1. State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China, Key Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Cui Hubei Road 2, Kunming 650091, P. R. China, Max Planck Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Strasse 8, D-07745 Jena, Germany, and Graduate University of Chinese Academy of Sciences, Beijing 100039, P. R. China