Soil microbial diversity affects soil organic matter decomposition in a silty grassland soil
Soil microbial diversity affects soil organic matter decomposition in a silty grassland soil
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DOI：
10.1007/s10533-012-9800-6
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发表时间：
2013-07-01
期刊：
影响因子：
4
通讯作者：
Maron, Pierre-Alain
中科院分区：
文献类型：
--
作者：
Baumann, Karen;Dignac, Marie-France;Maron, Pierre-Alain
土壤微生物在土壤有机质（SOM）周转中起着关键作用，其多样性是土壤生态系统功能的关键。然而，土壤有机质动态变化与土壤微生物多样性变化的关联程度在很大程度上仍然未知。在受控的实验室条件下，我们在两个月的孵育实验中沿着微生物多样性梯度表征了SOM的降解。通过稀释粉质草地土壤悬浮液，形成了土壤微生物多样性梯度。在含有相同无菌土壤的微环境中重新接种一种微生物多样性，并用C-13标记的小麦进行修饰，以评估SOM分解是否与土壤微生物多样性有关。利用固态C-13核磁共振分析小麦的结构组成，量化糖和木质素含量，并通过C-13化合物特异性分析确定标记小麦的贡献。结果表明，随着微生物多样性的增加，小麦o -烷基c含量降低。从小麦中提取的总非纤维素糖c不受微生物多样性的显著影响。微生物多样性低时，来自小麦糖（阿拉伯糖- c和木糖- c）的碳含量最高，表明微生物多样性低时，小麦糖分解减少。木糖c与细菌群落的Shannon多样性指数呈显著相关。土壤木质素- c与微生物多样性无关。在微生物多样性较低的情况下，香草素-木质素单元的氧化态显著降低。我们得出结论，微生物多样性改变了植物凋落物糖的总体化学结构，并影响了总香草木质素的微生物氧化，从而改变了SOM的组成。
Soil microorganisms play a pivotal role in soil organic matter (SOM) turn-over and their diversity is discussed as a key to the function of soil ecosystems. However, the extent to which SOM dynamics may be linked to changes in soil microbial diversity remains largely unknown. We characterized SOM degradation along a microbial diversity gradient in a two month incubation experiment under controlled laboratory conditions. A microbial diversity gradient was created by diluting soil suspension of a silty grassland soil. Microcosms containing the same sterilized soil were re-inoculated with one of the created microbial diversities, and were amended with C-13 labeled wheat in order to assess whether SOM decomposition is linked to soil microbial diversity or not. Structural composition of wheat was assessed by solid-state C-13 nuclear magnetic resonance, sugar and lignin content was quantified and labeled wheat contribution was determined by C-13 compound specific analyses. Results showed decreased wheat O-alkyl-C with increasing microbial diversity. Total non-cellulosic sugar-C derived from wheat was not significantly influenced by microbial diversity. Carbon from wheat sugars (arabinose-C and xylose-C), however, was highest when microbial diversity was low, indicating reduced wheat sugar decomposition at low microbial diversity. Xylose-C was significantly correlated with the Shannon diversity index of the bacterial community. Soil lignin-C decreased irrespective of microbial diversity. At low microbial diversity the oxidation state of vanillyl-lignin units was significantly reduced. We conclude that microbial diversity alters bulk chemical structure, the decomposition of plant litter sugars and influences the microbial oxidation of total vanillyl-lignins, thus changing SOM composition.