Glyphosate drift effect on some physiological features of eucalyptus plants

Abstract

This work aims to evaluate the effects of a simulated drift of glyphosate at different doses on some physiological characteristics of Eucalyptus grandis. A completely randomized design with five replications was used, where each pot contained an eucalyptus plant and was considered as one repetition. The plants received doses of glyphosate corresponding to 0, 30, 60, 90 and 120g ha-1, in the Scout® commercial formulation. The application was performed in three forms: leaves, stem and whole plant (leaf + stem). For foliar application, the stem was covered with plastic tape to avoid being hit by the solution, and leaves with a plastic bag when the stem was spayed. The application was performed by means ofa steady spray gun equipped with four XR 11002 tips, with a pressure of 200Kpa and a volume of 200l ha-1. Stomatal conductance, transpiration and leaf temperature were measured at 7 days after application (DAA). The eucalypt plants receiving applications in leaves and whole plant showed, at the highest glyphosate dosis (120g ha-1), a transpiration reduced by 22% and an 18% increase of stomatal resistance at 7 DAA. The lowest dose (30g ha-1) applied to the whole plant caused a transpiration stimulation of 18%, and a leaf to air difference in temperature of -1.66°C, while the difference between the highest and lowest dose used was 3.5°C.