海南霸王岭热带雨林常见植物丛枝菌根真菌调查

对海南霸王岭热带雨林的12科16种常见植物的丛枝菌根状况进行了调查,用碱解离-酸性品红染色法进行了真菌鉴定。结果表明,13种植物形成典型的丛枝菌根,占所调查植物的81%;3种植物没有形成丛枝菌根,占所调查植物的19%。用湿筛沉淀法从这些植物根际土壤中共分离鉴定出了3属11种丛枝菌根真菌(AMF),即无梗囊霉属(Acaulos-pora)3种,球囊霉属(Glomus)7种,巨孢囊霉属(Gigaspora)1种;其中,球囊霉属是样地的优势属。在AMF中,孔窝无梗囊霉(A.foveata)分离频率最高,在14种植物的根际土中都有发现;此外,大果球囊霉(G.macrocarpum)的相对多度最大,为59%,具有最强的产孢能力。同时,在11种植物的根中发现了深色有隔内生真菌(DSE),占调查植物的69%;其中,11种植物同时被DSE和AMF感染。     

丛枝菌根真菌伴生细菌的研究进展

在丛枝菌根真菌（Arbuscular mycorrhizal fungi,AMF）的孢子、菌丝的表面或内部栖息着细菌,称之为AMF伴生细菌。AMF伴生细菌种类多样、分布广泛,生态位点包括孢子壁的表面或内部、细胞质、菌丝、孢子果等。其可能的生物学意义包括影响AMF孢子萌发、菌丝生长、菌根形成等过程。由于伴生细菌与AMF联系紧密,其对AMF和土壤微生物生态学具有重要的意义。国际上在该领域的研究已有30多年的历史,就其研究进展进行综述。     

丛枝霸王（Zygophyllum dumosum）根际AM真菌生态学研究

AM真菌是一类广泛分布的土壤真菌,与宿主植物形成共生结构后,对于植物生长和植被恢复有多种有益的生理学和生态学作用。1999年11月至2000年10月,通过每月分别从0－10cm和10－20cm土层采集根际土样,对以色列荒漠地区丛枝霸王（Zygophyllum dumosum Boiss）根际AM真菌进行了系统的生态学研究。AM真菌的分布和定殖与季节变化和采样浓度密切相关。菌根真菌的最高定殖率并不伴随有最大的孢子密度,最高的定殖率发生在1999年11月,而最大的孢子密度则出现在2000年9月。10－20cm土层中的菌根真菌定殖率和孢子密度明显高于0－10cm土层。土壤温度与所有菌根结构的定殖率呈正相关,土壤有机质含量与泡囊和丛枝定殖率呈正相关,而土壤总可溶性氮对泡囊和丛枝定殖有显著正效应,对孢子密度有显著负效应。结果建议,孢子密度、泡囊和丛枝定殖程度可作为检测荒漠土壤状况的生态指标。研究应用于我国特别是西部荒漠地区的植被建立和恢复,可望发挥重任作用：（1）AM真菌能与绝大多数高奶系形成共生联合体,促进根系对土壤矿质营养和水分的吸收,提高植物对干旱、高温、盐碱、根部病害等的抗性,提高逆境条件下植物的成活率,深入研究荒漠生态系统中AM真菌动态分布,以及筛选优势AM菌种和人工接种,进行菌根化育苗,为植被建立和恢复提供优质苗木;（2）菌根的丛枝定殖时间短,主要发生在幼根,泡囊定殖时间长,主要发生在老根,而AM真菌的生长发育和繁殖所需的碳水化合物来自植物根系的分泌活动,所以,通过检测不同时期菌根各种结构的定殖程度和孢子的丰富度,可以获得宿主植物根系的生长状况,进而对土壤环境作出科学的评估。     

Synergistic effects of Arbuscular mycorrhizal fungi and plant growth promoting rhizobacteria in bioremediation of iron contaminated soils

Three Arbuscular mycorrhizal fungi (AMF) from Glomus, Acaulospora and Scutellospora, and four plant growth promoting rhizobacteria (PGPR) isolates related to genera Streptomyces, Azotobacter, Pseudomonas and Paenibacillus were found to be effective in phytoremediation of Fe³⁺ contaminated soil where Pennisetum glaucum and Sorghum bicolor were growing as host plants. Co-inoculation of AMF and PGPR showed better results in comparison to either, AMF and PGPR under pot conditions. Both AMF and PGPR were able to produce siderophores. AMF and PGPR associated to P. glaucum and S. bicolor plants increased the extent of iron absorption. AMF and PGPR combination exhibited superior (p < 0.01) phytoremediation efficiency with P. glaucum compared to S. bicolor. These findings warrant further investigations of these synergistic interactions and large-scale in situ studies for bioremediation of iron-contaminated soils.     

农业技术措施对AM真菌群落结构的影响研究进展

农业生态系统中AM真菌多样性丰富,并以独特的群落结构发挥其功能.寄主植物和环境因子对AM真菌群落结构具有重要影响,此外,农业技术措施对农业生态系统中AM真菌群落结构的影响也值得关注.本文系统总结了施肥、灌溉、轮作、间作、土壤耕作、化学药剂等农业技术措施对AM真菌群落结构的影响研究进展,分析了农业技术措施改变AM真菌群落结构的可能机制,探讨了提高农业生态系统中AM真菌多样性的可能途径,提出通过改进施肥体制及其配套技术、增加植物多样性和人工接种AM真菌等可提高农业生态系统中AM真菌多样性;并指出当前存在的问题和今后的研究方向.     

自然入侵条件下黄顶菊丛枝菌根定殖及发育的研究

为探讨丛枝菌根(arbuscular mycorrhiza,AM)真菌在黄顶菊Flaveria bidentis入侵过程中可能发挥的作用,首先调查和研究了黄顶菊AM的侵入和生长表现。在黄顶菊入侵严重的河北省选择采样地点,分别从衡水地区的滨湖新区小北田村、冀州市漳下村、枣强县北王庄村、桃城区八里庄村、滨湖新区顺民庄村和滨湖新区刘家台村6个地点按黄顶菊重、中、轻3种盖度和不同生育期(苗期、花期和结籽期)采集根系和根区土样。分离根区土壤中AM真菌孢子、观察AM发育特征、测定孢子密度、AM真菌侵染率、丛枝着生率等,并与土壤理化性质进行了相关性分析。结果在各采样地点均观察到AM典型结构,不同样地菌丝侵染率、I型丛枝密度以及孢子密度的最大值均出现在八里庄村,泡囊密度和A型丛枝密度的最大值分别出现在小北田村和刘家台村;不同盖度下AM真菌侵染率最高值均出现在重度侵染区;不同生长时期黄顶菊的AM也有差异,除了丛枝密度最高值出现在花期和菌丝侵染率差异不显著外,菌丝侵染率、泡囊密度和孢子密度均在结籽期出现最大值。土壤理化特性也显著影响黄顶菊AM的发育,菌丝侵染率与土壤有机质呈显著正相关,与p H值呈显著负相关,与速效P含量呈极显著负相关;A型丛枝密度与p H含量呈显著负相关;I型丛枝密度与土壤全N含量呈极显著正相关;孢子密度与有机质含量和全N含量均呈显著正相关。因此,AM真菌侵染可能会促进黄顶菊的入侵。     

长白山四种赤杨丛枝菌根真菌侵染多样性的巢式PCR-RFLP分析

采集中国吉林长白山不同海拔的4种赤杨根须样本,利用巢式PCR-RFLP方法检测丛枝菌根真菌(AMF)对样品的侵染情况,PCR结果经限制性内切酶分析. 结果表明,赤杨根内AMF存在丰富的基因多样性.AMF的侵染有从宿主混乱性向宿主专一性发展的趋势.东北赤杨AMF的宿主专一性水平最强,球囊霉属已成为东北赤杨的优势侵染类群;其余3种赤杨的AMF则出现宿主混乱现象.宿主因素比海拔因素对AMF侵染有更重要的影响.     

Influence of arbuscular mycorrhizal fungi on soil structure and aggregate stability of a vertisol

The influence of arbuscular mycorrhizal (AM) fungi on aggregate stability of a semi-arid Indian vertisol was studied in a pot experiment in which Sorghum bicolor (L.) was grown as test plant for 10 weeks. Pasteurized soil inoculated with AM fungi was studied with pasteurized and unpasteurized soils as references. A part of the soil in each pot was placed in nylon mesh bags to separate effects of roots and hyphae. The sorghum plants were planted outside the mesh bags which permitted AM hyphae to enter while excluding roots. Aggregate stability of the soil was determined by wet-sieving and turbidimetric measurements. Development of the AM fungi was quantified as colonized root length and external hyphal length. Soil exposed to growth of roots and hyphae (outside mesh bags) showed aggregates with larger geometric mean diameter (GMD) in pasteurized soil inoculated with AM fungi than in pasteurized uninoculated soil. There was no significant difference in GMD of the inoculated, pasteurized soil and the unpasteurized soil. No significant effects of inoculation or plant growth were found in pasteurized soil exposed to hyphal growth only (inside the mesh bags). However, the unpasteurized soil had significantly higher GMD than the pasteurized soil, irrespective of plants and inoculum. Turbidimetric measurements of soil exposed to roots and hyphae (outside mesh bags) showed the highest aggregate stability for the inoculated pasteurized soil. These results demonstrate that AM fungi contribute to the stabilization of soil aggregates in a vertisol, and that the effect is significant after only one growing season. The effect was associated with both AM hyphae and the stimulation of root growth by AM fungi. The contribution from plant roots and AM hyphae to aggregate stability of different size fractions is discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

丛枝菌根真菌对三叶草根系分泌的有机酸组分和含量的影响

比较洗根法、层析纸法和琼脂膜法收集土培条件下生长的菌根化和非菌根化三叶草根分泌物的效果。试验采用三室根箱装置 ,将根系与菌丝生长空间分开 ,三叶草生长 5 6d后 ,打开三室根箱装置 ,由于尼龙网的阻挡作用使根系均匀垫积在尼龙网内侧并形成根垫。分别采用洗根法、层析纸法和琼脂膜法 3种方法收集三叶草根系分泌物 ,并通过高效液相色谱方法测定分泌物中草酸、酒石酸、苹果酸、乳酸、乙酸、顺丁烯二酸、反丁烯二酸、柠檬酸、丁二酸等有机酸的含量。结果表明 :3种收集方法收集的三叶草分泌的有机酸无论在种类上还是在数量上都存在相当大的差别。从检测到的有机酸种类来看 ,琼脂膜法收集检测到苹果酸、乙酸、顺丁烯二酸、柠檬酸、丁二酸和乳酸 6种有机酸 ;洗根法收集的分泌物检测到酒石酸、苹果酸、乙酸、顺丁烯二酸、柠檬酸、丁二酸和乳酸 7种有机酸 ;层析纸法收集的分泌物检测到酒石酸、苹果酸、柠檬酸和乳酸 4种有机酸。从收集到的有机酸数量来看 ,洗根法收集到的有机酸总量为 2 9.97～ 2 32 .7μg/( gfw· 2 h) ;琼脂膜法集到的有机酸总量为 1 .5～ 7.3μg/( cm2· 2 h) ;层析纸法收集的有机酸总量为0 .2 3～ 6.5 8μg/( cm2 · 2 h)。丛枝菌根真菌侵染对三叶草根系分泌的有机酸的组分和含量都有一     

喀斯特地区丛枝菌根真菌遗传多样性

为探明喀斯特地区丛枝菌根真菌( AMF)的遗传多样性特征,利用巢式PCR和DGGE相结合的分子生物学方法对茂兰喀斯特多个植被类型下的AMF遗传多样性进行了研究.结果表明,喀斯特地区AMF遗传多样性指数和物种丰富度分别平均为3.50和41,远高于非喀斯特对照样地的2.68和17,分析表明,喀斯特地区较高的AMF多样性与此地区丰富的植物多样性以及特殊的生态环境有关,是与喀斯特生态系统长期相互选择的结果.不同植被类型下的AMF多样性差异显著,相似性指数最高为0.34,喀斯特地区AMF的群落结构随着植被类型的改变发生显著变化;基因测序显示,喀斯特地区AMF的优势菌属是生态适应性很强的球囊霉属,在喀斯特石漠化生态恢复中具有较强的利用潜力.     

丛枝菌根真菌产球囊霉素研究进展

球囊霉素（Glomalin）是由丛枝菌根真菌（arbuscular mycorrhizal fungi,AMF）产生的一种含金属离子的糖蛋白,由于丛枝菌根真菌在自然和人工陆生生态系统中广泛分布,丛枝菌根真菌在生态系统中的生态学功能一直是菌根生物学研究中诱人的问题。自1996年球囊霉素被发现以来,球囊霉素在土壤生态系统中的生态学功能、生态学地位日益受到重视。本文对球囊霉素作为土壤主要有机源和超级胶的功能作了简介,综述了球囊霉素的研究现状,并对其研究前景作了展望。     

Parasitism of arbuscular mycorrhizal fungi: reviewing the evidence.

In order to understand the functioning of mycorrhizal fungi in ecosystems it is necessary to consider the full suite of possible biotic interactions in the soil. While a number of such interactions have recently been shown to be crucially important, parasitism is a highly neglected feature in the ecology of arbuscular mycorrhizal fungi (AMF). A number of studies have classified some interactions between populations of bacteria and fungi with AMF as parasitism, generating discussion about its consequences at both 'parasite' and host population levels. This paper reviews these various publications, and based on a set of criteria that are necessary to demonstrate parasitism, it was concluded that parasitism has not been conclusively shown to exist in AMF, even though some data are highly suggestive of such a relationship. The difficulties in gathering data supportive of parasitism were discussed, and hypotheses for defense were offered. This paper concludes by presenting potential consequences of AMF parasitism at the population/community levels and by discussing applied aspects.     

入侵植物与丛枝菌根真菌的相互作用

入侵植物的入侵改变了入侵地生物群落的结构,导致生物多样性的丧失.丛枝菌根真菌(AMF)作为陆地生态系统中土壤微生物普遍的组成部分,它的种类和组成能够影响入侵植物的生长表现.这种真菌与寄主(入侵植物)特殊的关系也暗示了AMF能够影响入侵植物的入侵.反之,入侵植物的入侵同样也会影响AMF的群落结构和功能.本文在简要总结我国入侵植物种类及其危害的基础上,着重探讨了AMF与入侵植物入侵之间的关系,即AMF对入侵植物入侵过程中的作用、入侵植物入侵后如何影响AMF以及两者之间的相互作用机制.     

Synergistic effect of soil pathogenic fungi and nematodes reducing bioprotection of Arbuscular mycorrhizal fungi on the grass Leymus arenarius

We examined the role ofarbuscular mycorrhizal fungi (AMF) in thebioprotection of the sand dune grass Leymus arenarius against soil fungi andnematodes. Six soil fungi (Fusariumnivale, Fusarium sp., Cladosporiumherbarum, Cladosporium sp., Phomasp., Sporothrix sp.) and four species ofnematodes (Pratylenchoidesmagnicauda, Paratylenchusmicrodorus, Rotylenchus goodeyi, Merlinius joctus) were isolated from a coastalsand dune in Iceland where a population of L. arenarius was declining in vigour. Acommercial AMF inoculum (Microbio Ltd. England)containing Glomus caledonium, G.fasciculatum, and G. mossae was used.Seedlings of L. arenarius were grownunder controlled conditions in sterile sand andsubjected to the following treatments: (1)control, (2) + AMF, (3) + AMF + soil fungi, (4)+ AMF + nematodes, (5) + AMF + nematodes + soilfungi, (6) + soil fungi, (7) + soil fungi +nematodes, (8) + nematodes. Mycorrhizal plantshad significantly the highest root dry weightof all treatments. Mycorrhizal plants hadsignificantly higher leaf dry weight thanplants in other treatments, with the exceptionof AMF inoculated plants exposed to nematodes. Mycorrhizal plants exposed to soil fungi andnematodes had significantly higher growthparameters except total number of leaves thanAMF inoculated plants exposed to both soilfungi and nematodes. Mycorrhizal plantssubjected to a dual application of soil fungiand nematodes did not vary significantly in anygrowth parameters from plants without AMF thatwere exposed to a dual application of soilfungi and nematodes. This suggests asynergistic effect of soil fungi and nematodesthat break down the protection of AMF againstpathogens. The results are discussed inrelation to plant dynamics of sand duneecosystems.     

泰山丛枝菌根真菌群落结构特征

2007年对泰山植被根围内丛枝菌根(arbuscular mycorrhiza,AM)真菌群落组成、数量、分布及其与植物多样性的关系进行了研究。从泰山傲徕峰、黑龙潭库区等样地共分离出4属16种AM真菌:球囊霉属Glomus 9种、无梗囊霉属Acaulospora 4种、巨孢囊霉属Gigaspora 2种和盾巨孢囊霉属Scutellospora1种。其中,球囊霉属Glomus及聚球囊霉Glomus fasciculatum的孢子密度、相对多度、分布频度和重要值均最高,分别为泰山植被区根围内AM真菌优势属和优势种。各样地之间Sorenson相似系数在0.60和0.85之间。植被数量与孢子密度(r=0.80,p0.01)、植物种的丰富度与AM真菌种的丰富度(r=0.77,p0.01)以及与孢子密度(r=0.59,p0.01)均呈极显著正相关关系。研究结果表明植物多样性对于提高AM真菌多样性发挥极为重要的作用。