濒危植物夏蜡梅的繁育系统和传粉特性研究

On Breeding System and Pollinating Characteristics of Sinocaycanthus chinensis,an Endangered Plant in Dalei Mountain

夏蜡梅(Sinocaycanthus chinensis)为雌蕊先熟,其花部构造适合于异交;但花药开裂在花后第3天,提示该植物也可延迟自交。研究了天台大雷山夏蜡梅种群的繁育系统与传粉特性,结果如下:1)开花当天柱头就能接受花粉,但最高活性在花后第2天,在花药开裂时,柱头活性有所下降,但与最高值差异不显著。2)不去雄套袋的结实率显著高于去雄不套袋,自然条件下以自交为主,自交率为61.3%和73.6%。3)延迟自交的繁殖保障效应分别只有78.1%和84.8%,主要原因是结实的花粉限制和结实阶段轻度的近交衰退。

Sinocalycanthus chinensis displays showy flowers. Its pistil development and anther growth, belonging to protogyny, differed slightly. These floral syndromes were showed to favor outcrossing. However, the anthers dehisced at the third day after flower opening, suggesting that the species may occur in delayed selfing. In order to test this hypothesis, the pollination biology of two S. chinensis populations with different altitude in Dalei Mountain was studied. The main results were as follows： The stigma receptivi.ty of S. chinensis was the highest at the second day after flower opening. And it began to decline at the anther dehisced, but it was not significantly diminished. The seed set rate of S. chinensis under bagged without emasculation was 42.01% and 44.44%, and was significantly lower than that of the control, which was 53.82% and 52.43%. The seed set rate under emasculation without bagged was 21.53% and 13.89% respectively. It was significantly lower than that of the control, and was also significantly lower than that of trader bagged without emasclflation. The selfing rates were 61.3% and 73.6%,suggesting that the reproduclion of this species mainly depended on self-pollination.bThe reproductive assurances were only 78.1% and 84.8%. This result was mainly caused by the pollen limitation, and the mild inbreeding depression at early fruiting phase.