Karyotype constancy and genome size variation in Bulgarian Crepis foetida s. l. (Asteraceae)

摘要

Ten populations of Crepis foetida from Bulgaria belonging to the three subspecies foetida, rhoeadifolia, and commutata were analyzed karyologically using haematoxylin staining, Giemsa C-banding, fluorochrome banding, Ag-NOR staining, Feulgen cytophotometry (scanning densitometry and video-based image analysis), and propidium iodide flow cytometry. The quantitatively-evaluated karyotype structure was similar among all populations, with minor variation in a few intercalary sites only and in the amount of NOR-associated heterochromatin (satellites). In contrast to the karyotypic constancy the genome size of C. foetida subsp, commutata was about 10% lower than those of the other two subspecies, which had similar genome sizes. The genome size measurements using three different methods resulted in highly correlated data. The genome size difference adds some weight to previous taxonomic opinions treating C. foetida subsp, commutata at species level, as C. commutata.