Sorption and penetration of atrazine through plant cuticles were inves
tigated using enzymatically isolated tomato and pepper fruit cuticles.
Sorption was rapid and equilibrium was reached within 4 - 6 hours for
the two species. Mean values fdr cuticle/water partition coefficients
(K-cw) were 140 and 131 for pepper and tomato cuticles, respectively.
Sorption was not affected by pH solution between 3.5 and 8 but it was
reduced at pH 1.7. The amount sorbed (nmol mg(-1)) varied linearly wi
th concentration from 1.3 mu M to 0.1 mM. Atrazine was reversibly sorb
ed to cuticles and only 1 to 4% was still retained by cuticles after 4
8 hours washing. Diffusion of atrazine through cuticles increased line
arly with time. Permeability coefficient values determined at 0.1 mM a
trazine were 24.6 and 47.3 nn s(-1) for pepper and tomato fruit cuticl
es, respectively. Comparison with simazine showed that the cuticle/wat
er partition coefficient was markedly lower for this herbicide. K-cw w
as 48.4 and 46.2 for pepper and tomato cuticles, respectively. Diffusi
on of simazine through cuticles was also lower particularly for pepper
cuticles. Copyright (C) 1996 Elsevier Science Ltd.