不同放牧强度下克氏针茅(Stipa krylovii)草原的根系特征  

Root characteristics under different grazing intensities in Stipa krylovii steppe

作　　者：雒文涛[1,2] 乌云娜[2] 张凤杰[2] 霍光伟[1,2] 吕建洲[1] 

机构地区：[1]辽宁师范大学生命科学学院,辽宁大连116029 [2]大连民族学院环境与资源学院,辽宁大连116605

出　　处：《生态学杂志》2011年第12期2692-2699,共8页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(30870423;31170402);中央高校基本科研业务费专项(DC10050101);国家重点基础研究发展计划项目(2009CB421308)资助

摘　　要：以呼伦贝尔克氏针茅草原不同放牧强度下的演替群落为对象,开展群落及其群落建群种的地下生物量和根系形态特征研究。结果表明:从轻度放牧到重度放牧,群落种类组成和根系功能群类型趋于简单化;群落地下生物量的空间分布形态呈"T"型;不同放牧强度下草原群落的建群种出现了明显替代现象,轻度放牧样地群落建群种为密丛型根系的克氏针茅,中度放牧为疏丛型根系的糙隐子草(Cleistogenes squarrosa),重度放牧为鳞茎型根系的碱韭(Allium polyrhizum);随着放牧强度的增大,群落建群种根冠比逐渐增加,分别为0.47、1.0、4.1,并且群落建群种根系数量、根系体积、根系生物量、比根长及根长密度等各指标均发生了明显变化。另外,3种放牧强度样地群落建群种根冠比、根长密度均与土壤速效氮含量呈现显著正相关(P<0.05)。Taking three succession plant communities in Hulunbeier Stipa krylovii steppe under different grazing intensities as test objects,this paper studied the underground biomass and root morphological characteristics of the communities and their constructive species.With increasing grazing intensity,both the community species composition and the root functional group types tended to be simplified.The underground biomass of the three communities presented a T-shape spatial distribution.The constructive species of the communities under different grazing intensities had an obvious substitution,with S.krylovii,Cleistogenes squarrosa and Allium polyrhizum as the constructive species under light,moderate and heavy grazing,and the root/shoot ratios of the constructive species decreased with increasing grazing intensity,being 0.47,1.0,and 4.1 under light,moderate and heavy grazing,respectively.The root number,root volume,root biomass,specific root length,and root length density also varied with different grazing intensities.Moreover,the root/shoot ratio and the specific root length showed a significant correlation with the content of soil available nitrogen（P0.05）.

关 键 词：克氏针茅草原 放牧强度 根系类型 根系功能群类型配比 

分 类 号：S812[农业科学—草业科学]