In vitro growth of Brassocattleya orchid hybrid in different concentrations of KNO3, NH4NO3 and benzylaminopurine

Abstract

One of the most important applications of plant tissue culture is mass propagation of ornamental plants. This experiment evaluated the effect of different concentrations of NH4NO3 and KNO3 and BAP on the in vitro growth of orchid hybrid Brassocattleya 'Pastoral'. Seedlings of this orchid hybrid were used as explants and cultivated in medium with mineral salts and vitamins from the MS medium (Murashige & Skoog, 1962), with the macronutrients P, Ca and Mg reduced by half, and with an addition of 25 g L-1 of sucrose, 0.1 g L-1 of myo-inositol and 1.5 g L-1 of activated charcoal. Agar-agar was added (6.5 g L-1) and the pH was adjusted to 5.8. As treatments, four concentrations of the NH4NO3 and KNO3 (2x; 1x; ½ and ¼ MS medium) and three concentrations of BAP (0.0; 0.5 and 1.0 mg L-1) were assayed. The multiplication, growth in height, fresh and dry weight and sugar level in dry weight of sprouts were evaluated. There occurred a higher growth in height with 0.25x NH4NO3 and KNO3 salts concentrations of MS medium and higher rate of multiplication with combination of NH4NO3 and KNO3 reduced by half of the MS medium concentration and 1.0 mg L-1 BAP.