Invasive Species Compendium

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Abstract

Karyotype analysis of seven wild Clematis species.

Abstract

There are many significant differences in the wild species of Clematis, including differences in morphology, aroma, flower number, green period and life form. These differences reflect the species' complex genetic background. It is advantageous to study the chromosome karyotypes of the various Clematis species prior to any attempts at cross-breeding. In this study, traditional squashing methods were used to study the karyotypes of 7 wild Clematis species: Clematis orientalis, C. patens, C. heracleifolia, C. fusca, C. hexapetala, C. serratifolia and C. terniflora var. mandshurica. The results showed that six of the Clematis species were diploid (2n=2x=16), with the exception being C. terniflora var. mandshurica, which is tetraploid (2n=4x=32). The basic chromosome number was 8. The karyotypes of all the tested Clematis species were mainly made of median, submedian, subterminal and terminal chromosomes. Their karyotype formulae are as follows C. patens and C. heracleifolia; 2n=2x=16=5m+2st+t; C. fusca; 2n=2x=16=5m+3st; C. hexapetala; 2n=2x=16=5m+2st(SAT)+t; C. serratifolia: 2n=2x=16=5m(SAT)+2st+t; C. orientalis: 2n=2x=16=5m(SAT)+sm(SAT)+2st; C. terniflora var. mandshurica: 2n=4x=32=5m+2st+t. The karyotype formulae of C. orientalis, C. hexapetala and C. serratifolia had satellites in the long arm of their chromosomes. The asymmetry index of the chromosomes ranged from 62.27% to 66.77%. The karyotypes of these Clematis species were 2A, showing that these seven species are relatively primitive. The karyotypes of C. fusca and C. serratifolia are reported here for the first time.