ZnO nanoparticles enhance vernalized rapeseed yield under cadmium stress by boosting photosynthesis and antioxidant...

ZnO nanoparticles reverse vernalization-enhanced cadmium uptake in rapeseed through competitive inhibition, regulate flowering genes to shorten growth period, and achieve stable yield increase. Low-temperature vernalization of rapeseed (Brassica napus L.) seeds can shorten the growth period but enhances their cadmium uptake, while zinc oxide nanoparticle (ZnO NP) application can mitigate Cd toxicity in winter rapeseed. This study investigated the effects of ZnO NPs on vernalized rapeseed under cadmium stress. The results showed that application of ZnO NPs effectively alleviates yield reduction caused by low-temperature vernalization and stabilizes yield, and this yield enhancement is accompanied by a significant promotion of vegetative growth. Vernalization itself enhances cadmium uptake in rapeseed, but foliar application of ZnO NPs drastically reduces cadmium accumulation in leaves through competitive inhibition. At the molecular level, the combined treatment modulates the expression of key flowering-related genes, which collaboratively shorten the growth period. Ultimately, ZnO NP application to vernalized rapeseed enhances photosynthesis, boosts antioxidant enzyme activities, and regulates gene expression, thereby achieving stable and increased yield while significantly reducing cadmium accumulation.