秦岭岩白菜的传粉生物学特性与繁育系统

对珍稀濒危植物秦岭岩白菜(Bergenia scopulosa T.P.Wang)的开花特性、传粉适应及繁育系统进行了分析研究。结果表明:(1)秦岭岩白菜为蝎尾状聚伞花序,具(29±10)朵单花,单花期约15d,遇低温雨雪天气花冠闭合,可延长3~5d,花序花期约30d,种群花期近4个月。(2)花粉活力在花药开裂后的12h内最高(约90%),维持单花平均花粉活力在30%以上约6d;柱头在第1~4天内保持很强的可授性,维持可授性的时间约为9d。(3)秦岭岩白菜主要有效传粉昆虫为中华蜜蜂,平均访花频率为6.5朵/min,单花停留时间为(11.0±4.8)s。(4)秦岭岩白菜的花粉胚珠比(P/O)为589.8,杂交指数(OCI)为3;人工授粉实验显示,秦岭岩白菜不存在无融合生殖,自交亲和,主动自交罕见,生殖成功主要依赖传粉者。研究认为,秦岭岩白菜是兼性异交的繁育系统,胚珠受精过程中可能存在自交衰退。

Pollination Biology and Mating System of Bergenia scopulosa T.P.Wang,an Endangered,Indigenous Species in China

Knowledge of the basic breeding characteristics of endangered plants is critical and particularly important to develop successful conservation strategies.Here,we investigated the flowering characteristics,pollination adaptation and mating system of a rare and endangered plant,Bergenia scopulosa,using artificial pollination experiments and field observations in natural and ex-situ conservation populations.The results showed that:(1)the flowering span of the population,infloresence and single flowering were approximately 4 months,30 d and 15 d,respectively.The life span of single flower would prolong 3-5 d and the corolla closed when low temperature or rain and snow occurred.(2)Pollen viability achieved the maximum within 12 h after anther dehiscence in the first flowering day (about 90%) and maintained more than 30% about 6 d.Stigma shown acceptance in the first 9 days during the anthesis and kept the maximum in the first 1-4 days.(3)The main effective pollinator was Apis cerana cerana.The average visiting frequency of effective pollinator was 6.5 flowers·min^-1 and single flower residence time was (11.0±4.8) s.(4)The pollen-ovule ratio (P/O) was 589.8 and the outcrossing index (OCI) was 3.The results of artificial pollination experiments exhibited that B.scopulosa was self-compatible with autonomous selfing rarely happening,and reproductive success relied on pollinators without apomixes.The research suggested that the breeding system of B.scopulosa was facultative xenogamy and inbreeding depression played a role in the process of fertilization.