Interaction of Copper Oxide Nanoparticles with Plants: Toxicity, Uptake and accumulation

The expansion of industrialization, to meet development needs, requires specific target technology based on innovative systems including nanotechnology and nanomaterials that exploit the physical properties of nanoparticles (NPs). Among the variety of NPs manufactured on demand by industries, copper oxide nanoparticles (CuO NPs) are produced for several purposes and as a consequence, when released in the environment, can constitute a potential risks for exposed living beings and human. In fact NPs have unique characteristics such as high surface reactivity and nanoscaled size, which are now raising a concerns regarding the stresses they can cause. Therefore it is necessary to study the interaction between CuO NPs and living organisms, with a greater attention to plants, photosynthetic organisms at the basis of the food chain, thus indispensable for the life of all other living beings. Since copper is a plant micronutrient, the concentration of CuO NPs in soil is critical for its beneficial or toxic effects. Plants uptake CuO NPs through their roots then, through the vascular system, CuO NPs are transported to the aboveground part of the plant. High concentrations of CuO NPs in plants have been documented; when CuO NPs are accumulated at critical concentration in plant cells, many physiological processes can be affected and reactive oxygen species (ROS) can be generated in stressed cells. As a consequence antioxidant mechanisms become activated to help plants survive under CuO (NPs) stress. This chapter deals with the nature of CuO NPs, their toxic effects on different plant species at physiological and cellular levels, their uptake and translocation mechanism, and the tolerance mechanism generated by plants under stress conditions. The article also confers a critical assessment of the necessity of further research.