Absorption and Translocation of Glyphosate by Carrot Infected by Swamp Dodder

Abstract

Absorption of “C-labeled glyphosate by whole carrot (Daucus carota L.) plants infected or not infected by swamp dodder (Cuscuta gronovii Willd ex R & S) increased from 14% 1 day after treatment to 56% 14 days after treatment. Absorption of 14C-labeled glyphosate did not increase from 14 to 45 days after treatment. 14Carbon-labeled glyphosate appeared in the carrot root 1 day after application and its concentration increased with time in both infected and noninfected plants until 14 days after treatment. From 14 to 45 days after treatment, the concentration of 14C-labeled glyphosate in the roots decreased. At 1 day after treatment, dodder tissue contained as much 14C-labeled glyphosate as any physiological sink in the carrot. At 45 days after treatment, dodder tissue contained more 14C-labeled glyphosate than all other physiological sinks, except the petiole of the treated leaf. Swamp dodder stems had absorbed 14C-labeled glyphosate directly from a solution within 1 day after treatment. Chemical name used: N-(phosphonomethyl)glycine (glyphosphate).