减源(叶)对高寒草地狼毒生长和繁殖适合度的影响

Effects of source reduction(leaf removal)on growth and reproductive fitness of Stellera chamaejasme in alpine grassland

【目的】探究减源(叶)对狼毒个体营养生长和繁殖适合度的影响,从资源分配策略的角度理解高寒草地狼毒的生态适应机制。【方法】以祁连山东缘高寒草地狼毒(Stellerachamaejasme)自然种群为研究对象,通过对狼毒个体进行减源(叶)处理,分析不同处理对狼毒个体的株高、小花数和结籽数的影响。【结果】在个体水平上,减源处理对狼毒分枝营养生长的影响不显著,但显著降低了个体的繁殖适合度(P<0.001)。在分枝水平上,减源处理会显著抑制剪叶分枝自身的营养生长(P<0.001)和繁殖(P<0.05);同时,显著促进了同株不剪叶分枝的营养生长(P<0.05),一定程度上降低了同株不剪叶分枝的繁殖适合度。【结论】在资源限制条件下,狼毒株丛遵循最优化分配理论,在株丛水平会采取降低个体的繁殖投资、保证自身存活的生活史对策;在分枝水平会把更多的资源分配给有利于维持植株营养生长的分枝。

【Objective】The study aimed to explore the effects of source reduction treatment(i.e.,leaf removal)on the vegetative growth and reproductive fitness of Stellera chamaejasme for the purpose of understanding the mechanism of ecological adaptation of S.chamaejasme in alpine grassland from the perspective of resource allocation strategy.【Method】The natural population of S.Chamaejasme in an alpine grassland was selected as the research subject,which was located on the eastern edge of Qilian Mountains.The effect of different source-reduction treatments on the growth and reproduction of S.chamaejasme were determined by removing leaves of individuals and then measuring their height,florets and seed number.【Result】At the individual level,the source reduction treatment had no significant effect on the vegetative growth of S.chamaejasme,but could significantly reduce the reproductive fitness of the individuals(P<0.005).At the branch level,the source reduction treatment could significantly inhibit the vegetative growth and reproduction of the treated branches(P<0.05),but at the same time,the treatment significantly promoted the vegetative growth of the controlled branches within the same plant(P<0.05),while reduced the reproductive fitness of the controlled branches to a certain extent.【Conclusion】Under the condition of resource limitation,S.chamaejasme individuals followed the optimal resource allocation theory,and adopt the life-history strategies of reducing individual reproductive investment to improve their survival at the individual level;at the branch level,more resources would be allocated to the branches that are conducive to maintaining plant vegetative growth.