中文摘要：

观测了四药门花Loropetalum subcordatum的开花物候、开花动态和访花者；对其花粉组织化学、花粉胚珠比和花粉活力进行了检测；通过人工控制授粉实验检测了其繁育系统；使用扫描电子显微镜（SEM）观察了自花花粉在柱头上的萌发情况并使用荧光显微镜观察了花粉管在花柱中的生长情况。结果表明：四药门花花期为9月至次年2月，其中9–10月为开花高峰期；单花花期4–6d；雌蕊先熟，开花时柱头即有活性，并持续到花谢；花药于开花后12–24h内开裂，并能直接落置自花柱头；离体花粉寿命约26h，花粉为非淀粉型，花粉胚珠比为8420±720.86（n=10）；无花蜜分泌。未观察到任何外来的访花者，仅见到生活在头状花序中的蓟马Thrips sp.，且未见到蓟马在花间积极迁飞，表明蓟马不是其有效的传粉者。无处理套网和辅助异株授粉的结实率（5.30%±1.83%/6.67%±1.91%）与自然对照（4.79%±1.45%）差异均不显著（P=0.847/0.616），扫描电镜观察证明自花花粉能在柱头上顺利萌发，荧光显微镜观察证明花粉管能在24h内生长到花柱基部，说明四药门花是自花传粉，不存在无融合生殖。四药门花存在雌蕊先熟现象并且仍有异交可能，说明其祖先类型曾经是异交植物。花谢后子房于次年夏天才开始膨大而果实于10月间开花高峰期后成熟，说明存在胚发育延迟的现象。本文还讨论了金缕梅科Hamamelidaceae中自花传粉由蝇类传粉演化而来的可能性。

英文摘要：

The reproductive biology of Loropetalum subcordatum was studied. The floral phenology, pollen histochemistry, pollen-ovule ratio （P/O）, pollen viability and floral visitors were investigated and determined. Assisted pollination experiments were carried out to examine the breeding system of L. subcordatum. Scanning electron microscopy （SEM） and fluorescence microscopy （FM） were employed to check the pollen germination and the growth of pollen tubes. Results were obtained as follows： （1） The flowering period ofL. subcordatum was from September to the next February with a peak at September-October; the longevity of a single flower was 4-6 days. （2） L. subcordatum was protogynous, and pollen grains could be found on self-stigmata when the anthers opened 12-24 h after petals unrolling. （3）The pollen viability （MTT test） maintained for ca. 26 hours; the pollen was starchless; the P/O was 8420±720.86 （n=10）; no nectar secretion was observed. （4） Thrips （Thrips sp.） were the only floral visitors observed but which seldom moved among inflorescences, thus played limited role in pollination. （5） Fruit sets of untreated bagged （5.30±1.83%） and hand assisted cross pollinated flowers （6.67±1.91%） were not significantly different from that of open flowers （4.79±1.45%）. （6） SEM and FM observations proved that pollen germinated on self-stigmata and pollen tubes growed in self-styles. The results indicated that L. subcordatum was facultatively autogamous and without apomixes. The possibility of outcrossing and the protogyny might indicate that the species was originally a crosser. Flowers pollinated in September-October usually start ovule growth in next summer, and set mature fruits in next October （after the next flowering peak）, suggesting the occurrence of retard embryo development. The possibility that autogamy in Hamamelidaceae could have been developed from fly pollination was also discussed.