| Antimony（Sb）is a kind of heavy metal that is carcinogenic to human body.Due to the large-scale use of antimony and antimony compounds,the current antimony pollution problem is very serious,which has caused damage to the ecosystem.In this study,Typha orientalis was used as the test material,and the pot experiment method was used to set the antimony concentration gradient as 0,50,100,200,500,1000 mg·Kg-1,in which the blank control was marked as CK,and the Sb（Ⅲ）concentration gradient was marked as Sb3＿50,Sb3＿100,Sb3＿200,Sb3＿500,Sb3＿1000,Sb（V）concentration gradient labeled as Sb5＿50,Sb5＿100,Sb5＿200,Sb5＿500,Sb5＿1000,based on 16S r RNA high-throughput sequencing and metagenomic sequencing technology,to study the effects of different forms of antimony stress on the physiological growth of T.orientalis influence of indicators and rhizosphere microbial community structure and function.To provide scientific basis for the follow-up research on using T.orientalis,an aquatic plant,as a plant-microbe joint remediation material to remediate antimony-contaminated areas.Research shows:（1）With the increase of Sb（Ⅲ）concentration,the plant height of T.orientalis increased first and then decreased,showing the stimulant effect of Sb（Ⅲ）on T.orientalis,while with the increase of Sb（Ⅴ）concentration,the plant height of T.orientalis decreased trend.The increase of Sb content in soil can lead to T.orientalis chlorophyll content,net photosynthetic rate（Pn）,stomatal conductance（Gs）,transpiration rate（Tr）,photosystem II（PSII）maximum photochemical efficiency,PSII potential activity and actual photochemical efficiency（ΦPSII）showed a decreasing trend,but the intercellular carbon dioxide concentration（Ci）was positively correlated with Sb（III）,indicating that the decrease in Pn was mainly due to non-stomatal factors,possibly due to mesophyll cell damage;it was negatively correlated with Sb（V）.The correlation relationship shows that the decrease of Pn is mainly caused by stomatal factors.Under Sb stress,the root length and root surface area of T.orientalis showed a decreasing trend.The content of Sb in the aerial and underground parts of T.orientalis rose significantly with the increase of Sb content in the soil,and the root was the main accumulation organ of antimony.Sb can inhibit the growth and development of T.orientalis and change the physical and chemical indicators of rhizosphere soil,but high concentrations of Sb did not lead to the death of T.orientalis seedlings,indicating that T.orientalis has a certain adaptability and resistance to Sb,and can be used as a phytoremediation for antimony-contaminated areas candidate plants.（2）The bacterial community structure of T.orientalis rhizosphere soil was analyzed based on 16S r RNA high-throughput sequencing technology.The results showed that the bacterial community structure of T.orientalis rhizosphere soil under different treatments of Sb（III）and Sb（V）had significant differences,and the low concentration of Sb will lead to an increase in the diversity and abundance of bacteria in the rhizosphere soil,but the diversity and abundance of bacteria will be inhibited at1000 mg·Kg-1.After the original sequences of the 11 groups of samples were filtered by quality control,8057 OTUs were divided at the 97%similarity level,belonging to59 phyla,177 classes,409 orders,and 661 families.Among them,the dominant phyla are Actinobacteria,Proteobacteria,Acidobacteria,Firmicutes,Chloroflexi,etc.;the dominant bacteria classes include Thermoleophilia,Alphaproteobacteria,Gammaproteobacteria,Actinobacteria,etc.Correlation heatmap analysis showed that Alphaproteobacteria and Gammaproteobacteria had a significant positive correlation with total organic carbon（TOC）and Sb（P<0.05）,and Anaerolineae had a significant positive correlation with total nitrogen（TN）（P<0.05）.（3）The results of metagenomic sequencing showed that the microbial sequences in the rhizosphere soil of T.orientalis were mainly classified into Bacteria（97.95%）,Archaea（1.64%）,Eukaryota（0.30%）and Viruses（0.05%）.Proteobacteria was the most abundant phylum in all samples,with an average abundance of 37.15%,52.64%and 35.72%in CK,Sb3＿1000 and Sb5＿1000,respectively,followed by Actinobacteria（22.64%,11.81%,26.74%）,Acidobacteria（8.71%,5.26%,6.78%）,etc.COG functional annotation results show that high concentrations of Sb（III）in soil can cause cell wall/membrane/envelope biogenesis,inorganic ion transport and metabolism,translational ribosome structure,post-translational modification,protein turnover,chaperones and other related protein functional abundances significantly increased,and high concentration of Sb（V）will significantly increase the abundance of related functional proteins such as amino acid transport and metabolism,energy production and conversion,replication,recombination and repair,inorganic ion transport and metabolism,and transcription.The KEGG annotation results showed that high concentrations of Sb（III）in soil significantly increased the abundance of metabolic pathways such as amino acid biosynthesis,two-component systems,methane metabolism,and ribosomes,while high concentrations of Sb（V）the abundance of metabolic pathways such as microbial metabolism,quorum sensing,butyrate metabolism,methane metabolism,and fatty acid metabolism in different environments was significantly increased.Through the correlation analysis of environmental factors,it was found that the biosynthesis of secondary metabolites,carbon metabolism,metabolic pathways,oxidative phosphorylation,and purine metabolism were significantly positively correlated with TN and total phosphorus（TP）（P<0.05）.There was a significant negative correlation between amino acid biosynthesis and TOC（P<0.05）.Exogenous addition of Sb is the factor that leads to the change of TN and TP.Therefore,different forms of Sb can significantly affect the structure and function of microbial community in the rhizosphere soil of T.orientalis. |
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