1. Xi'an Botanical Garden of Shaanxi Province (Institute of Botany of Shaanxi Province) Xi'an Shaanxi 710061 China
2. Shaanxi Engineering Research Centre for Conservation and Utilization of Botanical Resources Xi'an Shaanxi 710061 China
3. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F University Yangling Shaanxi 712100 China
4. Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources Yangling Shaanxi 712100 China
5. Kasuya Research Forest Kyushu University Sasaguri Fukuoka 8112415 Japan
6. Arid Land Research Center Tottori University Hamasaka Tottori 6800001 Japan
7. School of Life Sciences Northwest University Xi'an 710069 China