Site of Uptake and Translocation of14C-Buthidazole in Corn (Zea mays) and Redroot Pigweed (Amaranthus retroflexus)

Abstract

Uptake and translocation of14C-buthidazole {3-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-4-hydroxy-1-methyl-2-imidazolidinone} in corn (Zea maysL.) and redroot pigweed (Amaranthus retroflexusL.) were studied following both foliar and root treatments under greenhouse and growth chamber environments. Following foliar application,14C-buthidazole was absorbed by the leaves of corn and redroot pigweed seedlings in similar amounts. Translocation occurred only toward the tip of the treated leaves in corn, whereas in redroot pigweed the14C moved both acropetally and basipetally. Rapid uptake by the roots and rapid movement to the leaves via the xylem seems to be the main pathway of uptake and translocation of14C-buthidazole supplied to the roots of redroot pigweed plants. Uptake by both the roots and the emerging coleoptile and transport to the foliage seems to be the pattern of absorption and translocation of buthidazole in corn following preemergence application. Differences in absorption did not appear to be an important factor contributing to selectivity of buthidazole between corn and redroot pigweed. However, translocation of14C-buthidazole supplied to the roots was faster to the redroot pigweed shoots than to corn shoots.