EFFECTS OF NAA AND BA ON PLB GROWTH OF PSYGMORCHIS PUSILLA

Psygmorchis (syn. Erycina) pusilla Dodson & Dressler, belonging to the subtribe Oncidiinae, is a small orchid distributed in Latin America. It has the lowest chromosome number (2n=12) in the orchid family, shorter life cycle, which is about one year from germination to flowering, and can be incubated easily through life in vitro. According to these features, P. pusilla has the possibility to be a model plant in the Orchidaceae to research orchid-specific characters, such as flower shape, column, pollinia or protocorm. To establish P. pusilla as a model plant, we investigated PLB growth with varying concentrations of NAA and BA on NDM medium or 1/2 MS medium. The fastest proliferation was found on NDM medium with 0.1 mg L-1 NAA + 1.5 mg L-1 BA. On the other hand, 2.0 mg L-1 BA with any NAA concentration showed lower growth of PLB, but more number of protrusions was produced.