Karyomorphology of epimedium (berberidaceae) and its phylo-genetic implications

Abstract

The karyomorphology of 21 species and one variety of Epimedium was investigated in this study, among which 14 species and one variety were reported for the first time. The interphase nucleus and mitotic pro-phase chromosomes were found to be of the complex chromocenter type, and the interstitial type, respectively. The chromosome numbers of all species studied were 2n = 2x = 12. The investigated Epimedium species had a uniform karyotype with 2n = 6m + 6sm, except for three species, E. platyplatum, E. pubescens and E. stellulatum, which had a pair of chromosomes with subterminal centromeres. A secondary constriction was commonly found on the proximal side of the short arm of the chromosome pair I in these species, except for E. pseudowushanense and E. elachyphyllum in which the constriction was on chromosome pair II. The karyotype symmetry of all the investigated species was relatively primitive 2A. Pericentric inversion was observed in E. leptorrhizum, and unequal translocation occured in E. franchetii, E. sutchuenense, E. dolichostemon and E. koreanum. These chromosomal variations probably result in speciation of Epimedium to some extent. The infrageneric and intergeneric relationships of Epimedium in Berberidaceae were discussed. © 2008 Taylor & Francis Group, LLC.