Effects of Rare Earth Oxide Nanoparticles on Plants

Abstract Rare earth oxide nanoparticles (REONPs) have a high privilege in agriculture due to their unique properties as compared to their bulk counterparts. The most important REONPs include scandium, cerium, and other lanthanides, which are frequently used as fertilizer additives in many countries. Several approaches are being adopted for the commercial synthesis of REONPs. The available literature presents contradictory reviews about their beneficial effects on living organisms. Beneficial or harmful effects on plant growth are mainly dependent on the concentration of REONPs and species of plant. Bioavailability and mobility of REONPs in soil is a pH-dependent process and is also affected by their interaction with anionic ligands because of the higher oxidation state of REONPs. Plants can uptake REONPs from the soil and distribute them to aerial parts including edible organs. Accumulation of REONPs within various plant parts exhibits the potential to initiate seed emergence, escalate root and shoot growth, enhance plant growth by increasing the availability of mineral nutrients, stimulate photosynthetic processes, support plants to cope with environmental stresses by acting as a scavenger of free radicles including oxygen species, start oxidase activity, initiate antioxidant systems, and modify the enzyme activation process. Along with all these blessings there are still controversies regarding their effects on plants. This chapter is helpful for answering all ambiguous questions related to the unique characteristics of REONPs, their uptake mechanism, their interaction with soil organic and inorganic components, and their impacts on plant growth. This discussion also elucidates the phytotoxicity of REONPs in plants and their potential to accumulate in plants. This discussion helps to explore new horizons for the beneficial use of REONPs to maximize plant growth and yield on a sustainable basis along with the quality of the produce.