Ollerton Jeff, Diaz Anita
School of Environmental Science, University College Northampton, Park Campus, Northampton, NN2 7AL, UK e-mail:
School of Conservation Sciences, Bournemouth University, Fern Barrow, Poole, Dorset, BH12 5BB, UK, , , , , , GB.
Oecologia. 1999 May;119(3):340-348. doi: 10.1007/s004420050794.
The relationship between flowering time and reproductive success was investigated in the fly-pollinated, monoecious perennial herb Arum maculatum L. (Araceae). This species temporarily traps its principle pollinator, a psychodid midge. Probability of fruit set was analysed in relation to early, peak and late periods of the flowering phenology of four British populations between 1992 and 1997. In three out of five cases, plants which flowered during early and late periods were significantly less likely to set fruit. In addition, one population showed a similar relationship for percentage fruit set of individual inflorescences, and seeds from peak-flowering plants were significantly heavier. There was no variation in number of female flowers per inflorescence over the flowering season. Probability of fruit set appears to be mediated by the likelihood of trapping psychodid midges that have previously been trapped and picked up pollen, an unlikely event during early and late flowering periods when few inflorescences are open. The majority of plants in all populations produce only one inflorescence which means that timing of flowering may be crucial to reproductive success. We interpret our findings as evidence that stabilising selection may be acting on some populations and/or during some years. The ultimate cause, however, can be related to the very short (12-18 h) female phase of each inflorescence, a phylogenetically conservative trait within the Araceae.
在蝇类传粉的雌雄同株多年生草本植物斑叶疆南星（天南星科）中，研究了开花时间与繁殖成功率之间的关系。该物种会暂时困住其主要传粉者，一种毛蠓。分析了1992年至1997年间英国四个种群开花物候的早期、高峰期和晚期的坐果概率。在五分之三的案例中，在早期和晚期开花的植株坐果的可能性显著降低。此外，一个种群的单个花序坐果率也呈现出类似的关系，且盛花期植株的种子明显更重。在整个开花季节，每个花序上雌花的数量没有变化。坐果概率似乎取决于困住先前已被困住并携带花粉的毛蠓的可能性，而在早期和晚期开花期，开放的花序很少，这种情况不太可能发生。所有种群中的大多数植株只产生一个花序，这意味着开花时间可能对繁殖成功至关重要。我们将研究结果解释为稳定选择可能在某些种群和/或某些年份起作用的证据。然而，最终原因可能与每个花序非常短（12 - 18小时）的雌花期有关，这是天南星科内一个系统发育保守的特征。
