Absorption and Translocation of Simazine in Parrotfeather

Root applications of 2-chloro-4,6-bis(ethylamino)- s -triazine (simazine) at concentrations greater than 1.0 × 10 -7 M inhibited growth of parrotfeather ( Myriophyllum brasiliense Camb.). Chromatographic analysis of exudate from detopped parrotfeather plants indicated that simazine was being tranlocated primarily as the intact molecule. A correlation coefficient of 0.985 was observed between the amount of simazine- 14 C removed from the treatment solution and transpiration during a 6-hr period. Absorption of simazine- 14 C by parrotfeather roots of intact plants was linear for the first 4 hr followed by a gradual decrease at the end of 6 hr. Simazine- 14 C at 1 and 2 hr after root applications was highest in the roots, intermediate in the lower part of the shoot, and lowest in the upper part of the shoot. After 192 hr, simazine- 14 C accumulated in the top of the shoot in a concentration higher than in the lower part of the shoot or the roots. A correlation coefficient of 0.988 was found between the amount of simazine- 14 C present in the tissue and the treatment concentration over a range of 1.2 × 10- 6 to 5.0 × 10- 6 M.