THE EFFECT OF LEAD TOXICITY ON GROWTH AND ANTIOXIDANT ENZYME EXPRESSION OF ABUTILON INDICUM L

Objective: The focus of the present study was to analyse the oxidative effects of lead nitrate on biosynthesis of antioxidant enzyme activities (superoxide dismutase (SOD) and glutathione peroxidase (GPX)) in Abutilon indicum. Methods: Seedlings of A. indicum were grown with supplementation of different concentrations (0, 25, 50, 75 and 100 μM) of lead nitrate for 15 and 30 days. The various growth parameters like shoot length, size and total number of leaves per plant were recorded. Extraction, assay and expression of super oxide dismutase (SOD) and glutathione peroxidase (GPX) were carried out with control (without metal salt) and lead nitrate treated plants.Results: The growth parameters exhibited a declining trend in the metal treated plants in a dose dependant manner. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of leaf and root protein extracts exhibited the appearance of some new proteins due to metal stress. At lower concentrations of the metal, antioxidant enzyme activity was enhanced with a gradual declination of higher concentration (75 and 100 μM). The enzyme activity reflects the deleterious impact of lead on the plants. Isoforms of SOD and GPX were separated using non-denaturing polyacrylamide gel electrophoresis and new isoforms were noticed in the stressed plants rather than the control during the investigation.Conclusion: Isoforms of the antioxidant enzymes synthesized due to Pb stress may be used as biomarkers for analysing the impact of heavy metals on other medicinal plants under metal stress condition.Â