An efficient protocol for cryopreservation of protocorm like bodies (PLBs) of Dendrobium nobile, based on encapsulation-dehydration (ED) and encapsulationvitrification (EV), was established. In both cryogenic procedures, PLBs were initially osmoprotected with a mixture of 0.4 M sucrose and 2 M glycerol, incorporated in the encapsulation matrix [comprising 3% (w/v) sodium alginate and 0.1 M CaCl 2 ]. Out of the two methods, EV resulted in higher survival (78.1%) and regrowth (75.9%) than ED (53.3 and 50.2% respectively). Incorporation of 0.4 M sucrose and 2 M glycerol in the encapsulation matrix resulted in higher survival percentage after cryopreservation. In both the cases (ED and EV), shoots regenerated from cryopreserved PLBs with an intermediary PLB formation. Regenerated shoots were successfully rooted in the medium containing 1.5 mg/l Indole-3 butyric acid. Successful acclimatization of plantlets was obtained in the compost containing brick pieces and charcoal chunks (1:1) ? a top layer of moss with a maximum survivability (82%). EV method proved to be most appropriate way to cryopreserve the PLBs of D. nobile. Regenerated plantlets showed normal morphology as that of control plants.

The present investigation was undertaken to mass propagate Cymbidium mastersii, an ornamental orchid of Northeast India by in vitro propagation method. This approach could also help for the conservation as well as commercialization of C. mastersii and other threatened and ornamental orchids.

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Synthetic seed technology is an exciting and rapidly growing area of research as deals with conservation and storage of rare, endangered and desirable genotypes along with its easy handling and transportation. As propagation of many ornamental and medicinally important plant species is labour intensive, application of different growth retardants and osmotica in simple artificial seed system would dramatically reduce labour requirement by storing the germplasm in vitro. Moreover, the primary aim of developing in vitro storage methods is to reduce the frequent demands of subculturing and preserving the unique genetic constituent of the germplasm. Dendrobium nobile is a pharmaceutically important orchid mostly used in the Chinese herbal drug industry for its medicinal property. Commercial exploitation of this species has considerably depleted their population in wild. Hence, for conserving this valuable germplasm, short term in vitro storage of Protocorm-Like Bodies (PLBs) of D. nobile was carried out using different osmotica (sucrose and mannitol). It was observed that incorporation of low sucrose and mannitol (3 and 5 %) in the encapsulating matrix showed almost similar results with that of control. In all these cases, more than half of PLBs burst out from the matrix thus making these concentrations of sucrose and mannitol along with control not suitable for storage studies. However, with the increase in concentration to 7.5 and 12.5 % in the encapsulating matrix, no outburst of encapsulated PLBs was recorded till 60 days of storage; hence it can be concluded that these concentrations play an important role in minimizing the growth of PLBs during storage condition.