Silicon Nutrition for Ameliorating Chromium Toxicity in Maize (Zea mays L.) by Suppressing Absorption and Translocation to Aerial Plant Tissues

Soil contamination with chromium (Cr) is posing a severe threat to global food security and safety. Conventional strategies being used to combat Cr toxicity are costly, destructive and environmentally problematic. The present study aimed to evaluate silicon (Si) nutrition for ameliorating Cr toxicity in maize (Zea mays L). Experimental plan comprised of four Cr levels, i.e. control (Cr₀), 5 mg kg⁻¹ (Cr₅), 10 mg kg⁻¹ (Cr₁₀) and 25 mg kg⁻¹ (Cr₂₅), and three Si levels including control (Si₀), 15 mg kg⁻¹ (Si₁₅) and 30 mg kg⁻¹ (Si₃₀) with three replications. Maize cultivar Hycorn-339 was used. Each pot was filled with 25 kg soil. Harvesting was done 30, 60 and 120 days after sowing. Cr contamination significantly (p ≤ 0.05) increased Cr concentration in plant tissues with a decrease in plant growth, yield and physiological characteristics, highest reduction with Cr₂₅. The said treatment decreased photosynthetic rate (P_n) by 42%, transpiration rate (T_r) 35%, stomatal conductance (G_s) 31%, relative water content (RWC) 32% and membrane stability index (MSI) 30% compared with Cr₀. Si nutrition alleviated the deleterious effects of Cr on maize growth and yield by decreasing its absorption while increasing retention in roots and subsequently restricting its translocation from roots to aerial plant parts. Si₃₀ improved P_n by 16%, T_r 19%, G_s 14%, RWC 12%, MSI 15% and grain yield 19% at Cr₂₅ compared to Cr₂₅ without Si. It was concluded that Si could ameliorate Cr toxicity in maize by restricting its absorption and translocation from roots to aerial plant tissues.