Absorption and translocation of glyphosate in Erythroxylum coca and E-novogranatense

Absorption and translocation of C-14-glyphosate was studied in greenhouse-g rown Erythroxylum coca and E. novogranatense. Autoradiography indicated tha t translocation patterns were similar for both species and that E. novogran atense absorbed and translocated more glyphosate than E. coca. In both youn g and mature plants, absorption of leaf-applied C-14-glyphosate increased w ith increased exposure rime, and 288 h after application, absorption was hi gher in E. novogranatense (79 and 52% of applied, respectively) compared wi th E. coca (60 and 14% of applied, respectively). Similarly, translocation of C-14-glyphosate increased with time in both species. In mature plants, a fter 288 h more C-14-glyphosate translocated in E. novogranatense (6.9% of applied) than E. coca (2.5%), but the opposite occurred in young plants. Mo st of the radioactivity translocated from the treated leaf accumulated in t he main stems and roots of both species with little accumulation in tissues above the treated leaf. However, most of the applied radioactivity remaine d in the treated leaf regardless of growth stage and species. The absorptio n of C-14-glyphosate in young and mature plants off. cora was 1.3 and 3.6 r imes lower, respectively, than in E. novogranatense 288 h after treatment. Differences in absorption and translocation of glyphosate in E. coca and E. novogranatense may partially explain the reported differential response to glyphosate.