AMF Abundance Research Articles

Ridge-furrow planting patterns with film mulching improve water use efficiency by enhancing arbuscular mycorrhizal fungi in the rhizosphere and endophyte of summer maize

In a rainfed agroecosystem with limited water resources, the symbiotic interactions between crop-arbuscular mycorrhizal fungi may have a significant impact on field productivity and water absorption and utilization. However, the interaction between AMF characteristics of root endophyte and rhizosphere soil and water use patterns of summer maize has not been studied under ridge-furrow with film mulching planting patterns (RFPM) in dry farmland. Based on a field experiment, we aimed to reveal the effects of different RFPM planting patterns (i.e., ridge/furrow ratio of 40:70 cm (RF40:70), ridge/furrow ratio of 55:55 cm (RF55:55), and ridge/furrow ratio of 70:40 cm (RF70:40)) on the root water use patterns of summer maize, the distribution characteristics of AMF in root endophyte and rhizosphere soil, and their interaction relationship by using the water isotope (δD and δ18O) tracer technique, the high-throughput sequencing technology, MixSIAR model, and the structural equation models. As a result, compared to flat planting without mulching (FP), RF40:70, RF55:55, and RF70:40 significantly increased grain yield by 29.74%, 35.24%, and 45.53%, and water use efficiency by 23.13%, 35.99%, and 50.25%, across the two growing seasons, respectively (P < 0.05). The root characteristic parameters of summer maize decreased with the increase in soil depth, and were mainly distributed in the shallow layer (0–20 cm) and middle layer (20–60 cm). Compared with FP, the distribution ratio of root surface area density, root length density, and root dry weight density in shallow soil layer was significantly increased by 5.03%, 7.46%, and 9.70% averaging the different RFPM treatments, respectively (P<0.05). Besides, compared to FP, the AMF abundance and diversity in rhizosphere soil and root endogenous averaged RFPM treatments increased by 32.32% and 29.66% and 5.88% and 28.43% respectively, in which the abundance and diversity gradually increased with the increase of the ratio of ridge-furrow. The PLS-PM results found that the larger ridge-furrow ratio could significantly increase the yield and WUE of summer maize mainly by increasing the root surface area density, root length density, and the abundance and diversity of AMF in the root endophyte and rhizosphere soil, which increased the water use of the middle and deep layer soils. In summary, the large ridge-furrow ratio can significantly increase the yield and WUE of summer maize by extending the hyphal network of maize root symbiotic AMF, which increases the water uptake of middle and deep layer soil.

Global arbuscular mycorrhizal fungal diversity and abundance decreases with soil available phosphorus

AbstractAimArbuscular mycorrhizal fungi (AMF) are widely distributed soil organisms that play critical roles in ecosystem functions. However, little is known about their global distribution and the underlying mechanisms. Here, we aimed to explore distribution pattern and key predictors of AMF diversity and abundance at the global scale.LocationGlobal.Time Period1987–2022.Major Taxa StudiedArbuscular mycorrhizal fungi.MethodsWe investigated the distribution pattern and key predictors of AMF diversity and abundance at the global scale by compiling 654 field studies.ResultsWe found that cold climate zones had relatively low AMF diversity. At the ecosystem level, grassland tended to have higher AMF diversity and abundance. Soil available phosphorus (P) and latitude were the most important predictors of AMF diversity. AMF richness and Shannon index decreased with increasing soil available P and latitude. Soil available P and soil pH were the main predictors for global distribution of AMF abundance. AMF colonization rate and spore abundance declined with soil available P and increased with soil pH. Mean annual precipitation was also an important, positive correlate of spore abundance.Main ConclusionsOur findings highlight soil available P as an important predictor affecting the distribution of AMF diversity and abundance, advancing our understanding of the mechanisms underlying the distribution patterns of mycorrhizal fungal diversity and abundance at the global scale.

Exploration and culture of arbuscular mycorrhizal fungi from wild sago

The sago palm (Metroxylon sagu Rottb.) contains significant potential for carbohydrates. When harvested, the plant produces more than 300kg of dry starch per plant. Arbuscular mycorrhizal fungi (AMF, Glomeromycota) are known to often form symbiotic associations with the majority of higher plants, but there are limited studies on their interaction with Sago. Therefore, this study aims to obtain information on the presence of arbuscular mycorrhizal fungi from the rhizosphere of sago palms as well as to prepare pure cultures of the dominant species. Samples were collected from the test plant’s rhizosphere by exploring the West Papua region with a shallow peat area as a base. The soil bulk density in the region was 0.11-0.20 g cm−3 with a low pH (H2O) of 4.1. At the initial stage, a trapping culture was prepared from the rhizosphere soil sample, and a pure culture was then made from the dominant spore using telang (Clitoria ternatea.L) as the host. The observation results of spore morphology revealed that they belonged to Acaulosporaceae, Gigasporaceae, and Glomeraceae. The low abundance and diversity of AMF were caused by abiotic factors, including soil physicochemical properties.

Responses of arbuscular mycorrhizal fungi to rice–upland crop rotations in an 8‐year paddy ecosystem

AbstractArbuscular mycorrhizal fungi (AMF), which can form symbiotic associations with many terrestrial plants, are critical for crop yields and agroecosystem sustainability. In this study, we assessed the influence of rice–upland crop rotations on soil AMF diversity and composition. We also explored the mechanisms of rice (Oryza sativa L.)–upland crop rotations that affect AMF using trait‐based guild methods. We found that rotations of rice with different plants differentially influenced soil AMF. Rice–wheat (Triticum aestivum L.) (RW) and rice–Chinese milk vetch (Astragalus sinicus L.) (RV) rotations significantly altered the soil AMF composition, with RW and RV significantly increasing and decreasing AMF diversity, respectively, compared with the rice–fallow treatment. In addition, RW and RV affected AMF abundance in intra‐ and extra‐radical portions in different ways. For example, both the RW and RV treatments increased AMF spore density, but decreased AMF colonization rate. Different AMF guilds showed different responses to rice–upland crop rotations. The RW treatment increased the rhizophilic guild by 4.9% and decreased the edaphophilic guild by 27.9%, whereas the RV treatment produced opposite trends. Thus, rice–upland crop rotations changed soil AMF diversity, AMF composition, and trait‐based guilds in different ways, and rice yield was mainly correlated with AMF colonization rate.

Amendment with Burkina Faso phosphate rock-enriched composts alters soil chemical properties and microbial structure, and enhances sorghum agronomic performance

Low soil available phosphorus (P) severely limits crop production in sub-Saharan Africa. The present study evaluated phosphate rock-enriched composts as locally available low-cost fertilizers for sorghum production. The treatments consisted of sorghum straw, compost (COMP), phosphate rock (BPR), BPR-enriched compost (P-COMP), BPR-rhizosphere soil-enriched compost (P-COMP-SOIL), nitrogen-phosphorus-potassium treatment (NPK, 60–39–25), and control (NK, 60–25). Sorghum straw and compost were applied at 1.34 tons ha−1. N, P, and K in all treatments, excluding the control, were adjusted to 60, 39, and 25 kg ha−1, with urea, BPR, and KCl, respectively. Sorghum vr. kapelga was cultivated and soil samples were collected at the S5, S8, and S9 growth stages. P-COMP-SOIL and NPK yielded better sorghum yields than the other treatments. The rhizosphere soil of P-COMP-SOIL had high abundance of soil bacteria and AMF, and genes involved in P solubilization, such as: acid phosphatase (aphA), phosphonatase (phnX), glucose dehydrogenase (gcd), pyrroloquinoline quinone (pqqE), phosphate-specific transporter (pstS). The superior performance of the P-COMP-SOIL was associated with its higher available P content and microbial abundance. Multivariate analysis also revealed vital contributions of N, carbon, and exchangeable cations to sorghum growth. Soils could be amended with phosphate rock-rhizosphere soil-enriched composts, as an alternative to chemical fertilizers.

Soil Microbiomes in Apple Orchards Are Influenced by the Type of Agricultural Management but Never Match the Complexity and Connectivity of a Semi-natural Benchmark.

Conversion of natural ecosystems into agricultural land may strongly affect the soil microbiome and the functioning of the soil ecosystem. Alternative farming systems, such as organic farming, have therefore been advocated to reduce this impact, yet the outcomes of different agricultural management regimes often remain ambiguous and their evaluations mostly lack a proper more natural benchmark. We used high-throughput amplicon sequencing, linear models, redundancy analyses, and co-occurrence network analyses to investigate the effect of organic and integrated pest management (IPM) on soil fungal and bacterial communities in both the crop and drive rows of apple orchards in Belgium, and we included semi-natural grasslands as a benchmark. Fungi were strongly influenced by agricultural management, with lower diversity indices and distinct communities in IPM compared to organic orchards, whereas IPM orchards had a higher AMF abundance and the most complex and connected fungal communities. Bacterial diversity indices, community composition, and functional groups were less affected by management, with only a higher network connectivity and abundance of keystone taxa in organic drive rows. On the other hand, none of the agricultural soil microbiomes matched the complexity and connectedness of our semi-natural benchmark, demonstrating that even more nature-friendly agricultural management practices strongly affect the soil microbiome and highlighting the essential role of (semi-)natural systems as a harbor of robust and functionally diverse fungal and bacterial communities.

Global negative effects of nutrient enrichment on arbuscular mycorrhizal fungi, plant diversity and ecosystem multifunctionality.

Despite widespread anthropogenic nutrient enrichment, it remains unclear how nutrient enrichment influences plant-arbuscular mycorrhizal fungi (AMF) symbiosis and ecosystem multifunctionality at the global scale. Here, we conducted a meta-analysis to examine the worldwide effects of nutrient enrichment on AMF and plant diversity and ecosystem multifunctionality using data of field experiments from 136 papers. Our analyses showed that nutrient addition simultaneously decreased AMF diversity and abundance belowground and plant diversity aboveground at the global scale. The decreases in AMF diversity and abundance associated with nutrient addition were more pronounced with increasing experimental duration, mean annual temperature (MAT) and mean annual precipitation (MAP). Nutrient addition-induced changes in soil pH and available phosphorus (P) predominantly regulated the responses of AMF diversity and abundance. Furthermore, AMF diversity correlated with ecosystem multifunctionality under nutrient addition worldwide. Our findings identify the negative effects of nutrient enrichment on AMF and plant diversity and suggest that AMF diversity is closely linked with ecosystem function. This study offers an important advancement in our understanding of plant-AMF interactions and their likely responses to ongoing global change.

Comparison of Arbuscular Mycorrhizal Spores Abundance Under Sengon (Falcataria moluccana (Miq.) Barneby &amp; Grimes) Planted on Deep Peat and Mineral Soils

Mycorrhizae are known as soil fungi because of their habitat in the rooting area (rhizosphere). Nearly 97% of terrestrial plant species interact or symbiotic with mycorrhizae. Symbiosis is formed in the form of an exchange between nutrients and carbohydrates and helps plants absorb P. elements. In Kalimantan, sengon often used as industrial material because it is fast-growing species and widely cultivated by the community. Sengon is a common species planted in mineral soils; however, due to the rising demand of sengon timber, it has been planted on peatlands. This study aims to compare the abundance of arbuscular mycorrhizal spores and identify the morphology of arbuscular mycorrhizal spores associated with Sengon planted on peatlands and mineral soils. This study used a wet sieving method and root staining from the modification of Vierherling et al. 1996 and calculation of root mycorrhizal colonization with gridline techniques. The research used the normality test of data distribution and the T test (Independent sample T test) to determine trends and comparison of differences in the abundance of FMA spores. The study results showed a significant difference in the abundance of AMF in the form of colonization by calculating the percentage of AMF colonization in the sengon root in mineral soils and peatlands of 23.56% 41.67%, respectively. The spore density on mineral soils and peatlands were 18.05 / 50gr and 1.09 / 50gr, respectively. Identification results showed that there were four genera found in peat soil locations, namely the genus Glomus, Gigaspora, Scutellospora, and Acaulospora, while in the mineral soil were found three generas namely genus Glomus, Scutellospora, and Acaulospora. Out of the four generas, the most abundant in both soil types was Glomus.

The Abundance of Arbuscular Mycorrhiza Infective Propagules Under Galam Stand at Shallow Peat of South Kalimantan

Colonization of arbuscular mycorrhiza on plants has been reported to give benefit to p lants, especially at extreme sites such as degraded peatland. Galam (Mela leuca ca juputi) is an indigenous peatland species which grows on acidic condition. The number of arbuscular mycorrhiza infective propagules is important to be determined concerning the galam regeneration due to its offered benefits that support colonization. This research aims to determine the abundance of arbuscular mycorrhiza infective propagules under galam stand and to describe symbiotic forms of AMF colonization on the roots of galam. The Most Probable Number (MPN) method, wet sieving, and root staining from the modification of Vierherlig et al., 1996, and the calculation of root’s mycorrhizal colonization by grid line technique were the methods that were used in this research. The research used Complete Randomized Design (CRD) with a 5-fold factorial pattern. The results of this study indicated a significant difference between the abundance of AMF under galam stands at the depth of 0-15 cm and 15-30 cm respectively . The results of spores identification showed 4 genera of spores, namely: Glomus, Gigaspora, Scutellospora, and Acaulospora. The structure of root colonizations were hyphae, spores, vesicles, and arbuscular.

Effects of nitrogen addition on DOM-induced soil priming effects in a subtropical plantation forest and a natural forest

Dissolved organic matter (DOM) plays a key role in soil organic matter (SOM) decomposition via the priming effect (PE). The DOM-induced soil PE is closely related to nutrient availability, especially nitrogen (N). Regardless of the widespread of chronic N addition, how elevated N deposition affects DOM-induced PEs remains poorly understood. To fill this knowledge gap, we studied the effects of N addition, 13C-labeled leaf-DOM (herein DOM) addition, and leaf-DOM plus N addition (DOM+N) on soil PEs in soils of a subtropical Chinese-fir (Cunninghamia lanceolata) plantation and a natural Castanopsis carlesii forest (hereafter referred to as Chinese-fir soil and Castanopsis soil, respectively). Soil properties (e.g., soil organic C, total N, available phosphorus, and ratio of C and N), dissolved organic C (DOC), soil microbial biomass C (MBC), phospholipid fatty acid (PLFA), and enzyme activities were also investigated, because these parameters predominantly affect the intensity and direction of soil priming. The addition of DOM induced positive PEs in the Castanopsis soil but negative PEs in the Chinese-fir soil. In addition, DOM addition increased MBC and fungal abundance and the activities of phenol oxidase (PhOx) and peroxidase (Perox) in the Castanopsis soil but not in the Chinese-fir soil. Compared with DOM-only addition, DOM+N addition significantly enhanced PEs in the Chinese-fir soil but not in the Castanopsis soil. Furthermore, compared with DOM-only addition, DOM+N addition significantly increased MBC, abundance of fungi and AMF, fungi to bacteria ratio (F:B), and activities of four enzymes [β-glucosidase (βG), N-acetyl glucosaminidase (NAG), PhOx, and Perox] in the Chinese-fir soil but not in the Castanopsis soil. The DOM+N addition also had a significant effect on composition of main microbial groups in the Chinese-fir soil but not in the Castanopsis soil. These results suggest the enhanced PE following DOM+N in the Chinese-fir soil was likely mediated by enhanced enzyme production associated with increased fungal abundance. Our study highlights that the effects of increases of DOM on soil C cycling is largely affected by N availability and mediated by the effects on the abundance of soil microbial groups and enzyme activities. Our result also demonstrated a case in which effects of DOM and N addition on soil C cycling differ between a Castanopsis forest and a Chinese-fir plantation forest, with Chinese-fir soil being more sensitive to N addition. This is an important finding that needs to be taken into consideration in estimating the soil C pools.

Soil microbial community and activity in a tropical integrated crop-livestock system

Soil carbon (C) sequestration has been considered as a tool for mitigating increased atmospheric CO2. The soil C sink can be increased by the use of no-tillage, cover crops, crop rotations, and integrated crop-livestock systems (ICLS). ICLS is a strategy that replaces degraded pastures with silvopastoral systems to mitigate land degradation, but effects on soil biology are unknown. The objective of this study was to investigate the effect of Eucalyptus integrated with palisade grass on the soil microbial community and activity in the tropics. The study was conducted on an 8-year-old ICLS where two species of Eucalyptus (E. grancam and E. urograndis) were introduced into palisade grass [Urochloa brizantha (Hochst. Ex A. Rich.) R. Webster ‘Marandu’]. Four sampling locations were collected at 0 (planting line), 2, 4, and 6 m (middle of the plots) from the Eucalyptus tree. A monoculture palisade grass pasture and a native savanna (Cerrado) were included for comparison. Soil water content was lower closer to the Eucalyptus plantation line. The introduction of Eucalyptus into the system resulted in C and nitrogen (N) stocks in the Eucalyptus line similar to the Cerrado and the monoculture pasture, supporting the potential of ICLS and the monoculture pasture to recover soil C and N stocks. Soil microbial community composition and enzymatic activity (β–glucosidase, acid phosphatase, and N–acetyl glucosidase) were reduced near Eucalyptus but increased in the pasture component of the ICLS likely due to improved soil water conditions. Soil microbial biomass, actinomycete, gram-positive bacteria, AMF, and fungi abundance were significantly higher in the native Cerrado than in the monoculture pasture and ICLS. Soil water, aggregate size, soil enzymes, and microbial communities were not dependent on the types of Eucalyptus species introduced into the system.

Responses of arbuscular mycorrhizal fungi to multiple coinciding global change drivers

Abstract A significant challenge for understanding how fungal communities may change in the Anthropocene are the multiple aspects of simultaneous environmental change. To address this challenge, we used a seven-year multi-factorial field experiment in southern California to examine how root-associated fungi respond to aridity, nitrogen deposition, and plant invasions. We hypothesized that all three global change drivers reduce the abundance of arbuscular mycorrhizal fungi responsible for nutrient uptake (edaphophilic AMF), while increasing the abundance of AMF that colonize roots at high rates (rhizophilic AMF). We found that invasive grasses hosted lower abundances of edaphophilic AMF, and higher abundances of rhizophilic AMF and opportunistically parasitic fungi. Aridity reduced overall AMF abundance while N addition altered the allocation of AMF biomass, increasing root colonization while reducing the density of extraradical hyphae. Overall, these results imply that ongoing global change will alter both the composition of AMF and how these fungi interact with plants.

Effects of environmental and temporal factors on Glomeromycotina spores in sand dunes along the Gulf of Valencia (Spain)

Abstract AMF symbiosis in sand dunes is the key for maintenance of stable vegetation. The main goal of this work was to determine the effects of environmental and temporal factors on AMF living in sand dunes (Gulf of Valencia, Spain). Soil samples were collected seasonally at 6 sites, during 2 yrs, from three habitats and four plant species and the frequency and relative abundance of AMF was examined. AMF were more frequent in mobile than in embryonic dunes, in spring and in sites with old vegetation. Ten AMF species were identified, their distribution depending mainly on the anthropogenic disturbance of the site. Gigasporaceae Cetraspora sp. and Dentiscutata sp. preferred undisturbed soil whereas Diversisporaceae, Glomeraceae and other Gigasporaceae were associated with recently restored soils. All AMF species were found in all plant species although Corymbiglomus corymbiforme was mainly associated with Echinophora spinosa. Our results might be of help for Mediterranean sand dune restoration.

Determinants of native and non‐native plant community structure on an oceanic island

AbstractUnderstanding the relative importance of environmental and anthropogenic factors in driving plant community structure, including relative dominance of native and non‐native species, helps predict community responses to biological invasions. To assess factors influencing plant communities on San Clemente Island, USA, we conducted an islandwide vegetation survey in which we measured plant species richness and percent cover of native and non‐native plants, as well as physical environmental variables, soil chemical properties, abundance of soil microbial functional groups (e.g., arbuscular mycorrhizal fungi [AMF]), and a human disturbance variable (distance to road). We found that total plant species richness decreased with increasing non‐native plant cover, soil pH, and AMF abundance. Native plant cover increased with increasing distance to a major paved road and decreased with increasing soil moisture and pH. Non‐native plant cover decreased with increasing distance to a major paved road and increased with increasing soil moisture, AMF abundance, and from southwest to northeast, a geographic/climatic gradient that represents increasing moisture. Nonmetric multidimensional scaling ordination further illustrated that trends in plant community composition were correlated with elevation, distance to a major paved road, and soil moisture, organic matter, and ammonium. These results suggest complex effects of physical environmental, soil chemical, and human‐related factors on plant community structure on an oceanic island, and moreover, that different factors affect cover of native and non‐native plants. Notably, our observation of apparent moisture limitation of non‐native plants suggests that, in some contexts, drought conditions can limit plant invasions and may even represent an opportunity for efficient control or eradication of invasive plants. The apparent negative effect of non‐native plants on native plant cover and overall plant species richness represents a conservation concern for native biodiversity on oceanic islands and suggests the potential for community reassembly as invasive species increasingly dominate due to anthropogenic disturbances.

The interaction between arbuscular mycorrhizal fungi and soil phosphorus availability influences plant community productivity and ecosystem stability

Summary Arbuscular mycorrhizal fungi (AMF) can influence plant community composition and diversity. Previous research has shown that the addition of nutrients reduces the effectiveness of AMF. However, the ways in which soil nutrient availability and AMF interact and affect plant community productivity and ecosystem stability are still poorly understood. We examined the impact of AMF suppression and phosphorus (P) addition on plant diversity, community productivity and temporal stability (TS) in a field experiment. AMF root colonization and the concentration of an AMF‐specific phospholipid fatty acid were significantly reduced after application of the fungicide benomyl as a soil drench. The TS of the plant community was higher in communities without benomyl application compared with communities with benomyl application indicating that AMF contribute to the TS of plant communities. AMF suppression increased productivity at the plant species, functional group and community levels under high P addition rates. At the zero P addition rate, AMF did not affect plant community productivity, as the dominant species Artemisia frigida was more abundant in control plots with AMF, while the subdominant species Stipa krylovii was more abundant in the benomyl‐treated plots with reduced AMF abundance. Compensatory effects between C3 grasses and non‐N2‐fixing forbs were observed in the control plots with AMF along the gradient of P addition rates, but these effects were not detected among plant species in the benomyl‐treated plots under AMF suppression above an addition rate of 4.76 P2O5 m−2 year−1. Although AMF suppression did not influence the diversity of the plant communities, it did decrease the diversity of N2‐fixing forbs at the zero P addition rate and above an addition rate of 18.90 g P2O5 m−2 year−1, indicating that AMF play key roles in the maintenance of N2‐fixing forbs at these P addition rates. P addition led to biodiversity losses at application rates below 2.36 g P2O5 m−2 year−1 at the community level. Synthesis. Arbuscular mycorrhizal fungi and soil P availability interact to influence the productivity and TS of a plant community by mediating compensatory effects among plant species and functional groups.

Arbuscular mycorrhizal fungi (Glomales, Zygomycota) of the Bledowska Desert, Poland

The occurrence of arbuscular mycorrhizal fungi (AMF; &lt;em&gt;Glomales&lt;/em&gt;, &lt;em&gt;Zygomycetes&lt;/em&gt;) associated with plants growing in sand dune soils of the Blędowska Desert, Poland, was investigated in 1995-1997. A total of 134 mixtures of soils and roots were sampled. The mixtures represented 26 plant species in 14 families and one unrecognized plant. Spores of AMF were found in 118 soil-root mixtures. The AMF spore populations comprised 20 described species of the genera &lt;em&gt;Acaulospora&lt;/em&gt;, &lt;em&gt;Gigaspora&lt;/em&gt;, &lt;em&gt;Glomus&lt;/em&gt; and &lt;em&gt;Scutellospora&lt;/em&gt;, as well as two undescribed morphospecies of the genus &lt;em&gt;Glomus&lt;/em&gt;. The AMF most frequently occurring in the field-collected soils were members of the genus &lt;em&gt;Scutellospora&lt;/em&gt; The AMF spore populations comprised 20 described species in the genera &lt;em&gt;Acaulospora&lt;/em&gt;, &lt;em&gt;Gigaspora&lt;/em&gt;, &lt;em&gt;Glomus&lt;/em&gt; and &lt;em&gt;Scutellospora&lt;/em&gt;, as well as two undescribed morpho-species of the genus &lt;em&gt;Glomus&lt;/em&gt;. The fungal species most frequently and numerously found was &lt;em&gt;Scutellospora armeniaca&lt;/em&gt;. The fungi relatively frequently present also were &lt;em&gt;A. rugosa&lt;/em&gt;, &lt;em&gt;A. lacunosa&lt;/em&gt;, &lt;em&gt;G. aggregatum&lt;/em&gt;, an undescribed &lt;em&gt;Glomus&lt;/em&gt; 142 and &lt;em&gt;Sc. dipurpurescens&lt;/em&gt;. The overall spore abundance of AMF averaged 69.1 and ranged from 0 to 837 in 100 g dry soil. The highest abundance of spores occurred among roots of the families &lt;em&gt;Cupressaceae&lt;/em&gt;, followed by the &lt;em&gt;Rosaceae&lt;/em&gt;, &lt;em&gt;Asteraceae&lt;/em&gt; and &lt;em&gt;Poaceae&lt;/em&gt;. Of the plant species investigated two and more times, most spores harboured &lt;em&gt;Juniperus communis&lt;/em&gt;. The overall average species richness was 2.4 and ranged from 0 to 6 in 100 g dry soil. Of the plant species sampled at lest two times, the highest average species diversity was found in the root zone of &lt;em&gt;Salix arenaria&lt;/em&gt;. The plant species that hosted the highest overall number of species of AMF was &lt;em&gt;Festuca rubra&lt;/em&gt;. Trap pot cultures with soilroot mixtures collected in 1997 revealed 10 species of AMF that were not found in field soils sampled in the same year. This suggests that a great part of AMF of Błędowska Desert is represented by rarely or non-sporulating species.

Taxonomic diversity and community structure of arbuscular mycorrhizal fungi (Phylum Glomeromycota) in three maritime sand dunes in Santa Catarina state, south Brazil

Community structure and species richness of arbuscular mycorrhizal fungi (Phylum Glomeromycota) were studied in sand dune sites at Itapiruba (southern), Joaquina (intermediate) and Praia Grande (northern) beaches along the coast of the state of Santa Catarina, Brazil. In each site, a 20 × 20 m plot was established and 20 soil samples collected in a regular grid pattern. Fungal spores were extracted from each sample, counted and identified to species level. A total of 25 species were recovered belonging to seven genera and five families in the Glomeromycota. Gigaspora albida and Acaulospora scrobiculata occurred in >50 % of samples at all three sites. Other common species whose sample frequency was >50 % in one or two sites were Scutellospora weresubiae , Scutellospora cerradensis and Racocetra gregaria , while the remaining majority of species were detected in <25 % of samples within a given site. Dune sites could be differentiated based on the higher frequency of occurrence of S. cerradensis and Acaulospora morrowiae in Itapiruba, S. weresubiae in Joaquina, and Scutellospora hawaiiensis in Praia Grande. No differences across sites were observed for species richness and total spore numbers, the latter averaging from 28.8 to 31.8 spores per 100 ml soil. Shannon diversity was significantly higher in Praia Grande compared to the other two sites. Differences in the relative spore abundance of genera among dunes were detected only for Scutellospora , which was significantly more abundant in the Joaquina beach. Community structure, as depicted by species rank/log abundance graphs, was not significantly different between areas according to the Kolmogorov–Smirnov two-sample test. Species accumulation curves demonstrated that 13 samples were enough to detect 90 % of all species. Overall, sand dune systems share similar arbuscular mycorrhizal fungal communities despite being geographically distant (150 km) from each other. ► Diversity of AMF in sand dunes is high. ► Community structure is similar among sand dunes. ► Diversity and abundance of AMF did not vary among dunes.

Provision of contrasting ecosystem services by soil communities from different agricultural fields

Several studies have shown that soil biotic communities from organically managed fields are more diverse and exhibit higher activity levels compared to conventionally managed fields. The impact of these different soil communities on plant productivity and the provision of soil ecosystem services are, however, still unclear. Here, we test the effects of soil inoculation from each of three organic and three conventional maize fields on maize productivity and nutrient loss during leaching events induced by simulated rain. In particular, we examine whether differences in productivity and nutrient loss are related to the abundance and species composition of arbuscular mycorrhizal (AM) fungi. We hypothesized that soil biota from organically managed fields would improve maize growth and reduce nutrient leaching significantly more than those from conventionally managed fields. In contrast to our hypothesis, we found that plant productivity was negatively affected by soil inoculation, and this effect was stronger with inoculum from organic fields. Plant productivity was inversely correlated with AMF abundance, suggesting that enhanced carbon allocation to AMF is at least in part responsible for plant growth reduction under our experimental conditions. However, soil inoculation did alter the ecological functioning of the system by reducing phosphorus leaching losses after simulated rain. Moreover, these leaching losses were lower with increased hyphal density and were related with abundance of particular AMF types, suggesting that abundance of AMF and their community composition may be useful indicators of phosphorus leaching losses. The results demonstrate that soil communities from different agricultural fields vary in their impact on plant productivity and nutrient leaching losses. The results further indicate that there is a potential tradeoff between positive effects of soil communities on sustainability and negative effects on crop productivity.

Intra- and Interspecific Variation in Mycorrhizal Associations across a Heterogeneous Habitat Gradient in Alpine Plant Communities

Spatial and temporal variation in mycorrhizal associations may significantly impact plant community dynamics. In this study we evaluated the distribution and abundance of mycorrhizal associations in alpine plant communities to gain a better understanding of the potential effects of microhabitat and host identity on plant-fungus mutualisms. We surveyed the abundance of ectomycorrhizae (ECM) associated with Salix sp. and the abundance of arbuscular mycorrhizae (AMF) associated with Taraxacum ceratophorum, T. officinale, Polemonium viscosum, and P. delicatum in plots under willow canopies and in adjacent open meadows. AMF colonization of T. ceratophorum, T. officinale, and P. viscosum was greater in open meadow than in understory habitats. Conversely, ECM abundance was greater in the willow understory than in the surrounding open meadow. AMF abundance in three of the four host species was negatively correlated with ECM abundance in the soil microsite. Taraxacum ceratophorum showed consistently high colonization by AMF regardless of habitat or ECM abundance. Our results suggest that willow-mediated heterogeneity in light and nutrient availability influence the distribution of AMF associations across the willow-meadow ecotone. Furthermore, species-specific plant life history traits related to growth strategies, carbon allocation patterns, and stress tolerance likely affect mycorrhizal dependence and interspecific variation in mycorrhizal associations.

Plant and arbuscular mycorrhizal fungal diversity – are we looking at the relevant levels of diversity and are we using the right techniques?

Plant and arbuscular mycorrhizal fungal diversity – are we looking at the relevant levels of diversity and are we using the right techniques?