ABSTRACT
The present work developed an efficient plant regeneration and propagation system via
direct organogenesis for Morinda officinalis How., a valuable endangered medicinal plant.
The effects of explant types on shoot induction, plant growth regulators on shoot
proliferation and elongation and the subsequent rooting ability of shoots were examined.
Among the various types of explant, direct shoot proliferation was successfully achieved
from shoot tips and nodal stem segments with around 95% of the explants producing
approximately 5 shoots per explant after 8 weeks of culture on optimal medium. On the
other hand, leaf and internodal explants did not produce any shoots. The most effective
cytokinin on shoot proliferation was 6-benzyladenine. When the concentration of 6-
benzyladenine was at 1.0-2.0 mg L-1, a high mean shoot number (about 5 shoots per
explant) was achieved. Shoot elongation was obtained satisfactorily by transferring the
shoots to Murashige and Skoog basal media containing 2.0-3.0 mg L-1 gibberellic acid-3
within 2 weeks. Rooting was 100% on half-strength Murashige and Skoog medium
containing 0.2 mg L-1 indole-3-butyric acid after 3 weeks of culture. The plantlets were
acclimatized in the greenhouse and subsequently transferred to the field with 90%
survival rate.
Keywords: Direct regeneration, Explants, Plant growth regulators.
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