Efficient Micropropagation of Bistorta amplexicaulis (D.Don) Greene: An Important Medicinal Plant of Western Himalaya.

Bistorta amplexicaulis (D.Don) Greene from the family Polygonaceae is an important medicinal plant species. The growing therapeutic use of B. amplexicaulis has led to its population depletion thus requiring its conservation. Herein, an efficient, reproducible and reliable propagation protocol system was established for B. amplexicaulis using nodal segments as explant. Various culture media were tested for the assessment of growth and development of this plant species. On the shoot proliferation and rhizogenesis of regenerated B. amplexicaulis plantlets, the effects of several plant growth regulators (PGRs) were assessed. Direct organogenesis from nodal segments was achieved by culturing the nodal explants on Murashige and Skoog medium supplemented with 2.0 mg·L^-1 6-benzylaminopurine (BAP). Shoot multiplication was widely affected by the kind and concentration of PGRs, and the subculturing of in vitro regenerated shootlets on fresh medium. After incubation for 4 weeks at optimum BAP concentration, cultures were transferred to secondary medium with BAP (optimized concentration) supplemented with different auxins (indole acetic acid, indole butyric acid, and naphthalene acetic acid [NAA]). Murashige and Skoog medium enriched with 2.0 mg·L^-1 BAP showed the highest shoot induction response (83% ± 3.61%) with mean shoot number (4.67 ± 1.45) and shoot length of 4.33 ± 1.45 cm. Growth medium fortified with 1.0 mg·L^-1 α- NAA exhibited maximum rhizogenesis with 4.33 ± 0.88 roots and average root length as 5.50 ± 0.76 cm from regenerated B. amplexicaulis shoots. Acclimatized plants of B. amplexicaulis showed 90% survival. The projected protocol may serve as a treasured tool for the rapid and large-scale multiplication of elite B. amplexicaulis and for germplasm conservation to ensure continuous supply of this plant amid the increasing demand.