Integrating leaf and root induced shoot regeneration and embryogenesis for the conservation of Atropa acuminata Royle ex Lindl - an endangered Himalayan herb

Atropa acuminata is an endangered and endemic Himalayan herb of prime importance in pharmaceutical companies. The chemical ingredients of A. acuminata and other related plants of the genus are present in many over-the-counter life saving drugs. The species is facing a severe habitat loss and overharvesting in its natural habitat. To address its propagation, we developed a reliable and reproducible micropropagation protocol to facilitate its conservation and sustainable propagation. Using Murashige and Skoog (MS) medium supplemented with various plant growth regulators (PGRs), we investigated seed germination, as well as morphogenetic responses from leaf and root explants. Gibberellic acid (GA₃) at 10 µM significantly enhanced seed germination (93.3 ± 0.7%) and reduced the mean germination time (MGT) to 14.9 days in full-strength MS medium. For adventitious shoot organogenesis and somatic embryogenesis, cytokinins such as thidiazuron (TDZ), 6-benzyladenine (BA), and meta-topolin (mT) were effective, with 7.5 µM TDZ promoting the highest average shoot formation (9.8 ± 0.14 shoots per leaf segment) and somatic embryo induction (15.0 ± 0.21 embryos per leaf segment). Root explants cultured in MS medium supplemented with 10 µM mT produced an average of 11.06 ± 0.14 somatic embryos per vial. Further, for adventitious shoot organogenesis MS medium supplemented with TDZ 5.0 µM proved effective inducing a peak mean number of 12.24 ± 0.15 shoots per vial. In vitro-derived micro-shoots and emblings exhibited 100% rooting in MS medium supplemented with 2.0 µM indole-3-butyric acid (IBA), with an average of 10.50 ± 0.37 per micro-shoot/embling. Transplanted plants acclimatized well to different substrates, with pure soilrite achieving 100% survival, and a garden soil: soilrite(3:1) yielding 75% survival. The successfully acclimatized plants were subsequently established in their native habitat in Kashmir, India.