A Study On The Classification And Biodiversity Of Soil Ciliates In The Farmland Ecosystem

The classification and biodiversity of soil ciliates in farmlands of eight types of crops(Pea bean field,Chilli field,Cocozelle field,Cowpea field,Potato field,Cucumber field,Radish field,Corn field)in Tanchang County,Longnan City,Gansu Province were studied using non-flooded petri dish method,directing-culture counting method,observation in vivo,protargol staining and molecular biological method from August 2018 to March 2021.The key results and conclusions are as follows:(1)71 ciliate species of 6 classes,13 orders,20 families and 34 genera were identified.Haptorida was the dominant group,with 30 species.Sporadotrichida was the subdominant group with 13 species.Cyrtolophosidida,Euplotida,Halteriida,Urostylida and Pleuronematida were the rare groups with 1 species respectively.(2)The research results of community diversity showed that the dominance index and evenness index in the Cucumber plot,the diversity index and richness index in the Chilli plot were the highest,the dominance index,diversity index,evenness index and richness index in the Corn plot were the lowest.(3)The morphological characteristic,infraciliature,and the taxonomic relationships between species and groups of 16 ciliate species,including 2 domestic new records(Neowallackia petergofi and Urosomoida galapagensis),1 domestic new record in soils(Monomicrocaryon euglenivorum euglenivorum),2 conformis species(Urosomoida cf.Agilis,Sterkiella cf.histriomuscorum)were studied in detail.The most of the morphogenesis characteristics of N.petergofi,S.cf.histriomuscorum and Gonostomum affine were studied.The molecular phylogenetic tree was constructed and the molecular systematic relationships were analyzed based on the SSU r DNA sequencing of Metagonostomum gonostomoida.(4)The morphological characteristic of 19 ciliate species,including 6 domestic new records(Phialina pupula,Protospathidium salinarum,Spathidium seppelti etoschense,Spathidium dispar,Rimaleptus mucronatus,Pseudoprorodon halophilus)were studied in detail.(5)The Pearson correlation analysis between the soil ciliates community parameters and soil physical-chemical factors showed that soil water content were significantly positively correlated with the diversity index(P≤0.05),and the correlation with other parameters were not significant;electric conductivity were extremely significantly positively correlated with the density(P≤0.01),and the correlation with other parameters were not significant.