The absorption and translocation of14C-labeled α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) and 2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione methazole from nutrient solutions of various temperatures by(Arachis hypogaeaL. ‘Starr’) seedlings were determined. The accumulation of trifluralin in roots at 24 hr after exposure to trifluralin was greatest at 21 C and decreased at higher temperatures up to 38 C. The amounts of trifluralin translocated and accumulated in hypocotyls, tops, and cotyledons were small but generally increased with temperature. The initial rate of absorption of trifluralin was greater in excised lateral root tips than in tap root tips, but there was a greater accumulation in excised tap roots at 24 hr. The initial rates of absorption were higher for excised lateral roots at high temperatures. Total absorption of trifluralin at equilibrium was not proportional to the initial rates of absorption but was highest at low (21 C) and high (38 C) temperatures for excised lateral roots. The absorption of methazole by roots and translocation to other plant parts increased linearly with temperature, and it tended to accumulate in the mature leaf tissue.

The absorption, translocation, and metabolism of14C-profluralin [N-(cyclopropylmethyl)-α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine] and14C-dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine) in sorghum [Sorghum bicolor(L.) Moench ‘RS6–12′], barnyardgrass [Echinochloa crus-galli(L.) Beauv.], soybean [Glycine max(L.) Merr. ‘Dare’], and Palmer amaranth (Amaranthus palmeriS. Wats.) were determined after treatment with14C-labeled herbicides in nutrient solution for 24 hr at 16 or 38 C.14C-profluralin accumulated in roots to a greater extent at 16 C, while metabolism was greatest at 38 C. Very little14C-profluralin was translocated to the tops of plants. Conversely,14C-dinitramine accumulated in the tops of plants to a greater extent at 38 C. Metabolism was not greatly affected by temperature. These effects may relate to excess toxicity of profluralin at 16 C and dinitramine at 38 C in species which normally exhibit resistance to the herbicides.