Comparative efficacy of foliar-applied biogenic copper and iron nanoparticles for mitigating salinity stress in chickpea ( Cicer arietinum L. )

Plant synthesized iron oxide nanoparticles (FeO NPs) and copper nanoparticles (Cu NPs) were evaluated to promote chickpeas growth under salt stress. The characterization of the FeO NPs and Cu NPs was carried out by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) analysis. Foliar applications of FeO (100 mg/L) and Cu NPs (75 mg/L) significantly improved chlorophyll (47% & 40%), carotenoids (59% & 56%), and total soluble sugars (36% & 30%) compared to the control. Growth parameters increased 31% to 53% by 100 mg/L FeO and 27% to 53% by 75 mg/L Cu NPs compared to the control. Similarly, the antioxidant’s superoxide dismutase, peroxidase, and ascorbate peroxidase were significantly increased, while malondialdehyde, hydrogen peroxide, and superoxide radical (O2–) were significantly decreased. Both NPs significantly reduced sodium (Na) concentration in roots (145% & 48%) and shoots (234% & 78%), while increasing potassium (70% & 51%) and calcium (71% & 47%) concentrations. Additionally, zinc and manganese uptake improved by 63% and 82% with FeO, and 56% and 76% with Cu NPs, respectively. The findings suggest that foliar application of biogenic FeO and Cu nanoparticles is dose-dependent with potential to reduce salinity stress in chickpea plants.