Study On The Difference Of Physiological Activity And Toxicity Of Cerium Dioxide Nanoparticles And Free Cerium On Soybean Plants

Cerium Nanoparticles have been widely used in industrial processes,where they are easily released into soil,interact with plants and pose a potential threat to the ecological environment and humans through the food chain.Therefore,it is necessary to evaluate the effects of CeO2 NPS on plant toxicity and nutritional quality.In this study,edible soybean(Glycine Max L.)plants were selected as experimental materials and planted in modified soil with concentrations of CeO2 NPs and CeCl3 at 0,25,75 and 225mg/kg,respectively,and the fruits were grown until the 96th day when they were ripe.The effects of CeO2 NPs on plant physiological growth and fruit nutritional quality during the whole life cycle of soybeans were studied.The environmental toxicity effect of nanoparticles on plants was expounded.The research conclusion has certain practical significance and theoretical reference.The main research results are as follows:(1)Exposment of CeO2 NPS at the early stage of plant growth(21d)significantly reduced the plant height,especially 75,225 mg/kg CeO2 NPS,but the difference was not significant at the fruit stage(96 d).Compared with the control group,225mg/kg CeO2 NPS also significantly reduced plant biomass at the 21st day,while high concentration of CeO2 NPS and Ce3+significantly reduced plant biomass at the 96th day.However,only high concentration of CeO2 NPS significantly reduced soybean fruit yield compared with the control group,and Ce3+showed no significant toxicity.The concentrations of CeO2 NPS and Ce3+exposed to different growth cycles had no significant difference in the relative chlorophyll content of leaves.The experiment showed that high concentration of CeO2 NPS could affect the growth and biomass accumulation of soybean,and the effect was more obvious with the increase of treatment time.(2)The antioxidant enzyme system of the plant was studied.Compared with the control group,the levels of CAT,SOD and POD in the roots did not change significantly after NP and Ce3+treatment until the 21st day after soybean culture.In addition,the MDA content of root was not significantly affected by all treatments.225 mg/kgCeO2 NPS treatment increased MDA content by 30.8%.With the growth of the plant,the root MDA was significantly decreased by high concentration of CeO2 NPs at the 96th day,but not significantly in the ion group.There was no significant difference in the effect of all treatments on leaf oxidase system.The results showed that the effect of nanometer cerium oxide on the antioxidant system of plant tissues was mainly concentrated in the root system,and the effect was more obvious with the increase of exposure time.(3)Analysis of the accumulation and morphology of cerium in roots showed that cerium was mainly distributed in roots,and less cerium was transported to leaves and fruits,and there was little difference in the concentration accumulation at 21 days and 96 days.At the same time,some Ce3+was transformed in the roots of CeO2 NPS treatment,and the conversion rate increased with the extension of time.In Ce3+treatment,some trivalent cerium ions were observed to be converted into tetravalent cerium ions,and this effect was more obvious on the 21st day.In plant tissues mineral elements content analysis indicates that CeO2 NPs and Ce3+influenced the distribution of mineral elements,especially compared with 21 days,the 96th day Ca,Mn content in soybean plant leaves increased significantly,P,S,Cu,Mo content is significantly reduced,and at this point,the change trend of mineral elements in roots and leaves are basically the same.The analysis of cerium and major and trace elements in plant tissues improved the understanding of the mechanism of action of nanoparticles on the distribution of plant nutrients.(4)The evaluation of fruit nutritional indexes showed that both treatments affected the nutritional quality of fruits,and 225 mg/kg CeONPS significantly reduced fruit yield.This experiment provides a new clue for further understanding the potential effects of nanomaterials on edible parts of plants,and also has certain reference significance for the nutrition of nanomaterials in agriculture.To sum up,our research suggests that CeO2 NPs long-term exposure to inhibit the growth of soybean plant breeding,soil and the change of soil organic matter,and then transferred to the ground part,a high concentration of ceria nanoparticles can reduce the fruit yield and quality of soybean,and through the food chain is transferred to a chance to environment.Investigating the potential effects of NPS on the edible parts of plants can provide a better understanding of the potential environmental threats that NPS may pose.