XVI International Botanical Congess

Responses of biochemical parameters to oxidative stress were investigated in Avena sativa seedlings. Oxidative stress was induced by treating two weeks old plants with the herbicide paraquat (methyl viologen) at concentrations of 10-6 M, 10-5 M and 10-4 M. During the experiment the plants were exposed to permanent light. We describe changes in the contents of reduced glutathione (GSH), glutathione disulfide (GSSG), gamma-glutamyl-cysteine-serine, cysteine, gamma-glutamyl-cysteine, ascorbic acid, dehydroascorbic acid, oxalate, tocopherols, chlorophylls, and carotenoids. Plants treated with 10-4 M paraquat showed degradation of pigments (chlorophylls, carotenoids and xanthophylls) and dramatically lost vitality.