Disassortative mating prevails in style-dimorphic Narcissus papyraceus despite low reciprocity and compatibility of morphs

Evolution to reduce inbreeding can favor disassortative (inter-morph) over assortative (intra-morph) mating in hermaphroditic sexually polymorphic plant species. Heterostyly enhances disassortative pollination through reciprocal placement of stigmas and anthers of morphs and appropriate pollinators. Stylar dimorphism in which there is not reciprocal anther placement may compromise disassortative mating, particularly when there is not intra-morph incompatibility. Variable rates of disassortative mating along with differential female fecundity or siring success among floral morphs could lead to variation in morph ratio. We investigated mating patterns, female fecundity and siring success of style-length morphs in Narcissus papyraceus, a self-incompatible but morph-compatible species with dimorphic (long- and short-styled) and monomorphic (long-styled) populations in central and north regions of its range respectively. We established experimental populations in both regions and exposed the...

在雌雄同体且具有性多态性的植物物种中，为降低近交（inbreeding）而发生的演化过程，更倾向于选择异选型（型间）交配（disassortative mating）而非同选型（型内）交配（assortative mating）。花柱异型性（heterostyly）可通过不同花型的柱头（stigma）与花药（anther）的交互排布，以及适配的传粉者（pollinator），强化异选型传粉效率。不存在花药交互排布的花柱二型性（stylar dimorphism），可能会削弱异选型交配，尤其是在不存在型内不亲和（intra-morph incompatibility）的情况下。异选型交配率的差异，以及不同花型间雌性繁殖力（female fecundity）或父本繁殖成功率（siring success）的分化，可能会导致花型比例的变异。本研究以纸黄水仙（Narcissus papyraceus）为研究对象，该物种为自交不亲和（self-incompatible）但型间亲和的物种，其分布区中部与北部的种群分别为二型种群（dimorphic population，长花柱型与短花柱型）和单型种群（monomorphic population，仅长花柱型）。我们调查了该物种不同花长型的交配模式、雌性繁殖力及父本繁殖成功率，并在两个区域建立了实验种群，同时对……