Selenium alleviates cadmium toxicity by preventing oxidative stress in sunflower (Helianthus annuus) seedlings

• Published in: Journal of plant physiology Vol. 171; no. 5; pp. 85 - 91
• Main Authors: Saidi, Issam, Chtourou, Yacine, Djebali, Wahbi
• Format: Journal Article
• Language: English
• Published: Germany Elsevier GmbH 01-03-2014
• Subjects: Antioxidants; Antioxidants - pharmacology; Biological Transport; Cadmium; Cadmium - metabolism; Cadmium - toxicity; Dose-Response Relationship, Drug; Environmental Pollutants - metabolism; Environmental Pollutants - toxicity; Glutathione; Helianthus - drug effects; Helianthus - enzymology; Helianthus - growth & development; Helianthus - metabolism; Helianthus annuus; Oxidative damages; Oxidative Stress - drug effects; Peroxidase; Plant Leaves - drug effects; Plant Leaves - enzymology; Plant Leaves - growth & development; Plant Leaves - metabolism; Plant Roots - drug effects; Plant Roots - enzymology; Plant Roots - growth & development; Plant Roots - metabolism; Plant Shoots - drug effects; Plant Shoots - enzymology; Plant Shoots - growth & development; Plant Shoots - metabolism; Plants (organisms); Seedlings - drug effects; Seedlings - enzymology; Seedlings - growth & development; Seedlings - metabolism; Selenium; Selenium - pharmacology; Stresses; Sunflowers; Toxicity; Cars; Cadmium; POD; Oxidative damages; Chl; APX; SOD; GR; MDA; H2O2; AsA; Antioxidants; Se; Helianthus annuus; CAT; Selenium; GSH
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/j.jplph.2013.09.024

The present study investigated the possible mediatory role of selenium (Se) in protecting plants from cadmium (Cd) toxicity. The exposure of sunflower seedlings to 20μM Cd inhibited biomass production, decreased chlorophyll and carotenoid concentrations and strongly increased accumulation of Cd in both roots and shoots. Similarly, Cd enhanced hydrogen peroxides content and lipid peroxidation as indicated by malondialdehyde accumulation. Pre-soaking seeds with Se (5, 10 and 20μM) alleviated the negative effect of Cd on growth and led to a decrease in oxidative injuries caused by Cd. Furthermore, Se enhanced the activities of catalase, ascorbate peroxidase and glutathione reductase, but lowered that of superoxide dismutase and guaiacol peroxidase. As important antioxidants, ascorbate and glutathione contents in sunflower leaves exposed to Cd were significantly decreased by Se treatment. The data suggest that the beneficial effect of Se during an earlier growth period could be related to avoidance of cumulative damage upon exposure to Cd, thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity.