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通过对濒危植物紫背天葵(Begonia fimbristipula Hance)野外定点观测和引种栽培,运用杂交指数、花粉活力及柱头可授性、花粉—胚珠比、人工授粉和套袋试验等方法,对其花部特征、开花动态及繁育系统进行研究。结果表明:紫背天葵单株花期25～30d,群体花期45～55d,花单性,雌雄同株同花序、异熟,雄蕊先熟。花药与柱头相距约2.0cm,花开放式样为雄花—雌花—雄花的开放顺序,雌花开放一般滞后雄花2～3d,杂交指数OCI≥4,P/O值为96.56,结合去雄、人工套袋和自然授粉坐果率判断,紫背天葵繁育系统为自交亲和为主,与异交并存的混合交配型系统。对生存环境的专一性依赖及其小居群长期自交的方式可能是导致该物种濒危的原因之一,“球茎”是其生殖补偿的有效途径。
Through the field observation and introduction cultivation of the endangered plant Begonia fimbristipula Hance, the floral index of pollen and ovule, pollen-ovule ratio, artificial pollination and bagging test were used to study the flower bud Characteristics, flowering dynamics and breeding system. The results showed that the flowering stage was from 25 to 30 days in florescence and 45 to 55 days in florescence. Anthers and stigma at a distance of about 2.0cm, flower open pattern male flowers - female flowers - male flowers open order, the female flowers open generally lag male flowers 2 ~ 3d, hybrid index OCI ≥ 4, P / O value of 96.56, combined with male, artificial bagging Judging from the natural pollination and fruit setting rate, the breeding system of Ziziphus chinensis was self-compatible and the mixed mating type system co-existed with out-crossing. The specific reliance on the living environment and the long-term selfing of its small population may be one of the reasons leading to the endangerment of the species. “Bulb” is an effective way of reproductive compensation.