Rain pollination provides reproductive assurance in a deceptive orchid
Rain pollination provides reproductive assurance in a deceptive orchid
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雨授粉为欺骗性兰花提供了繁殖保证
DOI：
10.1093/aob/mcs165
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发表时间：
2012-10-01
期刊：
影响因子：
4.2
通讯作者：
Gao, Jiang-Yun
中科院分区：
文献类型：
--
作者：
Fan, Xu-Li;Barrett, Spencer C. H.;Gao, Jiang-Yun
风或水的非生物传粉在开花植物中已经得到了很好的证实。在一些物种中，通过雨水飞溅授粉，一种被称为全亲性的情况，被认为是一种花的策略。然而，这种非生物授粉的证据仍然存在争议，许多报道的案例随后被证明是错误的。本研究调查了在中国西南地区，尽管在传粉者稀少的雨季开花，但该品种仍能保持高繁殖力的机制。观察并详细描述了僵木促进雨传粉的花机制。进行了对照授粉试验和访花者观察。在广西14个地点进行了雨棚田间试验，评价了雨授粉对坐果的贡献。在降雨期间，雨滴将花药帽弹开，暴露出授粉体。然后，雨滴导致花粉向上喷射，带状的柱头将它们拉回来，使它们落入柱头腔，导致自花授粉。水对花和花粉功能均无损害。虽然刚木属具有自交亲和性，但如果没有雨水的帮助，它无法自主自花授粉。遮荫试验结果表明，雨授粉对坐果率的提高有显著的促进作用，但这种促进作用的强度在不同地点存在差异。在雨季，当传粉者稀缺时，刚玉花的功能是在不影响异交机会的情况下提供生殖保证。
Abiotic pollination by wind or water is well established in flowering plants. In some species pollination by rain splashes, a condition known as ombrophily, has been proposed as a floral strategy. However, evidence for this type of abiotic pollination has remained controversial and many reported cases have subsequently been shown to be false. This study investigates ombrophily in the deceptive orchid Acampe rigida to determine the mechanism by which this species is able to maintain high fecundity, despite flowering during the rainy season in south-west China when pollinators are scarce.The floral mechanisms promoting rain pollination in A. rigida were observed and described in detail. Controlled pollination experiments and observations of floral visitors were conducted. A field experiment using rain shelters at 14 sites in Guangxi, south-west China, evaluated the contribution of rain pollination to fruit-set.During rainfall, raindrops physically flicked away the anther cap exposing the pollinarium. Raindrops then caused pollinia to be ejected upwards with the strap-like stipe pulling them back and causing them to fall into the stigmatic cavity, resulting in self-pollination. Neither flower nor pollen function were damaged by water. Although A. rigida is self-compatible, it is incapable of autonomous self-pollination without the assistance of rain splashes. The results of the rain-sheltering experiment indicated that rain pollination contributed substantially to increasing fruit-set, although there was variation among sites in the intensity of this effect.A. rigida flowers during the rainy season, when pollinators are scarce, and ombrophily functions to provide reproductive assurance without compromising opportunities for outcrossing.