Environmental Effects on Absorption and Translocation of 2,4,5-T in Winged Elm

The absorption and translocation of foliarly applied 14 C-labeled (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T-1- 14 C) in winged elms ( Ulmus alata Michx.) as affected by season of application, air temperature, and soil moisture were determined by autoradiography of bark samples and liquid scintillation counting of leaf tissue. Treatments at 3-week intervals throughout the growing season showed highly variable trends in absorption and translocation within and between growing seasons. Seasonal variations in the absorption of 14 C-2,4,5-T were similar to the variations in translocation. Translocation into the stem closely correlated with absorption into the leaves. Higher daily temperatures of 24 to 40 C appeared to enhance absorption and translocation. Variations in soil moisture showed little effect on absorption; whereas, a decrease in soil moisture reduced translocation from leaves to roots.