玉米种植改变了引黄灌区盐渍化土壤细菌多样性与功能

Corn cultivation alters bacterial diversity and function in salinized soils of the Diversionary Yellow River Irrigation Area

为了明确植物修复对盐渍化土壤细菌群落结构及多样性的影响,本文对宁夏引黄灌区盐渍化土壤玉米种植地根际和非根际土壤以及荒地土壤细菌多样性、群落结构及功能、细菌群落与环境因子之间的相关关系等进行研究。结果表明:玉米种植能够增加盐渍化土壤细菌物种数(OTU, Operational Taxonomic Unit)和多样性,各土壤细菌总物种数和特有物种数(OTU)从高到低依次为:非根际土壤>根际土壤>荒地土壤;土壤细菌多样性(即ACE指数、Chao1指数、Simpson指数与Shannon指数)由大到小均依次为:根际土壤>非根际土壤>荒地土壤, 3种土壤细菌多样性之间差异不显著。玉米种植改变了盐渍化土壤细菌群落结构和功能多样性,玉米种植显著提高了变形菌门(Proteobacteria)与放线菌门(Actinobacteria)两种优势菌门的相对丰度;丛毛单胞菌属(Comamonadaceae)、丝状菌属(Hyphomircobiales)和根瘤菌属(Rhizobiaceae)为3种土壤组间差异贡献最大的物种;玉米种植增加了盐渍化土壤中细菌参与新陈代谢功能与遗传信息处理功能物种的相对丰度,且有效磷、全磷、速效氮、全盐和pH是影响二级功能相对丰度的重要因子。玉米种植后其根际和非根际土壤细菌群落在生态位上与荒地之间存在明显分异。种植玉米修复盐渍化土壤能够改变土壤细菌群落结构、功能和多样性,对改善盐渍化土壤微环境,促进盐渍化土壤微生物功能发挥和盐渍化土壤种植结构优化具有重要意义。

Soil salinity is one of the global environmental problems affecting agroecosystems and sustainable development of agricul-ture.Bacteria are involved in nutrient cycling processes such as soil carbon,nitrogen and phosphorus,and play a crucial role in soil ecosystem stability and soil fertility maintenance.In order to clarify the influence of plant restoration on the structure and diversity of bacterial communities in salinized soils,we took salinized soils in the Yellow River Irrigation Area of Ningxia as samples,and used high-throughput macro-genome microbial sequencing technology to carry out comparative studies on the diversity of bacteria in the maize rhizosphere soil(CR),maize non-rhizosphere soil(C),and wasteland(H),analyze the characteristics of bacterial diversity and changes in community structure and function among the selected three soils,and reveal the correlation between microorganisms and soil environmental factors.The changes of diversity,structure and function of bacteria communities in the selected three soil types were analyzed,and the correlation between diversity of bacteria communities and soil environmental factors were revealed.The res-ults showed that bacteria detected in 12 soil samples from maize rhizosphere(CR),maize non-rhizosphere(C),and wasteland(H)be-longed to 50 phylums,67 classes,153 orders,350 families,1111 genera and 4455 species.The soil bacteria richness and diversity in maize rhizosphere soil(CR)and maize non-rhizosphere soil(C)were more complex than that in the salinized wasteland,and ACE in-dex,Chao1 index,Shannon index and Simpson index of the soil bacteria were in the following descending order:CR>C>H.At phylum level,compared with wasteland,the relative abundance of Proteobacteria and Actinobacteria in the maize rhizosphere soil(CR)and maize non-rhizosphere soil(C)increased by 4.53%and 3.33%,3.97%and 5.73%,respectively.At genus level,compared with wasteland,the relative abundance of Nocardioides,Idiomarina,Arthrobacter and Pseud Arthrobacter in the maize rhizosphere soil(CR)and maize non-rhizosphere soil(C)increased.Comamonadaceae,Hyphomircobiales and Rhizobiaceae were the species with the greatest contribution of inter-group differences.Compared with wasteland(H),significant divergence in ecological niche was observed in the maize rhizosphere soil(CR)and maize non-rhizosphere soil(C).Maize planting could enhance the metabolic capa-city of soil bacterial communities,and the relative abundance of maize rhizosphere soil(CR),and maize non-rhizosphere soil(C)bac-teria involved in metabolic functions increased by 1.44%and 0.56%,respectively.Soil effective phosphorus(AP),total phosphorus(TP),effective nitrogen(AN),total salts(TS),and pH showed large impacts on the relative abundance in the level 3 functions.In con-clusion,planting maize to repair salinized soil can change the structure and functional diversity of soil bacterial communities,which is of great significance in improving the microenvironment of salinized soil and promoting the microbial function of salinized soil and the sustainable use of land.