唐古特雪莲花部特征及生殖分配的海拔差异

为探究高山植物生殖分配策略以及分析唐古特雪莲花部特征对海拔梯度的响应机制,该研究利用采样调查法和烘干称重法,对分布在青藏高原东缘不同海拔14个居群的唐古特雪莲花部特征和生殖分配进行了研究。结果表明:(1)繁殖分配随个体大小(地上生物量和株高)的增大呈线性递减趋势。(2)花期植株地上生物量、株高、管状小花数目、繁殖器官及营养器官生物量均随海拔升高呈线性递减趋势,管状小花生物量随海拔升高呈线性递增趋势。(3)花期管状小花数量及大小、繁殖器官生物量与营养器官生物量、雄蕊重量和雌蕊重量以及花粉数目与花丝长度之间均存在权衡现象。由此推论:(1)海拔作为外界因子对唐古特雪莲花部特征具有显著的影响,个体大小对其繁殖分配也存在潜在调控作用。(2)在不同海拔梯度上,唐古特雪莲有效地整合了有限的资源,其适应性特征之一就是通过减小个体大小来削弱营养生长以达到促进生殖生长的目的。

Discrepancy caused by various altitudes in both floral traits and reproductive allocation of Saussurea tangutica

To investigate reproductive allocation strategies of alpine vegetation and analyze the response mechanism of floral characteristics to altitude gradient in Saussurea tangutica, the floral characteristics and reproductive allocation of fourteen populations of S. tangutica from different altitudes on the eastern edge of Qinghai-Tibet Plateau were determined through field investigation and drying-weighing method. The results were as follows:(1)Reproductive allocation presented a linear decline with increasing individual size(above-ground biomass and plant height);(2)Above-ground biomass, plant height, the number of tubulous, and the biomass of reproductive and vegetative organs at the flowering stage all showed a linear decline with rising altitude, while the biomass of tubulous increased with rising altitude;(3)There was a common balance between the number and size of tubulous, the biomass of reproductive and vegetative organs, the weight of stamens and pistils, as well as the number of pollen grains and the length of filaments. It can be concluded as follows:(1)As an external factor, altitude significantly affects the floral characteristics of S. tangutica, and individual size also potentially regulates reproductive allocation;(2)S. tangutica at different altitudes can utilize the limited resource effectively and decrease vegetative growth by reducing its size to promote reproductive growth.