4种榕树的授粉方式及其花粉特征  

Pollination Mode of Four Ficus species and Pollen Characteristics

作　　者：刘明新[1,2] 杨培[1] 杨大荣[1] 彭艳琼[1] 

机构地区：[1]中国科学院西双版纳热带植物园,云南勐腊666303 [2]中国科学院大学,北京100049

出　　处：《云南农业大学学报（自然科学版）》2017年第2期294-302,共9页Journal of Yunnan Agricultural University:Natural Science

基　　金：国家自然科学基金面上项目(31372253;31672373)

摘　　要：定量花粉是植物繁殖生物学中的一个重要环节,榕属(Ficus)植物花粉粒小、数量多,难于定量,一直用花药—胚株比(anther-to-ovule ratio,A/O)来判断榕树属于主动还是被动授粉方式。本研究选择4种雌雄同株榕树,通过比较榕树A/O,榕小蜂的授粉结构、行为来确定它们的授粉方式;同时测量了它们的花粉粒大小和数量,并研究授粉方式及其花粉特征的关系。结果表明:菩提树、高榕和垂叶榕的A/O小于0.16,并且它们的榕小蜂有发达的授粉结构和主动授粉行为,属于主动授粉方式。而钝叶榕A/O高(0.85),其榕小蜂的传粉结构、行为消失,是被动授粉的方式。4种榕树的花粉粒大小各有差异,每朵雄花产生的花粉量种间差异显著,而且每种果内的雄花数量也不相同,以至于单个果生产的花粉总量种间有显著差异,变异范围从11~4 000多万粒,最大相差340倍,而且花粉数量与花粉粒大小之间存在权衡关系。主动授粉的榕树雄花少、生产的花粉粒大、花粉量少;而被动授粉的榕树雄花多、花粉量大、花粉粒小。表明榕—蜂互惠系统中榕树的授粉方式、花粉的特征与榕小蜂的授粉结构已协同演化和匹配。4种榕树的花粉胚珠比(pollen-to-ovule ratio,P/O)种间差异也大,且P/O高的种类A/O不一定高,进一步用P/O替换A/O可完善榕树传粉生物学研究。用ElzoneⅡ5390颗粒计数与粒度分析仪计数花粉,高效、准确地自动输出结果,可批量研究该属更多种类的花粉量,并对应计数它们专一传粉榕小蜂携带的花粉量,有利于揭示榕树在雌雄繁殖功能上的分配策略,以及榕—蜂互惠繁殖系统的协同演化的机制。Quantifying pollen is very important in the reproductive biology of plants. The pollen of Ficus species is quite tiny and abundant so that it is difficult to count pollen grains. So the anther-to-ovule ratio（A/O） is used to determine the pollination mode which are active and passive pollination. In this study, four monoecious Ficus species were selected to investigate their A/O ratios, and the pollination structures and behaviors of species-specific pollinating fig wasps were observed in order to determine the pollination mode. At the same time, the pollen sizes and numbers were measured, and studied the relationship between pollination mode and pollen characteristics.The results showed that the A/O ratios of Ficus religiosa,Ficus altissima and Ficus benjamina were less than 0.16, and the pollinating fig wasps had developed pollination structures and active behavior, which three Ficus species belonged to active pollination. However, Ficus curtipes had a high A/O ratio （0.85）, and the coxal combs disappeared and pollen pockets degenerated, which was a characteristic of passive pollination. So F. curtipes was passive pollination. Pollen sizes of four Ficus species had significant variation. The numbers of pollen produced by a male flower were significant difference, and the figs had different numbers of male flowers so that the total numbers of pollen grains produced by a fig were significant difference among four Ficus species, which the range varied from 0.11 to 40 millions of grains per fig. The largest difference was 340 multiples between species. There was the trade-off relationship between the number of pollen and pollen sizes. Ficus species who was actively pollinated had few male flowers, produced large pollen grains and few pollen, while Ficus species belonging to passive pollination had more male flowers, produced small pollen grain and a lot of pollen. This suggests that the pollen characteristic and pollination structures of fig-pollinating wasps have evolved and matched with pollination mode in

关 键 词：榕树 授粉方式 花粉粒大小 花粉数量 

分 类 号：Q969.97[生物学—昆虫学] S722[农业科学—林木遗传育种]