1. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems; South China Botanical Garden; Chinese Academy of Sciences; Guangzhou 510650 China
2. University of Chinese Academy of Sciences; Beijing 100049 China
3. Department of Biological Sciences; Marshall University; Huntington WV 25755-2510 USA
4. Department of Microbiology and Plant Biology; University of Oklahoma; Norman OK 73019 USA