【作者】 盛敏；

【导师】 唐明；

【作者基本信息】 西北农林科技大学 ， 微生物学， 2008， 博士

【摘要】 本文研究了甘肃、宁夏和内蒙古代表性盐碱土中柠条、砂柳、胡杨、椿树、沙枣、白刺、枸杞、水稻、玉米、小麦、棉花、芦苇、向日葵、葱、乌拉尔甘草、骆驼刺、苜蓿、冰草、羊草、芨芨草、大米草、盐角草、筛草、寸草苔和马蔺等25种主要植物根际的VA菌根真菌资源及土壤因子对VA菌根真菌的影响，探索了盐胁迫条件下接种VA菌根真菌提高玉米耐盐性的内在机制。同时，本文还研究了土壤类型、土壤理化性质以及气候条件对加拿大萨斯卡彻温省农田生态系统中微生物多样性的影响，构建了VA菌根真菌和土壤理化性质对小麦N、P吸收的贡献模型。得出以下主要结论：1．VA菌根真菌的种类从25种植物根际土中分离并鉴定出浅窝无梗囊霉、皱壁无梗囊霉、细凹无梗囊霉、刺无梗囊霉、格氏原囊霉、薄壁原囊霉、幼套多孢囊霉、地表多孢囊霉、聚丛球囊霉、白色球囊霉、澳洲球囊霉、近明球囊霉、明球囊霉、缩球囊霉、副冠球囊霉、透光球囊霉、聚生球囊霉、地球囊霉、根内球囊霉、木薯球囊霉、摩西球囊霉、膨果球囊霉、具疱球囊霉、网状球囊霉、荫性球囊霉、三壁球囊霉、疣壁球囊霉和泡囊球囊霉等28种VA菌根真菌，分别隶属于球囊霉属、多孢囊霉属、原囊霉属和无梗囊霉属等4个属。其中泡囊球囊霉和三壁球囊霉为我国新记录种，球囊霉属、多孢囊霉属和原囊霉属为优势属，缩球囊霉、地球囊霉、根内球囊霉、地表多孢囊霉和薄壁原囊霉为优势种。2．菌根植物的多样性和VA菌根的结构类型所调查的14科25种植物全部被VA菌根真菌侵染。在以前研究认为没有或很少有VA．菌根真菌侵染的莎草科植物中发现寸草苔和筛草有菌根侵染现象。除筛草不能确定菌根结构类型外，其余24种植物的菌根结构类型以A型为主，占66．7％，少数为P型，占33．3％，没有发现I-型菌根结构。3．VA菌根真菌生态分布的影响因素VA菌根真菌侵染率与土壤pH和CO₃^2-含量呈显著负相关，与HCO₃^-含量呈极显著负相关。Cl^-、CO₃^2-、K⁺、Ca²⁺和有机质含量通过直接作用影响VA菌根真菌的侵染率，SO₄^2-、HCO₃^-、Na⁺、Mg²⁺、水溶性全盐、速效P、速效K、速效N含量和土壤pH则通过间接作用影响VA菌根真菌的侵染率。VA菌根真菌孢子密度与土壤中SO₄^2-含量呈显著负相关，与真菌和细菌数量呈显著正相关。SO₄^2-、速效P、速效K、速效N含量和土壤pH通过直接作用影响孢子密度，Cl^-、CO₃^2-、HCO₃^-、Na⁺、K⁺、Ca²⁺、Mg²⁺、水溶性全盐和有机质含量则通过间接作用影响孢子密度。植物种类不同其根际VA菌根真菌种的丰度及优势种不同。盐土、碱土和盐化灌淤土中的VA菌根真菌种的丰度不同，分别为24、18和17，但优势种、属相同。土壤理化性质影响着VA菌根真菌的物种多样性、种的丰度及相对多度。4．VA菌根真菌提高玉米耐盐性的机制在盐胁迫下接种VA菌根真菌促进了玉米植株的生长和干物质的累积，提高了玉米的耐盐能力。主要由于接种VA菌根真菌①提高了玉米叶片的组织含水量和水分利用效率，降低了水分饱和亏；②增加了玉米叶片的叶绿素相对含量、净光合速率、气孔导度、蒸腾速率、光化学和非光化学效率，降低了胞间CO₂浓度和Fo，调节能量在光化学和非光化学过程中的分配，提高了植株的光合作用能力；③降低了玉米植株的根冠比、比根长和细根（0～0．2 mm）占总根长的比例，增加了根系的平均直径、根系体积和根系活力；④提高了玉米叶片的过氧化氢酶活性，降低了玉米叶片中O₂^-、H₂O₂、丙二醛的含量和电解质透出率，增加了细胞膜的稳定性；⑤提高了玉米叶片的还原糖、可溶性糖、可溶性蛋白和游离有机酸含量，增加了植株的渗透调节能力。5．加拿大萨斯卡彻温省农田土壤中微生物多样性及其影响因素不同土壤类型的微生物群落结构存在显著差异。变性土的VA菌根真菌、真菌（除VA菌根真菌，下同）、G⁺细菌的生物量和微生物总量最高，褐灰钙土的真菌和细菌生物量之比及真菌的相对多度最高。真菌生物量及真菌和细菌生物量之比与土壤中Cu²⁺含量呈正相关，与7月、8月的平均降雨量和土壤中速效N、Mn²⁺、Zn²⁺、有机质含量呈负相关；G⁺细菌的生物量与土壤中速效P含量呈正相关，与土壤容重呈负相关；G^-细菌的生物量与土壤中速效P含量呈负相关，与土壤容重呈正相关。VA菌根真菌的生物量与5～8月的平均气温和5月的平均降雨量呈正相关，与8月的平均降雨量、土壤容重以及土壤中Mn²⁺、Zn²⁺含量呈负相关。从49个农田土壤样品中鉴定出何氏球囊霉、摩西球囊霉、Glomus sp．1和G.sp．24种VA菌根真菌。G．sp．1和何氏球囊霉主要分布于灰色淋溶土中；摩西球囊霉主要分布于暗棕钙土中；G．sp．2主要分布于灰漠钙土中。何氏球囊霉在土壤中的分布主要受5～8月的平均气温和土壤中Cu²⁺含量的影响，摩西球囊霉主要受5～8月的平均降雨量和土壤容重的影响，G．sp．1和G．sp．2主要受土壤中速效N、速效P、Mn²⁺、Zn²⁺和有机质含量的影响。VA菌根真菌和土壤理化性质对小麦N、P吸收的贡献模型为：Y₁=1．36350-0．00132X₁₁+0．06304X₁₂-1．64599X₁₃+18．39645 X₁₄模型1Y₂=0．27405-0．00014X₂₁-0．01429X₂₂+0．00184X₂₃模型2更多还原

【Abstract】 The composition community of AMF（Arbuscular Mycorrhizal Fungi）in rhizospheres of25 common plants（Allium fistulosum,Caragana korshinkii,Glycyrrhiza uralensis,Alhagisparsifolia,Medicago sativa,Oryza sativa,Zae mays,Agropyron cristatum,Leymus chinensis,Achnatherum splendens,Spartina anglica,Triticum aestivum,Phragmites australis,Elaegnusangustifolia,Nitraria tangutorum,Gossypium herbaceum,Helianthus annnus,Ailanthusaltissima,Saliconia europaea,Lycium chinense,Carex kobomugi,C.duriuscula,Salixgordejevii,Populus euphratica and Iris lactea）in saline alkaline soils of Gansu province,Ningxia Hui Autonomous Region and Inner Mongolia Autonomous Region was investigated.The relationship between AMF composition community and soil factors was analyzed as well.The influence of AMF（Glomus mosseae）on salt-resistant mechanisms of maize plants undersalt stress was studied in the greenhouse.Whilst,we analyzed the relationship between soiltype,soil properties,climate conditions and microbiological diversity in farmland soils ofSaskatchewan,Canada,and built two models to figure out the relationship among AMF,soilproperties and contents of N and P in wheat plants.The results are as follows:1.In total,twenty-eight AMF species belonging to 4 genera were identified fromrhizospheres of 25 common plants.There were 4 Acaulospora（A.lacunose,A.rugosa,A.scrobiculata and A.spinosa）,2 Archaeospora（At.Gerdemannii and Ar.leptotichum）,2Diversispora（D.etunicatum and D.versiforme）,and 20 Glomus（G.aggregatum,G.albidum,G.australe,G.claroideum,G.clarum,G.constrictum,G.coronatum,G.diaphanum,G.fasciculatum,G.geosporum,G.intraradices,G.manihotis,G.mosseae,G.pansihalos,G.pustulatum,G.reticulatum,G.tenebrosum,G.trimurales,G.verruculosum and G.vesiculiferum）.Among them,G.vesiculiferum and G.trimurales were new record species inChina.Glomus,Diversispora and Archaeospora were the dominant genera.G.constrictum,G.geosporum,G.intraradices,D.versiforme and Ar.Leptotichum were the dominant species.2.All twenty-five plant species,including Carex kobomugi and C.duriuscula of theCyperaceae,were colonized by AMF.The structural type of VA（Vesicular Arbuscular）mycorrhizae of C.kobomugi could not be identified;most other plant species（66.7%） belonged to the Arum-type,33.3% belonged to the Paris-type,the intermediate type was notfound.3.AMF spore density was negatively correlated with SO₄^2-concentration,but positivelywith the number of fungi and bacteria.AMF spore density was influenced directly by soil pHand concentrations of SO₄^2-,Olsen-P,Olsen-K and Olsen-N,but indirectly by concentrationsof Cl^-,CO₃^2-,HCO₃^-,Na⁺,K⁺,Ca²⁺,Mg²⁺,water-soluble salt and organic matter.AMFcolonization rate was negatively related with soil pH and concentrations of HCO₃^-and CO₃^2-.AMF colonization rate was affected directly by concentrations of Cl^-,CO₃^2-,K⁺,Ca²⁺andorganic matter,but indirectly by soil pH and concentrations of SO₄^2-,HCO₃^-,Na⁺,Mg²⁺,water-soluble salt,Olsen-P,Olsen-K and Olsen-N.The species richness and dominant speciesof AMF differed in rhizospheres of plant species.AMF species richness of saline soils,alkaline soils and salinized warped irrigation soils was 24,18 and 17,respectively.There wasno difference in dominant AMF genera or species among soil types.Soil properties werelinked to the biodiversity,species richness and relative abundance of AMF.4.VA mycorrhizae（Glomus mosseae）enhanced the ability of maize plants to cope withsalt stress.This may be because VA mycorrhizal symbiosis（1）triggered the regulation of theenergy biturcation between photochemical and non-photochemical events;（2）increased dryweight of shoot and root,water use efficiency,water content,relative chlorophyll content,netphotosynthetic rate,stomatal conductance,transpiration rate,photochemistry efficiency,non-photochemistry efficiency,root activity,average root diameter,root volume,CAT activity,and contents of reducing sugars,soluble sugars,soluble protein and free organic acid;（3）decreased water saturation deficit,intercellular CO₂ concentration,Fo,root to shoot ratio,specific root length,percentage of root length in 0～0.2 mm diameter class,the electricalpermeation rate,and contents of O₂^-,H₂O₂ and MDA.5.Microbiological diversity significantly differed in soil type of Saskatchewan,Canada.Among soil type,there was the highest biomass of total microbe,AMF,non-AMF fungi andG⁺ bacteria in Vertisol,and the highest fungi/bacteria ratio and fungal relative abundance inBrown Chemozem.The fungal biomass and fungi/bacteria ratio were positively correlatedwith Cu²⁺content,but negatively with the average precipitation of July and August andcontents of Olsen-N,Mn²⁺,Zn²⁺and organic matter.The biomass of G⁺ bacteria waspositively related with Olsen-P content,but negatively with soil bulk density.The biomass ofG bacteria was negatively related with Olsen-P content,but positively with soil bulk density.The biomass of AMF was positively correlated with the average precipitation of May and theaverage temperature of May,June,July and August,but negatively with the averageprecipitation of August,soil bulk density and concentrations of Mn²⁺and Zn²⁺. Totally,four AMF species（Glomus mosseae,G.hoi,G.sp.1 and G.sp.2）were identifiedfrom 49 farmland soil samples.G.sp.1 and G.hoi mostly distributed in Grey Luvisol;G.mosseae mostly in Dark-Brown Chernozem;G.sp.2 mostly in Dark-Grey Chernozem.Thedistribution of G.hoi in soil was related to Cu²⁺content and the average temperature of May,June,July and August;G.mosseae was linked to soil bulk density and the averageprecipitation of May,June,July and August;G.sp.1 and G.sp.2 was related to concentrationsof Olsen-N,Olsen-P,Mn²⁺,Zn²⁺and organic matter.Two models were built to figure out the relationship among AMF,soil properties andcontents of N and P in wheat plants.Y₁=1.36350-0.00132X₁₁+0.06304X₁₂-1.64599X₁₃+18.39645X₁₄Model 1Y₂=0.27405-0.00014X₂₁-0.01429X₂₂+0.00184X₂₃Model 2更多还原