拉萨入侵植物曼陀罗（Datura stramonium）传粉生物学研究

Studies on pollination biology of an invasive species-Datura stramonium in the Lhasa Valley

近几年曼陀罗(Datura stramonium)作为西藏的外来植物物种分布面积不断在扩大,为了研究其繁衍特性和传粉机制,通过野外观察和室内实验两种方式对拉萨地区曼陀罗的单花花期、昆虫访花情况、访花者类别、花部形态特征、繁育系统等进行了系统研究。结果表明:①曼陀罗群落花期为6月至10月上旬,单花花期为一天左右;②曼陀罗花粉/胚珠比(P/O)平均为286.69,杂交指数(OCI)值为4,不存在孤雌生殖,花粉对昆虫的吸引力较大,其繁育系统属于兼性异交,但通过观察拉萨地区的曼陀罗发现其自交率很高;③访花昆虫主要为蜂类和蝇类,其中蜂类有2种1属,蝇类有7种4属,因其虫媒物种的不同,昆虫在访花时间上差异较大,早上以蝇类为主,傍晚以蜂类为主,经鉴定蜂类为有效的传粉昆虫。

In recent years,the distribution area of Datura stramonium,as an exotic plant species in Tibet,has been expanding quickly.In order to understand the reproductive characteristics and pollination mechanism of Datura stramonium,the systematic research was carried out on single flowering period,insect visits,flower visitor,flower morphological characteristics and reproduction systems.The results showed that:①The flowering period of D.stramonium is from June to early October,and the flowering period of single flower is about one day.②The average pollen/ovule ratio(P/O)of it is 286.69,the hybridization index(OCI)is 4,there is no parthenogenesis in D.stramonium with attractive pollen to insects,the reproduction system of D.Stramonium belongs to facultative outcrossing,but the result of investigation in Lhasa Valley showed that its self-crossing rate of D.stramonium is also very high.③The flower visitor insects are mainly bees,consisting of 2 species and 1 genus,and flies consisting of 7 species and 4 genera.The visiting time of insects to flowers are quite different because of the different species of insects,flies visit flower mainly in the morning but bees visit mainly in the evening and it was identified as effective pollinator.