Observations on the functional action of dicamba (2-methoxy-3,6 dichlorobenzonic acid) in Cyperus rotundus

Abstract

Some aspects related to the foliar penetration of dicamba, the mode of transport of the C-labeled herbicide in leaves pretreated with dicamba, and the effect of dicamba on the transport in the xylem of monuron-Cas have been studied in the nutsedge (Cyperus rotundus L). Under favorable conditions for translocation, dicamba showed foliar penetration. A considerable fraction of the material that penetrates the leaf appears to remain confined externally to the cells, accumulated in intercellular spaces, cell walls, or dissolved in the cuticular layers. Xylem translocation of monmon-C14 in dicamba-treated plants was inhibited 10 days after herbicide application, suggesting a reduction in transpiration or another form of disruption in the conductive tissue in treated plants. When plants were pretreated with dicamba concentrations at the herbicide level and dicamba C was applied afterwards, an evident accumulation of the material was noted in the basal portion of the roots, which can be considered an alteration of the distribution mode described in the literature.