Ukr.Biochem.J. 2012; Volume 84, Issue 6, Nov-Dec, pp. 131-138

Participation of the active oxygen forms in the induction of ascorbate peroxidase and guaiacol peroxidase under heat hardening of wheat seedlings

Yu. E. Kolupaev, O. I. Oboznyi

V. V. Dokuchayev Kharkiv National Agrarian University, Ukraine;

The influence of one-minute hardening heating at 42 °C on the dynamics of hydrogen peroxide generation and activity of antioxidant enzymes in roots of winter wheat seedlings has been investigated. It was shown that the content of hydrogen peroxide increased within the first 30 minutes after heat influence, whereupon it approached the level of control variant. The activity of superoxide dismutase (SOD) increased significantly within 10 min after heating and was maintained at a high level during 24 hours of observation. The activi­ty of ascorbate peroxidase and guaiacol peroxidase increased after 3-6 hours after the hardening and reached its maximum after 24 hours, when there was the most significant increase in heat resistance of seedlings. The short-term increase in hydrogen peroxide content caused by hardening heating was suppressed by treatment of seedlings with H2O2 scavenger dimethylthiourea, inhibitors of NADPH-oxidase (imidazole) and SOD (sodium diethyldithiocarbamate). All these effectors levelled the increase of activity of ascorbate peroxidase and guaiacol peroxidase and significantly inhibited the development of heat resistance of seedlings. The conclusion was made about the role of hydrogen peroxide produced with the participation of NADPH­-oxidase and SOD in the induction of antioxidant system by heat harde­ning of wheat seedlings.

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