呼伦贝尔草原根系分布特征及其与植物功能类群及草原退化的关系

摘要

Using the data from 400 quadrats for aboveground biomass and 200 quadrats for under-ground biomass in 40 steppe plots,the root vertical distribution types of the meadow steppe,typical steppe as well as the degraded communities in Hulunbuir grassland were analyzed,and the relationship be-tween plant function groups and steppe degradation were also researched.The results showed that (1)the layered root distribution of Hulunbuir steppe communities had a diversity of distribution types,including V distribution type,Y distribution type,E distribution type,T distribution type,L distribution type,O distribution type and X distribution type.(2)The most common root distribution types in the steppe com-munity included V distribution type,Y distribution type,T distribution type and L distribution type.The dominant type of root distribution of bunch grass plant,forb plant group,rhizome grass group,Carex species group were V type,Y type,L type and T type respectively.(3)Different grassland degradation states had important influence on root distribution type.Seriously degraded community mainly formed T type root distribution,in which the constructive species for heavy degraded communities were dominant. The communities of V type root distribution kept natural state well,while the constructive species per-centage in moderately and heavily degraded communities increased in L type and Y type.The results has an important significance for a comprehensive understanding of steppe characteristics and in strengthening the protection of steppe environment.%利用呼伦贝尔草原40个样地、400个地上测产、200个根系测产数据,分析了草甸草原、典型草原及其退化类型的根系垂直分布构型及其与物种组成、草原退化的相互关系。结果表明：(1)呼伦贝尔草原群落根系的分层分布具有多样化的分布构型,包括 V 型分布、Y 型分布、E 型分布、T 型分布和 L 型分布、O 型分布及 X 型分布。(2)在草原群落中分布最为普遍的 V 型分布、Y 型分布、T 型分布和 L 型分布4种构型中,V 型以丛生禾草植物占居首位, Y 型以杂类草植物为首,L 型以根茎型禾草植物占据优势,T 型构型根茎苔草植物占有绝对优势,且与其他三种构型存在显著差异。(3)草原不同退化状态对根系分布构型具有重要影响,严重退化群落主要为 T 型分布,以重度退化群落建群种占据绝对优势。V 型构型的群落原生状态保持较好,而 L 型和 Y 型构型中轻度退化和重度退化建群植物所占比例有所提高。