EN
Barley (Hordeum vulgare) seedlings were treated with spermidine prior to water deficit to determine whether this polyamine is able to affect the activity of superoxide dismutase - SOD (EC 1.15.1.1) responsible for hydrogen peroxide and superoxide radical level. Short-term dehydration (24h) resulted in decrease of the SOD specific activity and a distinct increase in the superoxide anion and hydrogen peroxide contents. Polyamine treatment caused a substantial reduction in the contents of these two stress-raised reactive oxygen species and there by lowered the oxidative stress in plant cells. Antioxidant system as an important component of the water-stress-protective mechanism can be changed by polyamines, able to moderate the radical scavenging system and to lessen in this way the oxidative stress