Peculiarities of chromosomal variability in cultured tissues of Deschampsia antarctica Desv. plants with different chromosome numbers

Aim. To clarify the details of chromosome variation in calli derived from D. antarctica plants in the initial passages of the culture in vitro. Methods. Induction of callus from root explants of plants, which were grown from seeds, and consequent subcultivation of tissue culture. Cytogenetic analysis of squashed slides stained by acetic-orcein and counting the number of chromosomes in mitotic metaphase plates. Results. There were analyzed the cultured tissues derived from D. antarctica plants with different chromosome numbers: diploid plants (2n=26), mixoploid plant with B-chromosomes (2n=26+1-3B), and mixoploid plant with near-triploid modal class (2n=36, 38). Analysis of callus tissues of all plants at 2-4 passages revealed mixoploidy, presence of polyploid and aneuploid cells. The modal class in all studied calli was composed of diploid and aneuploid cells with near-diploid chromosome number. The cytogenetic structure of cell population of cultured tissues was found to vary with characteristics of the karyotype of donor plant. The largest range of variation in the number of chromosomes (from 18 to 63 chromosomes) was found in tissue culture of diploid plant (2n=26) from the Galindez Island, and the highest frequencies of polyploid (47 %) and aneuploid cells were in the culture of mixoploid plant with near-triploid modal class from the Big Yalour Island. Conclusions. In different D. antarctica cultured tissues at the early stages of the culture, the modal class was composed of diploid cells and cells with near-diploid chromosome number irrespective of karyotype of donor plant (diploid, mixoploid poliploid).Key words: Deschampsia antarctica Desv., plant tissue culture, chromosomal variability in vitro, mixoploidy.