Efeito de três classes de regulares de crescimento, citocinina, giberelina e auxina na propagação in vitro de Dendrobium phalaenopsis ‘deang suree’ - Orquidaceae

Abstract

Due to the importance and popularity of the orchid Dendrobium phalaenopsis for Brazilian orchid and world orchids, this work was carried out to evaluate the growth capacity during the in vitro propagation of 'deang suree' hybrid of this species. The culture was carried out in MS medium with different growth regulators, isolated and in combination, 6-benzylaminopurine (BAP), gibberellic acid (GA3) and indole butyric acid (IBA). The concentrations were previously defined, respectively 2.5; 0.1 and 0.1 mg L-1 and added to the MS culture medium, totaling 8 treatments. At 60 days of cultivation were evaluated: number and length of shoots, leaves and roots and fresh and dry masses of shoot and root system. A significant effect was observed for leaf number, number of roots, root length and fresh shoot mass. For the other variables, number of shoots, shoot length, leaf length, fresh mass of the root system and dry mass of shoot and root system, no significant effects were observed. The highest number of leaves per bud (4.0) was observed in the explants cultivated in medium containing IBA. The highest fresh mass value (2,740 mg) was also observed in this treatment. Explants cultivated in regulator-free medium showed a higher number of roots (7.6), the lowest number observed in explants treated with the combination of BAP + IBA + GA3. Explants cultivated in IBA or GA3 showed longer roots, approximately 1.0 cm in length, while culture in medium containing BAP + GA3 inhibited the elongation of the same.