Effect of sodium salicylate treatment on physiological and biochemical parameters of wheat seedlings under the influence of heavy metals

The objective of this work was to study the effect of cadmium sulfate and zinc sulfate on the growth and development of common wheat plants (Triticum aestivum L.) of the Moskvich variety. In order to determine the physiological and biochemical parameters of seedlings and the possibility of regulating their resistance to the stress factor, preplanting treatment of seeds with sodium salicylate (СNa) was carried out. Wheat seeds had been germinating in a solution of 0.1 mM СNa for 3 days at a temperature of 21–23 ºС and under a 16-hour daily illumination of 3000 lux illuminance. On the 4th day, the seedlings were transferred to plastic containers, where they continued to grow in a climatic chamber under periodic irrigation with solutions of CdSO4 and ZnSO4 salts with a concentration of 10-6-10-3 M. On the 7th day of the experiment, the length and fresh weight of the root system and shoots of the seedlings were measured, alongside with the lipid peroxidation (LPO) activity and the enzyme activity superoxide dismutase (SOD) in the cells of the leaves, as well as the content of proline in the leaves and roots of wheat seedlings. It has been found that for establishing the differences in the effect of cadmium and zinc ions on wheat plants using only biometric indicators is not sufficient. In our studies, the determination of LPO activity and proline content served as an indicator of the development of oxidative stress in the cells of wheat seedlings under the influence of CdSO4 and ZnSO4. At the same salt  concentrations, only CdSO4 contributed to increased LPO activity and the formation of proline, which could be a signal for triggering the protective reactions of the cell. The low SOD activity under these conditions is probably resulting from the fact that it is proline that reduces the formation of reactive oxygen species either by terminating the cascade of free radical reactions or by inhibiting the CdSO4 enzyme. ZnSO4 salt is less toxic, since in the same range of concentrations it does not cause an increase in the content of LPO and proline products. The influence of CNa on these parameters depended on the nature of the heavy metal and the strength of its action, and produced both pro- and antioxidant effects, both provoking oxidative stress or protecting against it.

sodium salicylate, lipid peroxidation, proline, superoxide dismutase, heavy metals