南方红豆杉丛枝菌根(AM)的研究

研究了南方红豆杉根部丛枝菌根真菌(AMF)侵染情况、菌根形态结构以及根际土中AMF孢子的种类与数量.结果显示:南方红豆杉可与AMF形成典型的丛枝-泡囊型菌根,侵染率在71.2%~94.4%,但是历山、蟒河自然保护区的侵染强度优于人工栽培区;在南方红豆杉根际土中共分离鉴定出5种AMF,无梗囊霉属1种、球囊霉属4种,分别是:光壁无梗囊霉、地表球囊霉、地球囊霉、缩球囊霉、明球囊霉,其中光壁无梗囊霉为优势种;南方红豆杉的根由表皮、外皮层、内皮层、中柱组成,AMF只侵染表皮层、内皮层,不能侵染中柱.这为将来利用AMF接种技术进行南方红豆杉的繁殖、移植栽培以及紫杉醇的积累等研究提供了理论依据.     

不同产地南方红豆杉根际AMF多样性

为调查南方红豆杉Taxus chinensis丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)资源的分布情况,从山西、浙江、江西、广东、四川和云南的12个地点采集南方红豆杉根际土样及根样进行AMF孢子的分离、鉴定及侵染率统计。共分离获得AMF 3属36种,其中,无梗囊霉属Acaulospora 13种,占36.1%;球囊霉属Glomus 20种,占55.6%;盾巨孢囊霉属Scutellospora 3种,占8.3%。无梗囊霉属和球囊霉属在12个样地都有分布,而盾巨孢囊霉属仅在浙江-1、浙江-3、浙江-5采样地有分布。空洞无梗囊霉A.cavernata和光壁无梗囊霉A.laevis为南方红豆杉根际的优势种。各采样点孢子密度分布在33–925个/50g干土之间,平均孢子密度为242个/50g干土。各采样点的物种平均丰度10.3种,其中以云南采样点丰度最高,广东采样点丰度最低。各采样点Shannon-Wiener指数和Simpson指数分别在1.12–2.55、0.57–0.91之间。AMF均可侵染不同采样地南方红豆杉根系并形成典型的丛枝-泡囊型菌根,侵染率为18%–82%,侵染级别为2–5级。各采样地天然林中的总球囊霉素和易提取球囊霉素的含量整体高于人工林。     

云南金顶铅锌矿区丛枝菌根真菌多样性的研究

对云南金顶铅锌矿区丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)资源进行了调查,从32种植物的83个根际土壤样本中分离鉴定出5属36种丛枝菌根真菌,其中无梗囊霉属Acaulospora 5种、内养囊霉属Entrophospora 2种、巨孢囊霉属Gigaspora 1种、球囊霉属Glomus 24种及盾巨孢囊霉属Scutellospora 4种。球囊霉属和无梗囊霉属为金顶铅锌矿区中丛枝菌根真菌的优势属,沃克球囊霉Glomus walkeri是我国的新记录种。近明球囊霉Glomus claroideum、明球囊霉G.clarum、缩球囊霉G.constrictium、地球囊霉G.geosporum、摩西球囊霉G.mossaea、膨胀球囊霉G.pansihalos和疣突球囊霉G.verruculosum是金顶铅锌矿区的优势种;金顶铅锌矿区土壤中丛枝菌根真菌的孢子密度为495-11175个/100g土,平均3368±291(SE,标准误差)个/100g土,每种植物根际土壤中丛枝菌根真菌的物种丰富度为2-20种,平均11.5种;金顶铅锌矿区植物根际土壤中较高的AMF孢子密度和物种丰富度说明AMF对重金属污染具有较强的抗(耐受)性。     

土壤因子对府谷清水川流域砒砂岩区刺槐和沙棘AMF的影响

应用相关性分析和通径分析研究了府谷清水川流域砒砂岩区土壤因子对刺槐(Robinia pseudoacacia)和沙棘(Hippophae rhamnoides)根际丛枝菌根真菌(AMF)的影响.结果表明:AMF可以与刺槐和沙棘形成良好的共生关系;从两种植物根际土中共分离鉴定出AMF 13种,其中摩西囊霉(Glomus mosseae)、地球囊霉(Glomus geospo-rum)和缩球囊霉(Glomus constrictum)为优势种;AMF平均侵染率为90.6%,平均孢子密度为559.1个?100 g-1干土;AMF的孢子密度、侵染率和种类之间没有显著的相关性;刺槐和沙棘根际AMF侵染率均与pH呈显著正相关,在刺槐根际,pH和有效氮通过直接作用影响侵染率,有机质和有效磷通过间接作用影响侵染率;在沙棘根际,pH和有效磷通过直接作用影响侵染率,有机质和有效氮通过间接作用影响侵染率;在沙棘根际,有机质和pH主要是通过直接作用影响AMF种类,有效氮主要通过有效磷的间接作用影响AMF种类.     

西双版纳四种壳斗科植物丛枝菌根状况的初步研究

研究了西双版纳热带次生林中杯丝锥(Castanopsis calathiformis)、红锥(C.hys-trix)、印度锥(C.indica)和截果柯(Lithocarpus truncatus)4种壳斗科植物的丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)的侵染状况,并从这些植物的根际土壤中分离鉴定了隶属于球囊霉属(Glomus)、巨孢囊霉属(Gigaspora)、盾巨孢囊霉属(Scutellospora)和无梗囊霉属(Acaulospora)的10种丛枝菌根真菌。这4种壳斗科植物根际AMF的孢子密度为14~22个.100g-1土壤,种的丰富度在4~7,平均频度为60.00%,相对多度为4.41%~22.06%,丛枝菌根真菌的定居水平达46.26%~51.40%。     

厦门市七种药用植物根围AM真菌的侵染率和多样性

调查了福建省厦门市7种常见药用植物根围丛枝菌根真菌分布情况、侵染率及其多样性。结果表明:7种药用植物均能与AM真菌形成良好的共生关系,且不同药用植物形成菌根的能力差异明显,盐肤木根围的孢子密度最高,29.0个/g土,喜树的侵染率最高,100%。含笑根围的孢子密度最低,4.7个/g土,鱼腥草的总侵染率最低,4.5%。共分离鉴定AM真菌4属63种,其中球囊霉属(Glomus)39种、无梗囊霉属(Acaulospora)18种、巨孢囊霉属(Gigaspora)4种、盾巨孢囊霉属(Scutellospora)2种,其中Glomus、Acaulospora为优势属,黑球囊霉G.melanosporum为优势种。盐肤木根围AM真菌种类最丰富,Shannon-Weiner指数H达到1.29。侵染率与各土壤因子均无显著相关;孢子密度与pH值极显著负相关;种的丰度与pH值显著负相关、与电导率极显著负相关、与孢子密度极显著正相关;Shannon-Weiner指数H与有机质极显著负相关;均匀度与有机质、孢子密度极显著负相关。厦门地区AM真菌资源十分丰富,多样性程度高,宿主植物不同,土壤因子对其侵染率、孢子密度、种的丰度、Shannon-Weiner指数、均匀度的影响也不同。为实现AM真菌生物技术应用于中药材规范化种植提供宝贵种质资源和理论依据。     

西双版纳热带次生林中的丛枝菌根调查

对西双版纳热带次生林中13个科的26种植物根系的丛枝菌根真菌（Arbuscular mycorrhizal fongii,AMF）侵染情况进行了研究,并从这些植物的根围土壤中分离鉴定了隶属于球囊霉属（Clomus）、巨孢囊霉属（Gigaspora）、盾巨孢囊霉属（Scutellospora）和无梗囊霉属（Acaulospora）的11种丛枝菌根真菌。该地次生林中AMF的孢子密度为13—29个／100g土壤,平均为19个;种的丰富度在4．9之间（平均为6）;平均频度为53．8％;相对多度为3．2％-26．5％;物种多样性指数和均匀度指数分别为0．94和0．93。丛枝菌根的侵染率达到44．8％．57．2％（平均为50．9％）;球囊霉属（Glomus）和无梗囊霉属（Acattlospora）是热带次生林根围土壤中菌根真菌的优势类群。     

大兴安岭落叶松林丛枝菌根真菌多样性

对大兴安岭落叶松林17个科26种植物丛枝菌根(AM)定居情况和丛枝菌根真菌(AMF)多样性进行了调查。在26种植物根样中形成典型AM定居的有23种,占88.46%。菌根侵染率为0～78.7%,平均为21.69%。在26种植物根样中,4种植物形成重楼型(Par-is-type)AM,占15.38%;10种植物形成疆南星型(Arum-type)AM,占38.46%;9种植物形成中间型(Intermediatetype)AM,占34.62%,3种植物未能形成AM菌根,占11.54%。从23种植物根围土样中分离到50种AMF,分属于5个属,其中无梗囊霉属(Acaulospora)24种占48%;球囊霉属(Glomus)19种占38%;内养囊霉属(Entrophospora)5种占10%;原囊霉属(Archaeospora)1种占2%;巨孢囊霉属(Gigaspora)1种占2%。Acaulospora和Glomus2属真菌在大兴安岭落叶松林土壤中占绝对优势;尼氏无梗囊霉(A.nocolsonii)和幼套球囊霉(G.etunicatum)是优势种。植物根围土壤中AMF的孢子密度平均为68.94个.100g-1风干土;AM...     

四川遂宁地区石油污染土壤中丛枝菌根真菌

调查了四川遂宁地区磨溪油田石油污染土壤中丛枝菌根(AM)真菌资源和菌根发育状况。结果表明:调查的14种植物中13种能形成AM,占93%,共分离出AM真菌19种,隶属球囊霉属(Glomus)、无梗囊霉属(Acaulospora)和原囊霉属(Archeospora),其中球囊霉属为该地区优势属,缩球囊霉(Glomus constrictum)和摩西球囊霉(G.mosseae)为优势种;植物根际土壤孢子密度在39~548个.100g-1土,平均为197个.100g-1土;菌根侵染率为17%~69%,菌根侵染强度为2%~24%,表明石油污染区植物具有较强的菌根依赖性。相关性分析表明,石油污染浓度与孢子密度呈显著负相关,与菌根侵染率及侵染强度无相关性。寄主植物一年蓬(Erigeron annuus)和艾蒿(Artemisia argyi)在石油污染浓度为11450和14950mg.kg-1时侵染率仍高达69%和47%,可能是抗石油胁迫的优势植物。     

金沙江干热河谷(元谋段)丛枝菌根真菌多样性研究*

从金沙江干热河谷(元谋段)75种植物的根际土壤中分离鉴定了44种丛枝菌根真菌, 分属无梗囊霉属Acaulospora、古孢霉属Archaeospora、内养囊霉属Entrophospora、巨孢囊霉属Gigaspora、球囊霉属Glomus和盾巨孢囊霉属Scutellospora, 其中,球囊霉属和无梗囊霉属为金沙江干热河谷中丛枝菌根真菌的优势属。齿状无梗囊霉A. denticulata、刺状无梗囊霉A. spinosa、瘤状无梗囊A. tuberculata,近明球囊霉Glomus claroideum、明球囊霉G. clarum、根内球囊霉G. intraradices、单孢球囊霉G. monosporum、弯丝球囊霉G. sinuosa是金沙江干热河谷(元谋段)的优势种。金沙江干热河谷土壤中丛枝菌根真菌的孢子密度为5~6400个/100g土壤,平均1504;每个根际土壤中丛枝菌根真菌的物种丰富度1~18种,平均9种。     

Effect of edaphic factors and seasonal variation on spore density and root colonization of arbuscular mycorrhizal fungi in sugarcane fields

Sugarcane fields in 14 different study sites were analyzed for the presence of different arbuscular mycorrhizal fungal (AMF) spores. A total of 23 AMF species representing four genera were identified, among which Glomus fasciculatum and G. mosseae were the dominant species. The mean spore density in the root-zone soils of sugarcane plants varied from 119 to 583 per 100 g of soil, and the mean percentage root colonization varied from 60 to 89 %. A study of the effect of edaphic factors on AM spore density and percentage root colonization revealed a positive correlation between pH and AMF spore density and root colonization and a negative correlation between electrical conductivity, nitrogen, and phosphorus. A positive correlation was observed between AMF spore density and root colonization. Season was also found to play a vital role in determining AMF spore density and percentage root colonization, with high spore density and root colonization observed during the summer season and lower spore densities and root colonization during the winter season.     

The influence of fertilizer level and spore density on arbuscular mycorrhizal colonization of transgenic Bt 11 maize (Zea mays) in experimental microcosms

Crop plants genetically modified for the expression of Bacillus thuringiensis (Bt) insecticidal toxins have broad appeal for reducing insect damage in agricultural systems, yet questions remain about the impact of Bt plants on symbiotic soil organisms. Here, arbuscular mycorrhizal fungal (AMF) colonization of transgenic maize isoline Bt 11 (expressing Cry1Ab) and its non-Bt parental line (Providence) was evaluated under different fertilizer level and spore density scenarios. In a three-way factorial design, Bt 11 and non-Bt maize were inoculated with 0, 40, or 80 spores of Glomus mosseae and treated weekly with 'No' (0 g L(-1) ), 'Low' (0.23 g L(-1) ), or 'High' (1.87 g L(-1) ) levels of a complete fertilizer and grown for 60 days in a greenhouse. While no difference in AMF colonization was detected between the Bt 11 and Providence maize cultivars in the lower spore/higher fertilizer treatments, microcosm experiments demonstrated a significant reduction in AMF colonization in Bt 11 maize roots in the 80 spore treatments when fertilizer was limited. These results confirm previous work indicating an altered relationship between this Bt 11 maize isoline and AMF and demonstrate that the magnitude of this response is strongly dependent on both nutrient supply and AMF spore inoculation level.     

广州地区7种菊科入侵植物丛枝菌根侵染和根际土壤孢子密度的生境差异性分析

为了解广州地区7种菊科(Compositae)入侵植物与丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)的互作共生关系,调查了这7种菊科入侵植物在4种生境中的AMF侵染和根际土壤孢子密度,并分析土壤因子对AMF的影响。结果表明,7种入侵植物根内均受到AMF侵染,根际土壤中均检测到AMF孢子;AMF侵染在宿主间差异显著,生境间的差异不显著;孢子密度在生境和宿主间的差异均显著,人工绿地、农田果园的AMF孢子密度均显著高于森林周边和滨海地带。相关性分析表明,农田果园生境的根际土壤孢子密度与土壤有机质含量呈显著负相关关系;森林周边生境的AMF总侵染率与土壤全氮呈极显著正相关关系;人工绿地的AMF总侵染率与土壤速效氮含量呈显著负相关关系;滨海地带的AMF总侵染率与土壤有效磷含量呈显著负相关关系。这些对理解菊科植物入侵机理具有非常重要的作用。     

贵州煤矸石山香根草根系及根际土丛枝菌根真菌（AMF）群落的季节动态研究

以煤矸石山种植年限为17年的香根草Vetiveria zizanioides为研究对象,采用高通量测序技术研究香根草根系及根际土丛枝菌根真菌（arbuscular mycorrhizal fungi,AMF）群落的季节动态。并利用Spearman、NMDS、RDA和Mantel-test等统计学方法分析了AMF孢子密度、菌根侵染率、土壤理化性质、丰富度及多样性指数之间的相关性。结果表明：（1）AMF孢子密度和菌根侵染率均表现为夏季显著高于春秋两季。（2）3个季节根系中共得到127个OTUs,根际土中共得到258个OTUs,根和根际土中共享96个OTUs,共分离鉴定4科7属AMF,球囊霉属Glomus是该煤矸石山的优势属。（3）根系中AMF多样性和丰富度指数随季节变化先降后升;根际土中AMF多样性指数随季节变化先降后升,但丰富度指数随季节变化呈递减趋势;春季根际土香农、Chao1和ACE指数均显著高于根系,夏季根际土Chao1指数显著高于根系。（4）NMDS分析表明,夏季根系AMF群落分布与其他季节差异显著。Spearman分析表明,根系全钾含量与多样性和丰富度指数显著正相关,速效磷与丰富度指数显著负相关。RDA分析表明,AMF群落组成在根系春季和夏季、根际土夏季和秋季与全磷、全氮、全钾和速效磷正相关,与有机质负相关。Mantel-test分析表明,pH、有机质、全氮、全钾、速效磷和采样季节极显著影响菌根侵染率,有机质和全氮是影响孢子密度的主导因子。     

Functional diversity of arbuscular mycorrhizal fungal isolates in relation to extraradical mycelial networks

We investigated the functional significance of extraradical mycorrhizal networks produced by geographically different isolates of the arbuscular mycorrhizal fungal (AMF) species Glomus mosseae and Glomus intraradices. A two-dimensional experimental system was used to visualize and quantify intact extraradical mycelium (ERM) spreading from Medicago sativa roots. Growth, phosphorus (P) and nitrogen (N) nutrition were assessed in M. sativa plants grown in microcosms. The AMF isolates were characterized by differences in extent and interconnectedness of ERM. Phenotypic fungal variables, such as total hyphal length, hyphal density, hyphal length per mm of total or colonized root length, were positively correlated with M. sativa growth response variables, such as total shoot biomass and plant P content. The utilization of an experimental system in which size, growth rate, viability and interconnectedness of ERM extending from mycorrhizal roots are easily quantified under realistic conditions allows the simultaneous evaluation of different isolates and provides data with a predictive value for selection of efficient AMF.     

Mycorrhizal Fungal Effects on Growth,Antioxidant Capacity,and Medicine Quality of <i>Paris polyphylla</i> var. <i>yunnanensis</i>

A field experiment was conducted to determine the effects of two commercial strains composed of mulple arbuscular mycorrhizal fungi (AMF) species on plant growth, antioxidant capacity, and medicine quality of Paris polyphylla var. yunnanensis in three subtropical soils from Wanzhou, Anshun and Baoshan in fields. The results showed that AMF inoculation enhanced the fungal colonization rate and activities of both succinate dehydrogenase and alkaline phosphatase, thereby, enhancing the mycorrhizal viability of P. polyphylla var. yunnanensis. The concentrations of photosynthetic pigments (chlorophyll a, b, a+b and carotenoids), soluble sugar, soluble protein and photosynthetic capacity were higher in AMF-inoculated plants than in non-AMF-treated plants in field. AMFtreated plants recorded higher activities of catalase, peroxidase and superoxide dismutase, and caused the reduction in malondialdehyde content, indicating lower oxidative damage, compared with non-AMF plants. Polyphyllin I, Polyphyllin II, Polyphyllin III, Polyphyllin IV and total polyphyllin contents were increased by AMF treatment. In conclusion, AMF improved the plant growth, antioxidant capacity and medicinal quality of P. polyphylla var. yunnanensis seedlings. Hereinto, AMF effects on the soil from Wanzhou was relatively greater than on other soils.     

Glomus intraradices dominates arbuscular mycorrhizal communities in a heavy textured agricultural soil

Arbuscular mycorrhizal fungal (AMF) spore communities were surveyed in a long-term field fertilization experiment in Switzerland, where different amounts of phosphorus (P) were applied to soil. Plots receiving no P as well as plots systematically fertilized in excess to plant needs for 31 years were used to test the hypothesis that application of P fertilizer changes the composition and diversity of AMF communities. AMF spores were isolated from the field soil, identified, and counted so as to quantify the effect of P fertilization on AMF spore density, composition, and diversity. Trap cultures were established from field soil with four host plants (sunflower, leek, maize, and Crotalaria grahamiana), and the spore communities were then analyzed in substrate samples from the pots. Altogether, nine AMF species were detected in the soil. No evidence has been acquired for effect of P fertilization on spore density, composition, and diversity of AMF in both the field soil and in trap cultures. On the other hand, we observed strong effect of crop plant species on spore densities in the soil, the values being lowest under rapeseed and highest under Phacelia tanacetifolia covercrop. The identity of plant species in trap pots also significantly affected composition and diversity of associated AMF communities, probably due to preferential establishment of symbiosis between certain plant and AMF species. AMF spore communities under mycorrhizal host plants (wheat and Phacelia in the fields and four host plant species in trap pots) were dominated by a single AMF species, Glomus intraradices. This resulted in exceptionally low AMF spore diversity that seems to be linked to high clay content of the soil.Electronic supplementary material Supplementary material is available for this article at and accessible for authorised users.     

不同林龄杉木人工林菌根侵染特征研究

丛枝菌根真菌是一种通过土壤侵染植物根系,与寄主植物互利共生的重要有益真菌。探究不同林龄杉木林中菌根侵染状况与土壤养分的变化规律,有利于深入认识丛枝菌根真菌—杉木相互作用的养分调控因素,从而为改善杉木人工林土壤肥力、促进杉木林可持续经营提供依据。分别选取10a、25a、45a杉木纯林,分析了不同林分菌根侵染率与孢子密度及部分土壤养分因子(全磷、速效磷、全钾、速效钾)的关系。结果表明:(1)菌根侵染率与孢子密度均呈现出随林龄增大而增大的趋势,pH随林龄增大而减少的趋势;(2)根际土中磷的含量总体偏低,而且受到土壤酸化流失和丛枝菌根真菌积累的双重影响呈现出先减少后增加的趋势;(3)虽然有效钾含量随林龄变化趋势不显著,但丛枝菌根真菌能促进土壤钾的积累。因此,丛枝菌根真菌能有效调控根际土的养分动力学特征,减缓土壤酸化造成的养分流失。     

Arbuscular mycorrhizal dynamics in a chronosequence of Caragana korshinskii plantations

Arbuscular mycorrhizal (AM) fungi in a chronosequence of 5–42-year-old Caragana korshinskii plantations in the semi-arid Loess Plateau region of northwestern China were investigated. AM fungi colonization, spore diversity and PCR-denatured gradient gel electrophoresis-based AM fungal SSU rRNA gene sequences were analyzed. AM fungi colonization [measured as the percent of root length (%RLC), vesicular (%VC) and arbuscular (%AC) colonization] and spore density were significantly correlated with sampling month, but not with plant age, except for %RLC. The percent of vesicular colonization was negatively correlated with soil total nitrogen and organic carbon, and spore density was negatively correlated with soil moisture and available phosphorus. Ten distinguishable AM fungal spore morphotypes, nine Glomus and one Scutellospora species, were found. Nine AM fungal Glomus phylotypes were identified by sequencing, but at each sampling time only four to six AM fungal phylotypes were detected. The AM fungal community was significantly seasonal, whereas the AM fungal species richness did not increase with plantation age. A significant change in AM fungal colonization and community composition over an annual cycle was observed in this study, and our results suggest that the changes of AM are the product of the interaction between host phenology, soil characteristics and habitat. Understanding these interactions is essential if habitat restoration is to be effective.