Plant Absorption And Transmission Mechanism Of Decabromodiphenylethane And Its Effect On Rhizosphere Process

Decabromodiphenyl ethane(DBDPE)is an additive brominated flame retardant.With the restrictions on the production and use of traditional brominated flame retardants,it is widely used as a substitute in various industries,and in environmental media and Commonly detected in living organisms.The current research on DBDPE mainly focuses on the distribution of environmental media,the toxic effects of animals and photodegradation.The research on its transport mechanism in plants is very limited,and the interaction between rhizosphere chemical and biological processes triggered by it is very limited.The effect is unclear.In view of the above problems,the following research has been carried out in this paper.Cucumber,corn,and wheat were exposed to DBDPE for 45 days by soil culture experiments,and samples of underground,above-ground,rhizosphere and non-rhizosphere soils of the plants were collected at 15,30,and 45 days,respectively.Pretreatment methods such as Soxhlet extraction,rotary steaming,nitrogen blowing,and composite silica gel columns were used to process the samples,and their metabolites and precursors were quantitatively analyzed by gas chromatography-mass spectrometry.The results showed that due to the increase of plant biomass,the DBDPE content of each part gradually decreased with time.Differences in plant species will lead to differences in DBDPE accumulation.The order of DBDPE accumulation in the lower parts of the three plants is cucumber>corn>wheat,and the absorption of DBDPE in the soil by the roots of the three plants is cucumber>corn>wheat.Decrease over time.The capacity of DBDPE for stem-to-stem transport is weak in plants,and the above-ground accumulation of three plants is wheat>corn>cucumber,and the stem-to-stem transport capacity also decreases with time.Analysis of the above-ground and underground lipid content of the system shows that lipids are an important factor affecting plant roots’ uptake of DBDPE,but are not the only factor that plants transfer to DBDPE stems.Soil samples were extracted with pure water for the extraction of soluble organic matter(DOM).Based on the high-resolution mass spectrometry technology,the DOM molecular diversity distribution characteristics were comprehensively analyzed.Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)was used to characterize more than 10,000 molecules in the sample.It was found that the interaction between microorganisms and DOM in interstitial soil was active,and a large number of carbon-containing products were produced.The three most abundant DOM components from large to small are lignin,lipids,and proteins.Among them,lignin and protein gradually decrease with increasing culture time,while lipids gradually increase.The differences of DOM components in rhizosphere and non-rhizosphere soils are mainly manifested in lipids,unsaturated hydrocarbons,concentrated aromatic hydrocarbons and proteins.Based on metagenomics and RNA sequencing technology combined with biological statistical methods,the microbial community structure of rhizosphere and non-rhizosphere soil under DBDPE stress and its interaction with DOM molecules were analyzed.The participation of DBDPE in the rhizosphere process increases the bacterial species richness in the rhizosphere soil.Proteobacteria,Actinobacteria and Acidobacteria are the three most abundant bacteria in the soil.The changes of microbial community in rhizosphere soil are complex,and there are correlations between various microorganisms and DOM molecules,and this correlation is also affected by plant species.