Hydrogen-rich water enhances vegetable growth and fruit quality by regulating ascorbate biosynthesis

Under aerobic conditions, the growth and fruit quality of vegetable crops are significantly influenced by reactive oxygen species (ROS) metabolism. Hydrogen-rich water (HRW) has emerged as a promising tool for enhancing resistance to abiotic stresses and delaying postharvest ripening and senescence. However, the physiological response and adaptation mechanisms of vegetable crops to HRW remain rarely understood. This study explores the effects of low concentrations of HRW on the growth and physiological processes of lettuce, tomato, and cucumber. The results indicate that HRW enhances seedling vigor, boosts photosynthetic efficiency, and promotes biomass accumulation. Additionally, HRW-irrigated cucumber fruit showed a 15-20 % increase in vitamin C (ascorbic acid) content, a 10-15 % rise in soluble sucrose levels, and an increase in fruit weight and diameter by 25-35 % and 8-12 %, respectively. Transcriptomic analyses revealed variations in genes associated with carbon fixation in photosynthesis, glyoxylate and dicarboxylate metabolism, hormonal regulation, and phenylalanine metabolism. These findings illuminate the mechanisms behind improved antioxidant production and L-ascorbate biosynthesis. Notably, this marks the documented case of HRW irrigation enhancing natural antioxidants in fruits. Given the unique properties of hydrogen and the potential of HRW technology in horticultural industry, the findings of this study provide valuable insights into hydrogen's role in biological processes and its impact on vegetable crops production and fruit quality.