Effect of plant growth regulators on shoot proliferation of endangered orchid species, Vanda dearei

The effect of different concentrations of plant growth regulators on shoot proliferation of Vanda dearei, an endangered orchid species was investigated. The in vitro microshoots of V. dearei were used as the plant material and allowed to grow on MS medium supplemented with different concentrations of BAP (0.5 mg/L, 1.0 mg/L and 1.5 mg/L) in the first phase with blank MS medium as control. In the second phase, different concentration of NAA (0.3 mgIL, 0.6 mg/L and 0.9 mg/L) with fixed concentration of BAP (1.5mgIL) were added in each culture media with 1.5mgIL BAP as control. The culture condition was maintained at a 16 light/8 dark photoperiod at room temperature of 25±2°C. The data was compared using three parameters which are the number of proliferated microshoots, the changes in the number of leaf and the increase of the microshoot length. The experiments were conducted in Completely Randomized Design (CRD) with three replicate per treatment, three explants per petri dish in the first phase and two explants per jar in the second phase. The highest shoot proliferation in the first phase was observed in MS medium supplemented with 1.5 mgIL BAP while the highest sheot proliferation in the second phase was observed in the MS medium supplemented with 1.5 mgIL BAP and 0.6 mg/L NAA