Published online by Cambridge University Press: 12 June 2017
The goal of this research was to determine if differing levels of tolerance to AC 263,222 exist in soybean. 14C-AC 263,222 was foliar-applied to ‘Coker 6955,’ ‘Hartz 6686,’ ‘Hutcheson,’ ‘9581 Pioneer,’ ‘9681 Pioneer,’ and ‘RA 606’ soybean cultivars. Differential absorption of 14C-AC 263,222 was evident among cultivars 48 and 96 h after application. Movement out of the treated leaf was both acropetal and basipetal, indicating xylem and phloem mobility. Although absorption and translocation differences occurred among cultivars, these differences do not explain the differential response of soybean cultivars to AC 263,222. Metabolism of 14C-AC 263,222 differed greatly among cultivars and increased with time. Ninety-six h after application, 9581 Pioneer metabolized 66% of the absorbed 14C-AC 263,222, compared to RA 606, which metabolized only 41%. The large differences in metabolism that occurred 48 and 96 h after application suggest that metabolism is responsible for the differential response of soybean cultivars to AC 263,222.