Evolving insights to understanding mycorrhizas

International audience

Arbuscular mycorrhizal fungi (AMF) have the potential to increase crop productivity and play a key role in the functioning and sustainability of most agroecosystems. However, limited information is available on the divervisity of AMF associated with upland rice varieties in Southwest Nigeria. Field survey was conducted to investigate colonization and diversity of AMF in 13 upland rice varieties commonly grown in Southwest Nigeria. Root and soil samples were collected from rice fields in 2012. The results showed natural root colonization of all the rice varieties by AMF with highest root colonization in ITA 157and Ofada. The spore densities retrieved from the different rhizospheres were relatively high, varying from 13 spores in UORW 111 to 174 spores in Ofada with a mean of 67.6 spores per 20 g dry soil. Glomus was observed to be the most abundant AMF genus. Funneliformis mosseae was the most frequently occurring AMF species (96.2%) with relative density (RD) of 32.2%, followed by Glomus intraradices, Claroideoglomus etunicatum, and Glomus clareium. This study showed that AMF naturally colonized the roots of these rice varieties and diversity of different AMF genera in rice rhizosphere. This study will help draw attention to natural colonization of AMF in rice producing areas of Nigeria that can influence future possibility of using inocula of the dominant AMF species in upland rice cultivation.

Fresh knowledge for an old relationship: new discoveries in molecular mycorrhizal research.

Elevated nitrogen (N) deposition may stimulate a plant’s dependency on arbuscular mycorrhizal (AM) fungi in phosphorus (P)-deficient subtropical forests. However, the ecological assembly processes and the responses of AM fungal diversity and community structure to N deposition in both the roots and rhizosphere are still unclear. We collected root and soil samples from a Cunninghamia lanceolata plantation forest after four years of N addition and examined the community structure and assembly of AM fungi. Elevated N deposition decreased the AM fungal community diversity in both rhizosphere soil and roots. Glomeraceae was the dominant family of the AM fungal community in both soil and roots across all N addition treatments, followed by Gigasporaceae and Ambisporaceae. However, N addition induced differential variation in the community composition of AM fungi between soil and roots. For soil AM fungi, N addition decreased the Glomeraceae abundance and increased the Gigasporaceae and Ambisporaceae abundance. In contrast, the root AM fungal community was dominated by Glomeraceae under N addition treatments. Furthermore, N addition increased the deterministic community assembly that acted as an environmental filter for soil AM fungi. In contrast, N addition decreased the importance of determinism, implying that the selection of plants on root AM fungi decreased with increasing N addition. Altogether, our findings suggest that the community structure of AM fungi responds differently to N deposition in the soil and roots in subtropical forests and highlight the important role of soil AM fungi in helping host plants respond to N deposition.

The disruption of mutualisms between plants and mycorrhizal fungi is a potentially powerful mechanism by which invasives can negatively impact native species, yet our understanding of this mechanism's role in exotic species invasion is still in its infancy. Here, we provide several lines of evidence indicating that invasive tamarisk (Tamarix sp.) negatively affects native cottonwoods (Populus fremontii) by disrupting their associations with arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) fungi. At a field site in the early stages of tamarisk invasion, cottonwoods with tamarisk neighbors had reduced EM colonization and altered EM fungal community composition relative to cottonwoods with native neighbors, leading to reductions in EM propagule abundance in the soil beneath tamarisk. Similarly, AM colonization of cottonwoods was reduced with a tamarisk neighbor, but there were no significant changes in AM fungal spore communities or propagule abundance. Root colonization by nonmycorrhizal fungi, including potential pathogens, was higher in cottonwoods with tamarisk neighbors. A greenhouse experiment in which AM and EM inoculation and plant neighbor were manipulated in a fully factorial design showed that cottonwoods benefited from mycorrhizas, especially EM, in terms of shoot biomass when grown with a conspecific, but shoot biomass was similar to that of nonmycorrhizal controls when cottonwoods were grown with a tamarisk neighbor. These results are partially explained by a reduction in EM but not AM colonization of cottonwoods by a tamarisk neighbor. Tamarisk neighbors negatively affected cottonwood specific leaf area, but not chlorophyll content, in the field. To pinpoint a mechanism for these changes, we measured soil chemistry in the field and the growth response of an EM fungus (Hebeloma crustuliniforme) to salt-amended media in the laboratory. Tamarisk increased both NO3- concentrations and electrical conductivity 2.5-fold beneath neighboring cottonwoods in the field. Salt-amended media did not affect the growth of H. crustuliniforme. Our findings demonstrate that a nonnative species, even in the early stages of invasion, can negatively affect a native species by disrupting its mycorrhizal symbioses. Some of these changes in mycorrhizal fungal communities may remain as legacy effects of invasives, even after their removal, and should be considered in management and restoration efforts.

Arbuscular mycorrhizal (AM) fungal diversity of arid lands : from AM fungal species to AM fungal communities

A glimpse into the past of land plants and of their mycorrhizal affairs: from fossils to evo‐devo

Arbuscular mycorrhizal (AM) fungi are a group of soil and root inhabiting fungi that represent an ancient plant-fungi symbiosis. These fungi interconnect multiple plant individuals and species simultaneously generating a complex fungal network belowground that plays a significant role in shaping plant community composition and ecosystem productivity. However, the underlying mechanisms as to how AM fungal networks and their diversity influence plant performance and community structure are not always predictable and are frequently debated. Although all potential plant hosts may be able to associate with all AM fungi, plant-AM fungal associations can result in a range of AM fungal facilitative and antagonistic effects on plants. Although the facilitative effects of AM fungi have long been studied, the extent and mechanisms of AM fungal antagonistic effects are much less understood. Moreover, AM fungi are observed to vary in their functional properties and temporal patterns adding further complexity to the potential mechanisms by which AM fungi and the diversity of AM fungi determine plant community composition and productivity through their facilitative and antagonistic effects on plants. Here we review the potential mechanisms by which AM fungal communities facilitate greater diversity and productivity in plant communities, as well as the potential mechanisms by which AM fungi may be antagonistic to plant performance. Specifically we address how AM fungal communities might facilitate greater plant community performance through functional complementarity among AM fungi as a result of functional, spatial and temporal niche segregation. We also address facilitative and antagonistic aspects of AM fungi through their ability to allocate resources among plant community members that consequently facilitates plant recruitment and alters plant-plant competitive outcomes. By considering the multiple facets by which AM fungi may be facilitative or antagonistic to plants we identify potential knowledge gaps in mechanistically predicting how AM fungal communities shape plant community composition and maintain ecosystem productivity.

In this contribution we discuss several interactions between mycorrhizal fungi and their host plants. In particular we illustrate how plant communities may be affected by mycorrhizal fungi, and how mycorrhizal fungal communities may be affected by plants and plant cultural practices. The justification for the study of the mycorrhizal symbiosis at the level of the community is rooted in the fact that organisms in nature are usually assembled into interactive communities and do not exist as solitary entities. The function of the symbiosis must, therefore, be viewed in the context of communities. An important focus in ecological research in recent years has been to understand which factors regulate the structure and diversity of natural populations and communities. It has long been hypothesized that diversity may be crucial for maintaining productivity the and also the stability of ecosystems and recent experimental investigations support these ideas. Therefore, in this chapter we also discuss the role of diversity in arbuscular mycorrhizal (AM) fungal communities and the effect this may have on diversity of plant populations and communities. Although we draw extensively from the ecological literature, the concepts discussed herein are also relevant to horticulture, agronomy, forestry, and land reclamation. We believe that successful use of mycorrhizal fungi in these fields requires an essentially ecological perspective. This chapter deals primarily with the arbuscular mycorrhizal (AM) symbiosis. We call to the reader’s attention other recent reviews on related ecological treatments of the mycorrhizal symbiosis including those by St. John and Coleman (1983), Hetrick (1984), Loree and Williams (1984), Fitter (1990), Allen (1991), Brundrett (1991), Marx (1991), Read (1991a,b), Soderstrom (1991), Fahey (1992), Newsham et al. (1995), among others.

James Hutton Institute, Dundee DD2 5DA, UKBelowground organisms, such as arbuscular mycorrhizal(AM) fungi, have long been credited with altering plant fit-ness. More recently, research on belowground organismshas revealed that AM fungi also influence a wide variety ofaboveground organisms via plants (reviewed in Van Dam H Bennett 2010). Schausberger et al. (2012) demon-strate that the presence of an AM fungus in the roots of ahost plant alters volatile emissions and host plant attractive-ness to parasitoids in the presence of herbivores. Thisextends previous studies that have focused on direct inter-actions of AM with plants (e.g. mycorrhizal fungal–plant–herbivore interactions; reviewed in Gehring & Bennett2009), but have not conclusively demonstrated how below-ground organisms, and AM fungi in particular, influencethird trophic level organisms such as parasitoids (Gange,Brown & Aplin 2003; Guerrieri et al. 2004; Hempel et al.2009; Leitner et al. 2010; Hoffmann, Vierheilig & Schaus-berger 2011a,b; Wooley & Paine 2011) via the release ofplant volatiles that attract parasitoids that attack herbivoreson host plants. Until recently, these studies failed to conclu-sively document the effects of AM fungi on both volatilerelease and attraction of parasitoids. For example, Wooley& Paine (2011) and Gange, Brown & Aplin (2003) haveshown variation in parasitoid attraction to plants hostingdifferent strains and species of Glomus as compared to non-mycorrhizal plants. Hoffmann, Vierheilig & Schausberger(2011a) also showed greater preference by parasitoids foreggs oviposited on plants associated with a single AMfungus. In addition, a single AM fungus in the roots of ahost plant has been shown to positively influence parasitoidlife-history characteristics (Hempel et al. 2009; Hoffmann,Vierheilig & Schausberger 2011b). However, none of thesestudies measured volatile profiles for host plants, so parasit-oid attraction could not be directly attributed to volatiles.A study on AM fungal influenced volatile release revealeddifferences but did not test whether changes in volatilesinfluenced parasitoids (Leitner et al. 2010). One study com-bined both parasitoid attractiveness and measurement ofvolatiles, but they primarily tested effects of attraction toplants in the absence of herbivory and never made compari-sons between mycorrhizal and non-mycorrhizal plantsexperiencing herbivory (Guerrieri et al. 2004). Unlike theseprevious experiments, Schausberger et al. measured bothchanges in volatile chemistry as well as parasitoid attractionin a fully factorial design.The results presented by Shausberger et al. open up multi-plefutureopportunitiesinabove–belowgroundresearch.Thefirst of these opportunities involves identifying the mecha-nisms by which AM fungi alter parasitoid attraction. Forexample,whatarethe biochemicalortranscriptionalchangesthat occur following AM fungal colonization that result inaltered volatile profiles? Are the mechanisms suggested forAM fungal alteration of direct chemical defences the samemechanisms that alter volatile profiles? Colonization by AMfungi has been shown to turn on the salicylic acid pathwaytemporarily,aprocessthatmayprimethejasmonicacidpath-way for herbivore attack (reviewed in Pozo & Azcon-Aguilar2007).Theinductionofvolatilesislinkedtothejasmonicacidpathway (reviewed in Heil 2008), and therefore, plants maybeprimedforafasterorgreaterreleaseofvolatileswhencolo-nizedbyAMfungi.However, there may be other mechanisms by which AMfungi influence volatile release. For example, given that AMfungi increase plant biomass and fitness in the PhaseolusvulgarissystemstudiedbyShausbergeret al.(aswellasmanyothersystems),itcouldsimplybethattheincreasedresourcesprovided by the mutualism allow plants to allocate moreresourcestoplantdefensivecharacteristics(e.g.directconstit-utiveandinduceddefencesaswellasindirectdefencesviavol-atile attraction; Bennett, Alers-Garcia & Bever 2006) or thatchanges in plant size or structure in association with AMfungi benefit or hinder parasitoid searching capabilities(Gange,Brown&Aplin2003).What characteristics of the volatile blends produced in thepresence of AM fungi are attractive for parasitoids? Shaus-bergeret al.showedtherewerefewerchemicalspresentinthevolatileblendsofAMfungalplantsbeforeherbivory(relativeto plants not hosting AM fungi), but this difference disap-peared after herbivory. However, different volatile chemicalswere released from plants experiencing herbivory and colo-nizedornotbyAMfungi(seealsoLeitneret al.2010).Shaus-berger et al. did not address whether increased attraction toplants hosting AM fungi is associated with a particular vola-

To understand the effects of agricultural management activities on soil arbuscular mycorrhizal (AM) fungi diversity, the high-throughput sequencing based on Illumina MiSeq platform, and the fatty acids fingerprints were used to examine the effects of maize straw returning on soil arbuscular mycorrhizal fungi. The relationships between AM fungal community composition, AM fungal biomass and soil factors after maize straw returning were examined for four continuous years. A total of 2430 operational taxonomic units (OTUs) of AM fungi were classified into 10 genera and 143 species, respectively, which belonged to 1 phylum, 3 classes, 4 orders, 8 families. There was no significant difference in AM fungal community richness (Chaoles index and ACE index) and diversity (Shannon, Simpson diversity indices) in different treatments. Paraglomus and Glomus were dominant genera among all AM fungal communities. With the increase of the maize straw returned amounts, the abundance of Glomus reduced. Under the treatments of 3000 and 9000 kg·hm-2 straw returned, the abundance of Glomus and Acaulospora had significant differences with the control (0 kg·hm-2). Compared with the control, there were significant differences between Archaeospora, Paraglomus and Glomus in the treatment of 3000 kg·hm-2 straw returned. Results from non-metric multi-dimensional scale (NMDS) analysis showed that under 9000 and 12000 kg·hm-2 straw returning treatments, the difference between the β diversity of soil AM fungi and the spatial distance of controls was farther apart than the other treatments. The effect of straw returning on the β diversity of AM fungi was significant. The multivariate analysis results revealed the relationship of the spatial variation between the soil physicochemical properties and AM fungi richness and diversity could be explained at 82.8% cumulative variables. The total nitrogen and available nitrogen were the most important factors driving soil microbial communities biomass marked by PLFAs and AM fungal biomass (NLFAs). The continuous maize straw returning to the field changed the genera composition of AM fungi. With the increases of straw returning amounts, the specific species of AM fungi decreased and the similarity between AM fungi community composition decreased. Straw returning increased soil AM fungi biomass and its contribution to soil total microbial biomass.

The aspect can affect plant communities and soil physical and chemical properties through different microclimates. However, little is known about the effect of aspect on arbuscular mycorrhizal (AM) fungal diversity and community composition, although AM fungi are beneficial for plant nutrient absorption and natural restoration. In this study, AM fungal community and diversity distribution patterns in the rhizosphere soil and roots of seven widespread plants in a natural Toona ciliata var. pubescens (Tc) forest on the north-facing (NF) aspect and south-facing (SF) aspect were investigated using Illumina PE250 high-throughput sequencing in the Guanshan National Nature Reserve, Jiangxi Province, China. Our results exhibited that aspect did not affect AM fungal diversity but significantly affected AM fungal community structure and composition. Glomeraceae was the most common and abundant family in the Tc natural forest. The Glomeromycota sequence proportion of root AM fungal community was significantly larger on NF than on SF (p < 0.05). The relative abundance of Acaulosporaceae of root AM fungal community differed significantly with aspect, being greater on NF than on SF (p < 0.05). In addition, the number of Glomeromycota sequences was significantly larger on SF than on NF, while the number of OTUs and the relative abundance of unclassified fungi in rhizosphere soil in Tc showed the opposite trend (p < 0.05). The soil properties (organic matter, nitrogen, potassium, phosphorus, and pH) were significantly correlated with these changes. These findings indicate that the habitat of NF with low insolation, high soil moisture, and high nutrient content might promote the functional realization of AM fungi; the habitat of SF with high insolation, low soil moisture, and low soil nutrient content might be beneficial for the proliferation and preservation of AM fungal groups. This study provides important information on the ecological processes of AM fungal community construction and microbiological mechanisms in natural Tc forests.

Climate models project overall a reduction in rainfall amounts and shifts in the timing of rainfall events in mid‐latitudes and sub‐tropical dry regions, which threatens the productivity and diversity of grasslands. Arbuscular mycorrhizal (AM) fungi may help plants to cope with expected changes but may also be impacted by changing rainfall, either via the direct effects of low soil moisture on survival and function or indirectly via changes in the plant community. In an Australian mesic grassland (former pasture) system, we characterized plant and AM fungal communities every 6 months for nearly 4 years to two altered rainfall regimes: (a) ambient, (b) rainfall reduced by 50% relative to ambient over the entire year and (c) total summer rainfall exclusion. Using Illumina sequencing, we assessed the response of AM fungal communities sampled from contrasting rainfall treatments and evaluated whether variation in AM fungal communities was associated with variation in plant community richness and composition. We found that rainfall reduction influenced the fungal communities, with the nature of the response depending on the type of manipulation, but that consistent results were only observed after more than 2 years of rainfall manipulation. We observed significant co‐associations between plant and AM fungal communities on multiple dates. Predictive co‐correspondence analyses indicated more support for the hypothesis that fungal community composition influenced plant community composition than vice versa. However, we found no evidence that altered rainfall regimes were leading to distinct co‐associations between plants and AM fungi. Overall, our results provide evidence that grassland plant communities are intricately tied to variation in AM fungal communities. However, in this system, plant responses to climate change may not be directly related to impacts of altered rainfall regimes on AM fungal communities. Synthesis. Our study shows that arbuscular mycorrhizal (AM) fungal communities respond to changes in rainfall but that this effect was not immediate. The AM fungal community may influence the composition of the plant community. However, our results suggest that plant responses to altered rainfall regimes at our site may not be resulting via changes in the AM fungal communities.

<p>Arbuscular mycorrhiza (AM) fungi are associated with almost all land plants and provide soil nutrients and other benefits to their plant hosts in exchange for photosynthetic products. While fertilization regimes in managed grasslands or agricultural systems are tailored for increasing plant biomass, their potential effects on AM fungi are rarely taken into account. Nutrient-driven changes in abundance and community composition of AM fungi, however, may feedback on ecosystem performance in the long term. Therefore, it is necessary to get a better understanding on how AM fungal communities respond to changes and imbalances in soil nutrient availabilities.</p><p>Here, we evaluated how long-term nutrient deficiency of phosphorus (P), nitrogen (N) and potassium (K) affects the abundance and community composition of AM fungi in a mountainous grassland. In addition, we investigated how the responses of AM fungi to those deficiencies were modulated by liming and the type of fertilizer addition (inorganic versus organic).</p><p>Our study was carried out on a long-term nutrient deficiency experimental grassland site in Admont (Styria, Austria), established in 1946. Different fertilization treatments were applied for more than 70 years in a randomized block design, including numerous combinations of inorganic (P, N, K with/without lime) and organic (solid manure and liquid slurry) fertilizers. The hay meadow at the site is cut three times per year and biomass is not returned to the system. Therefore, biomass and nutrients have been continuously removed for decades, leading to different types of soil nutrient deficiency. In this study, we collected both root and soil samples in July 2019 and quantified AM fungi and other microbial groups by measuring neutral fatty acid (NLFA) and phospholipid fatty acid (PLFA) biomarkers, respectively. Additionally, we applied DNA and RNA-based amplicon sequencing of the 18S rRNA gene to identify AM fungal community composition.</p><p>Our data shows that deficiencies of one or more elements had a major impact on both AM fungal biomass and community composition. AM fungal biomass was higher in plots that received no fertilizers compared to inorganically fertilized plots, but lower in plots which were deficient only in certain single or multiple elements, specifically in plots fertilized with inorganic N only (i.e., deficient in P and K). Conversely, liming and organic fertilizer amendments increased AM fungal biomass compared to plots containing inorganic fertilizers without lime. Across all treatments, AM fungal biomass was positively correlated with pH and soil water content, and negatively with dissolved N compounds, indicating indirect effects via responses of other soil parameters to nutrient deficiency. Long-term nutrient deficiency also altered plant community composition, which may also have indirectly affected AM fungal communities.</p><p>We conclude that long-term nutrient deficiency, and in particular the stoichiometry of available nutrients, strongly affects the abundance and community composition of AM fungi in grassland soil. This response may be linked to changes in plant community composition or soil chemistry both as a result and as a cause, emphasizing the complexity of feedbacks determining the response of grassland ecosystems to changing nutrient conditions.</p>

PDF HTML阅读 XML下载 导出引用 引用提醒 施氮对森林生态系统AM真菌群落组成及多样性的影响 DOI: 10.5846/stxb202003120515 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41877050，31300446） Can understory nitrogen addition overestimate the effects of nitrogen deposition on arbuscular mycorrhizal fungal community? Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:丛枝菌根（AM）真菌能够和绝大多数陆生植物形成互惠共生体，具有重要的生态功能。在氮（N）沉降日益严重的背景下，越来越多的土壤生态学家开始关注N沉降对AM真菌群落的影响，然而已有研究大多数集中在草地生态系统，对森林生态系统的关注相对较少，而在森林生态系统开展的模拟研究又多采用林下施N的方式，忽略了冠层发生的一系列生态过程，可能无法准确反映真实情形。依托鸡公山野外控制试验平台，采用高通量测序技术就不同施N方式（林下vs林冠）及速率对AM真菌alpha多样性和群落组成的影响进行了连续4 a的监测。试验综合考虑植被、坡向和坡度等因素，采用完全随机区组设计，包括4个区组（重复），每个区组随机设置5个样方，对应5个不同处理：对照（CK）、林冠施N 25 kg hm-2 a-1（CN25）和50 kg hm-2 a-1（CN50）、林下施N 25 kg hm-2 a-1（UN25）和50 kg hm-2 a-1（UN50）。结果发现，在目前的N素添加水平和时间尺度上，施N方式和施N速率对AM真菌的alpha多样性都没有显著影响，二者之间也无交互作用。然而，经过一年的试验处理，施N方式对AM真菌群落组成产生了轻微的影响，而施N速率有极显著的影响，且二者之间存在显著交互作用。当施N速率为25 kg hm-2 a-1时，林冠施N和对照相比差异不显著，而林下施N处理AM真菌群落组成与对照相比差异极显著，与林冠施N相比，差异也极显著；当施N速率为50 kg hm-2 a-1时，林冠施N与对照处理群落组成有略微差异（P=0.080），林下施N与林冠施N及对照处理相比AM真菌群落组成均没有显著变化。在接下来的三年中，施N方式和施N速率对AM真菌的群落组成都没有显著影响，二者之间也无显著交互作用。这说明在特定的施N速率和处理时间下，林下施N可能会高估自然N沉降对AM真菌群落组成的影响。随着处理时间的延长，不同处理下AM真菌群落有趋同的趋势，可能是因为AM真菌群落对N沉降产生了适应性。本研究评估了施N方式对森林生态系统AM真菌群落组成与结构的影响，在未来的研究中需要设定更多的N素梯度和更长的时间跨度，才能够更全面的认识N沉降的生态效应。 Abstract:Arbuscular mycorrhizal (AM) fungi can form symbiosis with most terrestrial plants and provide important ecological services. Under the intensified nitrogen (N) deposition, more and more soil ecologists pay attention to the impacts of N deposition on AM fungal community. However, most relevant studies were carried out in grassland ecosystems, while studies on forest ecosystem were very limited. Moreover, most simulation studies in forest ecosystems applied N to the forest floor, ignoring the canopy processes, may not accurately reflect the natural situations. We conducted a field experiment on the influence of N addition mode (understory vs canopy) and rate on AM fungi in a mixed deciduous forest of China. The experiment had a fully randomized block design with four blocks (replicates) and each block included five plots. Within each block, each plot was randomly assigned with one of the five treatments:ambient (CK), canopy addition of N at 25 (CN25) or 50 kg hm-2 a-1 (CN50), understory addition of N at 25 (UN25) or 50 kg hm-2 a-1 (UN50). AM fungal alpha diversity indices and community composition were determined by high-throughput sequencing. The results showed that under the experimental conditions, AM fungal richness and Shannon diversity indices were not significantly altered by N addition mode, rate or their interactions. However, after one year of experimental treatment, N application mode showed a marginal effect on AM fungal community composition, while N application rate showed an extremely significant effect, and the treatment interaction was also significant. At N addition rate of 25 kg hm-2 a-1, the difference between canopy N addition and control was not significant, while the AM fungal community composition was significantly changed by understory N addition. At N application rate of 50 kg hm-2.a-1, canopy addition of N slightly altered AM fungal community composition, but understory of N application did not change AM fungal community composition. In the next three years, N addition mode, rate or their interactions all showed no significant effects on AM fungal community composition. Overall, the results indicated that understory application of N may overestimate the effect of N deposition on the AM fungal community under natural conditions at certain N application rate and time scale. AM fungal communities under different treatments tend to converge over time, suggesting that AM fungal community may have adapted to N deposition over time. This study evaluated the effects of different N application modes on AM fungal community in forest ecosystem. We could have a more comprehensive understanding of the ecological impacts of N deposition by considering broader N gradients and longer observation period in future research. 参考文献 相似文献 引证文献