Cerium oxide as a nanozyme for plant abiotic stress tolerance: An overview of the mechanisms

Abiotic stress in plants is considered an important environmental constraint that ultimately reduces agricultural production. Nanotechnology is an advancing technology for improving plant growth and mitigating stress factors in modern agriculture. Cerium oxide, a rare lanthanide in Earth's crust, holds significant potential in various industrial sectors. Research on engineered cerium oxide nanoparticles has been proven to play a significant role in promoting plant growth and alleviating environmental stress factors at lower dosage levels. The accumulation of cerium oxide nanoparticles benefits plants by improving morphological attributes, antioxidants, and photosynthetic parameters. Application of cerium oxide nanoparticles as nanozymes under abiotic stress conditions activates stress signaling cascades in plants to scavenge the reactive oxygen species (ROS) generated. However, higher dosages can lead to toxicological effects in plants. Higher accumulation of cerium oxide nanoparticles in different plant tissues is critical for reviewing their interference with the food chain and safety. This review covers the impact of cerium oxide nanoparticles on plant performance, abiotic stress tolerance, and the underlying mechanisms when interacting with plants.