THE CONTRIBUTION OF MATING SYSTEM VARIATION TO REPRODUCTIVE ISOLATION IN TWO CLOSELY RELATED CENTAURIUM SPECIES ( GENTIANACEAE) WITH A GENERALIZED FLOWER MORPHOLOGY
THE CONTRIBUTION OF MATING SYSTEM VARIATION TO REPRODUCTIVE ISOLATION IN TWO CLOSELY RELATED CENTAURIUM SPECIES ( GENTIANACEAE) WITH A GENERALIZED FLOWER MORPHOLOGY
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DOI：
10.1111/evo.12345
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发表时间：
2014-05-01
期刊：
影响因子：
3.3
通讯作者：
Jacquemyn, Hans
中科院分区：
文献类型：
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作者：
Brys, Rein;Vanden Broeck, An;Jacquemyn, Hans
在物候和传粉媒介群落表现出强烈相似性的密切相关的植物物种中，育种系统的差异和花性状的相关变化可能对异种花粉流和杂交的大小和方向产生重要影响。在这里，我们通过一系列实验量化了兼性异交 Centaurium erythraea 和主要自交 C. littorale 之间的几个合子前和合子后屏障的强度，并使用分子标记估计了现场杂交的频率。主要负责阻止杂交的生殖障碍本质上是合子前的，并且这些障碍的作用不对称。由于花展示、花粉产量和花粉转移率的差异，异种花粉流主要发生从红花 C. erythraea 到 C. littorale。另一方面，在 C. littorale 中，紧密的花药柱头定位和由此产生的更高的自主自交能力，成为平衡杂种交配的较高风险的有效屏障。在这两个物种中，所有生殖障碍的作用导致杂交建立的机会很小，田间仅出现大约 1% 的假定杂交就证实了这一点。我们的研究结果证实，育种系统的差异会影响异种花粉转移模式，自主自交可以有效防止杂交。
In closely related plant species that display strong similarities in phenology and pollinator communities, differences in breeding system and associated shifts in floral traits may have important effects on the magnitude and direction of heterospecific pollen flow and hybridization. Here, we quantified the strength of several pre- and postzygotic barriers acting between the facultatively outcrossing Centaurium erythraea and the predominantly selfing C. littorale via a suite of experiments, and estimated the frequency of hybridization in the field using molecular markers. The reproductive barriers primarily responsible for preventing hybridization were essentially prezygotic and these acted asymmetrically. Due to differences in floral display, pollen production, and pollen transfer rates, heterospecific pollen flow occurred predominantly from C. erythraea to C. littorale. In C. littorale, on the other hand, close anther-stigma positioning and resulting higher capacity for autonomous selfing functioned as an efficient barrier to counterbalance the higher risk for hybrid mating. In both species the action of all reproductive barriers resulted in a small opportunity for hybrid establishment, which was confirmed by the occurrence of only approximate to 1% putative hybrids in the field. Our findings confirm that differences in breeding system affect heterospecific pollen transfer patterns and that autonomous selfing may efficiently prevent hybridization.