摘　要： 为阐明AM真菌对优良牧草和固沙植物沙打旺根际土壤理化性质的影响，本研究设置 70％，50％和30％等3个土壤相对含水量，比较了不同水分条件下接种摩西球囊霉（Glomus mosseae）、接种沙打旺根际土著AM真菌（优势菌种为透光球囊霉G．diaphanum，摩西球囊霉和瑞氏无梗囊霉Acaulosporareh— mii）和未接种沙打旺根际土壤理化性质的变化．结果表明：土壤易提取球囊霉素、酸性磷酸酶、碱性磷酸酶、脲酶活性和植株干质量随土壤含水量降低而显著下 降，土著AM真菌定殖率随土壤含水量降低而显著提高．不同水分条件下，接种AM真菌显著提高了菌根定殖率、土壤易提取球囊霉素、总球囊霉素、蛋白酶和脲酶 活性．土壤相对含水量为30％和50％时，接种AM真菌显著增加了土壤有机质、碱解N、酸性磷酸酶、碱性磷酸酶活性和植株干质量，显著降低了土壤pH值和 有效P含量，接种土著AM真菌的土壤总球囊霉素、碱性磷酸酶活性显著高于接种摩西球囊霉的根际土．土壤相对含水量为70％时，接种土著AM真菌显著提高了 土壤酸性磷酸酶、碱性磷酸酶活性和植株干质量．土壤水分和AM真菌交互作用对植株干质量、茵根定殖率、土壤pH值、养分、易提取球囊霉素、土壤酶有显著影 响．研究表明：接种AM真菌能够促进沙打旺植株生长，改善根际土壤理化性质，土著AM真菌菌根效应优于摩西球囊霉．

摘　要： 选择锡林郭勒盟正镶白旗南部额里图牧场羊草（Leymus chinensis（Trin.）Tzvel.）典型草原的严重退化地段,补播菌根羊草和非菌根羊草,探讨菌根接种对羊草菌根共生和羊草根围土壤主要养分和球囊酶素含量的影响。结果表明,与不接种（灭菌）处理相比,接种菌根显著提高了羊草根系菌根侵染率及孢子密度。接种菌根增加了土壤有机碳、碱解氮、有效磷以及土壤易提取球囊霉素和总球囊霉素的含量,菌根对其的贡献率分别为3.77%,6.32%,3.35%,19.65%,24.24%。AM真菌、球囊霉素及土壤养分的相关性分析表明,易提取球囊霉素与有机碳和菌根侵染率呈极显著正相关,相关系数分别为0.9281,0.9165;与有效磷显著正相关,相关系数为0.8568。总球囊霉素与有机碳、菌根侵染率和孢子密度呈显著正相关,相关系数分别为0.8482,0.9026,0.8300。接种AM真菌改善了羊草根围土壤养分环境,对播种羊草的定植与生长发育可能产生重要影响。

以白三叶草(Trifolium repens)为试材,在其栽培基质中接种丛枝菌根真菌地表球囊霉(Glomus uersiforme)和粘屑球囊霉(Paraglomus occultum),探讨了菌根真菌对植物根系形态的影响以及菌根调控根系形态的可能机制.结果显示:2种菌根真菌处理都显著促进了白三叶草的生长,增加了生物量(鲜重),提高了白三叶根系投影面积、表面积、体积、根尖数、分支数、交叉数和根系长度(主要是0.0cm＜L≤0.5cm根长),同时显著提高了白三叶叶片和根系的葡萄糖含量,但降低了蔗糖含量;此外,菌根真菌侵染率、白三叶葡萄糖含量和根系构型参数三者间有显著或极显著的正相关关系.该结果表明菌根真菌能对植株体内糖代谢产生影响,特别是诱导葡萄糖含量的增加,这将有利于根系构型的改善、菌根的形态建成以及根系—菌根共生体系的发展.

大气CO2浓度及温度逐年上升是当前全球范围内主要的两大气候特征,但不断升高的大气CO2浓度可以缓解高温对植物生长发育带来的负面影响.为了探究高浓度CO2在多年生禾草生长和抗氧化系统方面对热胁迫的响应,本试验以高羊茅(Festuca arundinacea cv.‘Barlexas’)为材料,进行CO2[当前浓度(400 μmol/mol)和高浓度(800 μmol/mol)]和温度[(最适生长温度(25/20℃)和热胁迫温度(35/30℃)]处理.结果表明,高温导致高羊茅的生长速率(Gr)、净光合速率(Pn)、光化学效率(Fv/Fm)、绿叶数、活性氧清除物质[超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)]活性等显著下降,叶片黄绿比、电解质渗漏率(EL)、丙二醛(MDA)、活性氧[过氧化氢(H2O2)、超氧阴离子(O2-·)]显著上升;热胁迫处理28 d时,高浓度CO2较正常CO2浓度使细胞膜稳定性增强(EL、MDA分别降低72％和39％),光合能力提高(Pn、Fv/Fm、绿叶数分别升高174％、17％和165％),活性氧积累减少(H2O2、O2-·含量分别下降46％和31％).以上结果说明:高浓度CO2通过提高高羊茅在热胁迫下的光合能力,维持细胞膜的稳定以及减少体内活性氧的积累减弱了热胁迫对植株的伤害,从而提高了高羊茅的抗热性.

本研究以高羊茅航天诱变新品系和贵州主推的育成品种水城高羊茅和黔草1号高羊茅共11份材料为研究对象,采用盆栽试验,在42℃/32℃(12 h/12 h)人工气候室进行高温胁迫试验,每4d测定可溶性蛋白、超氧化物歧化酶(SOD)、过氧化物酶(POD)活性、过氧化氢酶(CAT)生理生化指标,并应用隶属函数法和灰色关联度法对其生理指标及11份高羊茅材料耐热性进行综合评价.结果表明,可溶性蛋白质随着高温胁迫时间的延长总体呈下降趋势,SOD、POD、CAT含量随着高温时间的延长总体呈上升趋势.4个生理指标在11份材料间均存在显著性差异.利用隶属函数法对11份高羊茅材料进行综合耐热适应性评价,得出耐热性顺序为:SP5-85＞SP5-60＞SP5-71＞SP5-42＞SP5-94＞SP5-7＞SP5-88＞水城高羊茅＞SP5-5＞SP5-89=黔草1号高羊茅.利用灰色关联性分析法得出各耐热指标与耐热性的关联序为:SOD＞ CAT＞ POD＞可溶性蛋白质.

One gram of soil may harbor up to 10 billion microorganisms belonging to possibly more than 10 4 different species, most of which play vital roles in various biogeochemical cycles such as the release and fixation of nutrient elements and decomposition of organic matter. The microbial community is considered to be a functional indicator because changes in the soil environments in which they live can affect their structure and diversity. Microbial diversity is a growing field of study in soil science and microbial ecology. Increases in knowledge of soil microbial diversity depend on improvement in the approaches to its study. Over the last four decades, culture-dependent and culture-independent technologies have been developed to assess microbial diversity in soil. Conventional culture-dependent methods such as plate counts, morphology analysis and community level physiological profiling (CLPP) provide information on the active heterotrophic component and the functional role of the population. However, the evaluation of soil microbial diversity based on these methods has been limited to the cultivable cells, amounts of which are less than 1% of the microorganisms observed under the microscope. To overcome this issue, profiles based on biochemical components of cell membrane have been used to characterize the soil microbial community. The profiles mainly include phospholipids fatty acids and respiratory quinines, the structure of which can be used to classify microorganisms. Since these methods avoid the limits of selective culturing and isolating, they have been considered to be an approach to objectively reflecting soil microbial community diversity. With improvements in DNA extraction and polymerase chain reaction (PCR) technologies, a number of molecular-based methods, which are more reliable and accurate than the above-mentioned methods, have been developed to assess soil microbial diversity. These approaches include DNA reassociation, guanine+cytosine (G+C)% content, nucleic acid hybridization technologies such as fluorescent in situ hybridization (FISH) and DNA microarrays, soil metagenomics based on cloning and library screening of soil genomic DNA, PCR-based genetic fingerprinting such as terminal restriction fragment length polymorphism (T-RFLP), denaturing/temperature gradient gel electrophoresis (DGGE/TGGE), single strand conformation polymorphism (SSCP) and two-dimensional DNA gel electrophoresis(2-DGE)with high resolution. These molecular-based technologies can potentially provide excellent insights into diversity information of the cultivable as well as uncultivable soil microorganisms. Without a doubt, they have opened up novel ways to study soil microbial diversity in detail, and thus enable us to acquire a better understanding of the relationship between function and diversity of soil microorganisms. Genetic fingerprinting especially is a very suitable approach to monitoring changes of soil quality through analyzing temporal and spatial dynamics of microbial diversity. The culture-independent methods do not require the selection of culture media and conditions, and also enable us to obtain more abundant and accurate information of microbial diversity than the culture-dependent methods. However, each method has its own limitations. Therefore, when applying these methods to the assessment of soil microbial community, a combination of more than two methods is recommended. This review introduces their principles, advantages and disadvantages, as well as summarizing their application and progress in studying soil microbial diversity.

土壤微生物群落多样性是土壤微生物生态学和环境科学的重点研究内容之一。传统的土壤微生物群落多样性解析技术是指纯培养分离法(平板分离和形态分析法以及群落水平生理学指纹法)。后来,研究者们建立了多样性评价较为客观的生物标记法(磷脂脂肪酸法和呼吸醌指纹法)。随着土壤基因组提取技术和基因片段扩增(PCR)技术的发展,大量的现代分子生物学技术不断地涌现并极大地推动了土壤微生物群落多样性的研究进程。这些技术主要包括:G+C%含量、DNA复性动力学、核酸杂交法(FISH和DNA芯片技术)、土壤宏基因组学以及DNA指纹图谱技术等。综述了这些技术的基本原理、比较了各种技术的优缺点并且介绍了他们在土壤微生物群落多样性研究中的应用,展望了这些技术的发展方向。

One of the important ways to improve the properties and application effect is to add microbial community with biological activity into organic cultivation substrate.In this experiment,the effects of arbuscular mycorrhizal fungi (AMF) on seedling growth,fruit yield,photosynthesis,microbial diversity and enzyme activities in rhizosphere of Capsicum annuum L.plants were investigated by adding AMF in organic substrate during seedling and cultivation.The results showed that:(1)The growth of pepper seedlings was promoted.(2)The net photosynthetic rate( P n ),stomatal conductance( G s ),transpiration rate( T r ) and water use efficiency( WUE ) were significantly increased while intercellular CO 2 concentration( C i ) was decreased.Meanwhile,it has little effect on the maximum photochemical efficiency( F v / F m ),but the actual photochemical efficiency( Ф PSⅡ ),photochemical quenching( q P ) and table electron transport efficiency( ETR ) were increased by AMF,moreover,resulting in robust seedlings and higher yield.(3)The amount of bacteria and actinomycetes in rhizosphere of pepper plants was increased by AMF,but the amount of fungi was decreased,and the Shannon-Wiener and Shannon index of microbial diversity,the activities of catalase,urease and alkaline phosphatase in organic substrate were enhanced.Furthermore,the correlation coefficient between amount of bacteria,actinomycetes,fungi and activities of enzymes such as catalase,urease and alkaline phosphatase in AMF substrate reached to a significant or extremely significant level.Our results suggested that AMF increased stomatal conductance of Pepper leaves and improved electron transfer rate,raised CO 2 assimilation efficiency and net photosynthetic rate;meanwhile it also promoted the transformation process of substrate from low-fertility caused by fungi to high-fertility caused by bacteria,and enhanced microbial diversity and enzyme activities.AMF helps maintain the stability and harmony in rhizosphere ecological system of pepper plants,lead to more rapid seedlings growth and higher yield.In conclusion,it is an effective way to improve the application effect of organic substrate by adding AMF.

在育苗和栽培基质中添加具有生物活性的微生物群体是改善无土栽培有机基质性状和提高应用效果的重要途径。该试验通过在辣椒育苗和栽培基质中添加丛枝菌根真菌制剂恩益碧(NEB-F),研究了AMF对辣椒生长、果实产量、光合特性以及根际微生物多样性和酶活性的影响。结果显示:(1)基质添加AMF显著促进了辣椒植株生长,并明显提高了产量。(2)AMF处理显著提高了辣椒植株叶片的净光合速率( P n )、气孔导度( G s )、蒸腾速率( T r )、水分利用效率( WUE ),而使胞间二氧化碳浓度( C i )显著降低,同时对辣椒叶片最大光化学效率( F v / F m )的影响不大,而使实际光化学效率( Ф PSⅡ )、光化学猝灭( q P )和表观光合电子传递效率( ETR )显著提高。(3)基质添加AMF显著增加基质中细菌、放线菌数量,而降低真菌数量,并明显提高了根际微生物多样性指数以及过氧化氢酶、碱性磷酸酶和尿酶活性;添加AMF基质中的细菌、真菌、放线菌数量均与其过氧化氢酶、脲酶、碱性磷酸酶之间呈显著或极显著正相关关系。研究表明,基质添加AMF不仅增大了辣椒叶片气孔导度,而且促进电子传递速率,提高CO 2 同化利用效率和净光合速率;同时促使辣椒根际微生物区系从低肥力的“真菌型”向高肥力的“细菌型”转化,提高根际微生物多样性和酶活性,有助于维持辣椒根际生态系统的稳定性与和谐性,从而促进辣椒幼苗生长,并提高产量。基质中添加AMF是提高有机基质应用效果的有效途径。

Arbuscular mycorrhizal fungi (AMF, phylum Glomeromycota) could be the most widespread symbiotic organisms in nature. They can form symbioses with the roots from a majority of higher plant species. The research on AMF species diversity has attracted much attention because of the widespread distribution of these organisms in various types of ecosystems around the world and because of their great application potential in the areas of agriculture, forestry and environmental sciences. Recent study has shown that in these ecosystems the diversity and community structure of AMF can have significant effects on the diversity and productivity of plant communities, giving this research on AMF species diversity even greater significance. Despite their widespread world distribution, fewer than 250 morphological species of AMF have been reported to date. However, evidence is now accumulating that the overall AMF global diversity has been severely underestimated. In natural or non-natural ecosystems, the species diversity of AMF could be affected by such factors as the species composition of host plants, human disturbances and by a variety of environmental factors. On the other hand, our understanding of AMF species diversity depends to a large extent on the development of methodology and on the application of new techniques. For a long time, the obligate symbiosis character of AMF and the methodology limitations have greatly hampered the research progress on AMF species diversity. For many years, investigations of AMF species diversity depended on the morphological identification of AMF spores isolated from the rhizospheric soil of host species. However, the species diversity of AMF spores cannot truly reveal or reflect the diversity of the AMF species colonizing host plants, and the morphological identification of AMF species has relied too much on the research experiences of the investigators. The more recent application of the PCR-based molecular method in AMF species diversity studies has much improved our knowledge of AMF species diversity. On the one hand, the PCR molecular method can directly detect the AMF species diversity within the roots of host plants. On the other hand, as its procedures are more standardized, it can provide more reliable and comparable results. However, there are also several drawbacks of the molecular method. Firstly, the design of the AMF specific primer is dependent on the published DNA sequences; therefore the discovery of new AMF species is hampered. Secondly, large scale investigation of AMF diversity by molecular methods is still expensive, though the price for Sanger sequencing procedures has dropped significantly in recent years. Thirdly, the molecular method can only provide the results of AMF "taxa" diversity, not of AMF species diversity. For many years, these drawbacks hampered the further development of the field of AMF species diversity. In recent years, the improvement in methodology (e.g. the proposed DNA barcode region for AMF) and the development of second generation sequencing technology (e.g. the 454 pyrosequencing technology) have provided excellent opportunities to strengthen our knowledge of AMF species diversity. We believe that within the next few years there will be huge progress in elucidating AMF species diversity. In this review article, research advances in AMF classification systems, in understanding of global species diversity levels and affecting factors to AMF species diversity, and in development of methodology for studying AMF species diversity are described and further research fields that need focus are also analyzed.

丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)是自然界分布最广泛的一类植物共生真菌,能够与大部分高等植物的根系形成共生关系。由于它们在农林、环境等领域的巨大应用潜力,国内外关于AMF物种多样性的研究一直受到较高的关注。然而,AMF专性共生的特征以及研究方法不够理想等因素长期阻碍了AMF物种多样性的研究进展。近年来,研究方法的改进与新技术的应用为AMF物种多样性的研究提供了极好的机遇。简述了AMF的最新分类系统及全球物种数量、AMF物种多样性影响因素以及AMF物种多样性研究方法三个方面的研究进展,并分析了今后在AMF物种多样性相关领域值得关注的研究方向。

为揭示接种菌根真菌对采煤沉陷引起植物根系拉伤的修复作用,模拟矿区植物垂直方向上拉伤根系,采用三室分根装置以玉米为宿主植物,通过接种丛枝菌根真菌(Arbuscular mycorrhizal fungi,简称AM真菌)研究其对植物受损根系生理生化的影响。结果表明:接菌能缓解因伤根对玉米生长的不利影响。1/3伤根时接菌玉米的地上和地下生物量分别比未接菌显著提高43.8%和17.6%。2/3伤根时,接菌的玉米地上和地下生物量大于未接菌,但未达到显著水平。最大伤根程度时菌根室中AM真菌的侵染率和菌丝密度分别为71.1%和4.82 m/g,仍能与玉米形成稳定的互惠共生关系。接菌促进受损根系对矿质元素的吸收利用。伤根1/3时,接菌玉米地上部中N,P,K,Ca和Mg含量分别比未接菌显著增加1.55,0.43,5.23,2.81和0.28 mg/g,接菌分别比未接菌的玉米根系中N,P,K,Ca和Mg含量显著增加1.32,0.73,5.0,6.45和0.69 mg/g,且能恢复到未伤根时玉米的矿质元素含量水平。接菌能降低伤根对玉米根系内源激素产生的不利影响。伤根1/3时菌根室接菌玉米根系中生长素(IAA)、赤霉素(GA)和细胞分裂素(CTK)含量显著提高,脱落酸(ABA)含量显著降低,且达到未伤根时内源激素含量水平。伤根2/3时菌根室和根室中接菌根系的GA和CTK含量可以恢复到1/3伤根时根系中该激素含量水平。AM真菌的侵染率与菌丝密度与根系中GA和CTK含量显著相关,与IAA和ABA含量相关性不显著。接种菌根缓解了伤根对植物的生理生化不利影响。