ABSTRACT
This chapter aims to catalog herbicides as to how they interact with structural, physiological, and biochemical events in the plant (their mode of action). The majority of herbicide use is in crop production. Many biosynthetic pathways produce substances that are essential for normal plant growth and development. Herbicides that inhibit carotenoid biosynthesis react at several sites, although there appears to be a few common sites that are susceptible to attack. Regardless of the role of amino acid depletion, synthesis of two different amino acid classes are known to be strongly inhibited by herbicides: the aromatic amino acids and the branched chain amino acids. For plant cells to remain functional, their membrane systems, particularly the plasma membrane that separates the cytoplasm from the extracellular space must remain intact. The two herbicides that have their action at photosystem I of the photosynthesis light reaction are paraquat and diquat. The only synthetic herbicide that is known to inhibit glutamine synthetase is glufosinate.
