Effects of yttrium and phosphorus on growth and physiological characteristics of Microcystis aeruginosa

In this test, when yttrium is absent, the MDA content keeps rising, 0.2 mg/L phosphorus induces apparently lower MDA content in algae (P < 0.05) in 20 d. When yttrium dose is low or phosphorus is 0.2 mg/L, because of the scavenging effect of SOD to O2- in algae cells, large amounts of hydrogen peroxide (H2O2) are produced, ROS is reduced so that the membrane lipid peroxidation decreases, MDA content is naturally low. On the contrary, MDA content keeps high level. When yttrium concentration is too high, antioxidant system become disordered, the balance of ROS production and removal is broken, ROS accumulation increases in algae cells, resulting in algae cells damaged by membrane lipid peroxidation, MDA content rapidly increases, meanwhile, MDA would inhibit and reduce the activity of antioxidant enzymes and contents in turn.268