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

【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.