OXIDATIVE STRESS: A BIOLOGICAL TECHNIQUE FOR THE ASSAY OF CHROMIUM INDUCED PHYTOTOXICITYKiran Gupta, Sumati Gaumat and Kumkum MishraAbstract A study was performed to evaluate oxidative stress in response to Chromium [Cr(VI)] accumulation in Eichhornia crassipes. Plants treated with different concentration (0.0, 0.01, 0.1, 1.0, 2.5, 5.0 and 10.0 g ml-1) of Cr for 24, 48, 72 and 96 h accumulated significant (p<0.01) amount of Cr in a concentration duration dependent manner; which was more in roots (789.33 mg g-1 dw) than in leaves (335.6 mg g-1 dw). Cr induced oxidative stress was evident by increased level of hydrogen peroxide (H2O2), superoxide anion radical (O2) and MDA content. In contrast plants showed alleviated level of antioxidants in order to combat oxidative stress. Among enzymatic antioxidants, superoxide dismutase (SOD) and peroxidase (POD) activity increased upto 2.5 g ml-1 of Cr while catalase (CAT) showed sensitivity and increased only upto 1.0 g ml-1 Cr. On the other hand non enzymatic antioxidants (carotenoid and ascorbic acid content) scavenged free radicals efficiently showing elevation at all concentration and duration over control value. Therefore it can be concluded, E. crassipes can be utilized as a bioassay for phytotoxicity as well as bioindicator of polluted water bodies.
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