DAILY FLUCTUATIONS OF ANTIOXIDANTS IN BEAN (PHASEOLUS-VULGARIS L) LEAVES - THE INFLUENCE OF CLIMATIC FACTORS

During the period 0800-1700 h (GMT) of a typical summer day, rapid flu ctuations were observed in the levels of superoxide dismutase, ascorba te peroxidase, dehydroascorbate reductase, glutathione disulfide reduc tase, guaiacol peroxidase, glutathione peroxidase, catalase, ascorbic acid, dehydroascorbic acid, reduced glutathione and glutahione disulfi de measured in bush bean (Phaseoulus vulgaris L. cv. Horticultural) le aves. The antioxidant metabolites and the peroxidase enzymes showed th e widest periodical changes. The antioxidant fluctuations were associa ted to the possible intermittent over-production of partially reduced O2 forms, whose formation could have been stimulated by natural daily changes in environmental factors prone to cause oxidative stress.