INFLUENCE OF SURFACTANTS ON FOLIAR UPTAKE OF HERBICIDES

摘要

The effect of surfactants on the uptake of herbicides into plants depends not only on their chemical structure (hydrophobe and hydrophile moieties) and concentration, but also on the concentration of a.i.'s and the leaf surface character of the plant species. Non-ionic surfactants of higher ethylene oxide (EO) content provided greater uptake enhancement for glyphosate, whereas those of lower EO content promoted 2,4-D uptake. A C_(13)/C_(15) linear alkane appeared to be an efficient hydrophobe for the uptake of both herbicides. Glyphosate uptake into both bean and wheat foliage increased steadily with increasing surfactant concentration and reached a maximum at 0.5%. In the presence of a specific surfactant, higher herbicide uptake was obtained with higher concentrations of glyphosate, but lower concentrations of 2,4-D. The stomatal uptake of glyphosate in the presence of an oganosilicone surfactant also varied with plant species and surfactant concentration.