title: Effects of poly- and monodisperse surfactants on 14C-epoxiconazole diffusion in isolated cuticles of Prunus laurocerasus.
abstract: BACKGROUND
  Surfactants are known to enhance the foliar uptake of agrochemicals. It was the aim of this study to compare the enhancing effect of three polydisperse surfactants (Brij 30, Plurafac LF300 and Wettol LF700) and five monodisperse alcohol ethoxylates (C12 E3, C12 E4, C12 E5, C12 E6 and C12 E8) on (14)C-epoxiconazole diffusion in cuticles isolated from cherry laurel (Prunus laurocerasus L.).
  
  
  RESULTS
  Rate constants (k*) of (14) C-epoxiconazole diffusion were measured in the presence and in the absence of the surfactants. Polydisperse surfactants increased the rates of foliar penetration of (14) C-epoxiconazole by factors of between 8 and 16. With monodisperse surfactants, enhancing effects on cuticular penetration were 2-16-fold. Effects were highest with alcohol ethoxylates of intermediate size, whereas they were lower for the smaller, more lipophilic and the larger, more polar monomers. In addition, diffusion of four monodisperse alcohol ethoxylates (C12 E3, C12 E4, C12 E5 and C12 E6 ) across cuticles was measured. Rate constants of alcohol ethoxylates decreased with decreasing lipophility and increasing molecular weight.
  
  
  CONCLUSIONS
  The results indicate that enhancement of foliar penetration across cuticles by surfactants was most efficient when both (14)C-epoxiconazole and surfactants had similar mobilities in the transport-limiting barrier of the cuticles. This observation should be of interest in future strategies to optimise foliar uptake of agrochemicals using surfactants.
authors.affiliation: Institute of Cellular and Molecular Botany, Department of Ecophysiology, University of Bonn, Bonn, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Gutenberger
authors.forename: Viktoria V
authors.initials: VV
authors.lastname: Zeisler
authors.forename: Rainer
authors.initials: R
authors.lastname: Berghaus
authors.forename: Helmut
authors.initials: H
authors.lastname: Auweter
authors.forename: Lukas
authors.initials: L
authors.lastname: Schreiber
mesh_terms: D016573:Agrochemicals / Q000737:chemistry*; D002250:Carbon Radioisotopes / Q000032:analysis; D004058:Diffusion; D004852:Epoxy Compounds / Q000737:chemistry*; D004987:Ethers / Q000737:chemistry; D006018:Glycols / Q000737:chemistry; D019441:Plant Epidermis / Q000737:chemistry*; D027861:Prunus / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D014230:Triazoles / Q000737:chemistry*
chemical_list: D016573:Agrochemicals; D002250:Carbon Radioisotopes; D004852:Epoxy Compounds; D004987:Ethers; D006018:Glycols; D013501:Surface-Active Agents; D014230:Triazoles; C109476:epoxiconazole