engleski

Effects of Mercury, Cobalt and Manganese on Pea Seedlings

Exposure of plants to excess concentrations of heavy metals, both essentials and non essentials, results in oxidative injury. In this study the effect of mercury (Hg), cobalt (Co) and manganese (Mn) toxicity on pea seedlings was investigated. Antioxidant enzyme activity, catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX), as well as photosynthetic pigment content and protein content were measured in roots and shots of pea seedlings after 7 days of exposure with Mn, Co and Hg concentration of 100 µM. All treatments caused an increase in photosynthetic pigment content. The greatest reduction in protein content was in response to Hg (93% roots, 17% shots) while Co increased protein content of both roots and shots. The most pronounced increase in specific enzyme activity was in roots of Hg exposed plants (11-fold CAT, 22-fold APX and 18- fold GPX). APX and GPX activity in shots increased significantly (p<0.05) in treatment with Mn and Co, while an approximately 50% reduction in CAT activity occurred in all treatments. Exposure of pea seedlings to equal concentrations of Hg, Co and Mn revealed different responses of roots and shots.

heavy meal; toxicity; pea; stress

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