The antioxidant defense system and bioremediation

Abstract

Abstract High levels of heavy metals can lead to multiple toxic effects in plants. They have capability to influence plant growth and development by direct inhibition of molecular, biochemical, and physiological processes or through the production of reactive oxygen species (ROS), which can inhibit most cellular processes at various levels of metabolism. Plants counteract the heavy metal oxidative stress by inducing plant scavenging system including overexpressing of numerous signaling and antioxidative proteins and nonenzymatic antioxidants. Different efficiencies of ROS scavenging system during various environmental stress including heavy metals can result in developing plants that can overcome oxidative stress. The capability of plant species to accumulate and tolerate heavy metals has a great importance for plant selection useful for phytoremediation. This article details the toxicity of heavy metals, the sites of production, and the role of ROS as oxidative damage inducers and the link between heavy metals, oxidative stress, and antioxidative system activity in different plant species. The type of phytoremediation methods and mechanisms of plant tolerance for heavy metal toxicity are also presented.