ABSTRACT
Heavy metals can be essential, expensive, and radioactive, and their influence on humans and the environment depends upon their properties and exposure. Essential heavy metals play a crucial role in physiological and biochemical functions in living organisms. Heavy metals are found naturally; however, they may be released due to various natural actions in the environment. In recent years, anthropogenic activities caused the undesirable release of heavy metals into the environment affecting both humans and vegetation. Major impacts in the environment can be considered in terms of phytotoxicity due to the excess formation of reactive oxygen species (ROS) causing oxidative stress. They disrupt various metabolic processes of the plants. Generally, heavy metals are considered to be stable and bioaccumulate, causing more adverse effects. Plants can uptake heavy metals majorly from the soil, contaminated irrigation water, and foliar deposition. The excess formation of ROS affects the plants’ physiological, biochemical and metabolic activities, and ultimately the yield and biomass of major crops. Various mitigating measures such as the development of transgenic and phytoremediation techniques may reduce heavy metal stress.
