Do specialized flowers promote reproductive isolation? Realized pollination accuracy of three sympatric Pedicularis species
Do specialized flowers promote reproductive isolation? Realized pollination accuracy of three sympatric Pedicularis species
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特殊的花朵会促进生殖隔离吗？
DOI：
10.1093/aob/mct187
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发表时间：
2014-01-01
期刊：
影响因子：
4.2
通讯作者：
Huang, Shuang-Quan
中科院分区：
文献类型：
--
作者：
Armbruster, W. Scott;Shi, Xiao-Qing;Huang, Shuang-Quan
自达尔文以来，传粉者介导的植物花表型和物种形成的进化分化一直是植物进化研究的核心。专化授粉预计会导致生殖隔离和促进物种形成的同域物种之间的促进分区（1）的传粉者的物种使用，（2）当传粉者使用，或（3）花粉放置的网站。本文以横断山区马先蒿属（P.densispica）、三色马先蒿（P.tricolor）和二叉马先蒿（P.dichotoma）三种马先蒿属植物为研究对象，通过观察传粉者的行为，探讨了马先蒿传粉的机制。利用荧光粉和染色花粉，分别对马先蒿属3种植物的柱头与熊蜂的接触和花粉沉积的准确性进行了评价。结果表明，在三种花卉中，雌性函数的适应精度远高于雄性函数。虽然花粉沉积峰值对应于传粉者的最佳位置（即柱头接触的网站）为每个物种，大量的花粉分散在大部分的蜜蜂body.The马先蒿属物种在喜马拉雅东部地区的研究不符合赠款马先蒿模型的机械生殖隔离。这种多样化的植物群的特化花似乎不太可能增加生殖隔离的可能性或影响物种形成的速度。有人建议，而不是马先蒿分支的极端物种丰富度是以其他方式产生的，专门的花和大量的授粉准确性演变为选择产生的多样性共同发生的同源物。
Interest in pollinator-mediated evolutionary divergence of flower phenotype and speciation in plants has been at the core of plant evolutionary studies since Darwin. Specialized pollination is predicted to lead to reproductive isolation and promote speciation among sympatric species by promoting partitioning of (1) the species of pollinators used, (2) when pollinators are used, or (3) the sites of pollen placement. Here this last mechanism is investigated by observing the pollination accuracy of sympatric Pedicularis species (Orobanchacae).Pollinator behaviour was observed on three species of Pedicularis (P. densispica, P. tricolor and P. dichotoma) in the Hengduan Mountains, south-west China. Using fluorescent powder and dyed pollen, the accuracy was assessed of stigma contact with, and pollen deposition on, pollinating bumble-bees, respectively.All three species of Pedicularis were pollinated by bumble-bees. It was found that the adaptive accuracy of female function was much higher than that of male function in all three flower species. Although peak pollen deposition corresponded to the optimal location on the pollinator (i.e. the site of stigma contact) for each species, substantial amounts of pollen were scattered over much of the bees bodies.The Pedicularis species studied in the eastern Himalayan region did not conform with Grants Pedicularis Model of mechanical reproductive isolation. The specialized flowers of this diverse group of plants seem unlikely to have increased the potential for reproductive isolation or influenced rates of speciation. It is suggested instead that the extreme species richness of the Pedicularis clade was generated in other ways and that specialized flowers and substantial pollination accuracy evolved as a response to selection generated by the diversity of co-occurring congeners.