title: Arsenic toxicity in soybean seedlings and their attenuation mechanisms.
abstract: Even though vast areas contaminated with arsenic (As) are under soybean (Glycine max) cultivation, little is known about the growth and intrinsic antioxidant metabolism of soybean in response to As exposure. Thus, an evaluation was carried out of plant growth, root anatomy, antioxidant system and photosynthetic pigment content under arsenate (As(V)) and arsenite (As(III)) treatment. Soybean seedling growth was significantly affected at 25 μM or higher concentrations of As(V) or As(III), and the toxic effect on root growth was associated with cell death of root tips. Microscopic analysis of cross-sections of As-treated root showed a reduction in the cortex area, dark deposits in cortex cells and broken cells in the outer layer. Similarly, in the vascular cylinder, dark deposits within xylem vessel elements and phloem cell walls were observed. In all the analyzed parameters, the deleterious effect was more evident under As(III) than As(V) treatment. Arsenic-treated soybean seedlings showed increased activity of antioxidant enzymes [total peroxidases (Px) and superoxide dismutase (SOD)] in root and shoot harvested after 2 and 5 d of treatment. However, a reduction in chlorophyll content and an increase in membrane lipids peroxidation were observed. It is suggested that root structural alterations induced by As, such as the particular pattern of dark depositions in the vascular system, could be associated with an adaptation or detoxification mechanism to prevent As translocation to the aboveground tissues.
authors.affiliation: Departamento de Biología Molecular, FCEFQyN, Universidad Nacional de Río Cuarto, Ruta Nacional 36 Km 601, CP 5800 Río Cuarto, Córdoba, Argentina. Electronic address: aarmendariz@exa.unrc.edu.ar.
authors.forename: Ana L
authors.initials: AL
authors.lastname: Armendariz
authors.affiliation: Departamento de Biología Molecular, FCEFQyN, Universidad Nacional de Río Cuarto, Ruta Nacional 36 Km 601, CP 5800 Río Cuarto, Córdoba, Argentina. Electronic address: mtalano@exa.unrc.edu.ar.
authors.forename: Melina A
authors.initials: MA
authors.lastname: Talano
authors.affiliation: Departamento de Morfología Vegetal, FCEFQyN, Universidad Nacional de Río Cuarto, Ruta Nacional 36 Km 601, CP 5800 Río Cuarto, Córdoba, Argentina. Electronic address: ctravaglia@exa.unrc.edu.ar.
authors.forename: Claudia
authors.initials: C
authors.lastname: Travaglia
authors.affiliation: Departamento de Morfología Vegetal, FCEFQyN, Universidad Nacional de Río Cuarto, Ruta Nacional 36 Km 601, CP 5800 Río Cuarto, Córdoba, Argentina. Electronic address: hreinoso@exa.unrc.edu.ar.
authors.forename: Herminda
authors.initials: H
authors.lastname: Reinoso
authors.affiliation: Departamento de Biología Molecular, FCEFQyN, Universidad Nacional de Río Cuarto, Ruta Nacional 36 Km 601, CP 5800 Río Cuarto, Córdoba, Argentina. Electronic address: awevar@exa.unrc.edu.ar.
authors.forename: Ana L
authors.initials: AL
authors.lastname: Wevar Oller
authors.affiliation: Departamento de Biología Molecular, FCEFQyN, Universidad Nacional de Río Cuarto, Ruta Nacional 36 Km 601, CP 5800 Río Cuarto, Córdoba, Argentina. Electronic address: eagostini@exa.unrc.edu.ar.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Agostini
mesh_terms: D000222:Adaptation, Physiological; D000975:Antioxidants / Q000378:metabolism; D001149:Arsenates / Q000378:metabolism / Q000633:toxicity*; D001151:Arsenic / Q000378:metabolism / Q000633:toxicity*; D018053:Arsenites / Q000378:metabolism / Q000633:toxicity*; D018533:Biomass; D018384:Oxidative Stress; D010544:Peroxidases / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000033:anatomy & histology / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D018520:Plant Shoots / Q000033:anatomy & histology / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D036226:Seedlings / Q000033:anatomy & histology / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D013025:Glycine max / Q000033:anatomy & histology / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D001149:Arsenates; D018053:Arsenites; D010940:Plant Proteins; D010544:Peroxidases; D013482:Superoxide Dismutase; C015001:arsenite; D001151:Arsenic; C025657:arsenic acid
keywords: Arsenic; Glycine max; Oxidative stress; Root anatomy; Tolerance