1. College of Natural Resources and Environment; Northwest A&F University; Yangling Shaanxi 712100 People's Republic of China
2. Shaanxi Key Laboratory of Natural Products and Chemical Biology, College of Chemistry and Pharmacy; Northwest A&F University; Yangling Shaanxi 712100 People's Republic of China
3. Agricultural Center, School of Plant, Environmental, and Soil Sciences; Louisiana State University; Baton Rouge Louisiana