Study On The Structural And Functional Diversity Of Soil Microorganisms Of Mangrove Plants Under Different Redox Potential

Mangroves are types of evergreen woody plant that occupie tropical and subtropical estuaries and coastal intertidal zones.Due to its high productivity and high decomposition rate,mangrove wetland supports a complex and diverse soil bacterial community.These bacterial functional groups play an important role in promoting the utilization of nutrient elements by mangrove plants.Under the interactive influence of ocean tides and terrestrial freshwater input,there is significant spatial heterogeneity in many physicochemical factors dominated by soil redox potential in mangrove wetland soil.This spatial heterogeneity of soil physicochemical factors will inevitably affect the spatial variability of soil bacterial community structure and its functions.In addition,different mangrove wetlands with different developmental years usually also exhibit different soil physicochemical conditions and shape different soil bacterial communities.Understanding the sensitivity of soil bacteria to environmental temporal and spatial fluctuations can provide a basis for soil microbiology for the restoration and management of mangrove ecosystems.In this study,high-throughput sequencing technology and Biolog-ECO technology were used to analyze the rhizosphere and non-rhizosphere soils(bulk soil,rhizosphere soil and rhizoplane)of the roots of typical mangrove seedlings in Xiamen's Xiatanwei artificial mangrove wetland and Zhangzhou's Haimen Island mangrove natural wetland,aim to investigate the diversity and metabolic function changes of bacterial communities in tidal flat with different Eh.The main findings are as follows:In this study,with the increase of tidal flat with different Eh,soil p H,TOM and humidity of the Xiatanwei mangrove wetland park decreased,and soil EC increased significantly.With the increase of Eh,the bacterial diversity in the rhizosphere and non-rhizosphere soils of K.obovata decreased,and the relative abundance of dominant bacteria phyla decreased.Rhizosphere soil has higher bacterial diversity and richness than bulk soil.The rhizosphere soil of K.obovata is rich in Nitrospira(6.0%)and Planctomycetes.The diversity index of bacterial communities in the rhizoplane of K.obovata is much lower than that of rhizosphere soil and bulk soil.The results of Biolog-ECO showed that the carbon source utilization capacity of microorganisms decreased with the increase of tidal flat with different Eh.The microbial community around the bulk soil of the low Eh tidal flat has the highest carbon source utilization capacity,the main types of carbon sources used are Polymers and Carbohydrates,and rhizosphere soil bacteria mainly use carbon sources of Polymers,Carboxylic acids and Carbohydrates.Soil humidity and Eh affect the diversity of bacterial communities and the metabolic functions of soil microorganisms together.There is no significant difference in the overall flora composition between the Haimen Island natural mangroves and the Xiatanwei rtificial angrove wetland.The dominant flora is Proteobacteria(66.2-93.2%),and the bacterial species richness in the rhizosphere soil higher than the bulk soil,the abundance of Nitrospira in the rhizosphere of the natural mangroves in Haimen Island is higher than that of the Xiatanwei mangrove wetland.From the perspective of ? diversity,the soil of the A.marina mangroves in Xiatanwei,the bacterial diversity is higher than that of Haimen Island.The main carbon source type used by the A.marina rhizosphere soil in Haimen Island is Carbohydrates;The main carbon source used in the rhizosphere soil of A.marina in Xiatanwei artificial mangrove wetlands is Amino acid and Amino Amides;The main carbon source type used by the A.marina bulk soil in Haimen Island is Amino acid and Polymers;The main carbon source used in bulk soil of A.marina in Xiatanwei artificial mangrove wetlands is Amino acid,Polymers and Carboxylic acids.The above results indicate that there is no significiant differcet in the community structure and functional diversity of soil microorganisms in Haimen Island natural mangrove wetlands and Xiatanwei artificial mangrove wetlands.