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Modifications métaboliques, moléculaires et génotoxicité induites par le cadmium chez Vicia faba

Abstract : Bean seedlings (Vicia faba), aged 12 days under hydroponic conditions are treated with 50, 100 and 200 microM cadmium chloride for 12, 24 and 48 h. Signs of intoxication manifested by disturbances of leaf and root growth accompanied by a browning of treated roots. Our results also showed a decrease in total chlorophyll content, nutrititionnel disorder and disruption of water absorption in treated bean seedlings. On the distribution of Cd between the leaves and roots of bean, we have shown a low pass metal ions to the leaves and preferential localization of these ions in the roots. Cadmiques the presence of ions in the nutrient solution resulted in the installation of a state of oxidative stress characterized by increased production of O2-and H2O2 in roots and leaves of bean seedlings treated. In the roots, the production of active oxygen radicals is associated with increased production of MDA (malondialdehyde), stimulation of lipoxygenase activity (LOX) at the beginning of treatment and an increased rate of cell death . In leaves treated with cadmium, we have not shown changes in MDA production compared to controls. Cope with the stress of cadmium, bean seedlings mobilize antioxidant systems to eliminate reactive oxygen species (ROS). We noted disruption of the activities of antioxidant enzymes (SOD, CAT, GPX, and enzymes ascorbate-glutathione cycle), changes in relationships ASA / DHA and GSH / GSSG and increased production of phenolic compounds. In roots, organs accumulate Cd, we noted an increase in phytochelatin content and a change in the expression of some genes related to metal stress (hsp70.1, CuZnSODcy, GR). Meristematic areas of these bodies, we also showed a decrease in the mitotic index, micronuclei induction and the appearance of chromosomal abnormalities affecting structure and numbers of chromosomes.
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Submitted on : Monday, August 27, 2012 - 10:36:05 AM
Last modification on : Tuesday, February 23, 2021 - 3:16:03 PM
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  • HAL Id : tel-00725461, version 1
  • PRODINRA : 244639

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Dalila Souguir. Modifications métaboliques, moléculaires et génotoxicité induites par le cadmium chez Vicia faba. Biologie végétale. Université Blaise Pascal - Clermont-Ferrand II; Université d'Auvergne - Clermont-Ferrand I; Université du 7 Novembre, Carthage, Tunisie, 2009. Français. ⟨NNT : 2009CLF21937⟩. ⟨tel-00725461⟩

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