Effects of Mercury and Chromium on Peroxidase and IAA Oxidase Enzymes in the Seedlings of Phaseolus vulgaris

Authors : Nayna G PARMAR, Sumitra V CHANDA

Pages : 15-21

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Publication Date : 2005-12-01

Article Type : Research Paper

Abstract :Phaseolus seedlings insert ignore into journalissuearticles values(Phaseolus vulgaris L.); in light conditions were treated with 2 different concentrations of 2 heavy metals, mercury insert ignore into journalissuearticles values(0.05 mM and 0.4 mM); and chromium insert ignore into journalissuearticles values(0.5 and 1.0 mM);. Mercury was given in the form of HgCl2 and chromium was given in the form of K2Cr2O7. Peroxidase activity was measured with 4 different hydrogen donors insert ignore into journalissuearticles values(ferulic acid, caffeic acid, pyrocatechol and pyrogallol);. Both mercury and chromium inhibited root and hypocotyl length. The inhibition was about 50%-80%, depending on the concentration of the heavy metal. Peroxidase and IAA oxidase activities showed a clear inverse relation with growth. Seedlings treated with a lower concentration of mercury had similar activities to those treated with higher concentrations of chromium. The role of peroxidase and IAA oxidase activities in defense mechanisms in response to heavy metal toxicity is discussed.
Keywords : chromium, mercury, metal toxicity, peroxidase activity, defense mechanism