Assessment of antioxidant potential of plants in response to heavy metals

Abstract

Heavy metals (HMs) are consequential environmental contaminant, and their prodigious bioaccumulation in the surroundings has become an enigma for all living organisms including plants. Heavy metal has the potential to react with various indispensable cellular components like DNA, protein, and enzymes and in turn induce several stress responses in plants like oxidative stress which is the root cause for the progression of cell death in the plant. Stress responses inflicted by oxidative stress include severe morphological, metabolic, and physiological amendments in plants like DNA strand breakage, defragmentation of proteins, and damage of photosynthetic pigment, which may stimulate cell death. In reaction, plants have a range of mechanisms to minimize the heavy metal toxicity. Plants are endowed with antioxidant defense mechanism, which can be divided into two groups such as enzymatic antioxidants and nonenzymatic antioxidants, for instance, SOD, CAT, APX, GPX, GR and AsA, GSH, carotenoids, alkaloids, tocopherols, proline, and phenolic compounds, respectively, that together act as the scavengers for free radicals to mitigate the damaging impacts of heavy metal agglomeration in the cells. These antioxidant potentials could be assessed by different in vivo and in vitro methods such as hydrogen atom transfer and electron transfer through which we can evaluate the ROS detrimental action of antioxidant enzymes. Therefore, the present chapter attempts to provide the contemporary knowledge regarding the metal-influenced antioxidant status in plants and also provides the precise pathway that should follow for the future research in the area of antioxidant potentials.