IN VITRO EVALUATION OF ANTIOXIDANT POTENTIAL UNDER DROUGHT STRESS IN ENDANGERED DROUGHT STRESS IN ENDANGERED DROUGHT STRESS IN ENDANGERED WITHANIA SOMNIFERA

Abstract

The competence of any plant in regard to the antioxidant potential is of immense value.With this background the present investigation was carried on callus of different genotypes of Withania somnifera to check the antioxidant potential under drought stress as it is best expressed under such conditions. Genotypes responded positively in terms of increased antioxidant activity under stress. An enhancement of 213.51 and 200% in SOD activity was observed in case of genotype Nimitly after 15 and 30 days of stress respectively while of 24.30 to 37.37% for other genotypes after 15 days and 10.73 to 40.74% after 30 days. Best results in CAT activity were found at 1% PEG showing 274.88 > 199.85 > 155.58 > 66.68% enhancement in genotype Nimitly, J-20, Pratap and Chetak respectively after 15 days. PEG application also brought about an increment in non enzymatic antioxidant content. Here genotype Pratap found superior with maximum of 118.23 and 112.53% enhancement in Phenol and flavonoid content respectively. Increasing stress levels was also established as beneficial in improving ascorbate activity but it was found to be enhanced only up to 1% PEG level with a little increment of 5.97 to 12.72%. Conclusively Withania somnifera is a plant of higher antioxidant potential (either enzymatic or non enzymatic) and hence hold great medicinal importance even at callus level Abbreviations : SOD - Superoxide dismutase, CAT- Catalase, PEG - Polyethylene glycol, ROS - reactive oxygen species, GAE - Gallic acid equivalent, 2,4-D - 2,4 dichloro phenoxy acetic acid, BAP-6 benzyl amino purine, PGRs-Plant growth regulators, DAI – Days after inoculation, DAT- days after treatment