Abstract

Antioxidant enzymes comprise the immune system in plants against abiotic and biotic stresses. In one part of the current study, the level of activity of four antioxidants has been examined in four unexplored Egyptian xerophytes. Their antimicrobial activity against seven virulent bacteria was also determined. In a second part of the study, the level of antioxidant enzymes was compared to their levels in Schefflera arboricola plant upon the applications of three pesticides. It was believed that the biosynthesis of these enzymes under the effect of pesticide treatments was pesticide-specific. From total number of pesticides, two only led to a significant oxidative damage. The herbicide 'roundup' caused an abrupt increase in antioxidants in Schefflera leaf and hence to a protective mechanism against oxidative damage. Subsequently, the level of lipid peroxidation has decreased. In addition, our data have viewed that glutathione (GSH) was not efficient in scavenging the oxidative damage inSchefflera.

Key words: Antioxidant enzymes, drought, malonyldialdehyde, pesticides, Schefflera.

Abbreviation

CAT, Catalase; GSH, glutathione; MDA, malonyldialdehyde; POD,peroxidase; SOD, superoxide dismutase; ROS, reactive oxygen species; GSSG, oxidized glutathione; TBA, thiobarbituric acid; TCA, trichloracetic acid.