Moisture Stress Effects on Absorption and Translocation of Four Foliar-Applied Herbicides

Abstract

Laboratory experiments with14C-herbicides were conducted with grain sorghum as an indicator species to determine the effects of imposed moisture stress on absorption, precent recovery, and acropetal and basipetal translocation of the butyl ester of fluazifop, the methyl ester of haloxyfop, the ethyl ester of quizalofop, and sethoxydim. Haloxyfop was the only herbicide where recovery decreased between the 3-and 48-h interval. All plants absorbed more of the herbicide at the 48-h interval than at the 3- or 6-h interval under both stressed and non-stressed conditions. Increased drought stress caused more acropetal movement with fluazifop and sethoxydim and less acropetal movement with quizalofop at the 3-h interval. Basipetal transloation, although different among herbicides, responded similarly to imposed moisture stress, which decreased basipetal translocation approximately 19%.