Green-Synthesized Nanoparticles Enhanced Seedling Growth, Yield, and Quality of Onion (Allium cepa L.)

Green nanotechnology is rapidly expanding in sustainable precision agriculture that promises to revolutionize food production. In the present study, nanoparticles (NPs) were synthesized using a green process involving the use of onion extracts as reducing agents. Silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were synthesized using onion extract and characterized by UV-vis spectrophotometry, dynamic light scattering technique, X-ray diffraction, transmission electron microscopy, and liquid chromatography-mass spectrometry. In addition, two nanoemulsions were also prepared from turmeric oil and citrus oil using a low energy method based on spontaneous emulsification. These NPs and emulsions were used for priming aged onion seeds. Internalization studies conducted by instrumental neutron activation analysis and gas chromatography-mass spectrometry revealed that the treated nanoparticles and nanoemulsions were internalized into onion seeds. Multiple greenhouse and field studies demonstrated enhanced seed germination, emergence, growth, and yield compared with unprimed and hydroprimed seeds. Seed priming with AuNPs showed a significant change in emergence percentage (63.2%) compared to unprimed control (37.4%) during combined analysis of both year experiments. An average yield increase of 23.9% was observed in AuNPs treated onion, as compared to unprimed onion. The results of the present study demonstrate safe and sustainable use of nanomaterials in agriculture.