Absorption, Translocation, and Metabolism of Fluridone in Selected Crop Species

The uptake, translocation, and metabolism of the herbicide fluridone 1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone was studied in cotton (Gossypium hirsutum L. ‘Stoneville 213’) (fluridone tolerant) and corn (Zea mays L. ‘Migro 5040’), soybean [Glycine max (L.) Merr. ‘Calland’], and rice (Oryza sativa L. ‘Nato’) (fluridone susceptible). Uptake studies with 14C fluridone demonstrated that all species absorbed radioactivity with rice having the highest concentration. Equivalent concentrations of radioactivity were observed in corn, cotton, and soybean. Absorbed fluridone was retained primarily in the roots and the basal region of the stem of cotton, while in the herbicide susceptible species fluridone was readily translocated into the shoots. No appreciable metabolism of fluridone was observed in the roots or shoots of cotton and soybean. Tolerance of cotton to fluridone was primarily attributed to the limited translocation of the compound.