HEAVY METALS LEAD, CHROMIUM, AND COPPER IN CEREAL CROPS: SOURCES, ROLES, IMPACTS, STRATEGIES

Abstract

Heavy metals are metal elements generally harmful to human health and the environment. Heavy metals can cause stress and toxicity to plants, including cereal crops. Sources of heavy metals can come from nature or anthropogenic activities such as industry and agriculture. Heavy metals can accumulate in the environment and enter the food chain, thus endangering human health. It is very harmful to plants because it can cause reduced growth, deformation of cellular structures, ion homeostasis, decrease chlorophyll biosynthesis and photosynthesis, cause hormonal imbalances, and induce excessive production of reactive oxygen species (ROS) in plants. Heavy metals such as lead (Pb), chromium (Cr), and copper (Cu) have direct toxic effects on the growth and development of cereal crops. Strategies are needed to reduce the negative impact of heavy metal stress by using organic materials such as manure, compost, or biochar to reduce heavy metal levels in the soil. In addition, microorganisms such as phosphate-solubilizing bacteria, endophytic bacteria, and arbuscular mycorrhizal fungi can bind heavy metals and increase plant tolerance to heavy metal stress.