THE EFFECT OF SILICON FOLIAR AND ROOT APPLICATION ON GROWTH, PHYSIOLOGY, AND ANTIOXIDANT ENZYME ACTIVITY OF WHEAT PLANTS UNDER CADMIUM TOXICITY

Silicon (Si) application can boost plant growth and physiology under heavy metal toxicity. The article aimed to investigate how the foliar and root application of silicon (Si) affects the uptake, translocation, and concentration of cadmium (Cd) for winter wheat (Triticum aestivum L.), and in turn the plant's growth, physiology, and antioxidant enzyme activity, using a complete randomized block design (CRBD)? For this purpose, we used twelve treatments consisting of two levels of Si (0 and 3 mM Na2SiO3) against four levels of Cd (0, 50, 100, and 200 mu M CdCl2) with three replications. Results showed that all levels of Cd significantly enhanced membrane permeability measured as malonyldialdehyde (MDA) content, osmotic stress measured as hydrogen peroxide (H2O2) content, and triggered the enzymatic and non-enzymatic antioxidant system, resulting in a severe reduction in the growth of wheat seedlings. Besides, Si application either as root (SiR3) or foliar spray (SiF3) remarkably encountered Cd toxicity by further improving antioxidative enzymes activities, and by hindering Cd uptake, but more significant results were recorded for SiR3. Therefore, it might be established that Si root supplementation inhibited Cd translocation from root to shoot more effectively than foliar application, thereby lowering the potential health risk of Cd pollution.