Environmentally benign synthesis of phytochemicals-capped gold nanoparticles as nanopriming agent for promoting maize seed germination

Application of nanotechnology in agriculture is moving towards to improve the cultivation and growth of crop plants. The present study is the first attempt to propose a simple, yet cost-effective and ecofriendly synthesis of phytochemicals-capped GNPs using rhizome extract of galanga plant at room temperature. The synthesized GNPs were characterized by various characterization techniques. To promote the green nanotechnology applications in agriculture, GNPs solution at environmentally realistic dose (5 to 15 ppm) as nanopriming agent was used to activate the germination and early seedling growth of maize aged seeds. Priming with 5 ppm GNPs showed the best effects on promoting emergence percentage (83%) compared to unprimed control (43%) and hydroprimed groups (56%). Seed priming at both 5 and 10 ppm GNPs also enhanced seedling vigor index by 3 times over the control. Priming with GNPs at 10 ppm was found to enhance the best physiological and biochemical properties of maize seedlings. Internalization studies by inductively coupled plasma atomic emission spectroscopy (ICP-OES) and transmission electron microscopy (TEM) strongly supported that GNPs can internalize into seeds. However, ICP-OES analysis revealed that GNPs were not present in both shoot and root parts, suggesting that nanopriming approach minimizes the Au translocation from seeds into plant vegetative organs. Phytosynthesized GNPs were found to be less toxic than chemically synthesized GNPs. This is the first report showing phytochemicals-capped GNPs as a promising nanopriming agent for activating the germination of naturally aged seeds of crop plant. (C) 2016 Elsevier B.V. All rights reserved.