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中国西南山地特有植物黄杯杜鹃的传粉生态学研究

Pollination ecology of Rhododendron wardii (Ericaceae), a species native to the southwest mountains of China

  • 摘要: 为解析中国西南山地特有、易危植物黄杯杜鹃的繁殖特性,以云南西北部白马雪山的黄杯杜鹃种群为研究对象,开展了2年的传粉生态学研究。结果表明:黄杯杜鹃花序上的花数量以5~7朵花为主,花具有典型的雌雄异位特征,并产生花蜜;黄杯杜鹃不存在自动自花授粉和无融合生殖现象,具有部分自交不亲和的特性;人工授粉显著提高了座果率,表明黄杯杜鹃自然状态下的结实存在传粉限制;去雄后降低了座果率,表明存在一定程度由昆虫介导的花内自花传粉;黄杯杜鹃的访花昆虫包括蜂类、蝇类、蝶类和甲虫等4种类型,主要的传粉昆虫为蜂类和蝇类,但2类传粉昆虫的访花频率非常低,导致黄杯杜鹃的结实存在传粉限制。黄杯杜鹃的种群面临因传粉昆虫低频访花引发的传粉限制问题,因此可通过人工繁育提高植株密度以改善异花授粉条件。

     

    Abstract: To understand the reproductive traits of Rhododendron wardii (Ericaceae), a native shrub evaluated as least concern in the southwest mountains of China, pollination ecology of this species was investigated in a population on Baima Snow Mountain in northwest Yunnan in two years. The results showed that the flower number on each florescence ranged from 2 to 9, with 5-7 flowers per inflorescence as dominance. Flower of R. wardii was characteristics of herkogamy, and could produce nectar reward to animal pollinators. Both autonomous selfing and apomixis did not occur in R. wardii, and partial self-compatibility was identified in this species. Manual outcrossing increased fruit set significantly, indicating pollination limitation of seed production in R. wardii. Emasculation reduced fruit set significantly, indicating the occurrence of pollinator medicated selfing within one flower. Bees, flies, butterflies and beetles were observed to visit R. wardii, but bees and flies were determined as the effective pollinators, although the total visiting frequencies of bees and flies were very low, which could contribute to the pollination limitation of seed production. The results of this study suggest that pollen limitation of seed production resulted from low pollinator visiting frequency could be alleviated by artificial enhancement of plants via increasing potential outcrossing pollen grains, which would be helpful in population regeneration of R. wardii.

     

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