Loss of Picloram and 2,4,5-T from the Roots of Ash and Maple Seedlings
FORT DETRICK FREDERICK MD
Pagination or Media Count:
Sublethal concentrations of C14-picloram 4-amino-3,5,6- trichloropicolinic acid and C14-2,4,5-T 2,4,5-trichlorophenoxyacetic acid were foliarly applied to red maple and green ash seedlings grown in nutrient solution. C14-picloram was also applied to the leaves of white ash. Radioactivity was detected in nutrient solution samples from all treated plants within 24 hours. C14-picloram loss through the roots increased over a 3-week period, with the exception of a slight decrease in the amount lost on the 6th and 16th day from the green ash. The total radioactivity in the white ash nutrient solution increased over the 9-day experiment. The nutrient solution samples of the red maple treated with C14-2,4, 5-T yielded radioactivity within 24 hours this amount increased over the 3-week sampling period except for a decrease on the 16th day. The green ash nutrient solution showed C14-2,4,5-T activity at 48 hours and increased throughout the 3 weeks. Greater loss of both labeled herbicides occurred from red maple than from green ash. The fact that C14 activity in the exudates was associated with unaltered herbicide molecules was substantiated by bioassays.