Role of metal speciation in lead-induced oxidative stress to Vicia faba roots

Résumé fourni par la source

Chemical speciation of metals in soil/solution plays an important role in determining their biogeochemical behavior in soil-plant system. The current study evaluated the influence of applied form of Pb (metal speciation) on its toxicity to metal sensitive Vicia faba L. roots. Lead was applied to young V. faba seedlings alone or chelated by organic ligands (citric acid and ethylenediaminetetraacetic acid). Plants were exposed to all treatments for 1, 4, 8, 12, and 24 h in nutrient solution, and contents of H 2 O 2 and thiobarbituric-acid-reactive substances (TBARS) production were analyzed in V. faba roots. The results showed that Pb toxicity to V. faba roots depended on its applied chemical form and duration of exposure. Lead alone caused two burst of lipid peroxidation and H 2 O 2 induction at 1 h and 12 h. Addition of EDTA dose-dependently inhibited Pb-induced H 2 O 2 and TBARS production, indicating a protective role of this chelator against Pb toxicity during the first 24 h. In contrast, citric acid did not show significant effects on Pb-induced H 2 O 2 and TBARS production, but delayed the induction of these effects. This study suggested that Pb toxicity to V. faba roots varies with Pb speciation in growth medium.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.