马尾松混交林土壤微生物功能多样性的影响

Influences of Various Ratio of Conifer to Broad-leaved Trees in Mixed Forests on Soil Microbial Functional Diversity

研究不同混交比例对人工马尾松阔叶混交林土壤微生物群落功能多样性的影响,对石漠化地区植被恢复重建具有重要的意义。以贵阳市花溪区6个人工马尾松阔叶混交林为对象,采用Biolog-Eco技术,研究了0-20%（Ⅰ）、21%-40%（Ⅱ）、41%-60%（Ⅲ）、61%-80%（Ⅳ）、81%-100%（Ⅴ）这5种不同针阔混交比例下土壤微生物功能多样性。结果表明,平均颜色变化率（AWCD）表现为Ⅳ〉Ⅱ2〉Ⅴ〉Ⅱ1〉Ⅰ〉Ⅲ,Ⅲ与Ⅱ、Ⅳ差异显著（p〈0.05）;土壤微生物量表现为Ⅲ〉Ⅱ1〉Ⅳ〉Ⅴ〉Ⅰ〉Ⅱ2;Shannon-Wiener指数表现为Ⅳ〉Ⅴ〉Ⅱ2〉Ⅱ1〉Ⅰ=Ⅲ,Simpson优势度指数表现为Ⅳ〉Ⅴ〉Ⅱ2〉Ⅱ1=Ⅲ〉Ⅰ,Pielou均匀度指数表现为Ⅳ〉Ⅴ〉Ⅱ2〉Ⅲ〉Ⅰ〉Ⅱ1,除Pielou均匀度指数外均表现为Ⅰ与Ⅴ差异显著（p〈0.05）。主成分分析及聚类分析表明,Ⅳ、Ⅴ、Ⅱ2可归为一类,Ⅰ、Ⅱ1、Ⅲ归为另一类,阔叶树种比例的增加明显提升了马尾松林土壤微生物群落多样性,Ⅲ类样地土壤微生物多样性较低可能与土层薄、可利用基质较少有关;碳水化合物、多聚物、酚酸类3种碳源是不同混交比例的马尾松针阔混交林之间差异的敏感碳源。因此,混交比例的不同导致马尾松阔叶混交林土壤微生物群落功能多样性的差异。

Influences of different ratios of conifer（masson-pine） to broad-leaved tree on soil microbial communities in mixed forests regarding the vegetation rehabilitation in rocky desert areas were studied. In the case of six mixed forests in Huaxi District of Guiyang City, the Biolog-Eco technique was used to evaluate the diversity of microbial functions in terms of five ratios of conifer to the broad-leaved,i.e., 0-20%（Ⅰ）, 21%-40%（Ⅱ）, 41%-60%（Ⅲ）, 61%-80%（Ⅳ） and 81%-100%（Ⅴ）.Several indexes were investigated with respect to the different ratios, such as the AWCD（average well change development）,Shannon-Wiener index, Simpson dominance index and Pielou evenness index. According to the evaluation, both of the principal component analysis and the cluster analysis suggested that Ⅳ, Ⅴand Ⅱ2 could be grouped into one category and types of Ⅰ, Ⅱ1 and Ⅲ be classified into another. Clearly, the increased proportion of broad-leaved trees had improved the microbial community diversity; as to the lower microbial activities in the type Ⅲ, it might be attributed to the thin soil and less available nutrition. Moreover, the carbohydrates, polymers and phenolic acids were the sensitive carbon sources in research area. In conclusion, the variety of conifer-to-broad-leaved-tree proportion had brought about multiple diversity of soil microbial community in the mixed forests.