COMPARISON OF BIOASSAY TECHNIQUES FOR DETECTING IMAZAQUIN IN SOIL

Three corn root bioassays were evaluated for detecting imazaquin in so il. Two techniques, one which utilized a cone-shaped tube as the growt h container and another, a petri dish, were compared to a method that utilized a thin layer of soil between two 20 by 20 cm glass plates. Co m root growth responded logarithmically to imazaquin regardless of bio assay method. Com was most sensitive to low imazaquin concentrations w hen grown using the glass plate apparatus. At a low concentration (0.5 ng/g) of imazaquin, com root length was reduced 6% using the cone-tub e, 2% using the petri dish, and 24% using the glass plate method. In c ontrast, the cone-tube method provided a better measure of high imazaq uin concentration (200 ng/g) than the other methods.