A group of organic compounds based on two linked pyridine rings and including certain agricultural herbicides, notably Paraquat and Diquat. These generally kill all nonwoody plants and are used as nonselective weedkillers. They act by interfering with electron transport in photosynthesis and by generating superoxide anions, which damage chloroplasts and other cell components. These herbicides are also highly toxic to animals, and their use is strictly controlled.
Subjects: Biological Sciences.