ABSTRACT
A wide range of chemically diverse herbicides, including the phenylureas, triazines, and hydroxybenzonitriles, interact with the D1 polypeptide of the reaction center of photosystem II. Variations in the activity of bipyridinium herbicides might in some instances be related to major variations in the endogenous level of scavenging enzymes that could be linked to leaf age, environmental treatment, or seasonal changes. The herbicide aminotriazole has been used as a total-kill weedkiller, and after application leads to distinctive bleaching of leaf tissue. Although this herbicide may possess multiple sites of operation, its primary action is as a peroxisome catalase inhibitor. A major ambition in the field of crop protection is to enhance crop tolerance to herbicides. Considerable work has shown that the endogenous level of glutathione and glutathione-5-transferase can be enhanced by the addition of a so-called herbicide safener, such as N,N-diallyl-2,2-dichloroacetamide.
