秦岭典型林分夏秋两季根际与非根际土壤微生物群落结构

本试验主要以秦岭山脉锐齿栎(Quercus aliena var.acutidentata)、油松(Pinus tabuliformis)、华山松(Pinus armandii)、云杉(Picea asperata)4种典型林分为对象,利用BIOLOG微孔板法研究4种林分夏、秋两季根际与非根际土壤微生物群落代谢多样性。研究表明:(1)夏、秋季土壤根际与非根际的平均颜色变化率(AWCD)值截然不同,除秋季云杉外,其余处理均表现为非根际根际,且AWCD明显受到季节的影响。(2)夏秋两季4种林分根际与非根际土壤微生物功能多样性之间差异显著,其中锐齿栎林夏秋两季均表现为根际小于非根际,而其它3种针叶林则是夏季根际小于非根际,秋季根际大于非根际;锐齿栎林根际与非根际均为秋季低于夏季,其他3种针叶林则是非根际土秋季低于夏季,而根际土秋季高于夏季。(3)主成分分析显示各土壤微生物功能多样性具有显著差异,且4种林分夏秋两季根际与非根际主成分综合得分也有所不同,4种林分非根际土综合得分锐齿栎最高,其次是华山松和云杉,油松最低;根际土夏秋规律不同,夏季华山松和油松较高,云杉最低,秋季油松和云杉较高,锐齿栎最低,且综合得分与多样性指数达到显著或极显著的正相关。(4)冗余分析表明土壤理化性质的综合作用对土壤微生物群落功能多样性有显著影响。

Characteristics of microbial community in forest soil between rhizosphere and non-rhizosphere in summer and autumn in Qinling Mountains, China

This study focused primarily on the biodiversity of microbial communities in soil between the rhizosphere and non-rhizosphere in summer and autumn among four types of common trees-the Tooth Oak (Quercus aliena var. acutidentata), Chinese pine (Pinus tabuliformis), armand pine (Pinus armandii) and spruce (Picea asperata)-on the Qinling Mountain, China, using the micro BIOLOG method. We found that:(1) The Average Well Color Development (AWCD) of the soil in the rhizosphere was significantly different from that in the non-rhizosphere in most of the seasons, with AWCD in the non-rhizosphere being higher than that in the rhizosphere, except for the soil where spruce was grown in autumn. (2) Biodiversity of microbial communities differed remarkably between rhizosphere and non-rhizosphere in the soil where the four different types of trees were grown in either summer or autumn. For soil where tooth oak was grown, the biodiversity of microbes in the rhizosphere was lower than that of the non-rhizosphere in both summer and autumn, and both these values were in lower in summer than in autumn. While the biodiversity of microbes in soil among the other three coniferous trees showed similar trends to that of tooth oak in summer, they exhibited the reverse of this trend in autumn. Furthermore, the biodiversity of these soils in autumn was lower than that in summer in the non-rhizosphere but higher in the rhizosphere. (3) The results of principal component analysis indicated that the biodiversity of microbial communities in the soil for these four types of trees was significantly different, and the principal component scores for biodiversity among the four studied species in either the rhizosphere or non-rhizosphere in different seasons also varied substantially. The highest score among all studied species was found in the non-rhizosphere of the soil where tooth oak grew, followed by that of armand pine, and spruce, with that of Chinese pine being the least. The principal component score for the soil in the rhizosphere varied with season-in summer, the score was relatively high for Chinese pine and armand pine and lower for spruce. In autumn, the score was relatively high for Chinese pine and spruce and lower for tooth oak. The correlation between the comprehensive score and biodiversity index in all cases was positive or extremely positive. (4) Redundancy analysis showed that the combined effects of soil properties have a significant impact on the biodiversity of microbial communities in the soil.