Abstract：In order to effectively control water-bloom algae by using allelochemicals, the inhibitory mechanism of linoleic acid on M. aeruginosa was analyzed. After the linoleic acid added in the experimental groups, the chlorophyll a content of algal cells decreased, the electrical conductivity (EC) and the OD260 of algal extracellular fluid increased, the generation of malondialdehyde (MDA) and superoxide anion radical (O2 ) of the algal cells increased, activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) increased at the first 4 days and the expression of SOD isoenzyme enhanced at the concentration of linoleic acid being 0.1mg/L. But when antioxidants vitamin C was added the generation of O2 decreased, and algal biomass increased. All the results indicated that the mechanisms underlying the algal growth inhibition by linoleic acid involved the O2 generation that induced the lipid peroxidation of cell membrane, changed the penetrability of cell membrane, and resulted in the damage of DNA and some bio-macromolecules, inhibited the synthesis of the chlorophyll a and some relative proteins, breaking the algal cells and causing them melt in the end.
