Selenium alleviates cadmium toxicity by preventing oxidative stress in sunflower (Helianthus annuus) seedlings.
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.
Unité de recherche de Physiologie et Biochimie de la Réponse des Plantes aux Contraintes Abiotiques, Tunisia. Electronic address: issamfst@yahoo.fr.
Issam
I
Saidi
Unité de recherche de Physiologie et Biochimie de la Réponse des Plantes aux Contraintes Abiotiques, Tunisia.
Yacine
Y
Chtourou
Unité de recherche de Physiologie et Biochimie de la Réponse des Plantes aux Contraintes Abiotiques, Tunisia.
Wahbi
W
Djebali
D000975:Antioxidants / Q000494:pharmacology*; D001692:Biological Transport; D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity*; D006368:Helianthus / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D012643:Selenium / Q000494:pharmacology*
D000975:Antioxidants; D004785:Environmental Pollutants; D002104:Cadmium; D012643:Selenium
Antioxidants; Cadmium; Helianthus annuus; Oxidative damages; Selenium