Abstract:
Dendrobium chrysanthum (Orchidaceae) is highly valued in the ornamental industry
and has important medicinal properties used in the preparation of herbal medicines in
different parts of the world. However, this orchid species is getting depleted from its
natural habitats due to unsystematic collections. Therefore, in the present study, an
efficient mass propagation protocol through direct shoot bud formation from axenic
nodal segments of D. chrysanthum has been developed. The synergistic action between
thidiazuron (TDZ) and 6-benzyl amino purine (BAP) was applied to enhance proliferation
and elongation of shoots from the nodal segments. The explants were inoculated in MS
medium fortified with different plant growth regulators viz., 2, 4-dichlorophenoxy acetic
acid (2, 4-D), BAP, and TDZ, separately and in combinations. The maximum frequency of
explants forming buds (100%), highest number of shoots/explant (14.33±0.14), the bud
forming capacity (BFC) index of 14.33, and the maximum length of shoots (1.97±0.04)
were obtained in MS medium supplemented with 5 µM each of TDZ and BAP. Hundred
percent rooting of regenerated shoots with an average number of 11.26 roots/shoot and
having average root length of around 2.45 cm was obtained in MS medium fortified with
10 µM α-naphthaleneacetic acid (NAA). Sixty days after transfer to the greenhouse
following in vitro acclimatization for 30 days, 79% survival was recorded. The protocol
developed will not only help to alleviate the pressure on the natural population under
stress, but will also help in meeting its demands in pharmaceutical and ornamental
industries, and also form the basis for conservation.
Keywords: In vitro acclimatization, Conservation, Mass propagation, Thidiazuron; 6-benzyl
amino purine
