Silicon-mediated enhancement of abiotic stress tolerance in cereal crops: Biochemical mechanisms and agronomic implications

Rice seedlings exposed to prolonged drought show severe leaf curling within days, yet the same cultivar treated with silicon maintains turgor for markedly longer. This research examined how silicon supplementation modulates biochemical defense pathways in cereal crops under drought and salinity stress. Two rice varieties (Tainung 67 and Taichung Sen 10) were grown under controlled greenhouse conditions with and without sodium silicate (1.5 mM) and subjected to drought (withholding irrigation) or salinity (100 mM NaCl) for 14 days. Silicon-treated plants retained 84.3% of shoot length and 79.6% of root biomass under drought compared to 62.4% and 58.7% without silicon. Antioxidant enzyme activities (SOD, CAT, APX) increased significantly in silicon-supplemented groups. Malondialdehyde content, a marker of lipid peroxidation, was reduced by 34.4% in silicon-treated drought-stressed plants. These results confirm silicon as an effective mediator of abiotic stress tolerance through enhanced antioxidant capacity and membrane stability.