Hydrogen gas acts as a novel bioactive molecule in enhancing plant tolerance to paraquat-induced oxidative stress via the modulation of heme oxygenase-1 signalling system

Plant Cell Environ. 2013 May;36(5):956-69. doi: 10.1111/pce.12029. Epub 2012 Nov 19.


Hydrogen gas (H2) was recently proposed as a novel antioxidant and signalling molecule in animals. However, the physiological roles of H2 in plants are less clear. Here, we showed that exposure of alfalfa seedlings to paraquat stress increased endogenous H2 production. When supplied with exogenous H2 or the heme oxygenase-1 (HO-1)-inducer hemin, alfalfa plants displayed enhanced tolerance to oxidative stress induced by paraquat. This was evidenced by alleviation of the inhibition of root growth, reduced lipid peroxidation and the decreased hydrogen peroxide and superoxide anion radical levels. The activities and transcripts of representative antioxidant enzymes were induced after exposure to either H2 or hemin. Further results showed that H2 pretreatment could dramatically increase levels of the MsHO-1 transcript, levels of the protein it encodes and HO-1 activity. The previously mentioned H2-mediated responses were specific for HO-1, given that the potent HO-1-inhibitor counteracted the effects of H2. The effects of H2 were reversed after the addition of an aqueous solution of 50% carbon monoxide (CO). We also discovered enhanced tolerance of multiple environmental stresses after plants were pretreated with H2 . Together, these results suggested that H2 might function as an important gaseous molecule that alleviates oxidative stress via HO-1 signalling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological
  • Carbon Monoxide / pharmacology
  • Droughts
  • Drug Resistance*
  • Heme Oxygenase-1 / antagonists & inhibitors
  • Heme Oxygenase-1 / metabolism*
  • Hemin / pharmacology
  • Hydrogen / pharmacology*
  • Hydrogen Peroxide / metabolism
  • Lipid Peroxidation
  • Medicago sativa / drug effects*
  • Medicago sativa / enzymology
  • Medicago sativa / growth & development
  • Oxidative Stress*
  • Paraquat / pharmacology*
  • Plant Immunity / drug effects
  • Plant Leaves / enzymology
  • Plant Leaves / metabolism
  • Plant Proteins / metabolism
  • Plant Roots / drug effects
  • Plant Roots / enzymology
  • Plant Roots / growth & development
  • Protoporphyrins / pharmacology
  • Salinity
  • Seedlings / drug effects
  • Seedlings / enzymology
  • Seedlings / growth & development
  • Signal Transduction
  • Sodium Chloride / pharmacology
  • Thiobarbituric Acid Reactive Substances / metabolism


  • Plant Proteins
  • Protoporphyrins
  • Thiobarbituric Acid Reactive Substances
  • Sodium Chloride
  • Hemin
  • Carbon Monoxide
  • Hydrogen
  • Hydrogen Peroxide
  • protoporphyrin IX
  • Heme Oxygenase-1
  • Paraquat