Exploring the potential of green synthesized cerium oxide nanoparticles in mitigating chromium toxicity in maize

Problem: Chromium (Cr) contamination in agricultural soils poses a significant threat to maize productivity and food security, necessitating the development of innovative strategies to enhance Cr tolerance and mitigate its toxic effects on plant growth and development. Objective: The aims of current study are the green synthesis of cerium oxide nanoparticles (CeO 2 NPs) using Jasminum officinale L. plant extract and their application to alleviate chromium stress in maize plants. Methods: Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and elemental mapping methods were used to characterize the synthesized CeO 2 NPs. The cerium oxide NPs (0, 25, 75 and 100 mg/L) treatment levels applied through foliar and seed priming to check growth, physiological responses and metal uptake by maize plants and a fully random design was used to set up a factorial experiment. Results: The findings showed that foliar application of 100 mg/L CeO 2 NPs resulted in an improvement in the plant height (43 %), shoot fresh plant (41 %) and root fresh weight (84 %), and total chlorophyll concentrations (67 %) in maize plants as compared to seed priming (as 25, 32, 40 and 43 % respectively). It also effectively enhanced antioxidant enzymes including super oxide dismutase (75 %) and peroxidase (79 %). In maize plants, by foliar application over the control, CeO 2 NPs reduce electrolyte leakage (53 %), malondialdehyde contents (32 %), and chromium content in roots (70 %) under chromium stress. Conclusion: Therefore, these results suggested that increase in the concentration of CeO 2 NPs more efficiently 100 mg/L has high ability against chromium stress and act as a promising solution to reduce metal concentration, enhance maize growth and promote sustainable agriculture. Significance: This study 's implications for future research on CeO 2 NPs include elucidating their mechanisms in plant stress tolerance, exploring interactive effects with heavy metals, and expanding their use in plant stress management. Furthermore, this finding develops a novel strategy for improving maize cultivation in Crcontaminated soils, contributing to sustainable agriculture and food security.