TY - JOUR

T1 - Studies on octylphenoxy surfactants

T2 - XI. Effect on NAA diffusion through the isolated tomato fruit cuticular membrane

AU - Knoche, Moritz

AU - Bukovac, Martin J.

PY - 1993

Y1 - 1993

N2 - The effect of a homologous series of octylphenoxy surfactants [2‐{α‐[4‐(1,1,3,3‐tetramethylbutyl)phenoxy]poly(2‐ethoxy)}ethanol;‚ Triton‐X’ series], with five (TX‐45), 9–10 (TX‐100), 16 (TX‐165) and 40 (TX‐405) units of ethylene oxide (EO) on penetration of NAA [2‐(1‐naphthyl)acetic acid] through enzymatically isolated tomato (Lycopersicon esculentum Mill.) fruit cuticles was investigated. Surfactant effects on NAA flux were related to EO chain length and to surfactant concentration, compared on a basis relative to the critical micelle concentration (CMC, 2.5 × CMC and CMC/2.5). At concentrations above the CMC, TX‐45 and TX‐100 increased NAA flux 2.5‐ and 1.5‐fold, respectively, while TX‐165 was without effect and TX‐405 decreased NAA flux 0.7‐fold. At concentrations below the CMC, all four surfactants increased NAA penetration by 1.1‐ to 1.3‐fold. Time‐course studies of NAA flux on addition of surfactant revealed that, where NAA flux always increased it did so slowly, but any decrease of flux occurred rapidly. Sorption of NAA by cuticular membranes decreased progressively with increased EO chain length at surfactant concentrations 2.5 × CMC. Below the CMC, surfactants had little or no effect on NAA sorption. Our data provide evidence that surfactants increase transcuticular penetration of NAA by increasing the diffusion coefficient and, hence, the mobility of NAA in the cuticle.

AB - The effect of a homologous series of octylphenoxy surfactants [2‐{α‐[4‐(1,1,3,3‐tetramethylbutyl)phenoxy]poly(2‐ethoxy)}ethanol;‚ Triton‐X’ series], with five (TX‐45), 9–10 (TX‐100), 16 (TX‐165) and 40 (TX‐405) units of ethylene oxide (EO) on penetration of NAA [2‐(1‐naphthyl)acetic acid] through enzymatically isolated tomato (Lycopersicon esculentum Mill.) fruit cuticles was investigated. Surfactant effects on NAA flux were related to EO chain length and to surfactant concentration, compared on a basis relative to the critical micelle concentration (CMC, 2.5 × CMC and CMC/2.5). At concentrations above the CMC, TX‐45 and TX‐100 increased NAA flux 2.5‐ and 1.5‐fold, respectively, while TX‐165 was without effect and TX‐405 decreased NAA flux 0.7‐fold. At concentrations below the CMC, all four surfactants increased NAA penetration by 1.1‐ to 1.3‐fold. Time‐course studies of NAA flux on addition of surfactant revealed that, where NAA flux always increased it did so slowly, but any decrease of flux occurred rapidly. Sorption of NAA by cuticular membranes decreased progressively with increased EO chain length at surfactant concentrations 2.5 × CMC. Below the CMC, surfactants had little or no effect on NAA sorption. Our data provide evidence that surfactants increase transcuticular penetration of NAA by increasing the diffusion coefficient and, hence, the mobility of NAA in the cuticle.

UR - http://www.scopus.com/inward/record.url?scp=84989695158&partnerID=8YFLogxK

U2 - 10.1002/ps.2780380216

DO - 10.1002/ps.2780380216

M3 - Article

AN - SCOPUS:84989695158

VL - 38

SP - 211

EP - 217

JO - Pesticide Science

JF - Pesticide Science

SN - 0031-613X

IS - 2-3

ER -