Silver Whendee L, Miya Ryan K
Department of Environmental Science, Policy, and Management, Ecosystem Sciences Division, University of California, Berkeley, 151 Hilgard Hall no. 3110, Berkeley, CA, 94720-3110, USA.
Oecologia. 2001 Nov;129(3):407-419. doi: 10.1007/s004420100740. Epub 2001 Nov 1.
Root decomposition represents a significant C flux in terrestrial ecosystems. Roots are exposed to a different decomposition environment than aboveground tissues, and few general principles exist regarding the factors controlling rates of root decay. We use a global dataset to explore the relative importance of climate, environmental variables, and litter quality in regulating rates of root decomposition. The parameters that explained the largest amount of variability in root decay were root Ca concentrations and C:N ratios, with a smaller proportion explained by latitude, mean annual temperature, mean annual precipitation, and actual evapotranspiration (AET). Root chemistry and decay rates varied by plant life form (conifer, broadleaf, or graminoid). Conifer roots had the lowest levels of Ca and N, the highest C:N and lignin:N ratios, and decomposed at the slowest rates. In a stepwise multiple linear regression, AET, root Ca, and C:N ratio accounted for approximately 90% of the variability in root decay rates. Root chemistry appeared to be the primary controller of root decomposition, while climate and environmental factors played secondary roles, in contrast to previously established leaf litter decomposition models.
根系分解是陆地生态系统中一个重要的碳通量。根系所处的分解环境与地上组织不同，关于控制根系腐烂速率的因素，几乎没有通用的原则。我们使用一个全球数据集来探究气候、环境变量和凋落物质量在调节根系分解速率方面的相对重要性。解释根系腐烂中最大变异性的参数是根系钙浓度和碳氮比，较小比例的变异性由纬度、年平均温度、年平均降水量和实际蒸散量（AET）解释。根系化学性质和腐烂速率因植物生活型（针叶树、阔叶树或禾本科植物）而异。针叶树根系的钙和氮含量最低，碳氮比和木质素氮比最高，分解速率最慢。在逐步多元线性回归中，实际蒸散量、根系钙和碳氮比约占根系腐烂速率变异性的90%。与先前建立的凋落叶分解模型相比，根系化学性质似乎是根系分解的主要控制因素，而气候和环境因素起次要作用。
