DIRECT SHOOT REGENERATION FROM FOLIAR EXPLANTS OF AN EPIPHYTIC ORCHID, ACAMPE PRAEMORSA (ROXB) BLATTER AND MCCANN

An efficient and reproducible procedure is described for the large-sca le propagation of an epiphytic orchid, Acampe praemorsa (Roxb.) Blatte r and McCann using foliar explants. Shoot buds were induced in basal p arts of foliar explants on Murashige and Skoog medium supplemented wit h N-6-benzyladenine (BA), kinetin (Kn) or thidiazuron (TDZ), the latte r being most effective at 1.0 mg/l. Shoots formed to a TDZ-containing medium elongated following transfer to a substrate supplemented with 2 .0 mg/l I-naphthaleneacetic acid (NAA) and 0.5 mg/l BA. NAA at lower c oncentrations had no beneficial effects on shoot regeneration, whether added to the medium along with BA, Kn or TDZ. However, it promoted sh oot elongation and leaf expansion. Higher concentrations of NAA suppre ssed shoot regeneration. The frequency of shoot regeneration was great ly influenced by the developmental stage and orientation of the leaf. Shoots regenerated from the foliar explants were rooted successfully o n MS medium containing 1.0 mg/l indole-3-butyric acid. The plantlets w ere acclimated and eventually transferred to a garden.