A Novel Nanozyme for Sustainable Agriculture: Improving Wettability, Reducing Toxicity, and Enhancing Drought Resistance in Wheat and Rice

Drought stress causes a significant accumulation of reactive oxygen species (ROS) in crops, inhibiting their growth and development and threatening food security. This study constructs cerium-based metal–organic frameworks (CeMs) encapsulated with polydopamine (PDA), effectively eliminating ROS (O₂^•–, H₂O₂, ·OH, DPPH·, and ABTS^·+). Experiments showed that CeMs@PDA exhibits superior wettability and outstanding translocation capabilities in wheat and rice. Under drought conditions, CeMs@PDA (12.5 mg L^–1, 100 mg L^–1) significantly increased the vigor index (71.84%, 224.83%) of seeds (wheat, rice). The application of 25 and 100 mg L^–1 CeMs@PDA significantly alleviated drought-induced growth inhibition in wheat and rice seedlings, respectively. The inhibition of stem and root growth decreased from 28.07% and 38.15% to 3.72% and 4.43% in wheat seedlings, and the inhibition declined from 25.33% and 30.83% to 2.89% and 5.30% in rice seedlings, respectively. In addition, CeMs@PDA significantly increased the level of antioxidant enzyme activities in wheat and rice and showed better biosafety. This study opens valuable pathways for sustainable agriculture under water-limited conditions.