1. W.M.
Keck FTMS Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
2. Forest
Biotechnology Group, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina 27695, United States
3. State
Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China