Molybdenum-selenium doped carbon dots enhance cadmium detoxification in lettuce through root remodeling and multi-pathway regulation.

Heavy metal pollution, particularly cadmium (Cd), seriously threatens crop growth and health. Here, molybdenum-selenium carbon dots (MoSeCDs) were developed to mitigate Cd toxicity in lettuce, and their underlying mechanisms were systematically elucidated. The results demonstrate that MoSeCDs promote plant growth by protecting chloroplast structure and maintaining photosynthetic activity, while simultaneously activating plant hormone signaling to enhance root vigor and modulating cell wall components to strengthen Cd immobilization. Moreover, MoSeCDs regulate the expression of metal transporter genes, reducing Cd uptake and facilitating vacuolar sequestration, while activating the antioxidant system to alleviate oxidative damage. MoSeCDs treated lettuce significantly decreased Cd accumulation in roots and leaves by 30.8% and 62.7%, respectively, and also mitigated stress induced by Pb, Cu, and Al. This study reveals the multi-dimensional regulatory mechanisms of MoSeCDs in plant heavy metal detoxification, providing a theoretical basis and practical potential for developing effective strategies to protect crops from heavy metal stress.