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.