Efficient in vitro organogenesis, micropropagation, and plumbagin production in Plumbago europaea L.

In this study, an efficient method for in vitro regeneration of Plumbago europaea was developed using direct and indirect organogenesis. Accordingly, micropropagation and regeneration were obtained on Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of plant growth regulators. The effects of explant type and plant growth regulators on shoot organogenesis of P. europaea were evaluated. For the nodal explants, MS medium containing 0.5 mg/l TDZ (11.62 shoots per node) was the best medium for high frequency of micropropagation. In comparison, the highest percentage of direct organogenesis (70%) and number of shoots per explants (14.6) were acquired for the internode explants using 0.5 mg/l TDZ and 0.1 mg/l IAA. The obtained data revealed that TDZ is the most effective cytokinin for the direct shoot organogenesis. The highest indirect organogenesis rate was observed using 2 mg/l BA and 0.1 mg/l NAA for the internode explant. The maximum number of roots was distinguished on 1/2 MS medium containing 0.5 mg/l IBA (6.42). The rooted plantlets were gradually hardened and acclimatized under ex vitro conditions. As an important outcome, the active compound plumbagin was found mainly in the root tissues of the micro-propagated and regenerated plantlets. Taken all together, this study achieved a successful protocol for in vitro regeneration of P. europrea and could be considered for large-scale multiplication of this important medicinal plant.