渗出液
残留物(化学)
化学
土壤水分
分解
孵化
呼吸
微生物种群生物学
土壤碳
土壤呼吸
环境化学
细菌
植物
生物
生物化学
生态学
有机化学
遗传学
作者
Marie‐Anne de Graaff,Aimée T. Classen,Hector F. Castro,Christopher W. Schadt
标识
DOI:10.1111/j.1469-8137.2010.03427.x
摘要
Root carbon (C) inputs may regulate decomposition rates in soil, and in this study we ask: how do labile C inputs regulate decomposition of plant residues, and soil microbial communities? In a 14 d laboratory incubation, we added C compounds often found in root exudates in seven different concentrations (0, 0.7, 1.4, 3.6, 7.2, 14.4 and 21.7 mg C g(-1) soil) to soils amended with and without (13) C-labeled plant residue. We measured CO(2) respiration and shifts in relative fungal and bacterial rRNA gene copy numbers using quantitative polymerase chain reaction (qPCR). Increased labile C input enhanced total C respiration, but only addition of C at low concentrations (0.7 mg C g(-1)) stimulated plant residue decomposition (+2%). Intermediate concentrations (1.4, 3.6 mg C g(-1)) had no impact on plant residue decomposition, while greater concentrations of C (>7.2 mg C g(-1)) reduced decomposition (-50%). Concurrently, high exudate concentrations (>3.6 mg C g(-1)) increased fungal and bacterial gene copy numbers, whereas low exudate concentrations (<3.6 mg C g(-1)) increased metabolic activity rather than gene copy numbers. These results underscore that labile soil C inputs can regulate decomposition of more recalcitrant soil C by controlling the activity and relative abundance of fungi and bacteria.
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