天仙子的花部特征及延迟自交机制

通过实验观察和野外控制授粉等方法,对天仙子的自交亲和能力和自交传粉机制进行了研究。结果显示:(1)天仙子的花不完全雌性先熟,开花进程中雄蕊伸长是维持其混合交配系统的重要花部特征。(2)野外控制授粉实验证明天仙子的自交亲和性高,具有主动自交能力,主动自交发生的时间集中在晚花期,与花药和柱头接触的时间吻合。(3)在花粉活力和柱头可授期内,花药与柱头的接触能够发生自花授粉,这种依赖花药与柱头接触发生的自花授粉机制属于典型的延迟自交类型。研究表明,天仙子不仅在花结构上首先选择了适于异交的特征,而且还利用雄蕊伸长成功实现自花授粉,通过异交与延迟自交混合的交配系统为该物种提供了灵活的遗传与繁殖保障。

Floral Syndrome and Delayed Autonomous Selfing of Hyoscyamus niger

In this study,the self-compatibility and mechanism of self-pollination in Hyoscyamus niger were nvestigated in the field.The results showed that:(1)The flower was incompletely protogynous,stamen elongation was the main floral mechanism which to maintain the mixed mating system.(2)Pollination control treatments suggested the species was self-compatible and has autonomous self-pollination ability.The autonomous selfing occurs at the late floral stage which overlaps with the time of stigma and anthers contacting.(3)The contact of anthers and stigma when pollen was viable and stigma was receptive resulted in delayed selfing in this species.H.niger not only select the flower structure that adapt to outcrossing,but also promoting self-pollination through stamen elongation.These results indicate that H.niger has a well developed capacity for delayed selfing,which provided reproductive assurance in the study population.