| With the rapid development of the economy and the improvement of industrial productivity,the amount of pollutants discharged into the natural environment is also increasing year by year.Among all kinds of terrestrial pollutants,the harm of petroleum pollutants cannot be ignored.In recent years,due to the intensification of various pollutions,the Liaohe Delta wetland ecosystem has been seriously damaged.Its ecological environment risk has been paid more and more attention by the society and scholars.Phytoremediation not only has low cost,simple operation,low ecological risk,but also has good treatment effect.Suaeda heteroptera is an annual herb widely distributed in the coastal wetlands of the Liaohe Delta.It has an irreplaceable position in the succession of local communities.Therefore,this paper takes Suaeda heteroptera as the research object to explore its ability to remove petroleum pollutants.In this paper,based on the investigation of the current situation of the Panjin Red Beach environment,hydroponic and soil cultivation experiments on Suaeda heteroptera in the laboratory.Monitoring the changes in the concentration of petroleum hydrocarbons in the water and soil after the petroleum sewage passes through each system.Analyze of the removal effect of the Suaeda heteroptera system on petroleum pollutants.In addition,the transcriptome of Suaeda heteroptera was sequenced,analyze and compare differential genes and perform GO classification and KEGG enrichment analysis.Revealing its response mechanism to petroleum stress from the molecular level.The main conclusions obtained are as follows:(1)From March to July 2021,a survey on the pollution status of each station in Panjin Red Beach will be conducted.The results show that the average content of petroleum hydrocarbons in the surface seawater is 0.080 mg/L,which meets the third-class seawater quality standard.The average content of petroleum hydrocarbons in the sediments was 42.92 mg/kg,which met the first class marine sediment quality standards.(2)Hydroponics experiments found that at different growth periods,the removal rate of petroleum hydrocarbons by the system reached more than 90%.And the removal effect of middle(0.8mg/L)and high(1.2mg/L)concentration treatment group is better.The contents of petroleum hydrocarbons in each part of the plant are in descending order: root>stem>leaf.Suaeda heteroptera has the best removal ability of petroleum hydrocarbons when it is in the seedling stage.(3)Soil cultivation experiment found that in the two types of soil culture experiments,the removal rate of petroleum hydrocarbons by Suaeda heteroptera in different growth periods reached more than 90%.In the simulated tide experiment,the order of removal rate from large to small is: seedling stage>growth stage>mature stage.In the simulated enclosure experiment,the order of removal rate from large to small is: mature stage> growth stage> seedling stage.It shows that the removal effect of the system on petroleum hydrocarbons is different under different experimental environmental conditions due to various factors.The ability to remove petroleum hydrocarbons was the best when Suaeda heteroptera was in the seedling stage.(4)Transcriptome sequencing showed that compared with the blank control group(A),a total of 1027 differentially expressed genes were obtained in the acetone control group(B),among them,448 were increased and 579 were decreased.Compared with the acetone control group,522 differentially expressed genes were obtained in the low concentration stress group(C),1027 differentially expressed genes were obtained in the medium concentration stress group(D),632 differentially expressed genes were obtained in the high concentration stress group(E).The response to acetone stress by Suaeda heteroptera mainly involves plant-pathogen interaction,plant hormone signal transduction and MAPK signaling pathway;response to petroleum stress mainly involves glyoxylate and dicarboxylate metabolism,carbon metabolism and arginine and proline metabolism pathway. |
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