Rapid green synthesis of silver nanoparticles from blue gum augment growth and performance of maize, fenugreek, and onion by modulating plants cellular antioxidant machinery and genes expression.

Nanotechnology applications are increasingly utilized to improve crops. Besides their use as antifungal and antimicrobial agents, silver nanoparticles (AgNPs) are currently exploited to improve seed germination, plant development, and photosynthetic efficiency. In the current study, we evaluated the effect of biosynthesized AgNPs in the seedlings of Zea mays L., Trigonella foenum-graecum L., and Allium cepa L. AgNPs were biosynthesized in the blue gum (Eucalyptus globules) leaves and characterized by UV–Visible spectra, Fourier Transform Infrared (FTIR), and Scanning Electron Microscopic analyses. The biosafety of the AgNPs was tested by cytotoxicity assay, antibacterial activity, and determination of MIC and MBC. The effects of biogenic AgNPs application at different concentrations (25, 50, 75 < and 100 mg L−1) on seed germination, seedling growth, oxidative stress status, and antioxidant enzyme activities were studied. Applications of AgNPs significantly improved seed germination and growth of Z. mays L., T. foenum-graecum L., and A. cepa L. (p < 0.05). Notably, growth was stimulated by an increase in the concentration of AgNPs. Applications of AgNPs also enhanced the activity of antioxidant enzymes, including catalase, peroxidase, and ascorbate peroxidase as well as glutathione and ascorbate contents, whereas the malondialdehyde content was reduced by increasing the concentration of AgNPs. The expression levels of antioxidant enzymes were upregulated in AgNP-treated seedlings compared with those of the control. Our study demonstrated that the application of silver nanoparticles significantly enhanced seed germination and antioxidant machinery and improved the early growth characteristics in both monocot and dicot crops.