Chitosan-silicon nanofertilizer to enhance plant growth and yield in maize (Zea mays L.)

We report a novel chitosan-silicon nanofertilizer (CS-Si NF) wherein chitosan-tripolyphosphate (TPP) nano-matrix has been used to encapsulate silicon (Si) for its slow release. It was synthesied by ionic gelation method and characterized by dynamic light scattering (DLS), fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic absorption spectrophotometry (AAS). The developed CS-Si NF exhibited slow release of Si and promoted gowth and yield in maize crop. Seeds primed with different concentrations of CS-Si NF (0.04-0.12%, w/v) exhibited up to 3.7 fold increased seedling vigour index (SVI) as compared with SiO₂. Its foliar spray significantly induced antioxidant-defence enzymes' activities and equilibrated cellular redox homeostasis by balancing O₂^-1 and H₂O₂ content in leaf as compared with SiO₂. Application of nanofertilizer (0.01-0.16%, w/v) stirred total chlorophyll content (21.01-25.11 mg/g) and leaf area (159.34-166.96 cm²) to expedite photosynthesis as compared with SiO₂. In field experiment, 0.08% CS-Si NF resulted in 43.4% higher yield/plot and 0.04% concentration gave 45% higher test weight as compared with SiO₂. Fecund and myriad effects of developed nanofertilizer over SiO₂ could be attributed to slow/protective release of Si from nanofertilizer. Overall, results decipher the enormous potential of CS-Si NF for its use as a next generation nanofertilizer for sustainable agriculture.