3. Discussion3.1. Colchicine Switched the In Vitro Development of Blc. OrchidColchicine has been the main substance used for chromosome duplication in plants.However, colchicine phytotoxicity was reported in different types of tissues used as explants, where the different levels of toxicity depend on the concentrations and exposuretimes used to treat the plant material [24].In orchids, such as Bletilla striata, the treatment with the highest concentration ofcolchicine and longer exposure time (0.4% colchicine for 9 days) resulted in the lowest seedgermination rate [25]. Chung et al. [13] also induced polyploidy using hybrid seeds ofCalanthe (C. discolor × C. sieboldii) (Orchidaceae) and reported a slight gradual decrease inseed germination as a consequence of increasing concentration and exposure time of seedsto colchicine or oryzalin.