Preliminary assessment of nuclear DNA content in Chondrilla (Asteraceae) plants of European Russia and Western Kazakhstan using flow cytometry

Preliminary data on the genome size of representatives of the genus Chondrilla (Asteraceae) of European Russia and Western Kazakhstan were obtained using flow cytometry. Among all studied specimens of the genus, for specimens of C. ambigua and C. pauciflora, a direct dependence of the genome size on the number of chromosomes was established. In our study, the DNA content of the diploid C. ambigua was 2С = 1.69 pg, and that of the triploid C. pauciflora was 2С = 2.65 pg. 2С values are within 2.29–2.69 pg in most specimens of the genus Chondrilla (typical for 13 out of 23 specimens) belonging to the following taxa: C. paucifora, C. laticoronata, C. brevirostris, C. canescens, C. graminea, C. latifolia, C. juncea. Most likely, they are triploids, and in many cases with a number of chromosomes deviating from a multiple of the main number of chromosomes. The C. latifolia sample from the population of the Kamyshinsky district of the Volgograd region showed two peaks on the histogram of the relative fluorescence intensity, corresponding to two values of the relative DNA content, 1.68 and 2.58 pg, i.e. it turned out to be a mixoploid with two levels of ploidy (2n = 2x = 10 and 2n = 3x = 15). The diversity of genome sizes within the genus can be explained by the previously established high variability in the number of chromosomes associated with aneu- and mixoploidy.