Influence of thidiazuron on somatic embryogenesis and physio-biochemical studies of Withania somnifera L. dunal

Using nodal segments, an effective approach for in vitro regeneration of a multi-medicinal plant -Withania somnifera via direct somatic embryogenesis was investigated. The embryogenic potency of nodal segments was tested on Murashige and Skoog (MS) medium augmented with various doses of thidiazuron (TDZ) (0.8-3.5 μM). 2.0 μM TDZ was found more potent than other concentrations as maximum rate of somatic embryos was recorded in this treatment. All the steps i.e. initiation, elongation and sprouting of somatic embryos from explants was achieved in the same treatment. About 85% of the somatic embryos germinated into complete plantlets. The plantlets were acclimatized successfully with 92% survival in greenhouse. Histological analysis confirmed that somatic embryos were protruded directly from the surface of explants. Different physiological and antioxidative enzymes activities were also analyzed at various period of acclimatization and showed positive signs towards the protection of micropropagated plants against stress developed during acclimatization to natural conditions.