Effects of Fluometuron, Prometryne, Ametryne, and Diuron on Growth of Two Lemna Species

Abstract

The effect of the herbicides Fluometuron, Prometryne, Ametryne and Diuron on the autotrophic growth of the aquatic species Lemna major L. and L. perpusilla Torr. was determined. Fluometuron was the least toxic chemical to both species. Diuron was the most toxic herbicide to L. major, Ametryne most toxic to L. perpusilla. Concentrations of herbicides causing 50 percent growth inhibition of L. major were as follows: a) Fluometuron, 2.6 X 10^-6 M; b) Prometryne, 3.5 X 10^-7 M; c) Ametryne, 2.30 X 10^-7 M; and d) Diuron, 1.75 X 10^-7 M. Concentrations of herbicides causing 50 percent growth inhibition of L. perpusilla were as follows: a) Fluometuron, 2.05 X 10^-6 M; b) Diuron, 6.4 X 10^-8 M; c) Prometryne, 5.4 X 10^-8 M; and d) Ametryne, 4.6 X 10^-8 M. These herbicides applied at micromolar concentrations proved to be phytotoxic to both Lemna species tested.