ABSTRACT
Spraying of a sublethal concentration (0.2 mM) of glyphosate to 3-week-old American germander (Teucrium canadense L.) plants promoted the metabolism of the phytohormone indole-3-acetic acid (IAA) and inhibited the elongative growth of the plants. However, a pretreatment of the plant with 0.5 mM 2,6-dihydroxyacetophenone by either applying to the plants or adding to the soil 1 to 3 days before glyphosate application protected the plants from glyphosate-induced inhibition of growth and prevented the decrease in the free IAA level by inhibiting metabolism of IAA. The results suggest that phenolic compounds are involved in glyphosate action that affects IAA metabolism and plant growth.
