The Effect of Site of Application of14C-Fluazifop on Its Uptake and Translocation by Quackgrass (Agropyron repens)

Abstract

The effect of site of application on uptake and translocation of the butyl ester of fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy] phenoxy] propanoic acid} by quackgrass [Agropyron repens(L.) Beauv. # AGRRE] was investigated using14C-labeled herbicide and intact plants. Uptake and distribution of the label were significantly greater from the abaxial than from the adaxial surface of leaves. The addition of a nonionic surfactant4to the treatment solution increased the uptake significantly only through the adaxial surface. Uptake of14C by the apical, middle, and basal regions of the treated leaf lamina did not differ significantly. However, movement of the14C-label to stem areas and leaves both above and below treated leaves was greater from lamina base applications than from treatments to the lamina apex and middle. The older leaves absorbed more herbicide than did younger leaves, but the pattern of translocation did not differ. Considerably greater translocation occurred from treatments to the outside of the leaf sheaths in the lower regions of the stem than from applications to the upper leaf sheaths, with the14C-label moved to young and old leaves, roots, and rhizomes. Uptake from applications to the outside of the upper leaf sheaths also resulted in improved translocation mainly within the stem areas and into upper leaves.