Physiological response and removal ability of freshwater diatom <i>Nitzschia palea</i> to two organophosphorus pesticides
Yuhang Wang, Weijie Mu, Xiaoli Sun, Xinxin Lü, Yawen Fan, Yan Liu
Abstract
Organophosphorus pesticides, one of the most extensively used organic chemicals to control several insect pests, making them threaten the aquatic creatures. Here, we analysed the response mechanism of Nitzschia palea to insecticides (acephate and trichlorfon) exposure, through physiological, biochemical, morphological changes and the removal ability. Results showed that the growth of N. palea was inhibited by trichlorfon, with the cell density was significantly decreased at 7 days of exposure. Although the diatom growth was hardly inhibited after acephate treatment, the diatom valve significantly abnormal morphology be found at 50 mg L−1 acephate treatment after 7 days. Meanwhile, these insecticides had no negative effect on the chlorophyll a content of N. palea. In addition, acephate and trichlorfon induced the activities of superoxide dismutase (SOD) and catalase (CAT) in the diatom, which play a defensive role against various environmental stresses. For further analysis revealed that the content of malondialdehyde (MDA) and extracellular polysaccharides (EPS) increased on exposure to both insecticides. N. palea also promoted 24.44–32.75% removal of acephate. The biochemical changes in N. palea on exposure to acephate and trichlorfon indicate that the diatom undergoes an adaptive change in response to the insecticides-induced oxidative stress.