Trifluralin and root growth¹

Trifluralin inhibited root elongation and induced root tip swelling of Zea mays and Triticum aeslivum. Time-course experiments showed these effects occurred within 6 hr of treatment. As the roots treated with trifluralin enlarged, there was a concomitant increase in root growth inhibition. Bioassays were devised to quantitatively measure the radial enlargement of trifluralin-treated roots. Histological observations indicated that swollen root tissue was growing in a non-polar manner. The root swelling effect of trifluralin was inhibited 70% by the reducing agent, 2,3-dimercaptopropanol. Trifluralin had no effect on SH content of root tip protein of Z.mays.