Molecular Mechanisms Involved in Lead Uptake, Toxicity and Detoxification in Higher Plants

Abstract

Lead (Pb) is one of the most useful metals, and has contaminated most of the ecosystems. It has been known to influence various morphological, physiological and biochemical processes in plants. Higher plants have evolved sophisticated internal detoxification mechanisms, to deal with metal toxicity, that include selective metal uptake, excretion, chelation by specific ligands and compartmentalization. Despite these detoxification systems, Pb is able to induce the production of reactive oxygen species (ROS) which can cause harmful effects on vital constituents of plant cells: protein oxidation, lipid peroxidation, enzyme inactivation or DNA damages. Unlike other metals, little is known about the mechanisms involved in Pb uptake, toxicity, oxidative stress generation and detoxification in plants. This chapter reviews the recent understanding of physiological and biochemical mechanisms involved in Pb uptake and translocation into plants. It also provides a broad overview of the most important mechanisms of Pb toxicity and tolerance in plants.