不同生境下珠芽蓼(蓼科)的繁殖策略比较

Reproductive Performance in Two Populations of Polygonum viviparum (Polygonaceae) under Different Habitats

在青藏高原横断山区以海拔相同的高山流石滩和高寒草甸中的珠芽蓼(Polygonum viviparum)居群为研究对象,探讨该物种在不同生境条件下的繁殖策略以及无性繁殖和有性繁殖间的关系。结果发现,流石滩居群的珠芽蓼植株高度和珠芽数量显著低于高寒草甸居群,而珠芽和花总数量、花数量和每个花序上的花比例却显著高于高寒草甸居群。研究结果表明珠芽蓼在环境更为恶劣的高山流石滩生境中增加了对繁殖器官和花资源的投资,说明在高山植物中繁殖优先于营养生长,且有性繁殖比无性繁殖具有更为重要的作用。而对每个植株上花数量和珠芽数量的统计结果表明,两者呈显著的负相关关系,进一步证明了同一植株内无性繁殖和有性繁殖的权衡关系。

In this study, we present an investigation of the reproductive performance of two populations of Polygonum viviparum （Polygonaceae） in the Hengduan Mountains of the Qinghai-Xizang Plateau. Two populations were deliberately selected at the same elevation but with different habitats, alpine scree and alpine meadow, respectively. Our results show that the plant height and the bulbil number from the population in alpine scree are significantly lower than those in alpine meadow, but total number of bulbils and flowers, flower number and flower proportion of each inflorescence are obviously higher than those in alpine meadow, indicating that more resources are probably allocated to reproduction organs and flowers under harsh environments like alpine seree, and P. viviparum sets priorities of reproduction over vegetative growth, and sexual re- production over asexual reproduction. Furthermore, we also find a significantly negative relationship between flower number and bulbil number, suggesting the trade-off between sexual reproduction and asexual reproduction in this species.