两种广西特有报春苣苔属(苦苣苔科)植物传粉生物学研究

Pollination biology of Primulina repanda var.guilinensis and P.glandulosa var.yangshuoensis

通过野外观察和室内试验,对两种广西特有的桂林小花苣苔和阳朔小花苣苔的传粉生物学进行比较研究。结果表明:两种报春苣苔属植物花期从7月底至8月初;单花花期内花粉具有较高的活性,最高可达92.6%和94.5%;柱头可授性最高时可达90%和95%;花粉/胚珠比率(P/O)分别为110.28±17.45和229.65±18.00;柱头与花药之间存在着空间隔离,可防止自花授粉;在单花花冠裂片张开后第3天,花药开始散粉,但雌蕊在花朵刚开始开放时已伸长,待第3天时柱头已伸长到位于花冠筒口部,高于花药,便于接受异花花粉;该两种植物均不存在无融合生殖现象;两种报春巨苔属植物均高度自交亲和,但很难发生自发的自花授粉,必须依靠外力,因此传粉媒介对于结实率有重要影响,自然条件下基本不发生自花授粉;在自然状态下结实率明显低于两种人工授粉的结实率;小蜂和淡脉隧蜂是目前已知仅见的两种传粉者。

Study on pollination and breeding system of two endemic species of Guangxi,Primulina repandavar.guilinensis and P.glandulosavar.yangshuoensis, were compared in this study in nature and laboratory.The results showed that the flowering period of two species was from the end of July to early August,the highest viability of pollens was respectively 92.6%and 94.5%in flowering time,the highest acceptability of stigma was respectively about 90%and 95%,the mean P/O value was respectively 110.28±17.45and 229.65±18.00.There was spatial separation between stigma and anthers could prevent selfpollination.After the single flower opened three days after opening of the lobes of single corolla,anthers began to release pollens.However,stigma would extend on the third day after the opening of corolla lobes so that it would locate at the orifice of corolla and was higher than anthers,and was easy to accept pollens.All of our experiments on two varieties of Primulinashowed that they were self-compatible and there were no agamospermy.Tests showed that even if they were highly selfing affinity,it was very difficult to occur up spontaneous self-pollination because the pollination had to depend upon pollinator and bees.The percentage of setting seeds of two varieties in the nature was obviously lower than those by artificial pollination.Under natural conditions,two species do not self-pollinate.Chalcidi-dae sp.and Lasioglossumsp.are only two known pollinators of two species.