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中国特有种枝毛野牡丹传粉生物学及繁育系统研究

Pollination Biology and Breeding System of Melastoma dendrisetosum

  • 摘要: 对海南吊罗山国家级自然保护区枝毛野牡丹(Melastoma dendrisetosum)的开花进程,访花昆虫、访花行为、访花频率以及气候条件等进行观察记录,同时检测了花粉活力、柱头可授性、花粉胚珠比、繁育系统,并分析其致濒机制。结果表明:枝毛野牡丹是典型的异型雄蕊植物,5:30—8:30逐步开放,8:30—9:00完全开放,19:00花朵闭合,单花开放时间为12—14 h,群体花期36±2 d,无花蜜。访花昆虫主要有木蜂科、条蜂科、蚁科、食蚜蝇科的昆虫,最有效传粉昆虫为木蜂科昆虫。自然与人工授粉、套袋等试验结果表明,枝毛野牡丹不存在主动自花授粉、无融合生殖的生殖保障现象,为自交亲和的异交种,需要昆虫传粉,枝毛野牡丹繁育系统是兼性自交。枝毛野牡丹相对生殖成功率低仅为0.035,主要限制因子为花粉限制和传粉者限制。

     

    Abstract: To investigate the pollination characteristics of Melastoma dendrisetosum C. Chen, the flowering phenology, the pollinators, their behavior, the frequency of pollinator' visiting and climate condition were observed. Besides, the pollen viability, the stigma acceptability, P/O (pollen/ovule rate) and the breeding system of M. dendrisetosum were examined, which was studied in Diaoluo National Nature Reserve, Hainan Province, China. The results showed that M. dendrisetosum is typically heteranthery. The flowers of M. dendrisetosum come into blossom at 5:30-8:30 a.m., into ful1-blown at 8:30-9:00 a.m. and into petal-shut at 7:00 p.m. The florescence of individual flower and population flowers were 12-14 hours and 36±2 days respectively. There was no nectar in the flowers. The species of pollinator were Xylocopidae, Anthophoridae, Formicidae, Syrphidae and etc. The most effective pollinator was carpenter bee. The field experiments indicated that the fruit sets were significantly high in both artificially out-crossed and self-pollinated flowers, while no fruit set was observed in bagged emasculated flowers and the unpollinated bagged flowers. These indicated that there were no self-compatible, no self-pollination and agamospermy in this species. Pollinators were necessary for it. The breeding system of M. dendrisetosum was a typical facultative inbred type. The relative reproductive success (RRS) was 0.035, pollen and pollinator limitation were the most important limiting factors to M. dendrisetosum.

     

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