“…Although at present approximately 20 mechanisms of action of herbicides are known [21], over 50% of commercially available herbicides act by reversible binding to photosystem II (PS II), a membrane-protein complex in the thylakoid membranes, which catalyses the oxidation of water and the reduction of plastoquinone [22], and thereby inhibit photosynthesis [23][24][25]. Some organic compounds, possessing an amide (-NHCO-) group, e.g., substituted anilides [11,[15][16][17][18]20], or a wide variety of compounds containing the quinoline system [9,10,[12][13][14]19] were found to interact with tyrosine radicals Tyr Z and Tyr D (or their surroundings) which are situated in D 1 and D 2 proteins on the donor side of PS II. Due to this interaction, interruption of the photosynthetic electron transport occurs.…”