Promoting the growth of rice and reducing the accumulation of Cd in rice by pig bedding derived carbon dots (PBCDs) under Cd stress

Cadmium (Cd) causes significant disruption to plant growth and poses a threat to human health, necessitating urgent and effective measures to mitigate its absorption and translocation in rice. This study employed a co-treatment of carbon dots (PBCDs) with Cd. The potential mechanisms underlying the alleviation of Cd toxicity in rice by PBCDs were investigated by observing changes in photosynthesis, the antioxidant system, and the content of other divalent metals in rice. The results showed that under Cd stress, PBCDs mitigated the interference of Cd in photosynthesis. Notably, treatments with 100 and 250 mg L⁻¹ PBCDs significantly increased the rice fresh weight by 32.45% and 31.54%, and reduced Cd concentrations in rice leaves by 53.82% and 45.81%, respectively. Moreover, PBCDs effectively reduced the shoot-to-leaf translocation factor (TF) of Cd by up to 45.76%, likely due to enhanced Zn concentrations in shoots. Furthermore, PBCDs enhanced the activity of antioxidant enzymes (SOD, POD, CAT) in rice, resulting in decreased levels of MDA induced by Cd stress. In conclusion, PBCDs enhanced rice antioxidant enzyme activity, photosynthetic efficiency, and biomass while mitigating cellular damage and reducing Cd concentrations in various tissues. These findings provide theoretical guidance and data support for the study of novel nanomaterials to promote crop growth under Cd stress conditions and alleviate Cd accumulation in plants.