Micropropagation of Withania coagulans (Stocks) Dunal: A Critically Endangered Medicinal Herb

An efficient micropropagation protocol has been developed for Withania coagulans, a highly endangered medicinal herb and an important natural source of withanolides. Prolific multiplication of axillary buds occurred from the nodal segments taken from adult plant, and cultured on MS medium enriched with BA (0.5 mg l⁻¹), Kn (0.5 mg l⁻¹) and PG (0.5 mg l⁻¹). Nodal segments and shoot tips of elongated microshoots also behaved the same way in cultures and formed multiple shoots through axillary bud multiplication. Addition of PG (0.5 mg l⁻¹) in the regeneration medium significantly improved induction and elongation of shoot buds. Elongated shoots were placed on filter paper bridges soaked in MS medium with CC (10 mg l⁻¹) and PG (0.5 mg l⁻¹) for the initial 7 days’ pulse treatment and thereafter, they were transferred to rooting medium containing IBA (0.25 mg l⁻¹) + PAA (0.5 mg l⁻¹) + CC (2 mg l⁻¹). This protocol has the capacity of producing 1000 plants from one nodal segment after 4 subcultures of 2 weeks each.