biologia plantarum

Biologia plantarum 42:49-55, 1999 | DOI: 10.1023/A:1002159123727

Effect of Cadmium Ions on Antioxidant Defense System in Sunflower Cotyledons

S.M. Gallego¹, M.P. Benavides¹, M.L. Tomaro¹

¹ Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina

Sunflower (Helianthus annuus L.) seeds were germinated and grown in the presence of 50, 100 and 200 µM CdCl₂. The lower concentration (50 µM) of Cd² ions produced slight decrease in reduced glutathione (GSH) content and overall increase (except superoxide dismutase) in antioxidant enzyme activities, and in H₂O₂ concentration. Chlorophyll content, lipid peroxidation and protein oxidation were not affected under 50 µM CdCl₂. GSH content was diminished under 100 and 200 µM CdCl₂, and except for superoxide dismutase, which activity remained unaltered, overall decreases in the antioxidant enzyme activities (catalase, ascorbate peroxidase, dehydroascorbate peroxidase, glutathione reductase) and in guaiacol peroxidase were observed. These Cd² concentrations caused a decrease in chlorophyll content as well as an increase in lipid peroxidation, protein oxidation and H₂O₂ concentration. All the observed effects were more evident with the highest concentration of cadmium chloride used.

Keywords: chlorophyll; glutathione; Helianthus annuus; lipid peroxidation; oxidative stress

Subjects: cadmium, antioxidant defense system; chlorophyll, cadmium, antioxidant enzymes; glutathione, cadmium, antioxidant enzymes; Helianthus annuus; lipid peroxidation; oxidative stress, cadmium, antioxidant enzymes; sunflower, antioxidant defense system; superoxide dismutase, heavy metals

Published: July 1, 1999  Show citation