毛乌素沙地典型克隆植物根际AM真菌多样性研究

为阐明毛乌素沙地3种典型克隆植物沙鞭[Psammochloa villosa(Trin.)Bor.]、羊柴(Hedysarum leaveMaxim)和油蒿(Artemisia ordosica Krasch.)根际AM真菌多样性,2006年的5月、7月、10月从毛乌素沙地选取东北缘的中国科学院植物研究所鄂尔多斯沙地草地生态研究站和西南缘的陕西榆林珍稀沙生植物保护基地两个样地,按0~10 cm、10~20 cm、20~30 cm、30~40 cm、40~50 cm 5个土层采集3种克隆植物根际土壤样品,研究了其根际AM真菌物种多样性和生态分布。在分离出的4属23种AM真菌中,球囊霉属(Glomus)15种,无梗囊霉属(Acaulospora)5种,巨孢囊霉属(Gigaspora)2种,盾巨孢囊霉属(Scutellospora)1种。摩西球囊霉(G.mosseae)是沙鞭根际的优势种,黑球囊霉(G.melanosporum)是3种克隆植物共同的常见种;不同属种的AM真菌生态分布亦存在差异。AM真菌孢子密度、种的丰度和物种多样性指数均表现为在研究站样地的羊柴根际最高。该研究结果表明,毛乌素沙地的3种典型克隆植物与AM真菌之间形成良好的共生关系,这对开发漠境AM真菌资源和利用菌根生物技术维护沙地生态系统结构的完整性具有重要意义。     

黄土高原柠条锦鸡儿根际AM真菌生态学研究

对陕西省延安、绥德、横山和榆林4个自然生境下柠条根际AM真菌空间分布和土壤成分进行测定分析。结果表明,AM真菌泡囊定殖率及孢子密度与样地生态条件密切相关,泡囊定殖率和孢子密度在绥德最高,丛枝定殖率在榆林最高。采样深度对孢子密度有显著影响,最大孢子密度发生在10～20cm土层,而AM真菌定殖率在0～10cm或20～30cm土层有最大值。孢子密度与泡囊定殖率呈正相关,与丛枝定殖率呈负相关。孢子密度与土壤有机质、速效磷、速效钾和Cl-含量呈负相关,泡囊定殖率与土壤pH呈正相关,而与土壤湿度、速效钾和Cl-含量呈负相关。土样中AM真菌多为球囊霉属(Glomus)种类,也有少数无梗囊霉属(Acaulospora)和巨孢囊霉属(Scutellospora)种类。建议孢子密度和泡囊定殖率可作为检测土壤环境状况的指标。     

不同土壤类型下AM 真菌分布多样性及与土壤因子的关系

以禾本科植物群落为研究对象, 研究了宁夏六盘山林地、银川农耕地、暖泉农耕地、固原农耕地、盐池沙地、灵武沙地6 个采样地点5 种土壤类型(黑垆土、灌淤土、黄绵土、灰钙土、风沙土)下AM 真菌物种多样性及其与土壤因子的关系。结果表明: 5 种土壤类型采样点的植被根际土壤中共鉴定出5 属48 种AM真菌, 其中, 无梗囊霉属(Acaulospora)1 种, 巨孢囊霉属(Gigaspora)3 种, 球囊霉属(Glomus)37 种, 类球囊霉属(Paraglomus)1 种, 盾巨孢囊霉属(Scutellospora)6 种, 各采样点土壤均以球囊霉属为优势属。地球囊霉(G.geosporum)和木薯球囊霉(G. manihotis)是6 个采样地点中的优势种。不同土壤类型各采样点AM 真菌各属的频度存在明显差异, 球囊霉属在各点均有出现, 频度值最高。具有较高植被多样性的暖泉样点, AM 真菌的种属数量较多。土壤环境因子对AM 真菌孢子密度的影响因所处土壤、植被类型不同而异。pH、全盐、速效钾、速效磷等土壤肥力因子, 在PCA 轴上能最大程度地解释AM 真菌孢子密度与土壤环境因子之间相互关系的大部分信息。宁夏不同土壤类型区域中AM 真菌种类及分布一定程度上与该采样点的植被类型、植物多样性和土壤肥力特征相对应。     

贵州务川汞矿区土壤丛枝菌根真菌多样性研究

对贵州务川汞矿区不同水平汞污染植物根际土壤丛枝菌根(Arbuscular Mycorrhizal,AM)真菌资源分布及多样性进行分析，结果发现：本研究选取的务川汞矿区3个样地土壤汞含量在94.1～268.0 mg/kg，远高于国家规定的土壤汞含量，汞污染极其严重。随着汞含量增加，AM真菌侵染率、孢子密度显著降低，AM真菌群落丰富度、多样性及均匀度均有所降低，但差异未达显著水平，而仍有部分对汞污染耐受性较强的AM真菌有较高的分布。另外，管柄囊霉属AM真菌在5个样品中均有较高丰度，球囊霉属AM真菌在火棘根际的相对丰度随着汞含量升高而升高，因此，火棘–管柄囊霉属AM真菌或火棘–球囊霉属AM真菌联合进行汞污染修复，有一定的应用价值。     

内蒙古盐碱土中AM真菌的多样性与分布

在内蒙古盐碱土13种主要植物分离到3属26种AM真菌,其中球囊霉属(Glomus)22种,无梗囊霉属(Acaulospora)3种,原囊霉属(Archaeospora)1种。地球囊霉(Glomus geosporum)和地表球囊霉(Glomus ver-siforme)是该区域盐碱土中的优势种。13种主要植物均能被AM真菌侵染,其中玉米和马蔺的侵染率最高,达100%;根际土壤中AM真菌孢子密度范围为29~182个g-1烘干土,其中稻的孢子密度最高,达182个g-1烘干土;在不同土壤类型条件下植物的菌根侵染率具有明显的差异,其规律为草甸盐土>碱化盐土>盐化草甸土>碱化草甸土;根际土壤中孢子密度以碱化草甸土最高(101个g-1烘干土),其次为碱化盐土、草甸盐土和盐化草甸土。相关分析表明,根际土壤中AM真菌孢子密度与菌根侵染率无显著相关性。     

河北安国7种中药材AM真菌遗传多样性研究

为探明药用植物根围AM真菌遗传多样性,于2010年8月在河北省安国市3个样地(中药材种植基地、霍庄、大户村)用随机抽样法采集7种中药材根围土壤样品,分离筛选双网无梗囊霉(Acaulospora bi-reticulata)为试验菌种,进行孢子DNA提取、PCR扩增、序列测定及聚类分析,研究了双网无梗囊霉遗传多样性与土壤因子的关系,并选取两条代表菌株所测序列,连同从NCBI数据库中下载的4属28种AM真菌相应序列构建系统发育树。结果表明,双网无梗囊霉可侵染不同样地不同宿主植物,3个样地7种中药材双网无梗囊霉DNA相似性达99.2%以上,其遗传特征保持了高度稳定性,双网无梗囊霉在样地和植物间具有广谱性。同一样地不同中药材根围土壤因子相似性很高,AM真菌DNA碱基序列相似系数也很高,而不同样地同一中药材根围AM真菌DNA碱基序列相似系数低于前者,可见遗传多样性与土壤因子密切相关。土壤因子对双网无梗囊霉基因序列的影响大于宿主植物的影响。     

长期种植毛竹林土壤丛枝菌根真菌群落演变趋势

为揭示长期种植毛竹林土壤丛枝菌根（Arbuscular mycorrhizae, AM）真菌群落演变特征,通过磷脂脂肪酸（Phospholipid fatty acid, PLFA）和Illumina Miseq测序平台研究了AM真菌生物量及群落结构的演变趋势。结果表明,长期种植毛竹林土壤养分含量总体呈下降趋势,球囊霉素相关土壤蛋白（Glomalin-related soil protein, GRSP）含量及AM真菌生物量也显著降低（p<0.05）,其中易提取态球囊霉素相关土壤蛋白含量与有机质、速效钾、碱解氮显著正相关（p<0.05）,而AM真菌菌丝生物量（16:1ω5 PLFA）与碱解氮极显著正相关（p<0.01）。长期种植毛竹林显著降低了土壤2~0.25 mm大团聚体比例（p<0.05）,且与AM真菌菌丝生物量极显著正相关（p<0.01）。测序结果表明,毛竹林土壤AM真菌以球囊霉属（Glomus）为优势种群,其次是无梗囊霉属（Acaulospora）,长期种植毛竹后土壤球囊霉属相对丰度显著增加而无梗囊霉属显著降低（p<0.05）。非度量多维尺度转换排序（NMDS）分析显示,对照马尾松林与不同种植年限毛竹林土壤AM真菌群落显著区分（p=0.001）,土壤含水量（p=0.005）、有效磷（p=0.014）、碱解氮（p=0.001）对AM真菌群落结构变异具有重要贡献。长期种植毛竹显著降低了AM真菌生物量、球囊霉素相关土壤蛋白含量以及2~0.25 mm大团聚体比例,并改变了AM真菌群落结构,不利于土壤碳固存和维持生态系统稳定。     

木薯根域AMF群落结构特征及多样性研究

土壤微生物是土壤—作物系统养分循环的重要驱动力,其中丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)能够促进作物对养分的吸收。木薯是我国南方重要的经济作物,是多种行业的重要原材料。为揭示不同土壤质地木薯根域土壤AMF群落结构特征,解析土壤因子对AMF类群的影响。以木薯品种华南205 (SC205)为材料,通过田间根袋培养,利用高通量测序平台进行真菌扩增子测序,分析不同处理木薯根域AMF类群组成和多样性差异。结果表明,木薯根域土壤AMF主要为球囊霉属(Glomus)、无梗囊霉属(Acaulospora)、盾巨孢囊霉属(Scutellospora)、类球囊霉属(Paraglomus)和双型囊霉属(Ambispora)。优势属为球囊霉属和无梗囊霉属。两种土质各处理AMF属水平上无显著差异,种水平分布受土壤质地及根袋的影响,粘土AMF多样性(Simpson指数)高于砂质壤土。两种土质中都发现独有种,土壤质地对木薯根域AMF群落分布有一定的影响。RDA分析表明Glomus与速效磷、速效氮、铵态氮正相关;Acaulospora与速效磷,速效氮弱负相关;Scutellospora与所有速效养分负相关;Paraglomus与所有速效养分表现出正相关;Ambispora与大部分速效养分表现出负相关。木薯根域AMF资源丰富,不同土壤质地条件下的AMF群落组成和丰度存在差异,土壤速效养分与AMF群落结构差异密切相关。该研究为进一步探索AMF在木薯上的应用提供理论参考。     

黑土农田施加AM菌剂对大豆根际菌群结构的影响

为揭示在黑土农田条件下施加丛枝菌根(AM)菌剂对作物根际微生物群落的影响,试验以大豆为研究对象,田间播种时分别施加根内球囊霉(Glomus intraradices,GI)和摩西球囊霉(Glomus mosseae,GM)两种AM菌剂,以单施化肥处理(F)和不施加AM菌剂及化肥处理(CK)作为对照,采用传统与现代分子生物学手段,研究大豆根际土壤中菌群结构及根系内AM真菌多样性。结果表明:GI、GM处理的大豆菌根侵染率最高达到78.3%和86.6%;GI、GM、F处理的大豆根际土壤中可培养细菌、真菌和放线菌三大菌群的数量与CK处理相比显著提高(p0.05)。分离大豆结荚期根际土壤中AM真菌孢子,共获得Acaulospora属真菌3种,Glomus属真菌7种,孢子密度均较低,G.intraradices和G.mosseae均为各自处理的优势种群。对大豆结荚期根系和根际土壤PCR-DGGE图谱条带的丰度及优势条带测序分析,结果表明根际土壤中的AM真菌菌群数明显高于根系中AM真菌的菌群数量,GI处理的大豆根际土壤中AM真菌丰度值最大,GM处理大豆根系里的AM真菌丰度值最大,F处理的根际土壤中总AM真菌的数量最少;施加AM菌剂处理的大豆根系及根际土壤中的优势菌群分别为外源施加的两种AM真菌。     

喀斯特不同植被恢复阶段土壤AMF组成及多样性研究

选择贵州花江、织金、花溪3个典型喀斯特地段的不同恢复阶段(乔木、灌木和草本)土壤丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)为研究对象,基于AMF孢子的形态鉴定,计算AMF孢子密度、分离频度、物种丰度、重要值、物种均匀度指数及Shannon-Wiener多样性指数,研究喀斯特不同恢复阶段土壤AMF物种组成及多样性。结果表明:3个采样地段共分离AMF菌种4目8科10属68种,其中球囊霉属(Glomus)数量最大达35种,其次是无梗囊霉属(Acaulospora)为17种,巨孢囊霉属(Gigspora)、类球囊霉属(Paraglomus)及原囊霉属(Archaeospora)各1种;不同采样地段各植被恢复阶段的优势种不同,所有样地中层状球囊霉Glomus lamellosum具有最大的相对丰度、分离频度和重要值;AMF种分类水平上,花江样地不同恢复阶段AMF丰度表现为乔木灌木草本,织金样地为灌木草本乔木,花溪样地为灌木乔木草本;不同植被恢复阶段土壤AMF均匀度指数和香农多样性指数在花江和织金多表现为乔木灌木草本,花溪样地Shannon-Wineer指数则是灌木显著高于乔木和灌木阶段。研究表明,喀斯特土壤中因异质生境条件的差异AMF菌种组成和物种多样性具有较大的差异。     

Diversity of arbuscular mycorrhizal fungi in soils of yam (Dioscorea spp.) cropping systems in four agroecologies of Nigeria

The diversity of arbuscular mycorrhizal (AM) fungi in soils under a yam cropping system in four agroecologies of Nigeria was investigated. Soil samples were collected from yam fields at Onne (humid forest, high rainfall area), Ibadan (derived savanna), Abuja (Guinea savanna) and Ubiaja (humid forest, medium rainfall area). Soil characteristics, AM fungi species, spore abundance, Shannon diversity index, species richness and evenness were determined. A total of 31 AM fungi species was isolated from the four agroecologies with a range of 14–20 species found in a single location. Glomus species were the most abundant among AM fungi species with G. geosporum, G. intraradices and G. mosseae occurring in large populations in all locations. Ubiaja, which had a cassava/natural vegetation sequence before yam, had significantly higher spore abundance and species richness than the other locations, which had a yam/legumes or a maize/legume sequence before yam. However, diversity was significantly higher at Abuja, which had a maize/legume sequence with yam, than Ibadan, which had only a yam/legume sequence. The study revealed significant diversity in AM fungal species across agroecologies in yam-growing regions. Further research on the functional consequences of changing composition of AM fungi species across the region is recommended.     

Distribution of arbuscular mycorrhizal fungi spores in soils of smallholder agroforestry and monocultural coffee systems in southwestern Ethiopia

Arbuscular mycorrhizal fungi (AMF) are associated with the root system of coffee (Coffea arabica L.) plants, but their distribution in smallholder agroforestry and monocultural coffee systems is not well known. This study investigates the spatial distribution of AMF spores in a field study in southwestern Ethiopia. Soil samples from different depths (0–50 cm) were collected under the tree canopies of Acacia abyssinica, Albizia gummifera, Ficus sur, Ficus vasta and randomly selected unshaded coffee plants at different sampling points (canopy base, radius, edge and outside canopy). Significantly higher AMF spore densities were recorded at canopy bases and at 0–30 cm soil depth. Spore populations were found to belong to five genera: Acaulospora, Entrophospora, Glomus, Gigaspora and Scutellospora, with Glomus and Acaulospora dominating. Sampling points, sites and depths, shade tree species and shade tree/coffee plant age affected AMF spore density. Agroforestry practices including the use of leguminous shade trees effectively maintained AMF numbers in soils even at depth compared with unshaded coffee plants (monocultures).     

Reintroduction of a native Glomus to a tropical Ultisol promoted grain yield in maize after fallow and restored the density of arbuscular mycorrhizal fungal spores

Maize (Zea mays L.) is an important crop in central Thailand where fallow is widely practiced and farmers are interested in crop rotation and beneficial soil biota. A pot experiment using a Typic Paleustult (topsoil + subsoil) from the National Corn and Sorghum Research Centre, Nakhonratchasima Province, Thailand was undertaken over three successive crops to evaluate effects of agronomic practices on populations of arbuscular mycorrhizal (AM) fungi and to determine whether reintroduction of a local Glomus was beneficial to maintain maize yield. The three crops and their treatments were: (1) preceding crop: maize grown in all pots; (2) subexperiment 1: agronomic practices [maize, fallow ± soil disturbance, fallow with solarization, non–AM host (cabbage)]; and (3) subexperiment 2: maize ± Glomus sp. 3 at three rates of P fertilization (0, 33, 92 kg P ha^–1). The AM‐fungal community was established under the preceding crop. In subexperiment 1, the three fallow treatments decreased (30%–40%) the total AM spore number in the topsoil whereas there was no change under maize or cabbage. Glomus, the dominant genus, showed sensitivity to fallow. In subexperiment 2, inoculation with Glomus sp. 3 enhanced total AM spore number and root colonization when applied following the three fallow treatments. Furthermore, inoculation promoted grain yield; at nil P following fallow ± soil disturbance, at 33 kg P ha^–1 following fallow without soil disturbance, and following solarization. Two treatments, maize following maize and maize following cabbage, did not respond to inoculation with Glomus sp. 3. Overall, the results suggest that reintroduction of Glomus sp. 3, a local AM fungus in this soil, may overcome negative effects of fallow and promote effectiveness of P fertilizer. Further work is needed to evaluate the benefits of other indigenous AM species that persist under modern fertilization practices.     

Karlheinz richter zum 65. geburtstag

Studies were carried out on spatio-temporal variations of arbuscular mycorrhizal (AM) fungi associated with Carica papaya L. growing in two different geographic localities in Goa, India – Western Ghats and coastal area, differing in soil characteristics and plantation status. The study recorded considerable variation in root colonization, spore density and distribution of AM fungi in the selected sites. The mean total root colonization was at a maximum in the month of July, while spore density was highest in April. The study recorded a total 33 species of AM fungi. Western Ghats recorded a relatively higher diversity of AM fungi compared to coastal area. Species richness of AM fungi was at a maximum in April and coincided with maximum mean spore density. Edaphic as well as climatic factors influenced the AM fungal parameters. The study recorded the existence of seasonality in AM fungi.     

Arbuscular mycorrhizal associations in sesame under low-input cropping systems

The abundance and composition of arbuscular mycorrhizal fungi (AMF) are generally low under managed agroecosystems in comparison to natural ecosystems. The objective of the study was to determine the composition and species richness of AMF associated with sesame under traditional low-input cropping system in Kerala, India. Wide variability in root colonization by AMF as well as spore density in the rhizosphere existed in sesame. Correlation between frequency of colonization (F%) and spore density as well as between these variables and soil characteristics showed a negative relationship. The fungal variables were influenced by soil factors such as pH, soil organic carbon (OC) and available nutrients. Frequency of colonization was positively correlated (P < 0.01) with soil pH and potassium (K) and negatively correlated with OC, nitrogen (N) and phosphorus (P). AM spore density was positively correlated with OC, N and P and negatively correlated with pH and K. Ten taxa of AMF belonging to the genera Acaulospora, Diversispora, Funneliformis, Gigaspora, Glomus and Scutellospora were associated with sesame, with the predominance of Funneliformis and Acaulospora in both frequency and relative abundance over a wider soil nutrient range. Soil characteristics appear to have a profound influence on the composition and species richness of AMF under traditional low-input cropping systems.     

鄱阳湖湿地不同环境条件土壤AM真菌群落特征及其影响因素

丛枝菌根(AM)真菌可以与湿地植物共生，并在湿地生态系统的修复与维护过程中具有重要作用。然而，不同环境条件下湿地土壤AM真菌群落分布特征及其影响因素仍然有待明晰。选择鄱阳湖湿地不同水位条件(高水位和低水位)2种典型植物群落(南荻和水蓼)为研究对象，运用高通量测序技术探究水位和植被类型对鄱阳湖湿地土壤AM真菌群落结构和多样性的影响，比较不同环境条件下AM真菌群落结构和多样性差异，分析其与土壤理化性质的关系。结果表明，AM真菌OTU数为21～38,水位和植被类型影响鄱阳湖湿地土壤AM真菌OTU数，高水位下AM真菌OTU数高于低水位，水蓼群落高于南荻群落。被鉴别出的菌属为Glomus、Claroideoglomus和Paraglomus,其中，Glomus是优势属，占比85%以上，其相对丰度在高水位下显著高于低水位(p<0.05),南荻群落高于水蓼群落。AM真菌多样性指数(Simpson和Shannon指数)受水位和植被类型以及二者交互影响(p<0.01),低水位下不同群落之间的AM真菌多样性指数无显著差异，而高水位下水蓼群落AM真菌多样性指数显著高于南荻群落(p<0.05...     

Glycosidation of apigenin results in a loss of its activity on different growth parameters of arbuscular mycorrhizal fungi from the genus Glomus and Gigaspora

The effect of different concentrations (0.5, 2 and 8 μM) of apigenin and its glycosidated form 5,7,4′-hydroxy flavone glycoside on arbuscular mycorrhizal (AM) fungal spore germination, hyphal growth, hyphal branching, the formation of entry points and root colonization of Gigaspora. rosea, Gi. margarita, Glomus mosseae and G. intraradices was tested. The lowest apigenin concentration (0.5 μM) nearly doubled hyphal branching, the formation of entry points and root colonization of all four tested fungi, whereas higher concentrations (2 and 8 μM) nearly doubled the hyphal growth of Gi. margarita, G. mosseae and G. intraradices. In none of the treatments with the apigenin-glycoside any effect on AM fungi could be observed. Our data show that apigenin exhibits an AM fungal genus and even species activity and we provide strong evidence that glycosidation results in a loss of its activity towards AM fungi.     

Arbuscular mycorrhizal fungi in degraded typical steppe of inner Mongolia

Arbuscular mycorrhizal (AM) fungi may have some potential use in the restoration of degraded grassland through beneficial effects on plant growth and soil quality. A field investigation was conducted in three grassland sites of typical steppe in Inner Mongolia. The three plant communities, one of which was undegraded, one moderately degraded and the third severely degraded, were studied by collecting soil samples and samples of four plant species that occurred in all three sites. The percentage of root length colonized by AM fungi was estimated and the species composition and diversity of AM fungus spores recovered from the soil were determined using spore morphological characteristics. Although differences between the sites may have been due partly to other factors, it is likely that the degree of degradation was an important factor. No decline was found in the AM colonization of the roots of the indicator plant species in the moderately or severely degraded plant communities, and two plant species showed higher colonization status in the two degraded areas. Glomus geosporum and Scutellospora calospora were the dominant AM fungi in the undegraded steppe, while G. geosporum and Glomus aggregatum dominated the two degraded sites which also had low spore densities, species richness and diversity indices. However, different AM species showed different distributions among the three plant communities and the results indicate that both biotic and abiotic factors were important in determining the AMF communities, with biotic factors possibly the more important. Copyright © 2008 John Wiley & Sons, Ltd.