Absorption, Distribution, and Root Exudation of 2,4,5-T and Picloram by Ash and Maple
FORT DETRICK FREDERICK MD
Pagination or Media Count:
Liquid scintillation and autoradiography were utilized in conjunction with paper chromatography to study the uptake, distribution, and root exudation of foliarly applied C14-picloram 4-amino-3,5,6-trichloropicolinic acid and C14-2,4,5-T 2,4,5-trichlorophenoxyacetic acid in red maple, green ash, and white ash. A leaf-washing technique, which allowed direct counting of the herbicide retained on the surface of the treated leaves, revealed that a greater amount of 2,4,5-T than of picloram was washed off the leaves of all species after 22 days. Autoradiography indicated that 2,4,5-T was distributed throughout ash and ample tissues in greater quantities than picloram and microautoradiography of green ash stem tissue showed possible xylem to phloem exchange. Both picloram and 2,4,5-T were translocated acropetally and basipetally in all species, indicating utilization of both the apoplast and symplast by these two herbicides. Significant root loss of both picloram and 2, 4,5-T was demonstrated in all three species. Greater root loss of both herbicides occurred in red maple than in the two species of ash.
- Anatomy and Physiology