Fate of ectomycorrhizal fungal biomass in a soil bioreactor system and its contribution to soil organic matter formation
Fate of ectomycorrhizal fungal biomass in a soil bioreactor system and its contribution to soil organic matter formation
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DOI：
10.1016/j.soilbio.2015.05.012
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发表时间：
2015-09
影响因子：
9.7
通讯作者：
M. Schweigert;S. Herrmann;A. Miltner;T. Fester;M. Kästner
中科院分区：
文献类型：
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作者：
M. Schweigert;S. Herrmann;A. Miltner;T. Fester;M. Kästner
森林土壤是全球碳循环的主要碳库。虽然外生菌根真菌（EMF）是负责很大一部分的碳输入到这个池，EMF生物量转化为土壤有机质（SOM）的信息是稀缺的。为了定量分析电动势生物量对有机质形成的贡献，我们在一个封闭的生物反应器系统中培养了一个典型的森林砂质土与13 C-标记的真菌生物量从外生菌根担子菌双色蜡蘑231 d，使营业额的完全质量平衡的建立。28 d后，蜡蚧属特异性rDNA片段消失，表明该菌已死亡或腐烂。在实验过程中，13 C PLFA作为活生物量的替代物的量下降到初始值的大约10%，再次表明真菌生物体的有效分解。231 d后，63.5%的13 C转化为有机质，52%的13 C转化为非生物组分。对13 CO2形成（初始添加标记的36.5%）的分析表明，易降解部分的k1= 0.0615 d− 1，稳定部分的k2= 0.0005 d− 1（池大小分别为初始添加标记的74%和26%）为双池指数动力学。与农业土壤中细菌生物量的降解相比，易降解真菌生物量的池要小得多，真菌生物量的两个池（易降解和持久性C）的半衰期明显较高。总之，我们的数据允许的结论，电动势生物量是一个重要的来源，在森林生态系统中的SOM。
Forest soils constitute a major carbon pool in the context of the global carbon cycle. Although ectomycorrhizal fungi (EMF) are responsible for a large part of the input of carbon into this pool, information on the transformation of EMF biomass into soil organic matter (SOM) is scarce. In order to quantitatively analyze the contribution of EMF biomass to SOM formation, we incubated a typical forest arenosol with13C-labeled fungal biomass from the ectomycorrhizal basidiomycete Laccaria bicolor in a closed bioreactor system for 231 d, enabling the establishment of a full mass balance for the turnover. rDNA fragments specific for the genusLaccariadisappeared after 28 d, indicating death and decay of the organism. The amount of13C PLFA as a proxy for living biomass decreased to roughly 10% of the initial value in the course of the experiment, again suggesting efficient disintegration of the fungal organism. After 231 d, however, 63.5% of the initially added13C had been converted to SOM and 52% belonged to the non-living fraction. The analysis of13CO2formation (36.5% of the initially added label) suggested two-pool exponential kinetics with k1= 0.0615 d−1for the easily degradable and k2= 0.0005 d−1for the stable fraction (pool sizes 74% and 26% of the initially added label, respectively). When compared to the degradation of bacterial biomass in agricultural soils, the pool of readily degradable fungal biomass was considerably smaller and the half-lives of both pools (readily degradable and persistent C) were markedly higher for fungal biomass. In summary, our data allow the conclusion that EMF biomass is a significant source of SOM in forest ecosystems.