The role of zinc to mitigate heavy metals toxicity in crops

Abstract

Heavy metal (HM) contamination is a serious concern across the globe, and in recent times, HMs’ intensity has significantly increased, posing a serious threat to crop growth and productivity. Heavy metals pose serious health issues in humans by entering the human food chains. Therefore, it is direly needed to reduce the effects of HMs on plants and humans by adapting appropriate practices. In this context, application of micronutrients can be an essential practice to mitigate the toxic effects of HMs. Zinc (Zn) is a crucial nutrient needed for plant growth, and Zn application reduced the HM-induced toxicity in plants. This review highlights Zn’s role in mitigating the HMs toxicity in plants. We have systematically described the potential mechanisms mediated by Zn to mitigate HMs in plants. Zinc application reduced the HMs uptake and translocation plants, which is considered an essential mechanism of HM stress tolerance. Zn application also improves membrane stability, plant water relationship, nutrient uptake, photosynthetic performance, osmolytes accumulation, anti-oxidant activities, and gene expression. In addition to this, the Zn application substantially improves photosynthesis by enhancing the synthesis of photosynthetic pigments, photosystem activities, enzymatic activities, and maintaining photosynthetic apparatus structure, ensuring better growth under HM stress. Therefore, Zn nutrition could improve the plant performance under HM stress by modulating the plant’s physiological and biochemical functioning, anti-oxidant activities, osmolytes accumulation, and gene expression.