The Effect Of Diuron On Algae At The Physiologial, Biochemical And Genetic Rhythmic Expression Levels

Now,pollution of herbicide in aquatic environments is a world-wide problem.Algae are the primary producers of aquatic ecosystems and the cornerstone of aquatic ecosystem structure stability which is commonly used in the assessment of water pollution.In this study,we examine the toxicity targets of diuron in Phaeodactylum tricornutum and Anabaena azotica on the physiological,biochemical,and genetic rhythmic expression levels.The results showed that the growth of algae was inhibited after diuron exposure with concentration-dependent effect.From the results of the effects of diuron on the antioxidant enzyme activity(SOD,POD,CAT and GSH),lipid peroxidation level,chlorophyll level,reactive oxygen species,and the mRNA abundance level of photosynthesis,division and nitrogen fixation related genes,we detected that diuron disturbed electron transport chain,decreased pigments content,inhibited photosynthetic efficiency,and therefore caused algal cell oxidative injure.Microalgae have the circadian rhythm in photosynthesis,nitrogen fixation,and cell division.Therefore,we also selected diuron to research whether herbicide affected algal growth via regulating circadian clock genes.Our results demonstrated that diuron affected the circadian rhythm of algal metabolism gene expression,which may be one of the main reasons to cause plasmatorrhexis in algal cell.We also concluded that Phacodactylum tricornutum has higher tolerance to diuron.