IN VITRO REGENERATION OF GROUNDNUT: CHANGES IN ANTIOXIDATIVE ENZYMES AND HISTOLOGICAL STUDIES

Reactive oxygen species (ROS) produced during stress responses are implicated in a number of cellular responses including morphogenesis. The present study was undertaken to study the changes in antioxidative enzymes during in vitro morphogenesis of groundnut from de-embryonated cotyledon explants cultured on Murashige and Skoog’s medium supplemented with 5.0 mg l^-1 benzyl-adenine and 2.0 mg l^-1 2,4-dichlorophenoxyacetic acid. During the early in vitro ontogenic stages of groundnut, the activity of peroxidase (POD) and polyphenol oxidase (PPO) increased from stage 0 (0 day) to stage II (14 days) and decreased during stage III (25 days) and stage IV (45 days). The activity of superoxide dismutase (SOD) showed an inverse trend. The results could be correlated with the acquisition of competence, de-differentiation, division and induction which occurred during shoot organogenesis. Histological studies also showed that the mode of in vitro morphogenesis from the groundnut explants was via shoot organogenesis. In light of the above study, it could be concluded that the change in activity of the antioxidative enzymes studied could be used as a marker to characterize the mode of plant regeneration.