Plant Community And Arbuscular Mycorrhizal Fungal Diversity Of The Wulanhada Volcano Group In Inner Mongolia

As the only volcanic group discovered in the southern margin of the Inner Mongolia Plateau that erupted in the Holocene,the Wulanhada volcano group maintains the natural succession state in the main.It is an ideal model for exploring the succession of biological communities,biodiversity and their interactions with environmental factors in volcanic areas.This thesis took the Wulanhada volcano group as the research object,selected different periods,different types volcanoes and two lava flows together with their surrounding grasslands,and investigated the characteristics of plant communities and the soil physicochemical properties.At the same time,we assayed the composition and diversity of bulk soil AMF communities through morphological methods and high-throughput sequencing technology,and analyzed the correlation between the plant community,AMF community and environmental factors in the volcanic group.It aimed to explore the interaction relationship and synergistic succession mechanism between the vegetation and AMF community in the Wulanhada volcano group,and to provide a theoretical basis for the biological resources and environmental protection in the Mongolian Platea.The main results of this study were as follows:1.The vegetation type of the Wulanhada volcano group was dominated by typical steppes built by Stipa krylovii,accompanied by shrubs in local areas;among them the Holocene volcanic plant communities were built by Stipa krylovii,and the late Pleistocene volcano Heinaobao was built with Thymus mongolicus(a small semishrub),and the vegetation types were mainly herbs.The dominant species in the communities were Leymus chinensis,Potentilla acaulis,Artemisia frigida,Cleistogenes squarrosa,Carex korshinskyi,and Caragana microphylla,etc.2.The results of the Alpha diversity index analysis of the plant community showed that the plant diversity and the dominant species of the community presented changes and succession phenomenon,along with the change of the altitude of the volcanic cones.The plant diversity at the top of the volcanic cones was lower than that on the slope and foot.Among them,in the northern Liandanlu and the Heinaobao volcanic cones,the plant diversity showed a trend of first increasing and then decreasing with the increase of altitude,and that of the middle Liandanlu was negatively correlated with the altitude.The plant diversity of the volcanic cones was higher than that of the surrounding grassland areas.3.A total of 49 species of plants were collected in the study area,belonging to18 families and 40 genera.Among them,44 kinds of plants were infected by AMF,accounting for 89.80% of the total;arbuscular mycorrhizal types are virous,the Arum type accounted for 86.33%,the Paris type accounted for 6.82%,and the intermediate type accounted for 2.27%%.Mycorrhizal infection rates ranged from 1% to 78%,among which the average infection rate of Liliaceae was the highest.4.A total of 34 species of AMF in 4 families,7 genera and 34 species were isolated from the research area,including 1 genus and 10 species of Acaulosporaceae family,1 genus and 3 species of Claroideoglomeraceae family,1 genus and 1 species of Gigasporaceae family,4 genera and 20 species of Glomeraceae family.The dominant family was Glomeraceae,the dominant genus was Glomus,and the dominant species was G.reticulatum,which were distributed in each site.In addition,the high-throughput sequencing method found that soil AMF OTUs belonged to the genera Ambispora,Diversispora,Scutellospora,Glomus,Paraglomus and some unidentified genera,among which Glomus was the absolute dominant genus,which was consistent with the morphological identification results.5.The results of AMF community structure and alpha diversity analysis showed that the soil AMF spore richness at the top of the volcanic cones was higher than that on the foot,and the AMF spore density increased significantly(P<0.05)along with the distance gradient increased from crater in the direction of lava flow.Soil AMF species and relative abundances had higher similarity in Holocene volcanoes,which were quite different from the late Pleistocene volcano Heinaobao.The AMF diversity of late Pleistocene volcanic soils was lower than that of Holocene volcanic soils,and was highest in the middle Liandanlu volcano,lowest in the Heinaobao volcano.On the same volcanic cone,AMF diversity was higher at the top than the foot.6.The RDA results showed that vegetation diversity,soil p H,soil sucrase,soil organic phosphorus,soil available potassium and soil dehydrogenase in the study area had extremely significant effects on AMF diversity(P<0.01).Soil ammonium nitrogen and soil available phosphorus had significant effects on AMF community diversity(P<0.05).The GRSP content was lower at the foot of the volcanic cones and positively correlated with the AMF diversity.In summary,the plant community diversity of volcanic cones was higher than that of the surrounding grasslands on the Wulanhada volcano group and had obvious succession with the change of the altitude.While the AMF diversity was negatively correlated with the altitude and that of the late Pleistocene volcano was lower than the Holocene volcano.Moreover,the plant community diversity and soil physicochemical properties had a significant impact on the AMF community diversity in the research area.