不同年限沙柳沙障沙埋部腐化特性及真菌群落特征

Decay and fungal community characteristics of sand-buried sections of Salix psammophila sand barriers at different ages

为探究沙柳(Salix psammophila)沙障腐化程度与真菌群落组成之间的关系,采用Illumina MiSeq测序技术与室内试验测定法,以铺设1、3、5、7年的沙柳沙障为研究对象,新铺设的沙柳沙障作为对照(CK),结合RDA多元数据排序手段,分析影响真菌群落组成的主要驱动因子,为沙漠地区沙柳沙障资源合理利用提供参考.结果显示,沙柳沙障腐化过程中基本密度与抗弯强度呈下降趋势,而含水率与湿胀性呈上升趋势,铺设7年后,沙障纤维素、半纤维素和木质素分别下降了48.07%、43.99%和44.51%;真菌群落优势菌群以粪壳菌纲(55.83%)和散囊菌纲(23.87%)为主,随腐化程度的加剧,Shannon多样性指数、ACE丰富度指数与Heip均匀度指数均增大,真菌群落结构趋于复杂化;RDA分析结果表明,障体腐化特性对真菌优势菌群影响的大小顺序依次为木质素>含水率>抗弯强度>纤维素>湿胀性>半纤维素>基本密度.本研究表明随铺设年限的增加,障体沙埋部腐化程度加剧,真菌群落多样性与丰富度增加,菌群分布受多种环境因子综合影响,木质素与含水率是影响其丰度的主要因子;涵盖的腐化特性指标并不能完全解释真菌群落分布的差异,需结合障体周际土壤理化因子进一步探讨.(图7表4参37)

This paper deals with the relationship between fungal community composition and decaying stages of Salix psammophila sand barriers.Illumina MiSeq sequencing technology and laboratory tests were performed.Freshly laid sand barriers were used as controls.The fungal community composition was explored in the sand burial parts of S.psammophila sand barriers after being laid for one,three,five,and seven years.The main drivers were analyzed using the RDA multivariate data ranking method,which affects the composition of fungal communities in S.psammophila sand barriers and provides a theoretical reference for the rational utilization of sand barrier resources in desert fixing.The cellulose,hemicellulose,and lignin contents of the S.psammophila sand barriers decreased by 48.07%,43.99%,and 44.51%,respectively,after seven years.The fungal community during the decay of S.psammophila sand barriers was dominated by Sordariomycetes(55.83%)and Eurotiomycetes(23.87%)of Ascomycota.With the decay of S.psammophila sand barriers,the fungal community in sand burial parts displayed increased Shannon,ACE,and Heip indices,and their fungal community structure became more complicated.The densities of the physical and mechanical properties of S.psammophila sand barriers showed a downward trend in bending strength.However,the physical properties of moisture content and swelling gradually increased.The RDA results showed that the following sequences were the major factors affecting the fungal community in S.psammophila sand barriers:lignin>moisture content>flexural strength>cellulose>wet distention>hemicellulose>density.With the growth of S.psammophila sand barriers in deserts,the sand-buried section of the barriers gradually decayed,and their fungal community structure and amounts became more diverse and rich.The findings indicate that fungal communities are comprehensively affected by various environmental factors during the decay process of S.psammophila sand barriers.Lignin and moisture contents are the main environmental factors that influence fungal community composition and structure.The decaying characteristics of S.psammophila sand barriers are insufficient to fully explain the differences in the distribution of fungal communities.This remains to be further explored in the context of the physical and chemical factors of the soil around the sand barrier.