在花粉捐赠和接受方面可能表现出时间上的变化，以至于通过雄性和雌性功能所做出的适合度贡献在不同花朵之间可能会有所不同。雌雄异熟，即花序内传粉者的定向移动，会造成这样的情况：序列中处于不同阶段的花朵，作为潜在配偶的处于雌性阶段的花朵数量可能会有所不同。我们对雌雄同体植物中不同花朵在交配环境因花而异时预期的资源分配进行了进化稳定策略（ESS）分析。这为性别分配模型引入了一个模块化元素。我们的分析表明，花朵交配环境中的这种变化能够选择不同花朵之间的性别分配差异。当雄性和雌性育性是分配量的非线性函数时，资源可用性的变化也能够选择花朵之间性别分配的变化。讨论了雌雄异熟和传粉者方向性对花的性别分配的影响，并简要回顾了支持从该模型得出的预测的实证证据。讨论了我们的结果对雄花两性花同株和雌雄同株进化的影响。
