Absorption and Translocation of Atrazine in Quackgrass

The effect of temperature and relative humidity on root and foliar uptake of C-labeled atrazine (2-chloro-4-ethyl- amino-6-isopropylamino-s-triazine) in quackgrass (Agropyron repens (L.) Beauv.) was studied in a controlled environment growth chamber. Uptake and translocation of root-fed atrazine increased as temperature increased. Greater uptake and translocation of root- fed atrazine occurred under low relative humidity than under high relative humidity. Slightly greater uptake and translocation of foliar-applied atrazine occurred as temperature was increased from 60 to 80 F. HE absorption, translocation, and phytotoxic action T of an herbicide may be markedly influenced by environmental conditions. Currier and Dybing (3) re- viewed the literature concerning foliar penetration of herbicides and concluded that, in general, an increase in temperature and humidity effects a greater response of plants to a foliar-applied herbicide. Studies (2) on ab- sorption and translocation of foliar-applied radioactive