Although hydrogen gas (H₂)-treated soil improves crop biomass, this approach appears difficult for field application due to the flammability of H₂ gas. In this report, we investigated whether and how H₂ applied in hydrogen nanobubble water (HNW) improves the yield and quality of cherry tomato (Lycopersicon esculentum var. cerasiforme) with and without fertilizers. Two-year-long field trials showed that compared to corresponding controls, HNW without and with fertilizers improved the cherry tomato yield per plant by 39.7% and 26.5% in 2021 (Shanghai), respectively, and by 39.4% and 28.2% in 2023 (Nanjing), respectively. Compared to surface water (SW), HNW increased the soil available nitrogen (N), phosphorus (P), and potassium (K) consumption regardless of fertilizer application, which may be attributed to the increased NPK transport-related genes in roots (LeAMT2, LePT2, LePT5, and SlHKT1,1). Furthermore, HNW-irrigated cherry tomatoes displayed a higher sugar–acid ratio (8.6%) and lycopene content (22.3%) than SW-irrigated plants without fertilizers. Importantly, the beneficial effects of HNW without fertilizers on the yield per plant (9.1%), sugar–acid ratio (31.1%), and volatiles (20.0%) and lycopene contents (54.3%) were stronger than those achieved using fertilizers alone. In short, this study clearly indicated that HNW-supplied H₂ not only exhibited a fertilization effect on enhancing the tomato yield, but also improved the fruit’s quality with a lower carbon footprint.

Bok choy (Brassica rapa var. chinensis) experiences rapid postharvest quality decline, primarily due to water loss. This study aims to evaluate the effect of H₂-modified atmosphere packaging (MAP; containing 0.01%, 0.1%, and 1% H₂) on extending the shelf life of bok choy. First, we observed that the storage of bok choy for 9 d (4 °C and 85% relative humidity) was accompanied by a decreasing tendency of molecular hydrogen (H₂) production. Subsequently, the effects of hydrogen (H₂) administered via modified atmosphere packaging on the preservation of bok choy were investigated. The results showed that among the treatments, 0.1% H₂ MAP could effectively improve the storage quality of bok choy under identical storage conditions. Compared to the control groups at 9 d, the contents of chlorophyll a/b, carotenoids, total phenols and flavonoids, and total soluble solids were increased by 43.75%, 40%, 27.78%, 28.89%, 102.38%, and 7.29%, and weight loss rate and electrolyte leakage were reduced by 31.77% and 50.19% (p < 0.05). Meanwhile, the combined water fraction was increased and respiration rate was decreased. Biochemical evidence further showed that xyloglucan endotransglycosylase 2/3 (XET2/3) transcripts and xyloglucan endotransglycosylase (XET) activity, responsible for cell wall degradation, were decreased. By contrast, peroxidase 31/37 (POD31/37) genes and peroxidase (POD) activity, key to the synthesis of lignin, were increased. Importantly, these changes were positively matched with the maintenance of cell wall integrity by H₂ MAP. Together, the results clearly suggested that H₂ MAP could maintain the postharvest quality of bok choy via alleviating water loss and maintaining cell wall integrity. These findings thus provide a useful technology for improving the storage quality of vegetables prone to water loss.

Although hydrogen gas (H2) treated soil improves crop biomass, this approach appears difficult for the field application due to the flammability of H2 gas. In this report, we investigated whether and how H2 applied in hydrogen nanobubble water (HNW) improves the yield and quality of cherry tomato (Lycopersicon esculentum var. cerasiforme) with/without fertilizers. Two-year field trials showed that compared to corresponding controls, HNW without/with fertilizers improved cherry tomato yield per plant by 39.7% and 26.5% in 2021 (Shanghai), and 39.4% and 28.2% in 2023 (Nanjing). Compared to surface water (SW), HNW increased soil available nitrogen (N), phosphorus (P), and potassium (K) consumption regardless of fertilizer application, which may be attributed to the increased NPK transport related genes in roots (LeAMT2, LePT2, LePT5, and SlHKT1,1). Also, HNW-irrigated cherry tomato displayed higher sugar-acid ratio (8.6%) and lycopene content (22.3%) than SW-irrigated plants without fertilizers. Importantly, the beneficial effects of HNW without fertilizers on yield per plant (9.1%), sugar-acid ratio (31.1%), volatiles (20.0%) and lycopene contents (54.3%) were stronger than those achieved by fertilizers alone. In short, this study clearly indicated that HNW-supplied H2 not only exhibited fertilization effect on enhancing tomato yield, but also improved fruit quality with a lower carbon footprint.