黄土高原5种造林树种菌根根际土壤微生物群落多样性研究

Diversity of soil microbial communities in the mycorrhizosphere of five afforestation tree species in the Loess Plateau.

为了准确评估造林树种在黄土高原生态恢复中的作用,采用BIOLOG检测法,对黄土高原柠条、沙棘、狼牙刺、油松和刺槐5种造林树种菌根根际土壤微生物群落多样性进行了研究。结果显示,各树种根际土壤孔平均颜色变化率AWCD为油松>沙棘>狼牙刺>柠条>刺槐;不同树种菌根侵染率和菌根根际的微生物功能多样性均有显著差异;群落丰富度、多样性指数分析表明,油松外生菌根根际土壤微生物功能多样性和群落种群结构最丰富,其次为沙棘和柠条;碳源利用中与主成分1和主成分2相关的主要碳源分别是羧酸类、氨基酸类和糖类物质。相关性分析表明,菌根侵染率与土壤微生物功能多样性呈极显著正相关,随着菌根侵染率的提高,根际土壤微生物功能多样性增加。外生菌根树种有利于改善黄土高原退化土壤的微生物群落结构,优于泡囊丛枝菌根树种,油松作为黄土高原植被恢复的先锋造林树种,可以改善该区域干旱贫瘠土壤的微生物群落结构。

The study is conducted to accurately assess the roles of afforestation tree species in ecological rehabilitation of the Loess Plateau.It adopts BIOLOG method to examine the diversities of microbial communities in the mycorrhizospheres of five tree species,Caragana microphylla,Hippophae rhamnoides,Sophora viciifolia,Pinus tabulaeformis,Robinia pseudoacacia.It shows that in different tree species,the average well color development（AWCD） varies in order of Pinus tabulaeformis〉Hippophae rhamnoides〉Sophora viciifolia〉Caragana microphylla〉Robinia pseudoacacia.The different tree species differ significantly in both mycorrhizal infection rates and microbial functional diversities.The community richness and diversity indices of mycorrhizosphere microbes indicate that Pinus tabulaeformis presents the highest functional diversity and the richest structural diversity,followed by Hippophae rhamnoides and Caragana microphylla.The carbon sources related to principal component 1 and 2 are carboxylic acids,amino acids and carbohydrates.Correlation analysis indicates that the mycorrhizal infection rates appear significant positive correlation with the functional diversities of soil microbes,and the higher the mycorrhizal infection rates,the higher the functional diversities.The ectomycorrhizal tree species are beneficial to improving microbial community structures in degenerated soils of the Loess Plateau,thereby they are able to perform better than tree species of vesicular-arbuscular mycorrhizae.Pinus tabulaeformis as the pioneer tree species for the vegetation rehabilitation in the Loess Plateau is capable of improving the community structures of microbes in dry and barren soils.