The Impact Of Silver Nanoparticles On Arabidopsis Thaliana And Its Physiological And Biochemical Characteristics

Silver nanoparticles(AgNPs)are commonly used in consumer products for their antibacterial activity.AgNPs may adversely influence the organism when released into the environment.The present study investigated the effect of AgNPs on the morphological structure and physiological and biochemical characteristics of the terrestrial model plant Arabidopsis thaliana.The toxicity of AgNPs and AgNO3 was also compared.The results showed that AgNPs and AgNO3 could not significantly affect the dry weight and fresh weight of Arabidopsis thaliana,but could significantly affect the elongation of roots.20 mg/L AgNPs and AgNO3 could significantly inhibit elongation growth,and this inhibition effect in the same order of magnitude;1,2,5 mg/L AgNPs could promote elongation growth,and AgNO3 could not promote the Arabidopsis thaliana root elongation,20 mg/L of AgNPs and AgNO3 can lead to significant deflection of the Arabidopsis root system,resulting in the loss of gravity.AgNPs and AgNO3 significantly reduced the chl a content,Fv/Fm in Arabidopsis thaliana,and significantly increased the chl a/b.However,this change was recoverable.After one week of culture,the chlorophyll content and Fv/Fm of Arabidopsis thaliana returned to control level.AgNPs could induce oxidative stress in Arabidopsis thaliana,and the levels of ROS were significantly increased at 5-20 mg/L AgNPs,indicating that AgNPs induced oxidative stress.The treatment of 15 mg/L AgNPs resulted in a significant increase in MDA content;The corresponding antioxidant enzyme activity was changed to resist oxidative stress;and 800 ?g/L Ag+(equivalent to 20 mg/L AgNPs released by the amount of Ag+)can not change the ROS levels and antioxidant enzyme activity.Indicating that AgNPs can induce Arabidopsis thaliana to produce oxidative stress,which causes the accumulation of ROS,which leads to the change of antioxidant system,and these effects can not be caused by the release of Ag+ from AgNPs.AgNPs and AgNO3 could significantly affect the photosynthetic system-related enzymes of Arabidopsis thaliana.AgNPs could significantly inhibit the activity of RubisCO,but the inhibition effect of AgNO3 is better than that of AgNPs,indicating that AgNPs and Ag+ on RubisCO enzyme activity mechanism may be different.10 mg/L AgNPs and 30 mg/L Ag+ significantly reduced NADME enzyme activity.30 mg/L AgNPs treatment significantly increased the activity of the enzyme,while the other treatment groups were not significant levels.AgNPs and AgNO3 could significantly reduce PEPC enzyme activity.Indicating that AgNPs and AgNO3 could significantly alter the photosynthetic enzyme system of Arabidopsis thaliana,and effects of the same concentration of AgNPs and AgNO3 on the photosynthetic enzyme system were different.The above studies showed that the toxicity of AgNPs and AgNO3 were in the same level,but the mechanism may be different.