title: Absorption, translocation and metabolism of bispyribac-sodium on rice seedlings under cold stress.
abstract: BACKGROUND
  Rice production is highly affected by weed competition. The efficacy of chemical weed control and crop safety is a function of absorption, translocation and metabolism of herbicides. This study investigates the effect of cold stress 22/16 °C (day/night) on absorption, translocation and metabolism of (14)C-bispyribac-sodium on rice seedlings.
  
  
  RESULTS
  Maximum (14)C-bispyribac-sodium absorption occurred at 24 h after herbicide treatment and was stimulated by the warm 30/22 °C (day/night) temperature. A large amount of total absorbed herbicide was retained in the treated leaf, indicating that bispyribac-sodium had minimal translocation to other plant parts. Piperonyl-butoxide (a P450 inhibitor) plus herbicide caused greater injury than the herbicide alone. In addition, injury on rice plants was enhanced by exposure to cold, emphasizing the negative effect on herbicide metabolism. In the thin-layer chromatography metabolism experiment, cold-grown plants had higher injury and retained more of the parent herbicide than plants grown at a warm temperature.
  
  
  CONCLUSIONS
  Cold stress reduces bispyribac-sodium absorption and metabolism in rice, but has no effect on translocation.
authors.affiliation: Departamento de Fitossanidade, Universidade Federal de Pelotas (UFPel), Capão do Leão, Pelotas, RS, Brazil.
authors.forename: Luiz Fernando D
authors.initials: LF
authors.lastname: Martini
authors.affiliation: Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR, USA.
authors.forename: Nilda R
authors.initials: NR
authors.lastname: Burgos
authors.affiliation: Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina-Epagri/Estação Experimental de Itajaí, Itajaí, SC, Brazil.
authors.forename: José Alberto
authors.initials: JA
authors.lastname: Noldin
authors.affiliation: Departamento de Fitossanidade, Universidade Federal de Pelotas (UFPel), Capão do Leão, Pelotas, RS, Brazil.
authors.forename: Luis Antonio
authors.initials: LA
authors.lastname: de Avila
authors.affiliation: Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR, USA.
authors.forename: Reiofeli A
authors.initials: RA
authors.lastname: Salas
mesh_terms: D001565:Benzoates / Q000378:metabolism*; D003080:Cold Temperature; D006540:Herbicides / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism*; D010882:Piperonyl Butoxide / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D011743:Pyrimidines / Q000378:metabolism*; D036226:Seedlings / Q000378:metabolism
chemical_list: D001565:Benzoates; D006540:Herbicides; D011743:Pyrimidines; C549011:bispyribac; D010882:Piperonyl Butoxide
keywords: P450 monooxygenase; herbicide selectivity; injury; low temperature