Cadmium treatment effects on the growth and antioxidant system in barley plants under optimal and low temperatures

<p>The cadmium effect (100 μM) on the barley (<em>Hordeum vulgare</em> L.) growth, the content of <em>HvCu/ZnSOD</em>, <em>HvCAT2</em> and <em>HvPRX07</em> transcripts and the antioxidant enzymes activity (SOD, CAT and PRX) in roots and leaves of seedlings under optimal (22 °C) and low (4 °C) temperatures were studied. Exposure to cadmium at 22 °C did not inhibit the plants’ growth. In this case, the rate of the oxidative processes in the cells remained at the control level. This was achieved by a corresponding increase of the gene<em> </em>transcripts and the antioxidant enzymes activity in roots and leaves. In contrast, exposure to cadmium at 4 °C inhibited the seedlings’ growth despite of the lower metal content in the plants. Moreover the rate of lipid peroxidation in the roots and leaves increased significantly. It is assumed that this effect was connected with the accumulation of excess amounts of hydrogen peroxide due to a misbalance between its generation and neutralization. This assumption is confirmed by the obtained data, according to which the level of <em>HvCu/ZnSOD </em>expression and the total activity of SOD increased significantly under exposure to cadmium at 4 °C, although <em>HvCAT2</em> and <em>HvPRX07</em> transcripts and CAT and PXR activity did not rise.</p>