title: Phosphorous and sulfur nutrition modulate antioxidant defenses in Myracrodruom urundeuva plants exposed to arsenic.
abstract: We investigated if plant nutrition and antioxidant system activation are correlated features of arsenic (As)-tolerance in Myracrodruom urundeuva. Plants were grown for 120 days in substrates with 0, 10, 50 and 100mg Askg(-1) and its As-tolerance was demonstrated. As-concentrations greater than 10mgkg(-1) decreased plant growth and photosynthesis but did not induce plant death. Plants coupled alterations in stomatal conductance and transpiration to avoid As-deleterious effects to the photosynthetic apparatus. As-toxicity in M. urundeuva was due to lipid peroxidation induced by hydrogen peroxide accumulation. Ascorbate peroxidase (APX) and gluthatione peroxidase (GPX) had central roles in hydrogen peroxide (H2O2) scavenging in leaves, and their activities were linked to changes in redox potentials (ascorbate and glutathione pools). APX and GPX inactivation/degeneration led to H2O2 accumulation and related lipid peroxidation. Increased phosphorus (P) and sulfur (S) concentrations in leaves were related to increased APX and GPX activities by stimulating increases in glutathione biosynthesis. We concluded that P and S nutrition were directly linked to As-tolerance in M. urundeuva plants by increasing antioxidant system activities.
authors.affiliation: Université du Québec à Montréal, Institut des Sciences de l'environnement, Succ. Centre-Ville, C.P. 8888, H3C 3P8 Montréal, Québec, Canada. Electronic address: marcelopgom@yahoo.com.br.
authors.forename: M P
authors.initials: MP
authors.lastname: Gomes
authors.affiliation: Universidade Federal de Lavras, Departamento de Biologia, Campus UFLA, C.P. 3037, 37200-000 Lavras, MG, Brazil.
authors.forename: A M
authors.initials: AM
authors.lastname: Soares
authors.affiliation: Universidade Federal de Minas Gerais, Departamento de Botânica, C.P. 486, 31270-970 Belo Horizonte, MG, Brazil.
authors.forename: Q S
authors.initials: QS
authors.lastname: Garcia
mesh_terms: D027926:Anacardiaceae / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism*; D001151:Arsenic / Q000633:toxicity*; D060387:Ascorbate Peroxidases / Q000378:metabolism; D004785:Environmental Pollutants / Q000633:toxicity*; D005979:Glutathione Peroxidase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation; D010758:Phosphorus / Q000378:metabolism*; D010788:Photosynthesis; D018515:Plant Leaves / Q000201:enzymology / Q000378:metabolism; D013455:Sulfur / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D004785:Environmental Pollutants; D010758:Phosphorus; D013455:Sulfur; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D005979:Glutathione Peroxidase; D001151:Arsenic
keywords: Ascorbate; Enzymes; Glutathione; Phytoremediation; Trace elements