Synthesis of silver and cobalt nanoparticles and assessment of their effects on germination and biometric parameters in maize (Zea mays L.)

Nanomaterials composed of non-nutritive elements are gaining momentum in agriculture. In view of these advances, this study aimed to synthesize and assess the effects of silver (Ag) and cobalt (Co) nanoparticles as seed treatment in maize crops. Nanoparticles were synthesized by coprecipitation and characterized by X-ray diffractometry, transmission electron microscopy, surface area analysis, and Fourier-transform infrared spectroscopy. An experiment was carried out according to a completely randomized design with a 3 × 5 factorial arrangement. The factors were Ag and Co source (soluble, microparticle, and nanoparticle) and concentration (0, 20, 40, 80, and 160 mg L^-1). A total of 50 maize seeds were used per treatment. Seeds were placed on germination paper moistened with distilled water. Germination, biometric parameters (root and shoot lengths), and biomass production were evaluated. Characterization analyses showed that particles ranged from 20 to 100 nm in size and were composed of oxides, such as Ag₂O and Co₃O₄. Nanoparticle treatment improved germination and reduced the incidence of defects. The best results were achieved with 98-106 mg L^-1 Ag₂O and 75-80 mg L^-1 Co₃O₄. There was no significant change in biometric parameters between treatments.