Data from: Experimental insights on the function of ancillary pollen and stigma polymorphisms in plants with heteromorphic incompatibility

Most heterostylous plants possess a reciprocal arrangement of stigmas and anthers (reciprocal herkogamy), heteromorphic self-incompatibility and ancillary polymorphisms of pollen and stigmas. The topographical complementarity hypothesis proposes that ancillary polymorphisms function in the rejection of incompatible pollen thus promoting disassortative pollination. Here, we test this hypothesis by investigating patterns of pollen transfer and capture in populations of dimorphic Armeria maritima and A. pubigera and distylous Limonium vulgare (Plumbaginaceae), and by studying pollen adherence and germination patterns in A. maritima following controlled hand-pollinations. Armeria lacks reciprocal herkogamy allowing the evaluation of the extent to which ancillary polymorphisms affect the composition of pollen loads. We compared the amounts of compatible and incompatible pollen on stigmas in natural populations and calculated the proficiencies of pollen transfer for each mating type. We detected disassortative pollination in each species, and mating types did not differ in compatible pollen capture, although cob stigmas captured more incompatible pollen. Controlled hand-pollinations revealed the failure of incompatible pollen to adhere and germinate on stigmas. Our results provided evidence that, while structural in nature, pollen-stigma dimorphisms are tightly associated with heteromorphic incompatibility and likely function to promote disassortative pollination in the absence of reciprocal herkogamy.绝大多数异型花柱植物（heterostylous plants）均具备雌雄蕊交互排列结构（即交互雌雄异位，reciprocal herkogamy）、异型自交不亲和（heteromorphic self-incompatibility）以及花粉与柱头的附属多态性（ancillary polymorphisms）。地形互补假说（topographical complementarity hypothesis）提出，附属多态性可通过排斥不相容花粉，进而促进异配授粉（disassortative pollination）。本研究以二型性海石竹（Armeria maritima）、柔毛海石竹（A. pubigera）以及二型花柱补血草（Limonium vulgare，隶属于蓝雪科Plumbaginaceae）的种群为研究对象，通过探究其花粉传递与捕获模式，并结合控制性人工授粉（controlled hand-pollinations）后海石竹的花粉附着与萌发特征，对该假说进行验证。海石竹属植物不具备交互雌雄异位结构，这一特性使得我们可以评估附属多态性对花粉负载组成的影响程度。本研究比较了自然种群中柱头上相容花粉与不相容花粉的数量，并计算了不同交配型的花粉传递效率。我们在所有研究物种中均检测到异配授粉现象，且不同交配型的相容花粉捕获量并无显著差异，尽管cob型柱头捕获的不相容花粉更多。控制性人工授粉实验结果显示，不相容花粉无法在柱头上完成附着与萌发。本研究结果证实，尽管花粉-柱头二态性本质上属于结构特征，但其与异型自交不亲和紧密相关，且在缺乏交互雌雄异位的类群中，可能通过促进异配授粉发挥功能。