Salt stress in agricultural soils is a global issue and little information is available about the efficiency of silver nanoparticles (AgNPs) in plants under salt stress. The aim of current study was to assess the efficacy of AgNPs in improving plant growth and reducing the salt-induced damages in pearl millet. The exposure of pearl millet plants grown in pots containing soil to different doses of salinity (0, 120, 150 mM) and AgNPs (0, 10, 20 and 30 mM) significantly influenced the morphology, physiology and yield-related attributes. Salt stress remarkably increased the concentration of sodium (Na) and chloride (Cl) in different organs of pearl millet plants. This led to increase the enhancement of hydrogen peroxide (H2O2) and malondialdehyde (MDA) content and caused severe oxidative damage by augmenting the activities of antioxidant enzymes. The obvious decrease in plant growth, height, dry biomass of root and shoot, chlorophylls and carotenoid contents was observed in salt-stressed plants which ultimately reduced the yield of plants. The AgNPs remarkably improved the plant growth by reducing oxidative stress and Na and Cl uptake by salt-stressed plants. The AgNPs were also found to maintain the ionic balance of cell (Na+, K+ and Na+/K+ ratio). The AgNPs improved the superoxide dismutase, catalase activities and decreased the peroxidase activity while reduced the H2O2 and MDA contents in plants under salt stress. Overall, AgNPs increased the plant height, yield, and photosynthesis of salt-stressed plants in a dose-additive manner.
Keywords: Antioxidative enzymes; Biomass; Pearl millet; Photosynthesis; Salt stress; Silver nanoparticles.