Alteration of Transpiration and Dry Matter with Atrazine

Root applications of 9.0 μM 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) to soybean plants (Glycine max (L.) Merr., var. Chippewa) for 4 hr significantly reduced their transpiration rates. Similar reductions in transpiration rate were elicited by foliar applications of 900 μM. All atrazine treatments that reduced transpiration prevented dry weight accumulation by the plants and increased plant hydration. Root additions of glucose to de-rooted plants treated with atrazine had no influence on the transpiration reduction due to atrazine treatment but caused an increase in dry weight accumulation. There was a rapid accumulation of 14C-atrazine in the roots of the soybean plants from the culture solution with subsequent movement to the leaves. Leakage of 14C-atrazine out of the roots into the water medium after treatment termination was observed.