Photosystem II inhibitor herbicides

Abstract

The presence of weeds significantly decreases crop yields. The chemical control with herbicides that inhibit the photosystem II is essential for a high expression of the yield potential of many crops. The aim of this review was to systematically search the literature and identify the main studies on photosystem II inhibitor herbicides examining the mode of action, main crops, and regulated commercial products. The research methodology consisted of searching for the terms: 1 Photosynthesis. 2. Photosystem II 3. Herbicide, and 4. Resistance at the databases PubMed, Researchgate, ScienceDirect, Scielo, Tandfonline, Google Scholar, and books of the library of the Federal University of Tocantins/Campus Gurupi. Photosystem II inhibitors block the flow of electrons in the electron transport chain and cause oxidative damage to leaf tissues, as for example, the peroxidation of the lipid bilayer of membranes. The active ingredients with the largest number of product regulation are Ametryne, Atrazine and Diuron, and the main crops in which they are used are sugarcane, corn, and sorghum. FSII-inhibiting herbicides vary in their chemical and physical properties depending on the chemical groups. They can be weak bases, weak or non-ionizable acids, showing specificity for narrow and broad leaved weeds, and can be classified by systemic or contact action. There are 107 unique cases of weed resistance to photosystem II inhibitors in the world and seven of these cases were recorded in Brazil. Photosystem II inhibitors are essential in agriculture; however, it is necessary to search for better technologies and to raise farmer awareness to prevent the emergence of resistance. The use of natural herbicides is the alternative for the production of high amounts of foods with high phytosanitary quality.