Zinc-Selenium nanocomposite enhances drought tolerance in pearl millet by improving photosynthesis

Pearl millet (Pennisetum glaucum L.) is grown in arid and semi-arid regions of the world as a staple food crop owing to its better adaptability to different climatic conditions and nutrition. Due to climate change, occurrence of drought is becoming more frequent and in pearl millet, this drought stress at critical growth stages significantly reduces the yield. This generates the need to produce an appropriate technology for enhancing drought tolerance. Research shows that nanotechnology can provide an effective solution in the form of nanoparticle application. Previous studies have shown that foliar application of zinc-selenium quantum dot in maize under drought stress has shown to significantly enhance its drought tolerance. The pot culture experiment was conducted by adopting Factorial Completely Randomized Design (FCRD) design to evaluate the effect of zinc-selenium nanocomposite foliar application in mitigating the ill effects of drought stress in pearl millet at its peak vegetative stage. The zinc-selenium (Zn-Se) nanocomposite was applied at different doses which included 0 mg L-1 (water sprayed) as control, 5 mg L-1, 10 mg L-1, 15 mg L-1 and 20 mg L-1. Foliar application significantly reduced the impact of drought stress on growth and physiology of plant. It enhanced photosynthetic rate, transpiration rate, stomatal conductance, Fv/Fm ratio, plant height and plant girth compared to control plants. Also it reduces leaf temperature and F0 values in sprayed plants as compared to control. The study indicates that zinc-selenium nanocomposite at 20 mg L-1 was most effective in mitigating drought stress. Hence it can be concluded that foliar application of zinc-selenium nanocomposite at 20 mg L-1 can effectively enhance drought tolerance by stabilizing the photosynthesis associated traits thereby reducing the effect of drought stress in pearl millet at its peak vegetative stage.