In vitro conservation of rare, medicinally important species Dendrobum nobile Lindl. (Orchidaceae)

A comparative study was made to access the regeneration response of the stem-node discs of Dendrobium nobile procured from in vivo (greenhouse) grown plants and in vitro grown cultures. The response of stem-node discs, procured both from in vivo and in vitro source, was successfully tested in M (Mitra et al., 1976) medium alone and in combinations with cytokinins [N6-benzyladenine (6-BA - 0.5, 1.0 mg l -1 ), furfurylaminopurine (Kn - 0.5, 1.0 mg l -1 ) and auxin [α-naphthalene acetic acid (NAA - 0.5, 1.0 mg l -1 )]. The explants regenerated via shoot bud initiation in the cultures. Juvenility of the tissues and chemical stimulus were the major factors in initiating the response in the explants. The initiation of regeneration response in in vitro derived explants was not obligatory to a treatment with growth regulators as compared to those derived from in vivo ones. Cytokinins at 1.0 mg l -1 favoured optimum regeneration percentage in the explants and invoked additional supernumerary loci in the regenerants. The regenerants from in vitro derived explants developed plantlets early in cytokinins enriched combinations.