KU Leuven, Department of Biology, Plant Conservation and Population Biology, B-3001 Leuven, Belgium.
Research Institute for Nature and Forest, Kliniekstraat 25, BE-1070 Brussels, Belgium.
Sci Rep. 2017 Apr 21;7:46410. doi: 10.1038/srep46410.
Floral traits and the relative contribution of autonomous selfing to total seed set varies geographically and is often driven by the availability and abundance of suitable pollinators and/or the presence of co-flowering relatives. In the latter case, competition for pollinator services and costs of hybridization can select for floral traits that reduce interspecific gene flow and contribute to prezygotic isolation, potentially leading to geographic variation in floral divergence between allopatric and sympatric populations. In this study, we investigated variation in floral traits and its implications on the capacity of autonomous selfing in both allopatric and sympatric populations of two closely related Centaurium species(Gentianaceae) across two distinct geographic regions(UK and mainland Europe). Although the magnitude and direction of floral differentiation varied between regions, sympatric populations were always significantly more divergent in floral traits and the capacity to self autonomously than allopatric populations. These results indicate that mating systems can vary substantially within a species and that the joint occurrence of plant species can have a major impact on floral morphology and capacity of autonomous selfing, most likely as a way to reduce the probability of interspecific interference.
花部特征和自主自交对总结实率的相对贡献在地理上是不同的，通常是由适宜传粉者的可用性和丰度以及同域亲缘植物的存在驱动的。在后一种情况下，对传粉者服务的竞争和杂交成本会选择减少种间基因流动并有助于合子前隔离的花部特征，这可能导致异域和同域种群之间在花部分化上的地理变异。在这项研究中，我们调查了两个密切相关的 Centaurium 物种（龙胆科）在两个不同地理区域（英国和欧洲大陆）的异域和同域种群中的花部特征及其对自主自交能力的影响。尽管在不同地区花部分化的幅度和方向不同，但同域种群的花部特征和自主自交能力总是明显比异域种群更加多样化。这些结果表明，交配系统在一个物种内可能有很大的变化，并且植物物种的共同出现可能对花部形态和自主自交能力产生重大影响，这很可能是减少种间干扰的一种方式。
