Primary mechanism through which nanomaterials enhance plant photosynthesis.

Salinity is a major factor limiting the increase in crop yield around the world. Wheat starch and straw are important raw materials for producing bioethanol, and their productivity is adversely affected by salinity. Polyacrylic acid-modified Mn₃O₄ nanoparticles (PMO) have been reported to improve crop tolerance to stressors, including salt stress. Therefore, this study aimed to elucidate the mechanism by which seed soaking with PMOs enhances wheat salt tolerance. PMO seed soaking promoted wheat germination (increase of 30.9%) under salt stress, and seedlings treated with PMO seed soaking had a higher fresh weight (increase of 31.4%). PMO seed soaking increased the POD activity (by 31.9%) but decreased superoxide dismutase and catalase activities of wheat seeds and the O₂⁻ and H₂O₂ contents (by 25.0 and 71.4%, respectively). Furthermore, PMO soaking increased the ATP, NADPH, and NADH contents (by 367.6, 212.0, and 283.2%, respectively) by regulating sugar metabolism and enhanced the ascorbic acid–glutathione cycle. Additionally, the PMO soaking treatment optimized energy allocation in wheat under salt stress and increased yield (by 9.7%). PMO modulated sugar metabolism, thereby optimizing energy allocation to plant growth and the antioxidant system, which enhanced wheat germination and yield formation under salt stress.