... EI-Shora H. M. Activities of antioxidative enzymes and senescence in detached Cucurbita pepo under Cu- and oxidative stress by H 2 O 2 . Abstract The activities of antioxidative enzymes were determined in detached leaves of Cucurbita pepo exposed to either Cu stress or oxidative stress by hydrogen peroxide. ... On the other hand, hydrogen peroxide decreased the activities of GR, APOD, SOD, and DHAR but increased the activity of catalase. ... Moscow University Chemistry Bulletin . 2003, Vol. ...