Study On The Removal Ability Of Several PAHs By Suaeda Heteroptera

Polycyclic aromatic hydrocarbons(PAHs)are three pathogenic environmental pollutants,which tend to accumulate in the environment.Once absorbed by organisms,they will damage cells and inhibit the normal growth and development of organisms.With the rapid development of coastal cities and towns,enterprise production industrialization and oil exploitation,PAHs pollute the coastal zone more and more seriously.Red beach wetland is located at the estuary of the lower reaches of Liaohe River,which plays an important role in blocking and purifying the pollutants at the tail end of Liaohe River and maintaining the healthy ecosystem balance of the sea area around Liaodong Bay and offshore.In recent years,due to the intensification of environmental pollution,the red beach ecosystem has experienced ecological degradation.Through field investigation and research,this phenomenon may be related to the excessive accumulation of PAHs in local water and soil.Suaeda Heteroptera is an annual dominant plant in the red beach,which is tolerant to salt and alkali,increases the content of soil organic matter and grows in large quantities.Because of its good salt and alkali resistance and the ability to remove PAHs,Suaeda Heteroptera is also a pioneer plant to remove pollutants from saline and alkaline land.The purpose of this study was to monitor the content and distribution of polycyclic aromatic hydrocarbons in various stations of red beach,and to study the reducing effect of Suaeda Heteroptera on different concentrations of PAHs under hydroponic conditions.The transcriptome sequencing technology was used to analyze the transcriptome of Suaeda Heteroptera in response to PAHs stress,and to explore the related metabolic pathways.The specific results are as follows:1.Monitor the types and contents of PAHs in sediments,water bodies and Suaeda Heteroptera in Panjin red beach from 2020 to 2021.From 2020 to 2021,a total of 16 kinds of optimal PAHs were detected in red beach sediments,among the detected PAHs,fluoranthene,phenanthrene and benzo [g,h,I] perylene were higher.From2020 to 2021,a total of 16 kinds of PAHs were detected in the water body of station A of red beach,of which the detected contents of naphthalene and phenanthrene were high;From 2020 to 2021,the species of PAHs detected in the water body of station B of red beach decreased from 15 to 14,among which the detected contents of naphthalene,phenanthrene and benzo [g,h,I] perylene were higher.From 2020 to2021,the species of PAHs detected in Suaeda Heteroptera plants at Red Beach site B decreased from 16 to 14.In 2020,the content of PAHs detected in Suaeda Heteroptera plants at Red Beach site B was higher,including phenanthrene,fluoranthene and benzo [g,h,I] perylene.In 2021,the content of naphthalene and phenanthrene was higher.On the whole,the total content of PAHs in red beach sediments and seawater gradually increased from station A to station B,and the total content of PAHs in roots,stems and leaves of Suaeda Heteroptera decreased at station B.As there are oil fields and paddy fields near the red beach,it is speculated that PAHs produced by oil exploitation and biomass combustion will diffuse to site B along with water flow and atmosphere,resulting in an increase in PAHs content in sediments and seawater at site B.in addition,due to the COVID-19,the tourism pressure is reduced,Suaeda Heteroptera community recovers well and shares the PAHs pressure,which may be the reason for the decrease in PAHs content in Suaeda Heteroptera plants.2.To study the reducing effect of Suaeda heteroptera under different concentrations of PAHs through hydroponic experiments.Suaeda heteroptera has a certain reduction effect on PAHs.Under hydroponic conditions,in the treatment groups with different concentrations of PAHs,Suaeda heteroptera absorbed a certain amount of PAHs,and when the PAHs concentration was 100 ?g/L,Suaeda heteroptera had the most obvious reduction effect on total PAHs,the removal capacity was 82.351 ?g/kg/d;when the concentration of PAHs was 10 ?g/L,Suaeda heteroptera had the best reduction effect on phenanthrene,and the removal capacity was 2.874 ?g/kg/d;when the concentration of PAHs was 100 ?g/L,Suaeda heteroptera The reduction effect of benzo[a]pyrene was the best,and the removal capacity was 68.542 ?g/kg/d.When the concentration of PAHs was 10 and 100 ?g/L,the effect of Suaeda heteroptera on PAHs reduction was more significant with the change of time.3.The transcriptome of Suaeda heteroptera plants under PAHs stress was sequenced by high-throughput sequencing technology,and the enrichment degree of the difference results was compared.It was found that the enrichment degree of glyoxylate and dicarboxylate metabolism,carbon metabolism and pentose phosphate pathway was significant in the three control groups of A-vs-B,A-vs-C and A-vs-D.Down regulation of genes encoding glycine decarboxylase complex(GDC)and serine hydroxymethyltransferase(E2.1.2.1)in glyoxylate and dicarboxylate metabolism pathway.Genes related to the transformation of glucose-6p and the mutual transformation of ribose-5p and ribose-5p are up-regulated in the carbon metabolism pathway.D-ribulose-5-phosphate 3-epimerase(E5.1.3.1)and fructose-1,6-diphosphate aldolase(E4.1.2.13)genes in pentose phosphate pathway were down regulated,indicating that glyoxylate and dicarboxylateme tabolism,carbon metabolism and pentose phosphate pathway in Suaeda heteroptera were involved in stress response under PAHs stress.