Influence of triacontanol and paclobutrazol on growth and ex vitro survival of Cymbidium Lunavian Atlas

To minimize the effect of transplantation stress due to rapid water loss and excessive cuticular transpiration, the plantlets should be hardened off in vitro before being exposed to harsh field conditions. Incorporation of Triacontanol (Tria) and Paclobutrazol (BPZ) in the culture media has a great influence on the ex vitro survival. Plantlets with 2-3 leaf stage from the meristem culture of Cymbidium Lunavian Atlas, subcultured on Murashige and Skoog and Nitsch media supplemented with 1 g/1 of activated charcoal, Tria (0.25 and 0.5 mg/l) and PBZ (0.25 and 0.5 mg/l), showed that MS media was superior over Nitsch for optimum plantlets growth in vitro, as it resulted in maximum plantlet weight (1123.17 mg), maximum shoot length (210.56 mm) and well developed leaf and root. Presence of 0.25 mg/l Tria and 0.5 mg/l of PBZ resulted in longest leaf (116 mm), whereas broader leaf was obtained in media supplemented with 0.5 mg/l Tria and 0.5 mg/l PBZ. Pre conditioning of plantlets in Murashige and Skoog media containing 0.5 mg/l each of Tria and paclobutrazol recorded survival percentage of 95 % and 89% after 2 and 4 months after transfer respectively in ex vitro conditions.