Root growth of the seedlings of maize cultivars Premia and Blitz exposed to 2 µM cadmium (Cd), nickel (Ni) or both metals acting simultaneously (Cd + Ni) for 72 h was significantly reduced but not ceased. The effect was more pronounced in the seedlings of the cv. Blitz. The heavy metals (HMs) contents increased significantly in the roots. Simultaneous application of metals had an antagonistic effect on either Cd or Ni uptake in Premia but not in Blitz. In control roots the contents of ascorbic acid (AsA) and dehydroascorbic acid (DHA) were lower and gluthatione (GSH) content was higher in Premia than in Blitz. A decrease of AsA content was induced by all metal treatments in Premia but only by Cd + Ni in Blitz while an increase was induced by single metals in this cultivar. All metal treatments increased DHA contents in both cultivars. GSH content decreased significantly in Premia treated with Cd or Cd + Ni, and in Blitz treated with Ni. Unlike the contents of AsA, DHA and GSH, the increased metal concentrations in root cells did not affect the membrane potential (EM). The changes in antioxidant contents depended on both, maize genotypes and HMs treatments. Nevertheless, the results indicated a role of antioxidative system in minimizing the effects of oxidative stress and protecting cell membranes in both maize cultivars.

It is shown that for a maize the most effective protector of cadmium and nickel influence was zeastimulin, for a pea – agrostimulin.A protective function of emistim C for both cultures was insignificant. It is set that zeastimulin is influential in the increased metals absorption of a root system, however substantially (on 15% for a nickel and twice for a cadmium) reduces their translocation to above-ground part of plants. Previous treatment of pea seed by agristimulin also intensified the accumulation of nickel roots on 60% and did not influence on cadmium absorption and toxicants translocation to tissues of assimilatory organs. The protector role of growth regulators to cadmium and nickel joint influence shows up in the increase of ascorbic acid maintenance in the roots cells of both species to 34%, where as in leaves – at a maize resulted in the lowering of vitamin С amount (on 28%), but at a pea – increase on 20%.

Role of antioxidants in the protection against the combined effect of Cd, Zn, and Ni in wheat

No abstract