No abstract

Absorption of14C-chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonanide} by Canada thistle [Cirsium arvense(L.) Scop. # CIRAR] was 39% following foliar treatment and 16% when added to a nutrient solution in which the plants were growing. Translocation from the treated organ was limited regardless of treatment method; 10% of the applied14C moved out of the treated leaf and 10% moved from the roots to other parts of the plant following absorption from the nutrient solution. When applied as a foliar treatment,14C-chlorsulfuron had not been metabolized by Canada thistle 48 h later. However, when14C-chlorsulfuron was added to the nutrient solution and absorbed by the roots, nearly 25% of the14C in the plants was present as a polar product(s), 13% had an Rf value identical to benzenesulfonamide standards, and the remaining 62% was chlorsulfuron. Chlorsulfuron was not transformed similarly in a nutrient solution after 6 days in the absence of plants. Suppression of regrowth was the primary injury symptom observed following chlorsulfuron application. Chlorsulfuron also reduced whole plant weight and root bud number and weight.

No abstract

Absorption and translocation of14C-dicamba (3,6-dichloro-o-anisic acid) in seven salt formulations were determined 60 h after application to leaves of soybean [Glycine max(L.) Merr. ‘Williams’] grown in nutrient solution. The dimethylamine (DMA) formulation was consistently absorbed and retained in the plant in amounts equal to or greater (46% of recovered14C) than other formulations (which averaged 19% of recovered14C) when applied without surfactant. Absorption and subsequent retention of the DMA formulation in the plant was least affected of all formulations by the addition of a surfactant. With a surfactant, absorption of the DMA, monoethanolamine (MEA), and inorganic salt formulations was similar (>75% of recovered14C). Addition of seven surfactants to the K-salt of dicamba increased both the amount of14C absorbed by 35 to 56% and the amount recovered in the plant. All surfactants except one enhanced absorption of the K-salt of dicamba to a similar degree. Dicamba exhibited predominantly symplastic translocation with the majority of14C being recovered in the new second trifoliolate leaves and nutrient solution. As much as 66% of the radioactivity absorbed through the leaves was exuded by roots into the nutrient solution 60 h after leaf treatment.