Abstract
Polygala fallax Hemsley, 1886 is a perennial herb of the family Polygalaceae. Because of its antioxidant, anti-aging, anti-inflammatory, and antibacterial properties, it is regarded as a traditional medicinal plant in China with high economic value. Although this species has significant medicinal and health benefits, cytological research on it remains very limited. In the present study, the genome size and chromosome number of P. fallax were determined through k-mer analysis, flow cytometry, and cytogenetics. Firstly, a genome survey was conducted using Illumina NovaSeq 6000 DNA sequencing. K-mer analysis revealed that the genome size of P. fallax was approximately 2199.64 Mb (ca. 2.20 Gb), the heterozygosity rate was about 1.11%, and the proportion of repeated sequences was about 73.61%. As for flow cytometry analysis, Solanum lycopersicum Linnaeus, 1753 was used as internal standard species, and the 2C-DNA value of P. fallax is 2.49 Gb. We counted the chromosome number of P. fallax using a common cytogenetic method, and the result showed a chromosome number of 2n = 40. This comprehensive study offers a foundation for subsequent whole-genome sequencing of P. fallax, contributing valuable insights into its genetic characteristics and providing genomic information for further research on the synthesis mechanisms of its medicinal secondary metabolites, species conservation, and sustainable utilization.