1. MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University , Lanzhou 730000 , China
2. State Key Laboratory of Grassland Agro-Ecosystem, College of Ecology, Lanzhou University , Lanzhou 730000 , China
3. Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University , Beijing 100875 , China