engleski

Oxidative stress response in tobacco experimentally exposed to cadmium and zinc

Because of their persistence, heavy metals of either natural or anthropogenic origin are considered to be the most common environmental pollutants. Therefore, the effects of 10 and 15 μM cadmium (Cd), a nonessential toxic element and 25 and 50 μM zinc (Zn), an essential micronutrient, was investigated in tobacco plants after exposure to each metal alone or to their combinations. The assessment of Cd and Zn contents, in both shoots and root of tobacco plants, showed that both metals accumulate with time, but when present in combination, they reduced uptake of each other. As result, leaves exhibited oxidative stress in all treatments except the one with individual Zn concentrations. In roots, increased MDA and protein carbonyl content was recorded after treatment with either 10 or 15 μM Cd, although in combined treatments 25 and 50 μM Zn significantly reduced measured values. Among the investigated antioxidative enzymes, activity of SOD, PPX and APX was elevated in both leaves and roots after exposure to either Cd concentration, whose effect was substantially alleviated by addition of Zn. Interestingly, CAT activity failed to show any difference between applied treatments in leaves, while in roots CAT activity was significantly reduced in all treatments compared to control. In conclusion, combined treatments showed lower values of oxidative stress parameters in comparison to treatments with either metal alone, which indicates alleviating effect of Zn on oxidative stress in Cd-treated plants.

oxidative stress; tobacco; cadmium; zinc

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