Growth and physiological responses of maize (Zea mays L.) to porous silica nanoparticles in soil

The present study aims to explore the effect of high surface area (360.85 m² g⁻¹) silica nanoparticles (SNPs) (20–40 nm) extracted from rice husk on the physiological and anatomical changes during maize growth in sandy loam soil at four concentrations (5–20 kg ha⁻¹) in comparison with bulk silica (15–20 kg ha⁻¹). The plant responses to nano and bulk silica treatments were analyzed in terms of growth characteristics, phyto compounds such as total protein, chlorophyll, and other organic compounds (gas chromatography–mass spectroscopy), and silica accumulation (high-resolution scanning electron microscopy). Growth characteristics were much influenced with increasing concentration of SNPs up to 15 kg ha⁻¹ whereas at 20 kg ha⁻¹, no significant increments were noticed. Silica accumulation in leaves was high at 10 and 15 kg ha⁻¹ (0.57 and 0.82 %) concentrations of SNPs. The observed physiological changes show that the expression of organic compounds such as proteins, chlorophyll, and phenols favored to maize treated with nanosilica especially at 15 kg ha⁻¹ compared with bulk silica and control. Nanoscale silica regimes at 15 kg ha⁻¹ has a positive response of maize than bulk silica which help to improve the sustainable farming of maize crop as an alternative source of silica fertilizer.