title: Effects of glyphosate acid and the glyphosate-commercial formulation (Roundup) on Dimorphandra wilsonii seed germination: Interference of seed respiratory metabolism.
abstract: Glyphosate-formulations are widely used in the Brazilian Cerrado (neotropical savanna) with little or no control, threatening population of the endangered species Dimorphandra wilsonii. We investigated the toxicity of different concentrations (0, 5, 25 and 50 mg l-1) of glyphosate acid and one of its formulations (Roundup®) on seed germination in D. wilsonii. Glyphosate acid and Roundup drastically decreased seed germination by decreasing seed respiration rates. The activation of antioxidant enzymes, ascorbate peroxidase and catalase assure no hydrogen peroxide accumulation in exposed seeds. Glyphosate acid and the Roundup-formulation negatively affected the activities of enzymes associated with the mitochondrial electron transport chain (ETC), with Complex III as its precise target. The toxicity of Roundup-formulation was greater than that of glyphosate acid due to its greater effects on respiration. The herbicide glyphosate must impair D. wilsonii seed germination by disrupting the mitochondrial ETC, resulting in decreased energy (ATP) production. Our results therefore indicate the importance of avoiding (or closely regulating) the use of glyphosate-based herbicides in natural Cerrado habitats of D. wilsonni as they are toxic to seed germination and therefore threaten conservation efforts. It will likewise be important to investigate the effects of glyphosate on the seeds of other species and to investigate the impacts of these pesticides elsewhere in the world.
authors.affiliation: Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Botânica, Avenida Antônio Carlos, 6627, Pampulha, Caixa Postal 486, 31270-970, Belo Horizonte, Minas Gerais, Brazil. Electronic address: marcelopgom@yahoo.com.br.
authors.forename: Marcelo Pedrosa
authors.initials: MP
authors.lastname: Gomes
authors.affiliation: Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Botânica, Avenida Antônio Carlos, 6627, Pampulha, Caixa Postal 486, 31270-970, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Fernanda Vieira
authors.initials: FV
authors.lastname: da Silva Cruz
authors.affiliation: Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Botânica, Avenida Antônio Carlos, 6627, Pampulha, Caixa Postal 486, 31270-970, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Elisa Monteze
authors.initials: EM
authors.lastname: Bicalho
authors.affiliation: Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Botânica, Avenida Antônio Carlos, 6627, Pampulha, Caixa Postal 486, 31270-970, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Felipe Viègas
authors.initials: FV
authors.lastname: Borges
authors.affiliation: Fundação Zoo-Botânica de Belo Horizonte, Departamento de Jardim Botânico, Avenida Otacílio Negrão de Lima, 8000, Pampulha, 31365-450, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Marcia Bacelar
authors.initials: MB
authors.lastname: Fonseca
authors.affiliation: Université du Québec à Montréal, Department of Biological Sciences, GRIL-TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Succ. Centre-Ville, H3C 3P8, Montréal, Québec, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Juneau
authors.affiliation: Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Botânica, Avenida Antônio Carlos, 6627, Pampulha, Caixa Postal 486, 31270-970, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Queila Souza
authors.initials: QS
authors.lastname: Garcia
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001938:Brazil; D007887:Fabaceae / Q000187:drug effects*; D018525:Germination / Q000187:drug effects*; D005998:Glycine / Q000031:analogs & derivatives* / Q000633:toxicity; D006540:Herbicides / Q000633:toxicity*; D012639:Seeds / Q000378:metabolism; D000097797:Glyphosate
chemical_list: D000975:Antioxidants; D005998:Glycine; D006540:Herbicides; D000097797:Glyphosate
keywords: Agriculture; Antioxidant; Cerrado; Herbicides; Mitochondria; Toxicity