STUDIES ON CONIFER CHROMOSOMES UNDER INTRODUCTION IN BOTANICAL GARDENS, ARBORETUMS AND PARKS

The information obtained by the authors during the karyological study on conifers growing in arboretums, parks, and botanical gardens from different countries is summarized. Representatives of two genera, pine ( Pinus L.) and spruce ( Picea A. Dietr . ), have been studied in the Pinaceae family; these species have 24 chromosomes in diploid complement (2 n = 24). Seven species and one interspecific hybrid of pine and eight species of spruce were analyzed. In Cupressaceae family, five introduced species were studied, which are representatives of the genera thuja ( Thuja L.), cypress ( Cupressus L.), false cypress ( Chamaecyparis Spach) and Sequoiadendron ( Sequoiadendron J. Buchholz); karyotype of Cupressaceae representatives includes 22 chromosomes (2 n = 22). In species, forms and cultivars of conifers from Pinaceae and Cupressaceae families, which are under introduction, as well as being components of green plantations in settlements of different geographical regions, great variability of karyological features. There area variability of chromosome numbers (mixoploidy), changes in the morphology of chromosomes, an increase of the number of nucleolar loci, appearance of supernumerary chromosomes, a high occurrence and a wide range of chromosomes anomalies. The changes are probably caused by the acclimatization of plants in new growing conditions and adaptation to increased recreational load in park planting. They can cause an increase in phenotypic and genetic diversity. It should be taken into account during introduction and carrying out activities on breeding of conifer species. On the basis of the data obtained, problems of scientific, experimental production, educational and cultural significance can be solved, recommendations for the selection of species and intraspecific taxa suitable for landscaping settlements in a particular region can be developed.