# The Role and Mechanism of Hydrogen-Rich Water in theResponse to Chilling Stress.
> 水素水がキュウリの低温ストレス応答に果たす役割とメカニズムの解明


## Abstract

Cucumber, a warm-climate crop highly susceptible to low-temperature injury, suffers yield and quality losses when exposed to chilling conditions at any developmental stage. This plant study examined how exogenous hydrogen-rich water (HRW) at 50% saturation, applied to the root zone of cucumber seedlings, modulates the chilling stress response. Multiple growth parameters—including plant height, stem diameter, leaf area, fresh and dry weight, and root length—were elevated in HRW-treated seedlings relative to untreated chilling controls. Photosynthetic performance improved, as reflected by higher chlorophyll content and Fv/Fm ratios with reduced energy dissipation. Membrane integrity was better preserved, evidenced by lower relative electrolyte conductance (REC) and malondialdehyde (MDA) levels. NBT and DAB histochemical staining revealed diminished superoxide and hydrogen peroxide accumulation. Activities of antioxidant enzymes SOD, CAT, POD, GR, and APX were enhanced alongside upregulation of their corresponding genes. Concurrently, reduced glutathione (GSH) and ascorbic acid (ASA) contents rose while oxidized glutathione (GSSG) declined, indicating reinforced non-enzymatic antioxidant capacity. These findings collectively demonstrate that HRW root application effectively mitigates chilling-induced oxidative damage in cucumber seedlings.

### Mechanism

HRW enhances enzymatic antioxidant defenses (SOD, CAT, POD, GR, APX) at both activity and gene-expression levels, while simultaneously elevating non-enzymatic antioxidants GSH and ASA and reducing GSSG, thereby scavenging ROS and limiting membrane lipid peroxidation under chilling conditions.

## Bibliographic

- **Authors**: Wang X, An Z, Liao J, Ran N, Zhu Y, Ren S, et al.
- **Journal**: Int J Mol Sci
- **Year**: 2023 (2023-04-04)
- **PMID**: [37047675](https://pubmed.ncbi.nlm.nih.gov/37047675/)
- **DOI**: [10.3390/ijms24076702](https://doi.org/10.3390/ijms24076702)
- **PMC**: [PMC10095547](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10095547/)
- **Study type**: other
- **Delivery route**: hydrogen-rich water
- **Effect reported**: positive
- **H2 concentration**: 50%

## Delivery context

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

## Safety notes

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 37047675. https://h2-papers.org/en/papers/37047675
> **Source**: PubMed PMID [37047675](https://pubmed.ncbi.nlm.nih.gov/37047675/)