Absorption and translocation of MON 37500 in wheat and other grass species

A growth chamber study was conducted to evaluate the effects of temperature and soil moisture on the absorption and translocation of the new sulfonylu rea herbicide, MON 37500, in wheat, jointed goatgrass, wild oat, and downy brome. Treatment combinations of temperatures-25/23, 15/13, and 5/3 C-and s oil moistures of one-third, two-thirds, and full field capacities were assi gned to the germinated plants. Radiolabeled MON 37500 was applied to the se cond leaf of plants at the three-leaf stage. The plants were then harvested at 6, 24, and 96 h after application. The plants absorbed MON 37500 in the greatest quantity during the first 6 h; however, absorption did continue t o increase over time. Absorption was highest in wheat and lowest in wild oa t. Temperature influenced absorption, while soil moisture status appeared t o have no effect. Translocation of radiolabeled material out of the treated leaf increased over time; however, 90 to 97% of absorbed radioactivity rem ained in the treated leaf 36 h after treatment. Temperature affected transl ocation differently in each species, but increasing soil moisture increased translocation.