HIGH FREQUENCY PLANT REGENERATION IN WITHANIA SOMNIFERA (L.) DUNAL

At 1.5 mg/l BA, 78% of nodal explants produced shoots from the pre-existing axillary meristems (PEM) (4 shoots/node) within 6 weeks. A comparatively higher number of shoots were produced (11 shoots/node) at 1.5 mg/l BA with 0.3 mg/l IAA combination after 6 weeks. Three polyamines tested, spermidine at 20 mg/l induced maximum number of multiple shoots in 92% of nodal explants (42 shoots/node) after 6 weeks. At the end of the culture, each shoot grew to a length of 6–8 cm having an average of 8 nodes. The quantities of withanolide A, withanolide B, withaferin A, and withanone present in the methanolic extracts of leaves, stems, and roots of in vitro-derived plants were analyzed by HPLC and their levels were compared with field-grown parent plants of W. somnifera. The withaferin A and withanone content in the leaves, stems, and roots of in vitro-derived plants exhibited a marked increase over the respective organs of field-grown parent plants. Withaferin A and withanone content were 1 and 1.18 times higher in the leaves of in vitro-derived plants than in the leaves of field-grown parent plants, respectively. Of the different organs tested, the roots of in vitro shoots had shown nearly 1 times increase in withanolide A production than the roots of field-grown parent plants. The present study provides evidences that in vitro plant propagation can improve the biochemical quantity of the plant.