Silicon Application Modulates Growth, Physio-Chemicals, and Antioxidants in Wheat (Triticum aestivum L.) Exposed to Different Cadmium Regimes.

Silicon (Si) application enhanced the tolerance of plants against different environmental stresses. Therefore, objective of the study revealed that foliar applied Si alleviates the adverse effect of Cd by enhancing the growth, metabolite accumulation, strengthening the antioxidant defense system, reducing oxidative injury, improving plant nutrient status, and decreasing the Cd uptake in wheat. The surface sterilized seeds of Sahar-2006 (tolerant) and Inqalab-91 (sensitive) having the differential metal tolerance capacity were sown in plastic pots containing normal and Cd spiked sandy loamy soil. The design of experiments was completely randomized with 3 replicates per treatment. Two weeks after germination, plants were sprayed with different concentrations of Si (1.5 and 3 mM) with 0.1% surfactant in the form of Tween-20. The plants were harvested after 2 weeks of Si application to determine various attributes. High concentration of Cd (25 mg kg-1) decreased growth-related-attributes, essential nutrient uptake and increase the levels of oxidative stress indicators. The application of Si increased the growth-related attributes, photosynthetic pigments, essential nutrient uptake and also enhanced the activities of various antioxidant compounds (superoxide dismutase (SOD), peroxidase (POD, ascorbate peroxidase (APX) and catalase (CAT) by decreasing the contents of oxidative stress indicators and Cd uptake in root and shoot of both wheat cultivars. Sahar-2006 cultivar showed more tolerance to Cd regimes than that of Inqalab-91 as clear from greater plant dry masses. Thus, our results showed that the applied Si level (3 mM) is an efficient strategy for field use in the areas, where slightly Cd polluted soils limit the agriculture production.