Preparation, Characterization, and Application of Nano-selenium in Alleviating Cadmium Toxicity in Barley (Hordeum Vulgare L.).

Nano-selenium (nano-Se) has garnered widespread attention for its potential to alleviate plant abiotic stress. However, despite its promising applications, the specific effects of nano-Se on barley seedling growth under cadmium (Cd) stress largely unexplored. In this study, nano-Se was synthesized, and the optimized product was characterized. Additionally, the regulatory effects of different nano-Se concentrations on barley seedlings under Cd stress were investigated. The results revealed that a high concentration of nano-Se inhibited barley growth, whereas low doses promoted plant growth under Cd stress, with the highest growth parameters recorded at 2 µmol L^- 1 (µM) nano-Se. Furthermore, low doses of nano-Se increased chlorophyll levels and improved photosynthetic efficiency. Additionally, nano-Se application at low concentrations protected barley plants from oxidative damage by reducing the levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), as well as decreasing the activities of root peroxidase (POD) and superoxide dismutase (SOD) induced by Cd stress, as well as reducing the total flavonoid content.