Combined application of zinc oxide and iron nanoparticles enhanced Red Sails Lettuce growth and antioxidants enzymes activities while reducing the chromium uptake by plants grown in a Cr-contaminated soil

Abstract

Abstract Soils contaminated with chromium (Cr) have become a major ecological concern. Chromium poses serious health issues when become the part of our food chain. So, the key objective of the present experiment was to evaluate the impact of foliar applied zinc oxide nanoparticles (ZnO NPs) as varying levels (0, 25, 50, 100 mg L-1) as well as iron nanoparticles (Fe NPs) as varying levels (0, 5, 10, 20 mg L-1) on lettuce growth, biomass, photosynthetic process as well as essential nutrients and Cr uptake by lettuce plants under Cr stress. Foliar spray of ZnO and Fe NPs was applied as foliar spray and plants harvesting was done at maturity. Our results depicted that foliar application of ZnO NPs and Fe NPs improved the growth, photosynthesis, antioxidants enzymes activities and reduced the oxidative damage in lettuce plants by stimulating the antioxidative defense machinery. Additionally, application of ZnO and Fe NPs resulted in enhancement of Zn and Fe fortification in Red Sails Lettuce, respectively. Moreover, Zn and Fe NPs enhanced the uptake of the essential nutrients while limiting the Cr uptake by lettuce plants and Cr concentration in lettuce leaves was under the threshold limit for Cr.