Karyotypes of nineteen species of Asteraceae in the Hengduan Mountains and adjacent regions

摘要

The Hengduan Mountains region is a biodiversity hotspot. In this study, we report the karyotypes of 19 species (21 populations) of Asteraceae from this region, 14 of which are reported for the first time. We also examined polyploidy in Asteraceae plants and summarized karyotype data in the literature for 69 congeneric taxa. In these genera, there were five different ploidy levels in the region, though the most dominant was diploid (73.08%). There is no direct evidence that ploidy level and karyotype asymmetry are associated with the distribution of recorded Asteraceae species from the Hengduan Mountains. This suggests that polyploidy (26.92%) may not play an important role in the evolutionary history of these plants, even though, among these genera, the ratio of paleopolyploidy was high (46.15%).