Department of Biological Sciences, University of Wisconsin - Milwaukee, 3209 N. Maryland Ave, Milwaukee, Wisconsin, 53211, USA.
Department of Biology, University of Akron, Akron, Ohio, 44325, USA.
Am J Bot. 2019 Aug;106(8):1131-1136. doi: 10.1002/ajb2.1336. Epub 2019 Aug 12.
Genetically diverse sibships are thought to increase parental fitness through a reduction in the intensity of sib competition, and through increased opportunities for seedling establishment in spatially or temporally heterogeneous environments. Nearly all research on mate diversity in flowering plants has focused on the number of fathers siring seeds within a fruit or on a maternal plant. Yet as hermaphrodites, plants can also accrue mate diversity by siring offspring on several pollen recipients in a population. Here we explore whether mate composition overlaps between the dual sex functions, and discuss the implications for plant reproductive success.
We established an experimental population of 49 Mimulus ringens (monkeyflower) plants, each trimmed to a single flower. Following pollination by wild bees, we quantified mate composition for each flower through both paternal and maternal function. Parentage was successfully assigned to 240 progeny, 98% of the sampled seeds.
Comparison of mate composition between male and female function revealed high mate diversity, with almost no outcross mates shared between the two sexual functions of the same flower.
Dual sex roles contribute to a near doubling of mate diversity in our experimental population of Mimulus ringens. This finding may help explain the maintenance of hermaphroditism under conditions that would otherwise favor the evolution of separate sexes.
人们认为遗传多样性的同胞群体通过减少同胞竞争的强度，并通过增加在空间或时间异质环境中幼苗建立的机会，从而提高了父母的适应性。几乎所有关于有花植物配偶多样性的研究都集中在一个果实或母株内父亲的种子数量上。然而，作为雌雄同体的植物，它们也可以通过在种群中的多个花粉接受者上产生后代来积累配偶多样性。在这里，我们探讨了两性功能之间的配偶组成是否重叠，并讨论了这对植物生殖成功的影响。
我们建立了一个 49 株金莲花（猴面花）植物的实验种群，每个植物修剪成一朵花。在野蜜蜂授粉后，我们通过父本和母本功能对每朵花的配偶组成进行了量化。成功将 240 个后代的亲代分配给了取样的种子，占比为 98%。
对雄性和雌性功能之间的配偶组成进行比较，发现了高度的配偶多样性，同一朵花的两性功能之间几乎没有共享的异交配偶。
在我们的金莲花实验种群中，两性角色导致了配偶多样性的近两倍增加。这一发现可能有助于解释在其他情况下有利于独立性别进化的条件下，雌雄同体的维持。
