IN VITRO INDUCTION OF POLYPLOIDY IN CERCIS YUNNANENSIS HU ET CHENG

Abstract

Methods for in vitro induction of polyploid Cercis yunnanensis Hu et Cheng using oryzalin were developed and evaluated. Methods included treating either shoot or callus tissue for different exposure durations with either an aqueous solution of 150 micromolar oryzalin or the addition of oryzalin directly to solid media. Polyploid nuclei were determined by flow cytometry for all oryzalin treatments. Although the results indicate that most tissues measured were likely chimeras with respect to DNA content. Results indicate that treating shoot tissue with an aqueous solution of oryzalin for 12 to 96 hours produced tetraploid plants irrespective of the type of shoot explant treated. An unstable octaploid was formed from the treatment of a pre-cultured lateral shoot in an aqueous solution of oryzalin for 96 hours. In contrast shoots cultured on the solidified media failed to produce polyploid plants and there were no statistical differences between callus treatments regarding polyploid induction.