Variability of chromosome numbers in gymnosperms

The results of investigations of chromosome numbers in 48 species of gymnosperms (including 3 subspecies and 14 intraspecific forms) and 6 intraspecific hybrids of 8 genera belonging to 3 families are represented. The investigations were conducted for more than 250 provenances of gymnosperms from 18 countries. Analysis of the study data indicates that microevolutionary changes in gymnosperm populations, which provide for successful adaptation and intraspecific differentiation, can be related to the variability of the somatic number of chromosomes in ontogenesis. The frequency of cells with the chromosome number diverging from the diploid set increases in plants with abnormal growth and development, as well as those affected by extreme factors and introduction.