Biodiv Sci ›› 2021, Vol. 29 ›› Issue (11): 1470-1480.

• Original Papers:Plant Diversity •

A comparison of seed plants’ polyploids between the Qinghai-Tibet Plateau alpine and the Pan-Arctic regions

Jun Zhang1,2, Huanwen Peng2,3,*(), Fucai Xia1,*(), Wei Wang2,3

1. 1 Forestry College, Beihua University, Jilin, Jilin 132013
2 State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093
3 University of the Chinese Academy of Sciences, Beijing 100049
• Received:2021-04-18 Accepted:2021-07-03 Online:2021-11-20 Published:2021-07-27
• Contact: Huanwen Peng,Fucai Xia

Abstract:

Aims: Polyploidization is an important mechanism for plants to adapt to extreme environments. The Qinghai-Tibet Plateau (QTP) alpine and Pan-Arctic regions have a similar low-temperature environment, and there were closely biotic exchanges between the two regions. However, it is unclear whether the QTP alpine and Pan-Arctic floras have similar polyploid buildup or not. Here, we compared polyploid proportions between these two floras and explored the potential causes for the difference.
Methods: By comprehensive searches in the databases and various literatures, we obtained species lists with chromosome numbers and ploidy of seed plants for the QTP alpine and Pan-Arctic regions, and then calculated polyploid proportion in totality as well as polyploid proportion for different life forms in the two regions.
Results: A total of 1,770 species of seed plants with chromosome numbers were collected, of which 774 occur in the QTP alpine region and 996 occur in the Pan-Arctic. According to the statistical analyses, the proportions of polyploid plants are 20.9% in the QTP alpine region and 61.5% in the Pan-Arctic. The proportions of polyploids of annual herbs, perennial herbs and woody plants in the QTP alpine region are 20.7%, 21.6%, and 12.8%, respectively. The proportions of polyploids of annual herbs, perennial herbs and woody plants in the Pan-Arctic are 60.2%, 65.5%, and 38.3%, respectively.
Conclusions: The polyploid proportions in totality and for different life forms in the Pan-Arctic are higher than those in the QTP alpine region obviously, which is associated with the different evolutionary history of the two floras, as well as their different geological and climatic events. The modernization of the QTP alpine flora took place around the Oligocene-Miocene boundary, and since then the QTP has had a relatively constant low-temperate environment, whereas the Pan-Arctic flora did not develop until 3-4 Ma, and since then the Pan-Arctic flora experienced repeated glacial and interglacial periods and repeated sea-level fluctuations, which might have resulted in the polyploidization of plants. This study contributes to our knowledge on how polyploids adapt to low-temperate environments.