Study On Rhizosphere Soil Fungi And Root Symbiotic Fungi Of Five Plants In Siziwang Banner

Siziwang Banner is located at the important boundary between China's ecological environment and regional economy,which belongs to agro-grazing ecotone.It is an ecological barrier to combate desertification.It is an important water conservation zone and animal products supply area in the western pastoral areas of Inner Mongolia.The Siziwang desert ecosystem is typical and representative in Inner Mongolia.Artemisia frigida,Stipa breviflora,Reumuria songarica,Suaeda salsa and Nitraria tangutorum are representative plants in Siziwang Banner from south to north.The five plants have drought resistance,cold resistance and developed root system.These charateritcs can prevent wind and fix sand.The diversity of soil fungi and their community structure play an important role in the desert ecosystem.The symbiosis with fungi is one of the key strategies for plants to adapt to abiotic stress.Dark septate endophytes(DSE)and AM(Arbuscular mycorrhiza)fungi can colonize the roots of plants and promote the absorption of soil moisture and mineral nutrients.In this experiment,the rhizosphere soil samples and root samples of five plants were collected and the species diversity of soil fungi,AM fungi and DSE were studied by high-throughput sequencing method and traditional methods.The growth promoting effects of the synthetic flora were verified.The main results are as follows:1.According to Illumina MiSeq sequencing,there were 9 phyla,39 classes,93 orders,239 families and 513 genera fungi,1 phyla,3 classes,4 orders,6 families and 7genera AM fungi and 1 phyla,3 classes,8 orders,19 families and 35 genera DSE in rhizosphere soil.Alternaria was the dominant fungi genus in rhizosphere soil of Artemisia frigida and Suaeda salsa,Trichothecium was the dominant fungi genus in rhizosphere soil of Stipa breviflora and Aspergillus was the dominant fungi genus in rhizosphere soil of Nitraria tangutorum and Reumuria songarica.Glomus was the dominant genus of AM fungi in rhizosphere soil of five plants.Aporospora was the dominant DSE genus in rhizosphere soil of Stipa breviflora,Nitraria tangutorum and Artemisia frigida,Pleosporales was the dominant DSE genus in rhizosphere soil of Reumuria songarica and Suaeda salsa.2.NMDS analysis showed that the species composition of fungi and AMF in rhizosphere soil of Suaeda salsa,Reumuria songarica and Nitraria tangutorum were significantly different,but there were no significant differences between fungi and AMF in rhizosphere soil of Artemisia frigida and Stipa breviflora.There were no significant differences in DSE species composition among five plants.Correlation heat map analysis showed that fungi,AMF and DSE species in rhizosphere soil of five plants were significantly correlated with p H value,acid phosphatase enzymic activities and total potassium contents.3.The roots of five plants were dyed with trypan blue stain,which showed that five plants roots were infected by AMF and DSE.The symbiotic structure dominated by hyphae were formed.The total infection rates of five plants were 20.13%?95.67% and the highest infection rate of vesicles was 54.13%(Stipa breviflora)and the lowest was0.94%(Reumuria songarica).The highest infection rate of AMF hyphae was 95.66%(Stipa breviflora)and the lowest was 12.69%(Nitraria tangutorum).The highest infection rate of DSE hyphae was 63.83%(Stipa breviflora)and the lowest was 0.18%(Suaeda salsa).The highest infection rate of Sclerotinia sclerotiorum was 17.07% and the lowest was 0.24%.4.AM fungi spores were seperated and identified by soil wet sieving-sucrose gradient centrifugation and morphological identification.There are 6 Glomus,4Acaulospora,1 Diversispora and 1 Claroideoglomus.The 12 AM fungi were Acaulospora mellea,Glomus melanosporum,Acaulospora scrobiculat,Glomus caledonium,Glomus diaphanum,Glomus fragarioides,Glomus clarum,Acaulospora laevis,Acaulospora bireticulata,Diversispora spurcum,Claroideoglomus etunicatum,Glomus reticulatum,among which Glomus melanosporum,Glomus clarum and Glomus reticulatum were the AMF with a higher separation frequency in five plants.5.Using traditional fungal isolation and culture methods,DSE were isolated from five plants roots.163 DSE strains were obtained,which were identified as belonging to 8genera,namely Phialophora,Pleosporales,Darkidea,Paraphoma,Bipolaris,Curvularia,Chaetomium and Alternaria.Pleosporales sp.was the DSE with higher separation frequency in Artemisia frigida and Stipa breviflora roots.6.The selected AMF,DSE and growth-promoting bacteria were inoculated in Lolium perenne and Medicago sativa in single or mixed planting ways.The results showed that AMF,DSE and growth-promoting bacteria can promote the growth of Lolium perenne and Medicago sativa.The growth effect of mixed planting of Lolium perenne and Medicago sativa is better than that of single planting.The growth-promoting effect of mixed inoculation of DSE and AMF is the best.The height,ground diameter,first-class lateral roots,leaf number,aboveground dry weight and underground dry weight of Lolium perenne seedlings inoculated DSE and AMF mixture were higher than CK by 47.35%,8.74%,20.00%,60.00%,64.00% and 31.58%,respectively.The height,ground diameter,first lateral root,leaf number,aboveground dryweight and belowground dryweight of Medicago sativa seedlings inoculated DSE and AMF mixture were 15.34%,0.77%,81.25%,40.00%,14.06% and 45.45% higher than CK,respectively.