Seasonal differences in tree species influence on soil microbial communities
Seasonal differences in tree species influence on soil microbial communities
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DOI：
10.1016/j.soilbio.2013.05.018
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发表时间：
2013-07
影响因子：
9.7
通讯作者：
C. Thoms;G. Gleixner
中科院分区：
文献类型：
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作者：
C. Thoms;G. Gleixner
温带落叶林生态系统中树木多样性和土壤食物网之间的联系仍然不确定。利用微生物磷脂脂肪酸（PLFAs）分析了德国海尼希国家公园表层土壤中树种组成对微生物群落的影响。以前的研究结果表明，在秋季树种对微生物群落的直接影响最小，最有可能是由于低植物活性和高养分和能量输入凋落物。然而，微生物组成的影响是间接通过树种对土壤pH值的影响。在这项研究中，我们分析了PLFA配置文件在初夏，并与秋季采样的结果进行了比较。我们假设，植物为基础的性状将有更强的直接影响的丰度和结构的微生物群落在光合活跃期。结果表明，初夏树木多样性水平之间的土壤微生物群落差异比秋季明显。在初夏和秋季，腐解的榉木枯落物的酸化特性强烈影响土壤pH值，并间接影响土壤微生物群落的结构。然而，测得的差异，在初夏的微生物组成主要是由于凋落物质量。这种植物性状的直接影响似乎在秋季黯然失色，因为新鲜凋落物输入的高营养供应。然而，在表土凋落物分解后，基于凋落物的植物性状成为初夏土壤微生物群落结构的一个因素。我们的研究结果表明，PLFA i14：0和i15：0，指示革兰氏阳性菌，强烈参与分解过程，并可能促进容易获得的营养物质。此外，我们的研究结果表明，一个密集的根系网络与丛枝菌根真菌有力地支持微生物的生长在更多样化的林分。高比例的丛枝菌根真菌（PLFA 16：1ω5）、根相关微生物（PLFA 16：1ω9、16：1ω7、17：1ω8和18：1ω7）和食菌动物（PLFA 20：5）表征了这些研究地块初夏的微生物群落。我们的结论是，微生物群落的强烈影响，非生物控制。然而，在分析树木多样性或物种对土壤微生物群落的影响时，应考虑凋落物分解速率和根系活性的季节差异。
The linkage between tree diversity and the soil food web in temperate deciduous forest ecosystems remains uncertain. Using microbial phospholipid fatty acids (PLFAs), we analyzed the effect of tree species composition on microbial communities from topsoil collected in Hainich National Park, Germany. Previous results had shown minimal direct effects of tree species on the microbial community in autumn, most likely due to low plant activity and high nutrient and energy input from litterfall. However, microbial composition was affected indirectly through an influence of tree species on soil pH. In this study, we analyzed PLFA profiles in early summer and compared them with the results from autumn sampling. We hypothesized that plant-based traits would have stronger direct effects on the abundance and structure of the microbial community during the photosynthetically active period. The results showed that the soil microbial community differed more markedly between the tree diversity levels in early summer than in autumn. The acidifying character of the decaying beech litter strongly influenced the soil pH values and structured the soil microbial community indirectly in early summer as it had in autumn. However, the measured differences in the microbial composition in early summer could be attributed primarily to litter quality. This direct influence of plant traits appeared to be eclipsed in autumn because of the high nutrient supply from fresh litter input. Following litter decomposition in the topsoil, however, litter-based plant traits emerged as a factor structuring the soil microbial community in early summer. Our results suggest that the PLFAs i14:0 and i15:0, indicative of Gram-positive bacteria, are strongly involved in decomposition processes and may be promoted by readily available nutrients. Furthermore, our results indicate that a dense root network in association with arbuscular mycorrhizal fungi strongly supported microbial growth in the more diverse forest stands. High proportions of arbuscular mycorrhizal fungi (PLFA 16:1ω5), root-associated microorganisms (PLFAs 16:1ω9, 16:1ω7, 17:1ω8 and 18:1ω7) and bacterial grazers (PLFA 20:5) characterized the microbial community in early summer on these study plots. We conclude that microbial communities are strongly influenced by abiotic controls. However, seasonal differences in litter decomposition rates and root activity should be considered in the analysis of the effects of tree diversity or species on soil microbial communities.