The mechanism of linuron phytotoxicity in maize

Abstract

Summary: The mechanism whereby Iinuron changes the functional and structural characteristics of chloroplast membranes was studied. The primary effect of the herbicide, the inhibition of phoiosynihetic electron transport results in an immuediatecessa‐tion of carbon dioxide fixation and alterations in the membrane energization. These are accompanied by secondary processes contributing to phytotoxicity. The fundamental action in its phytotoxicity, as shown in a model system of isolated chloro‐plasts, is the peroxidaiive breakdown of the polyunsaturated membrane lipids. This leads to destruction of the pigments, changes in the energy transfer, disorganization of the chloro‐plast membranes, and accumulation of toxic organic peroxides.

Various effects of the photosystem II – inhibiting herbicides on 5-n-alkylresorcinol accumulation in rye seedlings

“…The non-cyclic photophosphorylation inhibitors may initially result in leaf chlorosis (a photooxidation of chlorophyll) and then develop to necrotic spots (a leakage of cell contents caused by the damage of membrane lipids) in sensitive plants [26,27]. In addition, the phytotoxicity of PSII inhibitors is affected by many environmental factors, especially by light [19].…”