Reducing Cd Uptake and Translocation in Wheat Seedlings through Integrated Approaches Using Nanosilicon and Extracellular Polymeric Substances

Cadmium (Cd) contamination severely threatens wheat productivity and global food safety. While traditional silicon amendments partially alleviate Cd toxicity, their limited efficacy necessitates more robust solutions. This study developed an innovative strategy integrating foliar-applied nanosilicon (SiNP) with soil-based microbial extracellular polymeric substances (EPS) to combat Cd stress in wheat by analyzing physiological responses. The combined treatment dramatically enhanced protein and polysaccharide contents on the root surface and elevated the wheat thiol compound by 26.95-45.45%, inhibited Cd flow by 30.49-78.13%, and strengthened related metabolic functions. Cd content in wheat root and leaves was reduced by 16.12-30.91% and 35.07-56.15%, respectively, and the proportion of Cd sequestered in cell walls was increased. Malondialdehyde (MDA) activity was notably reduced by 9.55-22.41%, and other antioxidant enzymes were significantly enhanced. Meanwhile, the photosynthetic capacity of wheat leaves was enhanced, with the net photosynthetic rate increasing by 4.23-27.87%, protecting the integrity of wheat cells. This study will provide valuable insights for related research.