Glyphosate intercepted by leaves is first adsorbed on the cuticle
prior to diffusing into leaf organic matter and being absorbed by
leaves. Desorption with a water solution made it possible to estimate
the amounts of glyphosate adsorbed, while the absorbed
fraction could be taken as the amount of glyphosate remaining in
the plant residues after water desorption. Foliar absorption of
glyphosate in washed leaves corresponded to 27.0 ± 10.6% AR in GT
oilseed rape, and to 30.6 ± 14.9% AR in non-GT oilseed rape. These
amounts are consistent with those reported by Doublet et al.
(2009), but they are lower than those evidenced by Nandula et al.
(1999). This may be due to the latter using glyphosate solutions
containing surfactants, as opposed to pure water solutions in our
case. Therewere no significant differences in glyphosate absorption
between GT and non-GT oilseed rape (P > 0.05).