Effect of Silicon Fertilization on Plant Growth and Drought Stress Tolerance in Wheat (Triticum aestivum).

The ability of crops to maintain high yield under drought stress is crucial in agricultural lands with scarce supply of water. The aim of this study was to investigate the efficacy of applied silicon (Si) in alleviating drought stress in wheat plants. Silicon amendments were applied to the soil before sowing and drought stress was applied by withholding watering throughout a week before flag leaf emergence. Foliar treatments were applied five times at one week intervals before the flag leaf emergence. All treatments were replicated four times and arranged in a randomized complete block design. Silicon uptake, distribution of silica bodies on leaf surface, chlorophyll, anthocyanin, proline, and lipid peroxidation contents were measured in wheat plants treated with different sources of Si: two Si granular sources (wollastonite – 23% Si and slag – 12% Si) applied at 504 kg Si ha^-1, foliar spray solution containing 60 mg Si L^-1 and no Si treatment as control. It was observed that wollastonite and slag effectively mitigated the adverse effects of drought on wheat than foliar Si treatments. Wollastonite application significantly increased plant fresh weight and chlorophyll content in stressed wheat plants. Lipid peroxidation and anthocyanin contents were significantly reduced by up to 50% compared to non-treated plants (p<0.05). A significant reduction in proline content was also observed in Si treated plants compared to non-Si treated plants under drought stress. The concentrations of Si determined by wet digestion in biomass samples was significantly different between Si treated and non-Si treated plots. The distribution of silica bodies based on SEM/EDX analysis showed that plants treated with Si had significantly higher Si bodies than those not treated with Si. These findings suggest that Si can improve physiological attributes of wheat plants and alleviate the adverse effects drought stress.