# Hydrogen-rich water confers plant tolerance to mercury toxicity in alfalfa seedlings.
> 水素水がアルファルファ幼苗における水銀毒性耐性に与える影響


## Abstract

This study examined how hydrogen-rich water (HRW) modulates the response of alfalfa seedlings to mercury (Hg) stress induced by HgCl2 exposure. Mercury treatment caused elevated reactive oxygen species (ROS) production, increased lipid peroxidation, and suppressed growth. HRW application markedly reduced these adverse effects, accompanied by lower ion leakage and decreased Hg accumulation in seedling tissues. While Hg elevated superoxide dismutase (SOD) total and isozyme activities, HRW reversed this elevation. Activities of guaiacol peroxidase (POD) and ascorbate peroxidase (APX) were upregulated by HRW at the transcriptional level. Ratios of reduced-to-oxidized glutathione (GSH), homoglutathione (hGSH), and ascorbic acid (AsA) increased alongside corresponding gene expression, correlating with reduced oxidative damage in roots. Collectively, HRW appeared to confer Hg tolerance by limiting Hg accumulation, suppressing growth inhibition, and restoring redox homeostasis.

### Mechanism

HRW upregulates POD and APX at the transcriptional level and increases reduced-to-oxidized ratios of GSH, hGSH, and AsA, thereby suppressing ROS-mediated oxidative damage and restoring redox homeostasis while reducing Hg accumulation in alfalfa roots.

## Bibliographic

- **Authors**: Cui W, Fang P, Zhu K, Mao Y, Gao C, Xie Y, et al.
- **Journal**: Ecotoxicol Environ Saf
- **Year**: 2014
- **PMID**: [24793520](https://pubmed.ncbi.nlm.nih.gov/24793520/)
- **DOI**: [10.1016/j.ecoenv.2014.04.009](https://doi.org/10.1016/j.ecoenv.2014.04.009)
- **Study type**: in vitro study
- **Delivery route**: hydrogen-rich water
- **Effect reported**: positive

## 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 24793520. https://h2-papers.org/en/papers/24793520
> **Source**: PubMed PMID [24793520](https://pubmed.ncbi.nlm.nih.gov/24793520/)