Funding for this research was provided by:
National Natural Science Foundation of China (31670295, 31670301)
Science and Technology Coordination Innovation Project of Shaanxi Province (2015KTTSNY03-07)
Received: 4 June 2019
Accepted: 5 December 2019
First Online: 19 December 2019
Ethics approval and consent to participate
: This study did not require ethics approval and consent as wild, no endangered or protected plant species were involved.
: Not applicable.
: The authors declare that they have no competing interests.