Root Absorption and Translocation of Atrazine in Oats

Visible symptoms of injury in susceptible oat plants were not apparent until 4 days after initial exposure to 1 ppm 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) solu- tion. However, the herbicide affected normal absorption and translocation over this period of time. The expected translocation and uniform distribution of xylem transported atrazine-C14 was stopped after 2 days of exposure to atrazine. The reduction in translocation of atrazine-C14 to the shoot apices in early stages of herbicidal injury was not due to reduced asborption but very likely to some other factor such as reduced transpiration. Reduc- tion in atrazine-C'4 absorption reduced translocation to the shoot apices, but this probably was not an important factor in the early stages of injury. Absorption of atrazine-C14 by oat plants was not reduced tuntil 3 days of exposure to atrazine. A reduction in carbohydrate concentration, resulting in injury to root tissues, nay be responsible for reduction in total atrazine-_C4 absorption.