Hydrogen-rich water delays post-harvest yellowing in broccoli by inhibiting ethylene and ABA levels, thereby reducing chlorophyll degradation and carotenoid accumulation

To investigate the mechanism of yellowing and explore control methods, this study focused on the impact and mechanism of hydrogen-rich water (HRW) treatment on broccoli floret yellowing. The research results indicate that HRW treatment maintains the structural integrity of chloroplasts in broccoli florets during post-harvest storage, slowing down the degradation of chlorophyll and the accumulation of carotenoids. RT-qPCR results show that HRW treatment inhibits the expression of chlorophyll degradation genes BoNOL1/6/10 , BoPAO , BoPOX , BoSGR1 , BoCLH1 , BoNCY , and BoNYC , as well as carotenoid-related biosynthesis genes BoPSY , BoPDS , BoZDS , BoZISO , BoCRTISO , BoCYP97C1 , and BoCCS-1 , while increasing the expression level of BoCCD1/4 . Furthermore, HRW treatment inhibits the production of endogenous ethylene through downregulation of its biosynthetic genes BoACO1/2 and BoACS1/2/7 . Simultaneously, HRW treatment downregulates ABA biosynthesis genes BoNCED2/3 and BoABA2 , resulting in a significant reduction in ABA levels. In summary, the HRW treatment delays the yellowing of broccoli after harvest by inhibiting ethylene and ABA levels, thereby reducing the degradation of chlorophyll and the accumulation of carotenoids. • HRW delayed the yellowing of broccoli after harvest by inhibiting ethylene and ABA levels. • HRW preserved the chloroplast morphology of postharvest broccoli. • HRW delayed the degradation of chlorophyll and the synthesis of carotenoids. • HRW down-regulated chlorophyll metabolic genes and carotenoid synthetic genes.