Laboratoire de Génétique et Évolution des Populations Végétales, FRE CNRS 3268, Bâtiment, Université des Sciences et Technologies de Lille - Lille 1, Villeneuve d'Ascq Cedex, France.
J Evol Biol. 2010 Dec;23(12):2636-47. doi: 10.1111/j.1420-9101.2010.02119.x. Epub 2010 Oct 7.
In sexually polymorphic plants, the spatial distribution of sexes is usually not random. Local variation in phenotype frequencies is expected to affect individual fitness of the different phenotypes. For gynodioecious species, with co-occurrence of hermaphrodites and females, if sexual phenotypes are structured in space and pollen flow is spatially restricted, local pollen availability should vary among patches. Female fitness may thus be low when hermaphrodites are locally rare. To test this hypothesis, we analysed how the reproductive output of females varied among patches within two natural study sites of the gynodioecious wind-pollinated Beta vulgaris ssp. maritima. Plants growing in female-biased areas and experiencing pollen limitation were found to have low fruit and seed sets but did not reallocate resources towards better offspring. Our results show that fine-scale processes influence individual fitness and the evolution of sex ratio in sexually polymorphic plants.
在性多态植物中，性别的空间分布通常不是随机的。表型频率的局部变化预计会影响不同表型的个体适合度。对于雌雄同体的物种，当雌雄同体和雌性共存时，如果性表型在空间上形成结构，并且花粉流动在空间上受到限制，那么局部花粉供应应该会在斑块之间发生变化。因此，当本地的雌雄同体数量较少时，雌性的适合度可能会较低。为了验证这一假设，我们分析了雌雄同体风媒传粉的 Beta vulgaris ssp. maritima 在两个自然研究点内的不同斑块中，雌性的繁殖输出如何变化。结果发现，在雌性偏多的地区生长并经历花粉限制的植物，其果实和种子数量较少，但不会将资源重新分配给更好的后代。我们的结果表明，微观过程会影响个体适合度和性多态植物中性别比例的进化。
