Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa.
Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
Ann Bot. 2019 Jan 23;123(2):225-245. doi: 10.1093/aob/mcy167.
The male fitness pathway, from pollen production to ovule fertilization, is thought to strongly influence reproductive trait evolution in animal-pollinated plants. This pathway is characterized by multiple avenues of pollen loss which may lead to reductions in male fitness. However, empirical data on the mechanistic processes leading to pollen loss during transport are limited, and we therefore lack a comprehensive understanding of how male fitness is influenced by each step in the pollination process.
This review assesses the history of studying male function in plants and identifies critical gaps in our understanding of the ecology and evolution of pollen transport. We explore male reproductive function along the steps of the pathway to paternity and discuss evolutionary options to overcome barriers to siring success. In particular, we present a newly emerging idea that bodies of pollinators function as a dynamic arena facilitating intense male-male competition, where pollen of rival males is constantly covered or displaced by competitors. This perspective extends the pollen-competitive arena beyond the confines of the stigma and style, and highlights the opportunity for important new breakthroughs in the study of male reproductive strategies and floral evolution.
从花粉生产到胚珠受精，雄性生殖途径被认为强烈影响着虫媒植物的生殖性状进化。该途径的特征是花粉大量损耗，这可能导致雄性生殖能力下降。然而，关于在运输过程中导致花粉损耗的机械过程的实证数据有限，因此我们缺乏对雄性生殖力如何受到授粉过程中每一步影响的全面理解。
本综述评估了研究植物雄性功能的历史，并确定了我们对花粉运输的生态学和进化理解的关键空白。我们沿着父权途径的步骤探讨雄性生殖功能，并讨论克服成功父亲障碍的进化选择。特别是，我们提出了一个新出现的观点，即传粉者的身体充当了一个动态的竞技场，促进了激烈的雄性间竞争，竞争雄性的花粉不断被竞争对手覆盖或取代。这种观点将花粉竞争的范围扩展到柱头和花柱的范围之外，并突出了在研究雄性生殖策略和花进化方面取得重要新突破的机会。
