Heavy metals and metalloids accumulation in common beans (Phaseolus vulgaris L.): A review

This review focuses on evaluating the accumulation and translocation of As, Cd, Hg, and Pb in Phaseolus vulgaris L. plants and on the possible effects of these elements on the growth of Phaseolus vulgaris L. in soil contaminated with these elements. Heavy metals (HMs) and metalloids (Ms) such as arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) represent serious environmental threats due to their wide abundance and high toxicity. HMs and Ms contamination in water and soils from natural or anthropogenic sources, is of great concern in agricultural production due to their toxic effects on plants, adversely affecting food safety and plant growth. The uptake of HMs and Ms by Phaseolus vulgaris L. plants depends on several factors including soil properties such as pH, phosphate, and organic matter. High concentrations of HMs and Ms could be toxic to plants due to the increased generation of ROS such as (O2•-), (•OH), (H2O2), and (1O2) and oxidative stress due to an imbalance between ROS generation and antioxidant enzyme activity. To minimize the effects of ROS, plants have developed a complex defense mechanism based on the activity of antioxidant enzymes such as SOD, CAT, GPX, etc., and phytohormones, especially salicylic acid (SA) that can reduce the toxicity of HMs and Ms in the factors that affect the uptake of these elements by bean plants, and in addition, defense mechanisms under oxidative stress caused by the presence of As, Cd, Hg, and Pb.