Effect of Silica Nanoparticles on Photosynthetic Performance of Chlamydomonas reinhardtii
[Objective]To reveal the effect of SiO2 NPs on algal photosynthesis in aquatic ecosystems by determining the changes in growth and photosynthetic indexes of green algae treated with silica nanoparticles(SiO2 NPs).[Method]The biotoxic effects of SiO2 NPs were studied in terms of growth,oxidative stress,chlorophyll content and chlorophyll fluorescence-induced kinetic curves using Chlamydomonas reinhardtii as experimental material.[Result]At 96 h and 25℃,the high concentration of 800 mg/L SiO2 NPs induced a 21.57% increase in reactive oxy-gen species(ROS)of Chlamydomonas reinhardtii and inhibited the photosynthesis of Chlamydomonas reinhardtii,which resulted in a 10.87% decrease in chl-a content and a 50.72% decrease in the photosynthetic performance index Pi-Abs.And the toxicity of silica nanoparticles was exacerbated by the temperature increase.When the temperature increased to 30℃,the high concentration of 800 mg/L of SiO2 NPs led to the increase of reactive oxygen species(ROS)of Chlamydomonas reinhardtii by 26.58%,the decrease of chlorophyll a and chlorophyll b content by 23.47% and 20.35%,and the significant decrease of the photosynthetic performance index Pi-Abs by 55.72% compared with that of the control group.High concentration of SiO2 NPs had a toxic effect on photosynthesis of Chlamydomonas reinhardtii,and the synergistic effect of increasing temperature and increasing concentration of SiO2 NPs will exacerbate the photosynthetic toxic effect of Chlamydomonas reinhardtii.[Conclusion]This study provides a theoretical basis and data support for exploring the photosynthetic effects of nanopowder materials on mi-croalgae.