羌塘雪兔子繁殖特征及资源分配的海拔差异

植物种群的生殖特性和资源配置策略是植物生活史研究的重要内容之一,对于理解和预测植被结构和全球变化过程中的适应策略至关重要。该文以青藏高原特有风毛菊属植物羌塘雪兔子(Saussurea wellbyi)为试验材料,分析6个海拔梯度18个居群的花期繁殖特征的变化,并用异速生长模型分析资源投入及资源分配的个体大小依赖关系。结果显示:(1)个体大小、繁殖器官生物量、营养器官生物量、管状小花数目、雄蕊重量、花药长度及花粉数与海拔高度呈负相关(P<0.05),管状小花重量、雌蕊重量、花丝长度及花柱长度与海拔高度呈正相关(P<0.01);(2)营养分配与海拔高度呈负相关(P<0.01),繁殖分配与海拔高度呈正相关(P<0.01);(3)管状小花的数量与重量(P<0.05)、雌蕊重量与雄蕊重量(P<0.01)、花丝长度与花药长度(P<0.01)、花丝长度与花粉数(P<0.01)之间均存在权衡关系;(4)资源投入及资源分配在不同海拔间与个体大小都呈显著正相关(P<0.05),且截距在海拔间差异极显著(P<0.01)。综合分析认为:羌塘雪兔子在不同海拔下的繁殖特征以及大小依赖的资源投入和资源分配模式是羌塘雪兔子与其所处的高山环境长期适应和进化的结果。

Altitude Differences in Reproductive Characteristics and Resource Allocation of Saussurea wellbyi

The reproductive characteristics and resource allocation strategy of plant population are one of the important contents in the plant life history. It is very important to understand and predict the vegetation structure and adaptation strategies in the process of global change. With Saueeurea wellbyi, a common plant distributing in the southern margin of the Qinghai-tibet Plateau, ANOVA was used to analyze the flowering characteristics and resource allocation of 18 populations in 6 altitudes, and the size-dependent relationship between resource input and resource allocation was analyzed by allometric growth model. The results showed that:(1)The size of the individual, the reproductive organs, the biomass of the vegetative organs, tubular loret number, the weight of stamen, the length of anther and the number of pollen were negatively correlated with the altitude. However, tubular loret mass, the weight of pistil, the length of filament and the length of style were positively correlated with the altitude. (2)There was a negative correlation between vegetative allocation and altitude, and reproductive allocation was positively correlated with altitude. (3)There is a trade-off between the number and mass of tubular loret, the weight of pistil and stamen,the length of filament and anther, the length of filament and the number of pollen. (4)There was a significant positive correlation between individual size of S.wellbyi and resource input and resource allocation at different altitudes. The intercepts are significantly different at altitude. Comprehensively, this series of results was the result of long-term evolution and adaptation to the stressful environment of alpine.