Presence of 14c Activity in Root Exudates and Guttation Fluid From Agropyron Repens Treated With 14c‐labelled Glyphosate

Summary The herbicide, N‐phosphonomethyl glycine (glyphosate), is readily absorbed by the foliage and translocated in the phloem of Agropyron repent (L.) Beauv. The roots and rhizomes were active sinks and, 8 days following herbicide treatment, 14C accumulated at the rhizome nodes, especially at the apical buds. Appreciable amounts of [14C]glyphosate were exuded from intact roots into surrounding solutions but very low levels occurred in the guttation drops collected from the leaf tips. Some implications of the work are discussed.