生草模式对枣园土壤真菌群落结构组成与共线性网络的影响

Effects of grass mode in jujube orchard on the structural composition and cooccurrence network of soil fungal community

果园生草能改变土壤微环境物理化学性状,增强植物间根系-土壤-根系相互作用,这可能会影响土壤真菌群落结构组成和功能稳定。本研究以5 a枣品种‘金丝4号’为研究对象,在枣园行间设置清耕、种植自然生草、种植长柔毛野豌豆3种耕作模式,通过土壤高通量ITS测序,旨在分析生草对枣园土壤真菌群落结构组成与共现性网络的影响。结果表明,长柔毛野豌豆组和自然生草组增加枣树根际土壤真菌群落Shannon指数和Simpson指数,但是降低了行间土壤真菌多样性。三种耕作模式下枣园真菌群落组成均以子囊菌门、担子菌门和被孢霉菌门为主,高达79.53%—93.24%。相对清耕组,长柔毛野豌豆组促进枣树根际土壤被孢霉菌门的相对丰度,抑制子囊菌门的相对丰度,而自然生草组增加子囊菌门的相对丰度,降低稀有菌门的相对丰度。冗余分析表明长柔毛野豌豆组土壤真菌群落多样性与土壤养分呈现正相关关系。Funguild分析表明种植长柔毛野豌豆明显有利于根际土壤腐生营养型真菌的繁殖,但抑制共生营养型真菌的相对丰度。共现性网络分析发现长柔毛野豌豆明显增加枣园土壤真菌网络节点与连接线数量,增强土壤真菌群落间互作关系及功能稳定性。本研究主要分析枣园生草对土壤真菌群落结构组成与功能网络的影响,为枣园生草的推广和应用提供科学依据。

Sown grass in orchard can change the physical and chemical properties of soil microenvironment and enhance the root-soil-root interaction between fruit tree and herb species,which may affect its structural composition and functional stability of soil fungal community.In this study,the five-year jujube variety‘Jinsi4’(Zizyphus jujuba Mill.)was selected as the research object,and three tillage treatments were set in jujube:clear tillage(CK),cropping with Vicia villosa(VV),and cropping with natural grass(ZR)in the interrow to further detect the effects of grass mode in jujube orchard on soil fungal community composition and ecological function by soil high-throughput sequencing.The results showed that the Shannon index and Simpson index of soil fungi community in the rhizosphere of jujube increased in VV and ZR groups,while the diversity of soil fungi in the interrow displayed a decreasing trend.The dominated phylum of the fungal community was occupied by Ascomycetes,Basidiomycetes and Mortieromycetes under the three cultivation modes,which reached 79.53%—93.24%.Compared to CK group,cropping with Vicia villosa promoted the relative abundance of Mortierellomycota,and inhibited the relative abundance of Ascomycetes,while cropping with native grass increased the relative abundance of Ascomycetes and reduced the relative abundance of rare phylum in the fungal community.Redundancy analysis showed that there was a positive correlation between the diversity of soil fungi community and soil nutrients in VV group.Funguild analysis showed that cropping with Vicia villosa was obviously beneficial to the propagation of saprotrophic fungi in rhizosphere soil,but inhibited the relative abundance of symbiotic trophic fungi.Co-occurrence network analysis showed that cropping with Vicia villosa in jujube orchard significantly increased the nodes and edges of soil fungal network,and promoted the correlation among fungal species and soil functional stability compared to the CK and ZR group.The study mainly analyzed the effects of grass on soil fungal community structure and functional network in jujube orchard,which provided scientific basis for the popularization and application of grass mode in orchard.