Hydrogen-based irrigation increases yield and improves quality of Chinese cabbage by enhancing nutrient composition and antioxidant capabilities

To meet the increasing demands for higher-value and nutrient-rich vegetables, this work aims to investigate whether molecular hydrogen (H₂)-based irrigation, in the form of hydrogen nanobubble water (HNW), could improve yield and quality of Chinese cabbage (Brassica chinensis L.). Field trials showed that compared to surface water (SW) irrigation (control group), HNW irrigation significantly increased Chinese cabbage yield by 32.70 ± 12.15%, and the single plant weight, height, the maximum leaf length and width were also significantly increased. Higher nutritional value, including the increased contents of soluble sugar, soluble protein, mineral nutrients (P, Fe, Zn, and Cu), and secondary metabolites (total carotenoids, proanthocyanidins, phenols, flavonoids, and ascorbic acid), as well as decreased nitrate content and higher antioxidant capability (assessed by DPPH, ABTS and FRAP values) were also observed. Molecular evidence further revealed that the expressions of genes related to Fe, Zn, and P absorption as well as ascorbic acid biosynthesis were obviously up-regulated, consistent with changes in Fe, Zn, P, and ascorbic acid accumulation achieved after HNW irrigation. These results clearly suggested that HNW might have a practical value in improving yield and quality of horticultural crops.