Cytotaxonomic studies of the Chinese pteridophytes: A review
1,2WANG Ren-Xiang 1LU Shu-Gang* 1,3DENG Xi-Chao 1(Institute of Ecology and Geobotany, Yunnan University, Kunming 650091, China) 2(College of Life Sciences, Guangxi Normal University, Guilin 541004, China) 3(Hechi University, Yizhou, Guangxi 546300, China)
China has a rich pteridophyte flora, which is composed of 2600 species of 230 genera belonging to 63 families. Approximately 10% of the species are endemic. Previous studies have recorded chromosome numbers of 395 species from China. This number accounts for only 15% of the Chinese pteridophytes, 48% of which are polyploids. This paper reviews comprehensively the history and present status of cytotaxonomic study of the Chinese pteridophytes. The applications of chromosome numbers and basic numbers in pteridophyte systematics are reviewed in detail. The significance of karyotype analysis, polyploidy, apogamy, and reticulate evolution in pteridophytic classification, evolution, and phytogeography is also reviewed. The cytotaxonomic study of the Chinese pteridophytes in the past twenty years indicates that the data of chromosome numbers, basic numbers, karyotypes, aneuploids, ploidy levels, and reproductive modes are useful to understand origin, evolution, and speciation of this plant group, and are also important for discriminating species and species complexes. Finally, some directions for the future cytotaxonomic study of the Chinese pteridophytes are suggested.