Tag Archives: ascorbate peroxidase
Ascorbate-glutathione cycle enzymes activity in zea mays leaves under salinity and treatment by adaptogenic compounds
O. O. Konturska, T. O. Palladina
M. G. Kholodny Institute of Botany, National Academy of Science of Ukraine, Kyiv;
e-mail: konturska@ukr.net
The effect of different salinity levels and synthetic compounds treatments on ascorbate-glutathione cycle enzymes activity in maize leaves has been investigated. One-day seedlings exposition with 0.05 М NaCl increased ascorbate peroxidase activity, whereas 10-day exposition did not affect it. However the exposition with 0.1 M NaCl, which is extreme for maize, decreased ascorbate peroxidase activity in leaves during 10 days. On the other hand glutathione reductase activity in leaves increased under both salt concentrations. Seeds treatments with Methyure and Ivine increased ascorbate peroxidase activity in the leaves of seedlings under 0.1 М NaCl, but did not affect glutathione reductase activity as compared to the salt control. The results obtained have shown differences of ascorbate-glutathione cycle enzymes responses to salt exposition of seedlings and the effects of adaptogenic compounds on the ascorbate-glutathione cycle via ascorbate peroxidase activation.
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;
e-mail: plant_biology@mail.ru
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.