MICROPROPAGATION OF RHYNCHOSTYLIS GIGANTEA L. ORCHIRD THROUGH PROTOCORM

Abstract

Rhynchostylis gigantea L. Orchid is an endangered tropical epiphytic orchid that is threatened with extinction due to over-collection and the loss of suitable habitats. A efficient protocol for micropropagation of Rhynchostylis gigantea L. was establisted successful through protocorm to conserve and develop this orchid. Culture mediums supplementing growth regulators BAP, NAA and coconut water (CW), potato homogenate (PH) and banana extracts for protocorm induction, biomass multiplication and shoot regeneration was investigated. Results showed that MS medium supplemented with 2.0 mg.l^-1 BAP is suitable for protocorm induction from callus, the rate is 100%. The most suitable protocorm multiplication medium is VW medium added 1.0 mg.l^-1 BAP, 0.5 mg.l^-1 NAA, 100 ml.l^-1 CW, 40 g.l^-1 PH, 30 g.l^-1 banana extracts. The highest protocorm biomass were gained 4.66 times. VW medium supplemented with 100 ml.l^-1 CW, 40 g.l^-1 PH, 30 g.l^-1 banana extracts (ST2 medium) showed the highest efficiency of PLBs biomass multiplication (17.9 times) and the best shoot regeneration. The most suitable rooting medium was the VW medium supplemented with 1.0 mg.l^-1 NAA, 50 g.l^-1 banana extracts with the highest number of roots/shoot (4.00), the root length was 2.33 cm. This procedure can be applied for large-scale production of Rhynchostylis gigantea L. seedlings.