| It is of great significance of researching the interaction mechanism of soil,plant and microorganism to agricultural production,vegetation restoration,forest protection and environmental pollution restoration and one of the research emphases of Ecology subject at present.Soil erosion,soil and water loss,soil desertification and soil nutrient deficiency are widespread in the dry-hot valley of Panzhihua.At present,vegetation restoration is the main measure to control its fragile ecosystem,but the overall ecological restoration benefit of the region is low due to various reasons.As an excellent vegetation with both ecological and economic benefits,Pennisetum sp.has strong drought resistance,alkali resistance,salt resistance,cold resistance and certain capacity of heavy metal absorption,and is regarded as the introduction plant for vegetation restoration in the dry-hot valley.In this study,Pennisetum sp.cultivated in the dry-hot valley of Panzhihua was taken as the research object,and samples were collected in different slopes and seasons,and the wasteland was taken as the control to explore the dynamic change of soil microbial community structure characteristics in Pennisetum sp.cultivated area.The main research results are as follows:(1)Compared with the control group,the total soil bacterial OTUs in the planting area of Pennisetum sp.was 20047,14045 in the control group.The total soil fungal OTUs in the planting area was 15208 7561 in the control group.Pennisetum sp.planting increased the number of soil bacteria and fungi,and bacteria in the overall population is more than the fungal.According to the Shannon and Chao indices,the community diversity of bacteria and fungi decreased in the mass,bacterial abundance present irregular change,fungal richness in general is higher than that of control group(except dry season in 2017).However,both bacterial and fungal diversity were significantly different in the early 2016 dry season,and the community structure tended to be stable with time.Meanwhile,the composition of soil bacterial community did not change significantly,while the composition of soil fungal community changed significantly.(2)In terms of slope position,the community structure differences analysis showed that the community composition difference of bacteria at the bottom and top of the slope reached the extremely significant level(p < 0.01),and the community composition reached the significant level in slope of middle and top(p < 0.05).The community composition of fungi at the top and bottom of the slope and at the top and bottom of the slope were significantly different(p = 0.001),and the community composition at the top and bottom of the slope was significantly different(p < 0.05).Among them,the OTU of soil bacteria is 6354 at the top,6965 in the middle and 6728 at the bottom.OTU of soil fungi is 4381 at the top,5368 at the middle and 5459 at the bottom > at the bottom of the slope and > at the top of the slope;The number of fungi at the bottom of the > slope and at the top of the > slope.The community composition and relative abundance of dominant phyla and genus were different in different slopes.In terms of phylum level,the dominant bacteria in all three slopes were Proteobacteria,Actinobacteria and Acidobacteria.On the whole,the phylum composition at the top of the slope is relatively abundant.Sphingomonas was the most dominant bacterium at the three slopes.Candidatus_Udaeobacter,the second most abundant,had a significantly higher content at the top of the slopes than other slopes.The total amount of different slopes with relative abundance less than 1% was similar.The relative abundance of some dominant bacteria was increased and the number of some decreased in different levels.Although the community composition and relative abundance of dominant genera in different slopes were similar,the contents of some genera in different slopes were quite different.From the perspective of fungi phylum level,community composition and relative abundance were significantly different.On the whole,the phylum composition at the bottom of the slope was relatively abundant,while the relative content of >1% dominant phylum in the slope was relatively high.At the level of fungi genera,the genera at the bottom of the slope were abundant in general,while the relative content of >1% in the slope was relatively high.(3)In dry and wet seasons,the community composition of dry and wet seasons was significantly different(p < 0.01).The community composition of dry season and wet season was significantly different(p = 0.001).OTUs of soil bacteria in the dry season was 7176,8053 in the wet season.OTUs of soil fungi in the dry season was 4655,7463 in the wet season.The number of soil bacteria and fungi in the planting area of Pennisetum sp.in wet season was more than that in dry season.In terms of community composition,the phylum,genus and community composition in wet season were more abundant than those in dry season,and the content of some dominant bacteria was relatively higher.Proteobacteria,Acidobacteria and Verrucomicrobia phylum in wet season were higher than those in dry season,and the contents of Actinobacteria and Chloroflexi in wet season were lower than those in dry season.The content of Candidatus_Udaeobacter genus in wet season was higher than that in dry season,and Arthrobacter genus in dry season was higher than that in wet season.The dominant phyla of fungi in the dry and wet seasons were Ascomycota and Basidiomycota.The composition of the wet season community is more complex.In conclusion,the planting of Pennisetum sp.in the hot and dry valley of panzhihua increased the richness and diversity of soil bacteria and fungi in the early stage,but with the increase of planting time,the diversity of soil bacteria and fungi community decreased to a certain extent,and synergistic effect was produced,making the microbial community structure develop towards a relatively stable direction.The species and number of bacteria and fungi in different slopes increased at the bottom and the middle of the slope,and were significantly different from the top of the slope,which may be positively correlated with the growth of Pennisetum sp..The change of dry and wet seasons had an influence on the bacterial and fungal communities in the planting area of megalobium,but the influence of the fungal community was more obvious,and the influence of the wet season was more obvious than the dry season. |
PDF Full Text Request