Polyploid Induction in <i>Viola acuminata</i> Ledebour using Colchicine

Abstract

This study was aimed to obtain polyploid plants of viola (<em>Viola acuminata</em> Ledebour) using the antimitotic agent colchicine. Experiments consisted in using colchicine on ungerminated seeds. The seeds were plunged into colchicine solutions in concentrations of 0.01, 0.05, 0.10 and 0.20% for 24 and 48 h. Polyploidy levels (diploid, tetraploid and hexaploid) were firstly detected by chromosome counting (karyotype), and then confirmed by anatomical and morphological parameters. The greatest percentage of polyploids was induced with 0.10% colchicine for 24 h. The chromosome number was 2n = 18 in diploids, 2n = 36 in tetraploid, and 2n = 54 in hexaploid. Differences in some morphological and anatomical parameters were significant between polyploid and control plantlets. The highest number of chloroplasts in guard cells was obtained in plantlets obtained from treated seed with 0.10% colchicine for 24 h. Exposure times of 48 h did not significantly influence polyploidisation. New ornamental varieties with improved characteristics may be produced <em>by</em> polyploid induction.