Karyomorphological Study of Taraxacum in Northeast China

Background: Dandelions ( Taraxacum ) comprise more than 2,000 species distributed worldwide, including 70 species in China and over 20 species in Northeast China. It is an edible plant used also in traditional Chinese medicine. Methods: Chromosome number was determined by conventional tableting, and karyotypes were analyzed. We determined the number of mitotic chromosomes, karyotype characteristics, and morphology of Taraxacum germplasm resources collected in Northeast China. The data were compared with those in the Chromosome Counts Database (CCDB) using principal component analysis (PCA) and cluster analysis. Results: The collected Taraxacum species included diploids, triploids, and tetraploids, with chromosome numbers of 2n = 16, 24, and 32, respectively. The karyotypes showed metacentric and submetacentric chromosomes and satellites. The absolute length of a single chromosome was 3.56–31.68 μm, and the karyotype asymmetry coefficient was 59.68%–67.45%. PCA of karyotype data showed that chromosome size, long arm length, and short arm length formed PC1. Cluster analysis based on karyotype data of the 18 species supported the taxonomic classification of this genus in the Flora of China . Conclusions: Our results indicate that karyotype analysis can be used as cytological evidence for Taraxacum taxonomy. We also determined that among the 18 Taraxacum species, triploid species were more evolved than diploid and tetraploid species. We believe that our results provide a basis for further research in Taraxacum germplasm resources and lay the experimental foundation for further development of Taraxacum in traditional Chinese medicine.