海南三七（姜科）的食源性欺骗传粉

Food deceptive pollination in Kaempferia rotunda (Zingiberaceae)

关键词:  海南三七  食源性欺骗  克隆繁殖  传粉生物学  繁育系统

Key words:  Kaempferia rotunda  food deception  clonal reproduction  pollination  breeding system

摘要:

有花植物为繁殖成功，进化出各种各样的花部特征来吸引传粉者，如为传粉者提供花蜜、花粉、栖息地等，然而在33科146属的被子植物中也存在着不提供任何报酬而欺骗昆虫为其传粉的现象。这种欺骗性传粉模式主要出现在高度进化的具有多样化传粉模式的兰科植物中。报道了在姜科植物中首次发现的食源性欺骗传粉模式。对姜科山柰属海南三七进行连续2年的传粉生物学观察和研究发现，海南三七的花在早上5：30～6：00之间开放，下午17：00～18：00左右闭合萎蔫，持续大约11～12 h。开花过程中花粉活性与柱头可受性均保持较高水平(＞90%)。花粉/胚珠比率(P/O)为82.20±47.89(n=20)。木蜂是其主要的访花和传粉昆虫，访花目的是吸取花蜜。海南三七虽有细长线形的蜜腺，但并不分泌花蜜作为传粉昆虫访花的报酬，采用食源性欺骗的方式欺骗木蜂为其传粉。繁育系统的研究表明广西弄化的海南三七居群主要是通过根茎进行无性繁殖。

Abstract:

Most animal pollinated plants for the success of reproduction have evolved a variety of floral morphological characters to attract pollinators，such as providing nectar，pollen，brood sites for the pollinators. However，non rewarding flowers by deceptive pollination are found in 146 genera from 33 angiosperm families. These deceptive pollination patterns mainly appear in highly evolved orchid family which is renowned for its enormous diversity of pollination mechanisms. Recently，many kinds of pollination mechanisms and breeding systems were found in Zingiberaceae，such as delayed selfing mechanism，flexistyly and self pollination by sliding pollen. Here a food deceptive pollination mechanism in Kaempferia rotunda which was a new addition to the pollination systems in Zingiberaceae was reported. The pollination biology of K.rotunda was investigated in Nonghua，Guangxi Province in 2006 and South China Normal University Botanical Garden in 2007. The brilliant purple flowers open in the morning at about 5：30-6：00 and wither at 17：00-18：00，lasting for about 11～12 h. During anthesis，both pollen viability and stigma receptivity remained at a high level(＞90%). The mean P/O ratio was 82.20±47.89(n=20). Our observations showed that carpenter bee(Xylocopa sp.)was the main pollinator，and visits flowers only for nectar. However，the flowers produce no nectar. We speculated that K.rotunda exploited food deceptive mechanism to attract pollinators. Breeding system experiments showed that there was rare fruit set in Nonghua population of K. rotunda，which indicated K.rotunda might abandon sexual reproduction for some form of clonal reproduction.