盐胁迫下接种丛枝苗根真菌对甜菊生长和氮磷吸收的影响

盐胁迫是普遍而严重的世界性环境问题,丛枝菌根(Abuscular mycorrhizal,AM)真菌被认为是提高植物抗盐性的有效的生物方法.甜菊(Stevia rebaudiana)作为一种新兴的保健型糖源植物,分布范围较广.通过设置盐胁迫(0mmol/L和200 mmol/L)和接种AM真菌(未接种和接种摩西球囊霉)4种处理组合,解析AM真菌对甜菊抗盐性的作用机理.结果发现,盐胁迫显著降低了甜菊的各部分鲜重和干重、基质pH值和菌根化结构形成的强度,但显著增加了植株的氮、磷含量.在非盐胁迫下,接种AM真菌显著增加了植株各部分的鲜重和干重;而在高盐处理下,AM真菌的促进效应则不明显,这可能与高盐下AM真菌结构的形成和发育状况的显著降低有关.此外,接种AM真菌显著增加了甜菊植株的磷含量尤其是在高盐胁迫下,且随着盐浓度的升高,甜菊的氮依赖性显著下降而磷依赖性显著升高,促进磷元素的吸收可能是AM真菌提高甜菊耐盐性的内在机理.本研究表明,接种摩西球囊霉可显著增加非盐胁迫下甜菊的生物量,同时有利于高盐胁迫下甜菊植株磷元素的吸收,这可为甜菊的产业化经营和管理提供一定的理论依据.     

胁迫生境深色有隔内生真菌生态分布与功能研究进展

深色有隔内生真菌(dark septate endophytes,DSE)是一类定殖于植物根内的小型真菌,广泛存在各种生境中,其在胁迫生境中的生态分布、生态功能与作用机理是近年来的研究热点.对DSE的生态分布、胁迫生境DSE的生态功能和DSE真菌增强植物抗逆性的作用机理等方面进行综述.研究进展表明,从平原低地到热带、温带、冻原及南北极地区,野生植物根部普遍定殖着DSE真菌,尤其在干旱、高温、寒冷、盐害、重金属污染和养分贫瘠等胁迫生境中,DSE真菌的分布更为普遍.环境胁迫条件下,植物根部共生DSE真菌能够改善植物矿质营养和光合生理、调节植物内源激素平衡、增强植物抗氧化生理,从而促进宿主植物生长、增强植物抗逆能力,以及改变植物对重金属的吸收累积,在植物耐受和适应胁迫环境中起着重要的调节作用.但这些研究主要从生态现象进行了研究,目前对DSE增强宿主植物抗逆性的作用机理仍很缺乏、不够系统深入.未来应建立DSE真菌种质资源库,加强DSE真菌的应用技术研究;结合现代生物技术和方法,系统深入研究DSE真菌提高植物抗逆性的生理和分子机制,为利用DSE真菌增强植物适应环境胁迫提供理论依据.(表1参92)     

菌根真菌增加植物抗盐碱胁迫的机理

菌根是菌根真菌与高等植物根系形成的一种共生体，能够促进植物在瘠薄土壤中的生长。文章通过综合近20年来国内外在菌根植物抗盐碱研究方面的成就，论述了在高盐胁迫下，菌根对其寄主植物耐盐碱能力的影响；指出菌根植物可能主要通过以下4个方面增加对高浓度盐碱环境的抗性：增加植株对P等矿质营养元素的吸收，改善了盐胁迫引起的营养亏缺；改变植物体内离子平衡，降低其生理毒害；增加植株对水分的吸收和利用能力，缓解了生理性干旱；改变了植物根系形态，促进根系水分吸收能力。在分析菌根真菌增加植物抗盐碱胁迫机理的基础上，还对该问题的研究前景提出了设想，为盐碱地改良提供参考依据。     

丛枝菌根提高滨海盐碱地植物耐盐性的作用机制及其生态效应

滨海盐碱土成陆和复垦年代短,具有土壤含盐高、养分低和矿化度高等特点,增加了植物的定植难度,不利于盐碱地复垦和生态修复。丛枝菌根真菌(Arbuscular Mycorrhizal Fungi,AMF)广泛存在于土壤生态系统中,自然界中90%以上的植物根系都能够与丛枝菌根形成菌根共生体,AMF能提高宿主植物的抗逆性(抗旱、抗盐、抗重金属和耐酸性等)和适应进化,AMF分泌的球囊霉素相关蛋白(Glomalin-related soil protein,GRSP)及其菌丝体促进土壤改良和培肥、保持土壤健康和可持续生产力等方面发挥着重要作用。文章综述了高盐碱胁迫对AMF-宿主植物共生关系的影响,明确AMF的孢子萌发与生长、菌丝体对高盐碱胁迫的响应;重点揭示AMF提高宿主植物对矿质养分和土壤水分的吸收、改善根际盐碱土矿质元素有效性、调控宿主植物生理生化特性、调节宿主植物抗氧化酶的活性和激素参与下的分子调控等方面作用机制,详细诠释AMF提高宿主植物的抗盐性机理;结合滨海盐碱地面临的重要生态问题,解析AMF在盐碱地治理中促进植物生长、提高土壤微生物活性、改善土壤肥力和结构等方面的应用进展和潜力,并结合AMF在盐碱地治理研究中存在的问题以及研究方向进行展望。AMF提高了滨海植物的耐盐性,促进了植物的生长和改善了土壤的微生态环境,AMF不能纯培养的特性限制了其在滨海盐碱地中大面积推广。基于此,今后在AMF菌种筛选、宿主植物的选择和菌种规模生产方面还需持续探索,从而为滨海盐碱地微生物复垦和生态修复提供技术支持。     

Cd胁迫下丛枝菌根对花生生长、光合生理及Cd吸收的影响

为了解丛枝菌根(AM)真菌对花生抗Cd胁迫的作用及其机理,采用温室盆栽试验,研究了Cd胁迫下接种AM真菌对花生生长、根系形态、Cd吸收及光合生理的影响.结果显示,AM真菌能与花生形成良好的共生关系,施Cd对菌根侵染率无影响;Cd胁迫下接种AM真菌能够显著改善花生生长状况,植株体内P含量与吸收量分别提高1.16—1.52、1.22—1.79倍,叶片叶绿素相对含量平均增幅11.79%,地上部分和根系生物量分别增加7.55%—8.19%、10.86%—14.05%,同时接种处理显著增大了花生根系的根长、根表面积、根体积,降低了植株地上部分Cd含量;对于同一施Cd水平而言,菌根花生叶片的最大光化学效率(Fv/Fm)和潜在光化学效率(Fv/Fo)均显著高于非菌根植株,接种AM真菌使花生叶片的净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)均显著增大,而胞间CO_2浓度(Ci)显著低于不接种处理.研究表明AM真菌可通过改变花生根系的形态结构来吸附固持重金属Cd,从而减少Cd向花生植株地上部分的转移,降低Cd胁迫对花生植株造成的伤害;另一方面,通过提高花生对矿质元素P的吸收来增加植株体内叶绿素含量及改善叶片叶绿素荧光和光合作用,增强花生抗Cd毒害的能力,进而促进花生生长,提高植株生物量.     

丛枝菌根-植物修复重金属污染土壤研究中的热点

随着菌根研究和植物修复技术的发展,利用丛枝菌根强化重金属污染土壤的植物修复逐渐受到人们的重视。本文系统综述了当前的几个研究热点:(1)菌根植物吸收和转运重金属的分子机制;(2)AM真菌对超富集植物重金属吸收的影响及其机制;(3)AM真菌对转基因植物重金属吸收的影响及其机制;(4)AM真菌与其他土壤生物在植物修复中的复合作用;(5)丛枝菌根与化学螯合剂在植物修复中的复合作用;(6)重金属复合污染土壤的丛枝菌根-植物修复;(7)放射性污染土壤的枝菌根-植物修复;(8)丛枝菌根-植物修复的田间试验研究。在未来的丛枝菌根-植物修复研究中,要筛选优良的宿主植物和与之高效共生的AM真菌,加强相关理论和应用基础研究,并构建高效基因工程菌。     

空心莲子草入侵对土壤AM真菌生物量和群落结构的影响——以湖北省典型区域为例

土壤丛枝菌根(Arbuscular mycorrhizal,AM)真菌具有维持植被稳定性和多样性的重要作用.为了解空心莲子草入侵过程中与AM真菌的相互作用,采用脂肪酸甲酯(FAMEs)和基于18S rDNA的PCR-DGGE方法对湖北咸宁、仙桃和武汉三地空心莲子草(Alternanthera philoxeroides)入侵前后土壤AM真菌的生物量和群落结构进行了比较分析.结果发现,基于FAMEs表征的AM真菌生物量在空心莲子草入侵后变化不大,仅仙桃地区显著增加(P<0.05).尽管DGGE图谱显示咸宁、仙桃和武汉三地AM真菌优势类群的群落结构均发生了明显演替,但群落间物种组成差异的多样性指数βWH在2.55-2.73之间、群落多样性指数H′在1.22-1.38之间,变化均不大.结果表明,空心莲子草入侵所形成的植物更替明显改变了AM真菌优势类群的结构,但对AM真菌的生物量和多样性影响很小.     

根瘤菌、丛枝菌根（AM）真菌与宿主植物共生的分子机理

丛枝菌根(AM)真菌和根瘤菌是两类重要的共牛微生物,分别能够与宿主植物形成丛枝菌根和根瘤,其中,对二者共有的宿主植物--豆科植物而言,则能够形成AM真菌-豆科植物-根瘤菌三重共生体.两类微生物与宿主植物共生关系建立的关键是二者之间的相互识别以及随后的侵染,其相互识别过程就是它们相互交换信号分子、相互作用的过程,而这两类微生物与宿主植物的识别过程具有许多相似之处.本文就根瘤菌、AM真菌与宿主植物在分子水平上的共生机理进行了综述,在对宿主植物分泌信号分子识别的基础上,提出植物根系对两类微生物侵染的感应机制,分析了共生体形成过程中相关基因的转录与表达,进而阐明了共生体的形成过程,并对本领域的未来发展提出了建议.     

Influences of global environmental changes on arbuscular mycorrhizal fungal communities: a review北大核心CSCD

丛枝菌根(arbuscular mycorrhizal, AM)真菌是生态系统地上地下部的重要连接体,对其群落结构特征的研究有助于菌种资源的发掘和生态系统的可持续发展.人类生产生活活动对全球环境带来了一系列的改变,如二氧化碳和臭氧浓度升高、氮沉降、增温及降水减少/增多等,全球环境变化对AM真菌群落结构的影响也引起了广泛关注.针对二氧化碳和臭氧浓度升高、增温、氮沉降和降水减少/增多等全球环境变化因子,总结其对AM真菌群落结构影响的国内外研究进展,探讨全球环境变化对AM真菌群落的可能作用途径.已有模拟全球环境变化实验研究主要集中于北半球的草原、农田和森林系统.大多研究发现二氧化碳和臭氧浓度升高未对AM真菌多样性产生不利影响,但使AM真菌群落结构显著分异.氮沉降和增温对AM真菌多样性的影响表现为降低、无显著影响和增加等多种情况,对AM真菌群落结构的影响也表现为未显著和显著分异,主要与模拟实验处理方式、增加幅度、土壤养分水平和生态系统类型等因素有关.降水减少未显著影响AM真菌群落结构和多样性,而降水增加使AM真菌群落结构发生显著分异.这些研究主要注重AM真菌群落结构和多样性如何改变等生态现象而潜在机理探索以及热带和南半球不同生态系统下的研究尚不足.另外,鉴于全球变化因子间的关联性,复合因子对AM真菌群落结构的影响值得重视.(图1表4参113)     

喀斯特生境下AMF侵染对任豆生长的影响

喀斯特地区土壤退化,植被定植更新困难,丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)具有增强植物养分吸收能力和抵抗逆境胁迫能力。研究喀斯特生境下植物与AMF共生效果,选择优势菌种促进喀斯特植被恢复,对于提高植物定植成活率具有重要作用。以豆科植物任豆(Zenia insignis)幼苗为试验材料,盆栽条件下,选取喀斯特优势菌种-摩西球囊霉(Funneliformis mosseae)、根内球囊霉(Rhizophagus intraradices),2种菌根真菌混合菌剂进行接种,培养180 d,研究贫瘠喀斯特土壤生境和养分较高的滇柏林下土壤生境下AMF对任豆生长影响。结果表明:摩西球囊霉、根内球囊霉和混合接种均能侵染任豆根系,幼嫩根系更易侵染,木质化根系侵染率下降。接种摩西球囊霉,贫瘠喀斯特土壤生境下,株高、地径、地上生物量、地下生物量和总生物量分别提高68.92%、56.18%、83.90%、42.20%和67.34%;养分较高的滇柏林下喀斯特土壤生境下,株高、地上生物量、地下生物量和总生物量分别提高48.05%、6.77%、7.92%和8.89%;根内球囊霉处理接种效应低于摩西球囊霉和混合接种处理,对生物量增长为负效应,混合接种处理接种效应介于单接种之间,摩西球囊霉接种效果优于根内球囊霉和混合接种。摩西球囊霉在贫瘠喀斯特土壤生境下发挥的促生效应优于养分较高的喀斯特土壤,可作为喀斯特侵蚀区植被恢复菌根真菌干扰途径的优势菌种,混合接种作为接种剂具有单接种兼容效应。     

丛枝菌根对土壤-植物系统中重金属迁移转化的影响

丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)是一类在自然和农业生态系统中广泛存在并能与多数陆生植物形成共生关系的土壤真菌,在重金属污染土壤中对宿主植物的生长及吸收累积重金属具有重要影响,因而对污染土壤的生物修复具有潜在应用价值。以重金属从根际土壤进入植物并在植物体内再分配过程为主线,介绍丛枝菌根在这一过程中对重金属环境行为,特别是根际土壤中重金属赋存形态及植物吸收重金属的影响。最后,对丛枝菌根影响植物重金属耐性机制研究前沿和菌根修复技术的应用前景进行展望。     

Biotic contexts alter metal sequestration and AMF effects on plant growth in soils polluted with heavy metals

Investigating how arbuscular mycorrhizal fungi (AMF)-plant interactions vary with edaphic conditions provides an opportunity to test the context-dependency of interspecific interactions. The relationship between AMF and their host plants in the context of other soil microbes was studied along a gradient of heavy metal contamination originating at the site of zinc smelters that operated for a century. The site is currently under restoration. Native C3 grasses have reestablished, and C4 grasses native to the region but not the site were introduced. Interactions involving the native mycorrhizal fungi, non-mycorrhizal soil microbes, soil, one C3 grass (Deschampsia flexuosa), and one C4 grass (Sorghastrum nutans) were investigated using soils from the two extremes of the contamination gradient in a full factorial greenhouse experiment. After 12 weeks, plant biomass and root colonization by AMF and non-mycorrhizal microbes were measured. Plants from both species grew much larger in soil from low-contaminated (LC) origin than high-contaminated (HC) origin. For S. nutans, the addition of a non-AMF soil microbial wash of either origin increased the efficacy of AMF from LC soils but decreased the efficacy of AMF from HC soils in promoting plant growth. Furthermore, there was high mortality of S. nutans in HC soil, where plants with AMF from HC died sooner. For D. flexuosa, plant biomass did not vary with AMF source or the microbial wash treatment or their interaction. While AMF origin did not affect root colonization of D. flexuosa by AMF, the presence and origin of AMF did affect the number of non-mycorrhizal (NMF) morphotypes and NMF root colonization. Adding non-AMF soil biota reduced Zn concentrations in shoots of D. flexuosa. Thus the non-AMF biotic context affected heavy metal sequestration and associated NMF in D. flexuosa, and it interacted with AMF to affect plant biomass in S. nutans. Our results should be useful for improving our basic ecological understanding of the context-dependency of plant-soil interactions and are potentially important in restoration of heavy-metal-contaminated sites.     

Mycorrhizal benefit differs among the sexes in a gynodioecious species

Both plant sex and arbuscular mycorrhizal (AM) symbiosis influence resource acquisition and allocation in plants, but the interaction between these two components is not well established. As the different plant sexes differ in their resource needs and allocation patterns, it is logical to presume that they might differ in their relationship with AM as well. We investigate whether the association with AM symbiosis is different according to the host plant sex in the gynodioecious Geranium sylvaticum, of which, besides female and hermaphrodite plants, intermediate plants are also recognized. Specifically, we examine the effects of two different AM fungi in plant mass allocation and phosphorus acquisition using a factorial greenhouse/common garden experiment. Cloned G. sylvaticum material was grown in symbiosis with AM fungi or in non-mycorrhizal condition. We evaluated both the symbiotic plant benefit in terms of plant mass and plant P content and the fungal benefit in terms of AM colonization intensity in the plant roots and spore production. Our results suggest that G. sylvaticum plants benefit from the symbiosis with both AM fungal species tested but that the benefits gained from the symbiosis depend on the sex of the plant and on the trait investigated. Hermaphrodites suffered most from the lack of AM symbiosis as the proportion of flowering plants was dramatically reduced by the absence of AM fungi. However, females and intermediates benefited from the symbiosis relatively more than hermaphrodites in terms of higher P acquisition. The two AM fungal species differed in the amount of resources accumulated, and the fungal benefit was also dependent on the sex of the host plant. This study provides the first evidence of sex-specific benefits from mycorrhizal symbiosis in a gynodioecious plant species.     

污泥堆肥利用中AM对稗草生长及Cu、Pb吸收的影响

在滨海盐渍土中分别混加质量分数为0%、20%、40%和60%的污泥堆肥,作为盆栽基质,研究摩西球囊霉（Glomusmosseae）和根内球囊霉（Glomus intraradices）2种AM真菌对稗草（Echinochloa crusgalli）生长及其吸收Cu、Pb的影响,分别以不接种AM真菌的处理为各自的对照。结果显示：添加污泥堆肥处理中稗草接种苗菌根侵染率均显著高于纯盐泽土处理。同时,随着盐渍土中污泥堆肥含量增加稗草生物量上升,其中在含有40%和60%污泥堆肥处理中接种AM真菌稗草的地上及地下部生物量显著高于未接种苗。接种AM真菌显著提高了稗草Cu、Pb富集总量;接种AM真菌显著提高了稗草地下部Cu富集量,却降低了地下部Pb累积量,提高了Pb向地上部的转运,增加了地上部Pb累积量。这些结果表明污泥堆肥中接种AM真菌可以促进稗草的生长和提高对重金属Cu、Pb的富集能力。     

Characterisation of growth and biochemical response of Onopordum acanthium L. under lead stress as affected by microbial inoculation

Microbial associations may influence the negative effects of potentially toxic elements on plants. In a greenhouse experiment, the growth; biochemical response; and Pb, Fe, and Zn uptake of Onopordum acanthium L. were investigated in response to inoculation with arbuscular mycorrhizal fungi, AMF (a mixture of Funneliformis mosseae, Rhizophagus irregularis, and Rhizophagus fasciculatus) and plant growth-promoting rhizobacteria, PGPR (a mixture of Pseudomonas species including P. putida, P. fluorescens, and P. aeruginosa) at increased Pb levels in soil. The treatments were arranged as a factorial experiment based on a randomised complete block design. Results revealed that inoculation with AMF and PGPR decreased Pb toxicity in plants. Inoculated plants with AMF and PGPR had higher shoot and root dry weight compared with the non-inoculated plants. In this study, AMF and PGPR inoculation led to a significant increase (P?≤?.05) in chlorophyll a, b, chlorophyll a+b, carotenoid, proline, and relative water content of plants. Furthermore, AMF and PGPR inoculation likely played a more important role in growth and Pb uptake in O. acanthium L. Our results suggest that AMF and Pseudomonas bacteria could be effective bio-inoculants for enhancing the plant growth and Pb uptake by inhibiting the adverse effects of Pb in O. acanthium.     

Plant species differ in their ability to reduce allocation to non-beneficial arbuscular mycorrhizal fungi

Theory suggests that cheaters threaten the persistence of mutualisms, but that sanctions to prevent cheating can stabilize mutualisms. In the arbuscular mycorrhizal symbiosis, reports of parasitism suggest that reductions in plant carbon allocation are not universally effective. I asked whether plant species differences in mycorrhizal responsiveness would affect both their susceptibility to parasitism and their reduction in allocation to non-beneficial arbuscular mycorrhizal fungi (AMF) in high-phosphorus soils. In a greenhouse experiment, I found that two C3 grasses, Bromus inermis and Elymus repens, effectively suppressed root colonization and AMF hyphal abundance. Increases in soil phosphorus did not reduce the degree to which AMF increased plant biomass. In contrast, two C4 grasses, Andropogon gerardii and Schizachyrium scoparium, more weakly reduced root colonization and failed to suppress AMF hyphal abundance. Consequently, they experienced strong declines in their response to AMF, and one species suffered parasitism. Thus, species differ in susceptibility to parasitism and their reduction in allocation to non-beneficial AMF. These differences may affect the distribution and abundance of plants and AMF, as well as the stability of the mutualism.     

Uptake of zinc, cadmium and phosphorus by arbuscular mycorrhizal maize (Zea mays L.) from a low available phosphorus calcareous soil spiked with zinc and cadmium

In a multifactorial pot experiment, maize (Zea mays L.) with or without inoculation with the arbuscular mycorrhizal (AM) fungus Glomus mosseae BEG167 was grown in a sterilized soil spiked with three levels of zinc (0, 300 and 900 mg Zn kg⁻¹ soil) and three levels of cadmium (0, 25 and 100 mg Cd kg⁻¹ soil). At harvest after 8 weeks of growth, the proportion of root length of inoculated plants colonized decreased with increasing Zn or Cd additon, and was 56% in the absence of both metals and was reduced significantly to 27% in the presence of the higher levels of both metals. Mycorrhizal plants had higher biomass than non-mycorrhizal controls except at the highest soil level of Cd. Cadmium had more pronounced effects on plant biomass than did Zn at the levels studied and the two metals showed a significant interaction. The data suggest that mycorrhizal inoculation increased plant growth with enchancement of P nutrition, perhaps increasing plant tolerance to Zn and Cd by a dilution effect. AM inoculation also led to higher soil solution pH after harvest, possibly reducing the availability of the metals for plant uptake, and lowered the concentrations of soluble Zn and Cd in the soil solution, perhaps by adsorption onto the extrametrical mycelium.     

菌根类型对森林树木净初级生产力的影响

菌根是土壤真菌与植物根系形成的共生体,存在于绝大多数植物（90%）的根系和生境中。菌根共有7种类型,在生态系统的过程和功能方面都扮演着十分重要的角色。为了增强对菌根在森林生态系统中重要功能的理解,文章基于全球森林数据库,在全球尺度上研究了不同菌根类型对森林树木净初级生产力（NPP）的影响。结果表明,森林树木NPP随菌根类型的不同而不同,AM类型菌根森林的NPP[679.49 g.m-2.a-1（以C计）]要显著高于含ECM类型菌根的森林[479.00 g.m-2.a-1（以C计）];菌根类型的不同对森林树木地上和地下及其各组分NPP的影响和贡献也存在着显著的不同,AM类型菌根对地下NPP的贡献要高于ECM菌根,而ECM菌根对地上NPP的贡献则较大。菌根类型对地上、地下NPP组分的影响分析则表明,AM类型的菌根对树叶和细根NPP的贡献较大,而ECM类型菌根则对树木主干和枝NPP的贡献较大。可见,森林树木总体NPP及其各组分NPP都随着菌根类型的不同而存在显著的差异。     

Mycorrhizal fungal identity and diversity relaxes plant-plant competition

There is a great interest in ecology in understanding the role of soil microbial diversity for plant productivity and coexistence. Recent research has shown increases in species richness of mutualistic soil fungi, the arbuscular mycorrhizal fungi (AMF), to be related to increases in aboveground productivity of plant communities. However, the impact of AMF richness on plant-plant interactions has not been determined. Moreover, it is unknown whether species-rich AMF communities can act as insurance to maintain productivity in a fluctuating environment (e.g., upon changing soil conditions). We tested the impact of four different AMF taxa and of AMF diversity (no AMF, single AMF taxa, and all four together) on competitive interactions between the legume Trifolium pratense and the grass Lolium multiflorum grown under two different soil conditions of low and high sand content. We hypothesized that more diverse mutualistic interactions (e.g., when four AMF taxa are present) can ease competitive effects between plants, increase plant growth, and maintain plant productivity across different soil environments. We used quantitative PCR to verify that AMF taxa inoculated at the beginning of the experiment were still present at the end. The presence of AMF reduced the competitive inequality between the two plant species by reducing the growth suppression of the legume by the grass. High AMF richness enhanced the combined biomass production of the two plant species and the yield of the legume, particularly in the more productive soil with low sand content. In the less productive (high sand content) soil, the single most effective AMF had an equally beneficial effect on plant productivity as the mixture of four AMF. Since contributions of single AMF to plant productivity varied between both soils, higher AMF richness would be required to maintain plant productivity in heterogeneous environments. Overall this work shows that AMF diversity promotes plant productivity and that AMF diversity can act as insurance to sustain plant productivity under changing environmental conditions.