title: The phytotoxic effect of exogenous ethanol on Euphorbia heterophylla L.
abstract: This study investigated the effects of exogenously applied ethanol on Euphorbia heterophylla L., a troublesome weed in field and plantation crops. Ethanol at concentrations ranging from 0.25 to 1.5% caused a dose-dependent inhibition of germination and growth of E. heterophylla. Measurements of respiratory activity and alcohol dehydrogenase (E.C. 1.1.1.1) activity during seed imbibition and initial seedling growth revealed that ethanol induces a prolongation of hypoxic conditions in the growing tissues. In isolated mitochondria, ethanol inhibited the respiration coupled to ADP phosphorylation, an action that probably contributed to modifications observed in the respiratory activity of embryos. A comparison of the effects of methanol, ethanol, propanol and acetaldehyde on germination and growth of E. heterophylla indicates that alcohol dehydrogenase activity is required for the observed effects, with the conversion of ethanol to acetaldehyde playing a role in the ethanol-induced injuries.
authors.affiliation: Laboratory of Biological Oxidations, Department of Biochemistry, University of Maringá, 87020900 Maringá, Brazil.
authors.forename: Kátia Aparecida
authors.initials: KA
authors.lastname: Kern
authors.forename: Erica Marusa
authors.initials: EM
authors.lastname: Pergo
authors.forename: Fernanda Lima
authors.initials: FL
authors.lastname: Kagami
authors.forename: Luis Saraiva
authors.initials: LS
authors.lastname: Arraes
authors.forename: Maria Aparecida
authors.initials: MA
authors.lastname: Sert
authors.forename: Emy Luiza
authors.initials: EL
authors.lastname: Ishii-Iwamoto
mesh_terms: D000079:Acetaldehyde / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000378:metabolism; D000426:Alcohol Dehydrogenase / Q000378:metabolism*; D000438:Alcohols / Q000494:pharmacology; D019069:Cell Respiration / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000633:toxicity*; D028481:Euphorbia / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects*; D010100:Oxygen / Q000378:metabolism*; D010766:Phosphorylation; D010935:Plant Diseases / Q000139:chemically induced*; D036226:Seedlings / Q000187:drug effects / Q000502:physiology; D012639:Seeds / Q000187:drug effects / Q000502:physiology
chemical_list: D000438:Alcohols; D000431:Ethanol; D000244:Adenosine Diphosphate; D000426:Alcohol Dehydrogenase; D000079:Acetaldehyde; D010100:Oxygen