The Physiological Effect of Foliar Spraying of Zinc Nanoparticles in Reducing the Harmful Effects of Cadmium on Faba Bean Plants

Heavy metal pollution is the one of the most important factors that limit the growth and yield of faba bean plants in the world. In recent years, nanotechnology has showen promising result in reducing the harmful effects of heavy metal stress on various crops such as peas (Pisum sativum), faba beans (Vicia faba leguminosae). This experiment aimed to study the effect of foliar spray of zinc nanoparticles (ZnO NPs) at two concentrations (100 and 200 ppm) on the growth parameters shoot length, root length, fresh and dry weight of shoots and roots, and leaf area of faba bean plants. In addition, the content of chlorophyll and carotenoids were measured under Cd stress (20 and 100 ppm). The samples were collected twice, 15 and 30 days after treatments. The results showed that Cd had adverse effects on shoot and root lengths, shoot fresh and dry weights, root fresh and dry weights, and leaf area. The treatment with ZnO NPs significantly reduced the side effects of Cd on the level of growth parameters at two stages. ZnO NPs 200 was more effective than ZnO NPs 100. From our results, ZnO NPs can be used to mitigate the Cd stress in agricultural soils.