Seasonal changes in pollen limitation and femaleness along the snowmelt gradient in a distylous alpine herb, Primula modesta

Flowering phenology of alpine plants is strongly determined by the timing of snowmelt, and the conditions of pollination of widely distributed plants vary greatly during their flowering season. We examined the reproductive success of the distylous alpine herb, Primula modesta, along the snowmelt gradient under natural conditions, and compared it with the result of artificial pollination experiments. In addition, the compositions and visit frequencies of pollinators to the flower of P. modesta were examined during the flowering period. The pin and thrum plants of P. modesta growing at the same site have an equal ability to produce seeds if a sufficient amount of legitimate pollen grains are deposited on the stigma surface. However, under natural conditions, their seed-set success was often (even if not always) restricted by pollen limitation, and the functional gender of the pin and thrum plants biased to the female and male, respectively, associated with their growing sites. These varia...高山植物的开花物候（flowering phenology）强烈受融雪时间调控，广布植物的传粉条件在其开花季内差异显著。本研究以二型花柱高山草本植物早花报春（Primula modesta）为对象，在自然条件下沿融雪梯度调查其繁殖成功率（reproductive success），并与人工传粉实验结果进行对比。此外，本研究还于开花期内调查了P. modesta花朵的传粉者组成及访花频率。 生长于同一生境的P. modesta长花柱型（pin）与短花柱型（thrum）植株，若柱头表面接收足量合法花粉，二者结籽能力并无差异。但在自然条件下，二者的结籽成功率往往（即便并非始终）受限于花粉限制（pollen limitation），且长花柱型与短花柱型植株的功能性别（functional gender）分别偏向雌性与雄性，该特征与其生长生境相关。上述差异……