高寒退化草地不同海拔狼毒种群花大小与叶大小、叶数量的关系

Relationship between flower size and leaf size,number of Stellera chamaejasme population of degraded alpine grassland along an altitude gradient

植物花大小与叶大小、叶数量的关系反映了植物长期与环境相互作用形成的外在形态方面的适应对策,不同生境中其生长关系的变异体现了植物对异质环境的适应方式。本文研究了祁连山北坡高寒退化草地4个不同海拔狼毒(Stellera chamaejasme)种群花大小与叶大小、叶数量的关系。结果表明:随着海拔的升高,草地群落的高度、密度和地上生物量均呈先升高后降低的倒U型分布;狼毒的地上生物量、株高和叶大小均呈减小趋势,而繁殖分配、花大小和叶数量均呈增大的变化趋势;在海拔梯度上,狼毒花大小与叶数量呈极显著正相关(P<0.01),与叶大小呈不显著负相关(P>0.05),说明狼毒种群花大小与叶数量具有显著的依赖关系;生境对狼毒花大小与叶数量之间的依赖关系产生显著影响,高海拔的环境胁迫导致狼毒个体减小,植株通过增加花大小和叶数量、减小叶大小的资源分配策略来保证物种的繁衍。

The relationship between ilower size and leaf size and number reflects the plant adap- tation strategies in external morphology during the long-term interaction of plants with different environments, and the variation of the relationship reflects plant adaptation to heterogeneous envi- ronments. In this study, an investigation was carried out to examine the relationship between flow- er size and leaf size and number of Stellera ehamaejasme along four different altitude gradients in an alpine grassland in the northern slope of Qilian Mountains. The results showed that, with in- creasing elevation, the height, density, and aboveground biomass of the plant communities dis- played a pattern of initial increase and then a decline. The aboveground biomass, plant height and leaf biomass of S. chamaejasme declined gradually, while reproductive allocation, flower size and leaf number both increased gradually. Flower size of S. chamaejasme was significantly posi- tively correlated with leaf number （P〈0.01）, but negatively with leaf biomass, while there was no significant correlation between flower size and leaf biomass （P〉0.05）. Therefore, habitat had a significant influence on the dependency among size of flower and leaf size and number. The plant size would be decreased by the environmental stress at high altitude, and both flower size and leaf number are increased while the leaf size is declined to ensure the reproductive success of S. chamaejasme.