Chemistry, biochemistry of nanoparticles, and their role in antioxidant defense system in plants

Abstract

As time passes, engineered nanoparticles (ENPs) are more frequently found in medical and consumer products, as well as in industrial and agricultural applications. The intensive production, use, and disposal of ENPs-containing wastes increase the likelihood of emission of such products to the environment. During the last two decades, a body of scientific literature has shown that ENPs interact with living components of ecosystems in different ways. The literature indicates that ENPs impact on plant growth, cell structure, and physiological and biochemical functions. In this chapter we discuss the stress induced by ENPs on higher plants. Although some references about carbon-based ENPs are included, most of the references are related to metal-based ENPs. The discussion is mainly focused on the effects of ENPs on photosystems and the mechanisms of generation/scavenging of reactive oxygen species (ROS). Effects on the enzymes catalase (CAT), guaiacol peroxidase (GPOX), ascorbate peroxidase (APOX), superoxide dismutase (SOD), glutathione reductase (GR), and dehydroascorbate reductase (DHAR) are discussed. Information about low molecular weight antioxidant thiols (GSSG or GSH) and ascorbate is also included.