期刊
PLANT AND SOIL
卷 419, 期 1-2, 页码 127-140出版社
SPRINGER
DOI: 10.1007/s11104-017-3334-6
关键词
Exudate; Soil microbial community; Extracellular enzyme; Carbon loss; Subalpine coniferous forest
资金
- National Key R&D Program of China [2017YFC0505200]
- CAS [QYZDB-SSW-SMC023, Y6C2051100]
- National Natural Science Foundation of China [31670449, 31500445]
- Youth Innovation Promotion Association, CAS [2013242]
- Sichuan Youth Science and Technology Foundation [2016JQ0037]
- Key Laboratory of Mountain Surface Processes and Ecological Regulation of CAS
Root exudates play a vital role in driving ecosystem carbon (C) cycling; however, few studies have examined the degree to which a specific exudate component affects soil C loss. The objective was to examine the impacts of different exudate components on microbially-mediated C decomposition and their underlying mechanisms. In a well-controlled simulated rhizosphere system, we added exudate chemicals (glucose, glycine and oxalic acid) to spruce (Picea asperata) plantation soils over a 35-day period. The total C contents, net N mineralization rates, microbial communities and extracellular enzymes were measured. The three exudate components induced different C losses by different mechanisms. Oxalic acid promoted net C loss by accelerating microbial mineralization of soil organic matter (SOM). In contrast, glucose resulted in a net C accumulation, which challenged the assumption that glucose serves as a co-metabolite in driving SOM decomposition to lose C. Glycine increased the total C content via negative priming effects. Exudate-induced rhizosphere priming effects are not entirely dependent on the energy properties of root exudates. Different exudates may affect SOM decomposition differently, thus the component-specialized rhizosphere processes induced by individual exudate components on soil C dynamics should be integrated into forest C cycle-climate feedbacks under environmental changes.
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