Multifunctional Mode of Action of Substituted Nitrodiphenylethers in Scenedesmus Cells

Abstract

Nitrodiphenylethers substituted with Cl, CF3, and other comparatively simple substituents are compared with respect to their primary effects on the photosynthetic apparatus. These are direct electron-transport inhibition, energy-transfer inhibition (of ATP synthesis), and pigment bleach­ ing, the latter accompanied by decrease of electron transport activity. Certain substituents and their positions at the diphenylether skeleton can be correlated with a particular influence on these phytotoxic effects. The unicellular alga, Scenedesmus, is an appropriate species to fumisch quantitative data on these primary herbicidal modes of action within a 24-h assay period.