微生物菌剂对楸树幼苗生长及根际土细菌群落结构的影响

Effects of microbial agent on the growth of Catalpa bungei seedlings and the diversity of bacterial community in rhizosphere soil

为探究球毛壳ND35微生物菌剂对楸树幼苗生长及土壤肥力的作用机制,本研究楸树幼苗为研究对象,采用室内盆栽试验,设计0(CK),10(T1),15(T2),20(T3)4种微生物菌剂施用量,测定幼苗生长情况、土壤微生物组成结构、土壤酶和土壤养分等特征。研究结果如下:(1)球毛壳ND35微生物菌剂可显著促进楸树幼苗的生长,株高、地径、地上及地下生物量显著提高(P<0.05),T2处理下促生效果最好。(2)施用球毛壳ND35微生物菌剂可显著提高土壤中有机质、硝态氮、铵态氮含量及脲酶、磷酸酶、蔗糖酶活性(P<0.05)。(3)球毛壳ND35微生物菌剂可显著影响土壤细菌群落组成,提高细菌群落的丰富度和多样性,使土壤中β-变形菌纲(Betaproteobacteria)、γ-变形菌纲(Gammaproteobacteria)的相对丰度显著下降,α-变形菌纲(Alphaproteobacteria)、δ-变形菌纲(Deltaproteobacteria)的相对丰度呈显著提高,可使土壤中鞘氨醇单胞菌属(Sphingomonas)的相对丰度显著提高21.88%—103.56%(P<0.05),芽孢杆菌属(Bacillus)的相对丰度提高66.28%—65.97%(P<0.05),酸杆菌属(Acidibacter)的相对丰度提高12.76%—38.06%。(4)冗余分析(RDA)结果表明,土壤硝态氮、铵态氮、有机质是影响土壤细菌群落分布和多样性的重要环境因子,土壤细菌群落结构的改变会显著影响土壤脲酶、蔗糖酶、碱性磷酸酶的活性。因此,施用球毛壳ND35微生物菌剂可通过影响植物根际土壤的化学性质及生物性质,促进楸树幼苗的生长。这一研究结果为楸树繁育提供了新的指导方向,亦为将其用于困难立地及退化生态系统植被恢复提供基础理论指导。

In order to investigate the mechanism of the Chaetomium globosum ND35 microbial agent on the growth and soil fertility of Catalpa bungei seedlings,the C.bungei seedlings were taken as the research object and 0,10,15,and 20 g microbial agents were applied on the C.bungei seedlings′root.And the growth status of the seedlings,the composition structure of soil microorganisms,soil enzymes and soil nutrients were measured.The results were obtained as follows:(1)the C.globosum ND35 could significantly promote the growth of C.bungei seedlings.The plant height,ground diameter,aboveground and underground biomass were significantly increased(P<0.05).And there was a best promotion effect at T2.(2)The contents of organic matter,nitrate nitrogen,ammonia nitrogen and the activity of urease,phosphatase and sucrose enzyme in soil were significantly improved by applying the C.globosum ND35 microbial agent(P<0.05).(3)The composition of soil bacterial communities was significantly influenced by C.globosumND35.And the diversity of soil bacterial communities was also increased significantly.The relative abundance of Betaproteobacteria and Gammaproteobacteria were significantly declined after using C.globosum ND35.And the relative abundance of Alphaproteobacteria,Deltaproteobacteria,Sphingomonas,Bacillus,Acidibacter were significantly improved.Among them,the relative abundance of Sphingomonas,Bacillus,Acidibacter increased 21.88%—103.56%(P<0.05),66.28%—65.97%(P<0.05),12.76%—38.06%,respectively.(4)Redundancy analysis(RDA)ascertained that the distribution and diversity of bacterial communities were closely related to the organic matter,nitrate nitrogen and ammonia nitrogen.And the activity of urease,sucrase and alkaline phosphatase were significantly altered with the change of soil bacterial community structure.Therefore,applying C.globosum ND35 microbial agent could promote the growth of C.bungeiseedlings by affecting the chemical and biological properties of rhizosphere soil.The results could provide a new direction for the breeding of C.bungei seedlings and theoretical guidance for the C.globosum ND35 microbial agent application in vegetation restoration of degraded ecosystems.