Antioxidative Defence in Winter Wheat Plants during Early Cold Acclimation

Changes in the activities of four enzymes involved in antioxidative plant defence against low temperature treatment were studied in winter wheat plants (Triticum aestivum L cv. Sadovo 1) grown on acid soil (pH 4.2, KCl) under controlled environmental conditions. To investigate the effect of molybdenum (Mo) deficiency on antioxidative defence of these plants, Mo was added to part of the plants at early second-leaf stage as [NH4]6Mo7O24 x 4 H2O in 1 mg Mo/kg concentration. Enzyme activities of catalase (CAT, EC 1.11.1.6), ascorbic acid peroxidase (APX, EC 1.11.1.11), peroxidase (POX, EC 1.11.1.7), and glutathione reductase (GR, EC 1.8.1.7) were measured in leaves of both Mo-deficient and Mo-supplied plants during the early period of plant cold acclimation at 2°C. Results demonstrated higher level of APX activity and slightly increased activity of GR due to Mo-deficiency under normal growth temperatures. On its part CAT activity was found to be higher in Mo-supplied plants by contrast with POX activity. Mo-deficiency provoked changes only in APX and POX activities at low temperature.