Effect of 2,4-D on Ametryne Toxicity

Abstract

Nontoxic concentrations of 2,4-D [(2,4-dichlorophenoxy)acetic acid] increased the toxicity of ametryne [2-(ethylamino)-4-(isopropylamino)-6-(methylthio)-s-triazine], when applied to the roots of waterhyacinth [Eichornia crassipes(Mart.) Solms], when applied to the roots or foliage of corn (Zea maysL.), and to a lesser extent, when applied to the roots of soybean [Glycine max(L.) Merr.]. Nontoxic concentrations of 2,4-D frequently also increased the absorption of ametryne, water, and radioactive calcium by all three species. Mixtures containing toxic concentrations of 2,4-D with ametryne were not synergistic and sometimes the mixtures were less toxic than ametryne alone. Toxic concentrations of 2,4-D also decreased plant dry weight and the absorption of ametryne, water, and calcium. Low concentrations of ametryne increased the absorption of water and sometimes calcium while high concentrations decreased dry weight and the absorption of water and calcium.