destructive effects of reactive oxygen species on cell defensive power leaf aging in wheat

a hydroponics study was carried out in order to understand the behavior of antioxidant enzymes, soluble protein content and its effect on cell death in different old leaves of durum wheat. two month after planting, the different old leaves were sampled and the activity of super oxide dismutase (sod), catalase, ascorbat peroxidase and guaiacol peroxidase were measured. furthermore, the rate of cell death and total protein content were analyzed. in old leaves, sod activity was diminished and amongst its isozimes, cu/zn-sod was the one demonstrating a significant reduction in activity. catalase and ascorbat peroxidase decreased in old leaves significantly, but reduction in glutathione peroxidase activity was no significant. in general, aging caused reduction in soluble protein content. accumulations of oxidative factors were seen by reduction of antioxidant enzymes activity. subsequent, metabolic malfunctions led to higher cell death rate as leaves were aged.