Effect of plant growth regulators on in vitro proliferation of orchid Catasetum and in vivo induction of polyploidy in orchid Dendrobium by colchicine

Orchids are one of most popular ornamental flowers in all over the world and their production has been turned to great industry in global flower trade. In this study, the effect of growth regulators on micropropagation of Catasetum has been explored due to the numerous advantages of micropropagation in comparison to other production methods. Also, in order to achieve desirable and marketable characteristics in Dendrobium, polyploid induction by colchicine was used. In micropropagation, protocorms of orchid were cultured as an explant in MS media containing different concentrations of indole-3-butyric acid (IBA) (0.00, 0.10, 0.20 and 0.50 mg/l) and kinetin (Kin) (0.00, 0.20, 0.50, 1.00 and 2.00 mg/l). Results indicated that the maximum leaf number and root number were obtained in plantlets grown on medium enriched with 1 mg/l Kin together with 0.5 mg/l IBA. In in vivo induction of polyploidy, fully 5-months-old orchid plantlets were plunged in different concentrations of colchicine solution (0.00, 0.05, 0.1 and 0.15%) with Nonident P-40 (NP-40) as a surfactant for 3 days. Flow cytometery analysis revealed that tetraploid plantlets were produced through treatment with 0.15% colchicine. Investigation of cytological and morphological traits confirmed the presence of tetraploidy in plantlets treated with 0.15% colchicine.