Duan Y W, Zhang T F, He Y P, Liu J Q
Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai, China.
Plant Biol (Stuttg). 2009 Nov;11(6):796-802. doi: 10.1111/j.1438-8677.2009.00195.x.
Wind pollination can provide reproductive insurance for animal-pollinated dioecious plants in the absence of available pollinators, but combinations of insect and wind pollination (ambophily) have rarely been studied in hermaphrodite herbs. We examined the stable occurrence of insect pollination and wind pollination over 4 years in a population of a biennial Aconitum species (A. gymnandrum) with actinomorphic and degenerate sepals. The total frequency of visits of two bumblebee species showed no distinct fluctuations in the studied population among the 4 years. However, seed production of netted flowers after emasculation indicated wind pollination had occurred. The seed number of bagged flowers with one visit by bumblebees was significantly less than that of netted flowers after one visit, or in control flowers. Both seed number and fruit set of netted flowers were significantly lower than in control flowers. These results suggest that wind pollination provides supplementary pollen to unvisited and/or once-visited flowers, but accounts for only a small amount of seed production compared to bumblebee pollination in natural conditions. Such a combination of insect and wind pollination might play an important role in maintaining sexual reproduction of this biennial herb, allowing it to persist in arid habitats on the Qinghai-Tibetan Plateau, especially during Quaternary glacial periods when pollinator populations oscillated extensively.
在缺乏可用传粉者的情况下，风媒传粉可为虫媒传粉的雌雄异株植物提供繁殖保障，但在雌雄同株草本植物中，虫媒和风媒传粉的组合（兼性传粉）很少被研究。我们对一种具辐射对称且萼片退化的两年生乌头属植物（甘青乌头）种群在4年时间里虫媒传粉和风媒传粉的稳定发生情况进行了研究。在所研究的种群中，两种熊蜂的访花总频率在这4年里没有明显波动。然而，去雄后网罩花的种子产量表明发生了风媒传粉。熊蜂访花一次的套袋花的种子数量显著少于访花一次的网罩花或对照花的种子数量。网罩花的种子数量和坐果率均显著低于对照花。这些结果表明，风媒传粉为未被访及和/或只被访及一次的花朵提供了补充花粉，但与自然条件下熊蜂传粉相比，其在种子产量中所占比例较小。这种虫媒和风媒传粉的组合可能在维持这种两年生草本植物的有性繁殖中发挥重要作用，使其能够在青藏高原的干旱生境中生存，尤其是在第四纪冰川期传粉者种群大幅波动的时候。
