title: Enzymatic adaptations to arsenic-induced oxidative stress in Zea mays and genotoxic effect of arsenic in root tips of Vicia faba and Zea mays.
abstract: Agronomic plant species may display physiological and biochemical responses to oxidative stress caused by heavy metals and metalloids. Zea mays plants were grown hydroponically for eight days at different concentrations of As (0, 134 and 668 μM) and at different pH (4, 7 and 9). Metabolic variations in response to As toxicity were measured using physiological parameters and antioxidant enzymatic activities. A significant decrease in SOD activity was observed in the leaves and roots of Z. mays with the majority of As treatments. As decreased G-POX activity less in leaves than in roots. An increase in the concentration of As increased APX activity in leaves and roots, except As(V) at pH 4 and pH 9 in the leaves and As(III) at pH 9 in the roots, when there was a significant decrease in APX activity at low As concentrations. After exposure to As(V), CAT activity was the same as in the control. As(III) led to an increase in CAT activity in leaves and to a decrease in roots. With increasing concentrations of As(III), CAT activity increased in both leaves and roots whatever the pH. To obtain more detailed knowledge on the effects of arsenate and arsenite exposure on Vicia faba and Z. mays, root meristems were also examined. Roots were fed hydroponically with 134, 334, 534 and 668 μM arsenate or arsenite and 4 × 10(-3)M of maleic hydrazide as positive control, at three different pH. Physiological parameters, the mitotic index and micronuclei frequencies were evaluated in root meristems. At all three pH, the highest As(V) and As(III) concentrations induced a substantial modification in root colour, increased root thickness with stiffening, and reduced root length. High concentrations also caused a significant decrease in the mitotic index, and micronucleus chromosomic aberrations were observed in the root meristems of both species.
authors.affiliation: Clermont université, Université Blaise-Pascal, Piaf, BP 10448, 63000 Clermont-Ferrand, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Duquesnoy
authors.forename: Gabrielle Marie
authors.initials: GM
authors.lastname: Champeau
authors.forename: Germaine
authors.initials: G
authors.lastname: Evray
authors.forename: Gérard
authors.initials: G
authors.lastname: Ledoigt
authors.forename: Agnès
authors.initials: A
authors.lastname: Piquet-Pissaloux
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology; D000975:Antioxidants / Q000378:metabolism; D001152:Arsenicals; D060387:Ascorbate Peroxidases; D018533:Biomass; D002374:Catalase / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D015162:Micronucleus Tests; D008940:Mitotic Index; D018384:Oxidative Stress; D009195:Peroxidase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology; D010940:Plant Proteins / Q000032:analysis / Q000096:biosynthesis; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D012639:Seeds; D013482:Superoxide Dismutase / Q000378:metabolism; D031307:Vicia faba / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D003313:Zea mays / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*
chemical_list: D000975:Antioxidants; D001152:Arsenicals; D010940:Plant Proteins; D010544:Peroxidases; C121048:guaiacol peroxidase; D060387:Ascorbate Peroxidases; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase