美国凌霄柱头行为——一种促进传粉的机制(英文)

引起美国凌霄(campsis radicans(L.)Seem.ex Bureau.)柱头开合行为的原因迄今未知。在本研究中,机械刺激、自花授粉、异花授粉以及不同授粉数量的授粉分别给予美国凌霄的柱头,以期找到影响其柱头行为的原因。研究结果表明,单纯的机械刺激可以使柱头闭合,但不能使之永久闭合;只有柱头表面落置了足够量的花粉(>350)时柱头才会最终闭合。美国凌霄的柱头行为对自花或者异花花粉没有差异,两种花粉授于柱头后花粉管都能成功地萌发并生长。研究结果说明:美国凌霄的柱头行为不是一种异交机制,而是一种促进传粉进而增强繁殖成功的机制。

A Mechanism Facilitates Pollination due to Stigma Behavior in Campsis radicans (Bignoniaceae)

The precise factors affecting stigma behavior in Campsis radicans (L.) Seem. ex Bureau. remain unclear up to now. In this study mechanical touch, self- and cross-pollination, and pollination with variable amounts of pollen grains separately contacting with stigmas have been conducted to determine the exact factor affecting the stigma behavior. Results show that mechanical touch alone cannot make the stigmas close permanently. It is the adequate pollen (>350) deposition that causes the stigma permanent closure, which is in accordance with previous reports that sufficient pollen grains are necessary for fruit development. In addition, the stigma behavior does not display differences when pollinated with cross- or self-pollen separately; both self and cross pollen grains can germinate and grow successfully. Our results cannot demonstrate that the stigma behavior in C. radicans is an outcrossing mechanism, but strongly indicate it acts as a mechanism to facilitate pollination, and then enhance the reproductive success.