中文摘要：

补偿生长反映了植物的耐牧性,受采食和土壤养分资源获得性的共同影响。但何种条件易于引起植物发生超补偿是长期以来争论的问题。通过一项野外调查试验,研究了高寒矮嵩草（Kobresia humilis）草甸3种生境（Ⅰ.畜圈,富养,放牧;Ⅱ.牧道,低养,放牧;Ⅲ.封育草地,低养,不放牧）中粗喙薹草（Carex scabrirostris）的补偿生长模式与机制,以及采食率、土壤养分和水分因子对补偿生长的相对贡献。粗喙薹草补偿生长量和分株盖度、密度及高度在生境Ⅰ显著高于生境Ⅱ和生境Ⅲ,在生境Ⅰ和生境Ⅱ均发生超补偿生长,在生境Ⅲ为低补偿。分株生物量对生长器官的分配在生境Ⅰ和生境Ⅱ相同,并都高于生境Ⅱ;生物量对储藏器官的分配在生境Ⅱ最高,生境Ⅲ次之,生境Ⅰ最低。储藏分配与生长分配和克隆繁殖分配间,生长分配与有性繁殖分配间均存在负偶联（trade-offs）关系。对补偿生长贡献最大的因子是相对生长率和6月份土壤有机质含量,其次是8月份土壤氮素营养和采食率。研究结果表明,粗喙薹草的补偿生长和生物量分配具有可塑性,并决定着补偿生长模式随生境条件而变化。不论在富养环境或低养环境,储藏分配高的粗喙薹草都容易发生超补偿,富养生境条件能降低采食的负面效应,增加植物的耐牧性。

英文摘要：

Aims Compensatory growth is affected by defoliation ratio,water and soil nutrient availability,but it is unclear which factor is most important in the overcompensatory response to herbivores in a particular area.Our objectives were to examine how compensatory growth of Carex scabrirostris varies with different habitats in an alpine Kobresia humilis meadow and determine relative effects of these factors on compensatory growth.Methods Our field experiment at the Haibei Research Station of the Chinese Academy of Sciences from April to September 2007 included three habitats （habitat I：pen pasture,grazed × high nutrient availability;habitat Ⅱ：pass pasture,grazed × low nutrient availability and habitat Ⅲ：ungrazed pasture,null defoliation ratio × low nutrient availability） with three plots per habitat.In each plot,12 quadrats （0.5 m × 0.5 m） were divided into two groups：6 caged and 6 uncaged.For each of these sets of 6 quadrats,3 quadrats were sampled in mid-June and 3 in mid-August.We used canonical correspondence analysis （CCA） with potential impact factors selected by the forward selection procedure for the compensatory growth of C.scabrirostris ramets to determine the relative effects of defoliation ratio,water and soil nutrient variables on compensatory growth.Important findings The compensatory increase in dry weight,cover,density and height of ramets were higher for the habitat Ⅰ than for habitats Ⅱ and Ⅲ.Overcompensation of aboveground biomass per ramet occurred in habitat Ⅰ and Ⅱ,whereas undercompensation was found in habitat Ⅲ.The biomass allocation to growth function per ramet in habitat Ⅰ was equal to that of Ⅲ but higher than that of Ⅱ.Storage allocation was greatest in habitat Ⅱ,moderate in Ⅲ,and least in Ⅰ.Storage allocation was negatively correlated with growth and clonal propagation allocations,and growth allocation was negatively correlated with sexual reproductive allocation.The most important factors that induced compensatory growth were relative gr