ARSENIC EFFECTS ON LIPID PEROXIDATION AND ANTIOXIDATIVE ENZYME ACTIVITIES IN BARLEY CULTIVARS ROOTS

Antioxidant enzymes are related to resistance to various abiotic stresses including heavy metal stress. In this study, physiological parameters of Sladoran and Balkan 96 species of barley (Hordeum vulgare) Arsenic (As) such as germination rate, root length and dry and wet weight were evaluated in 10 mu M (low and non-toxic dose) and 50 mu M (high and toxic dose) two concentrations, its effect on antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APx), Guaiacol peroxidase (GPx) in root tissue of arsenic and effect on lipid peroxidation which is an important determinant of oxidative stress were evaluated, the effect of barley on arsenic toxicity was analyzed in biochemical sense. Parallel to dose increase, arsenic inhibits root growth in both species of barley, dry and wet weight decreased distinctly, it caused lipid peroxidation in the roots. Besides, against oxidative stress caused by arsenic, barley reacted in root tissue with changes in antioxidative enzyme activities such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APx), Guaiacol peroxidase (GPx). While there was a significant (p<0.005) decrease in activities of APx and CAT enzyme activities, there was increase in SOD enzyme activities. There was no significant change in GPx enzyme activity. The results of the present experiment coincided with the conclucion that As may be involved in the metabolic or physiological changes in plants.