1. State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, P.R. China
2. State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, P.R. China, and Institute of Microbiology PO Box 61, Beijing Forestry University, Beijing 100083, P.R. China