Karyological analysis of larch species from Siberia and the far east of Russia

Abstract

Data on karyological studies of five larch species - Larix sibirica Ledeb., L. gmelinii (Rupr.) Rupr., L. cajanderi Mayr, L. ochotensis Kolesn., L. × amurensis Kolesn. in different parts of area are presented. Karyotype of Larix (2n = 24) consists of 24 chromosomes (2n = 24) and includes 6 pairs of symmetric (metacentric) and 6 pairs of asymmetric (submeta- and intercentric) chromosomes. Except A-chromo-somes some populations have B-chromosome (2n = 24+1B). The number of genome and chromosome mutations including polyploid and aneuploid cells, ring and dicentric chromosomes, fragments was higher in extreme conditions. Based on the number of secondary constrictions in chromosomes the genus Larix was subdivided into some karyotypic groups. Species with one pair of nucleolar chromosomes consist of the first group. Larix taxa with two pairs of nucleolar chromosomes consist of the second group. Many species have three or more pairs of chromosomes with secondary constrictions and form the third group. © 2007, Taylor & Francis Group, LLC.