Amine oxidase, peroxidase, catalase and acid phosphatase activities in powdery mildew infected plants of Cucumis sativus

The plants of Cucumis sativus infected by powdery mildew Sphaerotheca fulig inea showed significant increase in the peroxidase activity and extractable protein content five days after the inoculation and about two-fold increas e in the amine oxidase activity thirteen days after the inoculation. Change s of the activities of acid phosphatase and catalase in healthy and infecte d plants were not evident. Histochemical detection of peroxidase confirmed the increased activity of the enzyme that is located in the cell wall and e pidermis of infected plants. Expression of three stress-related peroxidase isoenzymes after infection by powdery mildew were observed by native electr ophoresis in polyacrylamide gel.