The effect of water deficit on the activity of hydrogen peroxide-scavenging enzymes in two barley genotypes

Abstract

Two barley (Hordeum vulgare L.) genotypes, the cv. Aramir and line R567, were subjected to water deficit by immersing their root systems in polyethylene glycol solution of osmotic potential -1.0 MPa. The stress caused a decline in the leaf-relative-water content (RWC) and affected membrane damage in both the genotypes. A higher decline in RWC and a higher membrane injury index was observed in R567 in comparison to 'Aramir'. Water deficit induced an increase in the activity of guaiacol peroxidase (GPO) and catalse (CAT). A higher increase of CAT than GPO peroxidase activity has been noted in both the genotypes. The results. together with our earlier reports (Bandurska et al. 1997) show that detoxification of hydrogen peroxide under water stress conditions in those two barley genotypes was associated with the action of GPO and CAT, and that the latter was more involved in that process.

Keywords

• barley
• catalase
• guaiacol peroxidase
• membrane injury
• water deficit