Impact of arbuscular mycorrhizal fungi and earthworms on soil aggregate stability, glomalin, and performance of pigeonpea, Cajanus cajan

Soil Research ◽  
2019 ◽  
Vol 57 (1) ◽  
pp. 53 ◽  
Author(s):  
Mary N. Muchane ◽  
Mirjam M. Pulleman ◽  
Bernard Vanlauwe ◽  
Joyce Jefwa ◽  
Thomas W. Kuyper

Earthworms and arbuscular mycorrhizal fungi (AMF) modify soil physical and chemical properties. However, little is known about how their interactions affect water-stable aggregation, glomalin and crop performance. A greenhouse experiment was run for 9 months to test the effects of earthworms (endogeic, Pontoscolex corethrurus; and epigeic, Dichogaster bolaui) and AMF (none, Glomus etunicatum and Scutellospora verrucosa) on water-stable aggregation, glomalin levels in aggregate size classes and crop performance. The test crop was pigeonpea (Cajanus cajan (L.) Millsp.). The soil material used for the experiment was a humic nitisol from central Kenya mixed with sand (ratio 1:1). Grass residue (equivalent to 20tha–1) was placed on top. The AMF root colonisation and external hyphal length, water-stable macroaggregates and microaggregates, total and easily-extractable glomalin in aggregate size classes, plant biomass and plant N and P uptake were measured. Earthworms were a major source of variation for soil aggregation, glomalin content and crop performance. The epigeic earthworms (D. bolaui) increased the amount of water-stable macroaggregates (by 10%) and glomalin in microaggregates and improved crop (growth and biomass) performance. The endogeic earthworms (P. corethrurus) reduced external hyphal length, root colonisation and crop performance but had no effect on water-stable aggregates and glomalin levels in in aggregate size classes. A significant AMF×earthworm interaction was observed for plant biomass and concentrations of nitrogen (N) and phosphorus (P). The AMF species together with epigeic earthworms increased plant biomass and N and P concentrations. Our results contribute to the understanding of interactions between AMF and earthworms in relation to soil aggregation, plant productivity and nutrient uptake.

2021 ◽  
Author(s):  
Jacinta Gahan ◽  
Achim Schmalenberger

Sulfur (S) exists in organically bound complexes (~95%), predominantly as sulfonates, and are not directly plant available. Specific soil bacteria can mobilise sulfonates but very little is known about these bacteria in the hyphosphere. Since mycorrhizal fungi support growth of the majority of land plants, hyphosphere desulfonating bacteria may be of substantial benefit to the plant host. This study analysed the effect of AM inoculation with Rhizophagus irregularis (former G. intraradices, Glomus) and a mix of six AM species (Mixed) on PGP, microbial communities and sulfonate mobilising bacteria with L. perenne, Agrostis stolonifera and Plantago lanceolata as plant hosts in bi-compartmental microcosms and A. stolonifera in PGP pot experiments. AM inoculation significantly increased plant growth, percentage root colonisation and the quantity of cultivable desulfonating bacteria in the hyphosphere over pre-inoculated soil for all plants. Community analysis via PCR-DGGE revealed significantly different bacterial and fungal communities post inoculation. Analysis of the sulfonate mobilising asfA gene revealed a significantly altered community and novel bacterial isolates with this important functional ability post-inoculation. The results demonstrate that AM inoculation increased plant biomass yield, AM root colonisation and altered bacterial and fungal community dynamics in the hyphosphere. AM inoculated microcosms had an increased abundance of desulfonating bacteria that may be beneficial for plant-S supply.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mohamed S. Sheteiwy ◽  
Dina Fathi Ismail Ali ◽  
You-Cai Xiong ◽  
Marian Brestic ◽  
Milan Skalicky ◽  
...  

Abstract Background The present study aims to study the effects of biofertilizers potential of Arbuscular Mycorrhizal Fungi (AMF) and Bradyrhizobium japonicum (B. japonicum) strains on yield and growth of drought stressed soybean (Giza 111) plants at early pod stage (50 days from sowing, R3) and seed development stage (90 days from sowing, R5). Results Highest plant biomass, leaf chlorophyll content, nodulation, and grain yield were observed in the unstressed plants as compared with water stressed-plants at R3 and R5 stages. At soil rhizosphere level, AMF and B. japonicum treatments improved bacterial counts and the activities of the enzymes (dehydrogenase and phosphatase) under well-watered and drought stress conditions. Irrespective of the drought effects, AMF and B. japonicum treatments improved the growth and yield of soybean under both drought (restrained irrigation) and adequately-watered conditions as compared with untreated plants. The current study revealed that AMF and B. japonicum improved catalase (CAT) and peroxidase (POD) in the seeds, and a reverse trend was observed in case of malonaldehyde (MDA) and proline under drought stress. The relative expression of the CAT and POD genes was up-regulated by the application of biofertilizers treatments under drought stress condition. Interestingly a reverse trend was observed in the case of the relative expression of the genes involved in the proline metabolism such as P5CS, P5CR, PDH, and P5CDH under the same conditions. The present study suggests that biofertilizers diminished the inhibitory effect of drought stress on cell development and resulted in a shorter time for DNA accumulation and the cycle of cell division. There were notable changes in the activities of enzymes involved in the secondary metabolism and expression levels of GmSPS1, GmSuSy, and GmC-INV in the plants treated with biofertilizers and exposed to the drought stress at both R3 and R5 stages. These changes in the activities of secondary metabolism and their transcriptional levels caused by biofertilizers may contribute to increasing soybean tolerance to drought stress. Conclusions The results of this study suggest that application of biofertilizers to soybean plants is a promising approach to alleviate drought stress effects on growth performance of soybean plants. The integrated application of biofertilizers may help to obtain improved resilience of the agro ecosystems to adverse impacts of climate change and help to improve soil fertility and plant growth under drought stress.


Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 370
Author(s):  
Murugesan Chandrasekaran

Arbuscular mycorrhizal fungi (AMF) are obligate symbionts of higher plants which increase the growth and nutrient uptake of host plants. The primary objective was initiated based on analyzing the enormity of optimal effects upon AMF inoculation in a comparative bias between mycorrhizal and non-mycorrhizal plants stipulated on plant biomass and nutrient uptake. Consequently, in accomplishing the above-mentioned objective a vast literature was collected, analyzed, and evaluated to establish a weighted meta-analysis irrespective of AMF species, plant species, family and functional group, and experimental conditions in the context of beneficial effects of AMF. I found a significant increase in the shoot, root, and total biomass by 36.3%, 28.5%, and, 29.7%, respectively. Moreover, mycorrhizal plants significantly increased phosphorus, nitrogen, and potassium uptake by 36.3%, 22.1%, and 18.5%, respectively. Affirmatively upon cross-verification studies, plant growth parameters intensification was accredited to AMF (Rhizophagus fasciculatus followed by Funniliforme mosseae), plants (Triticum aestivum followed by Solanum lycopersicum), and plant functional groups (dicot, herbs, and perennial) were the additional vital important significant predictor variables of plant growth responses. Therefore, the meta-analysis concluded that the emancipated prominent root characteristics, increased morphological traits that eventually help the host plants for efficient phosphorus uptake, thereby enhancing plant biomass. The present analysis can be rationalized for any plant stress and assessment of any microbial agent that contributes to plant growth promotion.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Peng Wang ◽  
Yin Wang

Morphological observation of arbuscular mycorrhizal fungi (AMF) species in rhizospheric soil could not accurately reflect the actual AMF colonizing status in roots, while molecular identification of indigenous AMF colonizing citrus rootstocks at present was rare in China. In our study, community of AMF colonizing trifoliate orange (Poncirus trifoliataL. Raf.) and red tangerine (Citrus reticulataBlanco) were analyzed based on small subunit of ribosomal DNA genes. Morphological observation showed that arbuscular mycorrhizal (AM) colonization, spore density, and hyphal length did not differ significantly between two rootstocks. Phylogenetic analysis showed that 173 screened AMF sequences clustered in at least 10 discrete groups (GLO1~GLO10), all belonging to the genus ofGlomusSensu Lato. Among them, GLO1 clade (clustering with uncultured Glomus) accounting for 54.43% clones was the most common in trifoliate orange roots, while GLO6 clade (clustering withGlomus intraradices) accounting for 35.00% clones was the most common in red tangerine roots. Although, Shannon-Wiener indices exhibited no notable differences between both rootstocks, relative proportions of observed clades analysis revealed that composition of AMF communities colonizing two rootstocks varied severely. The results indicated that native AMF species in citrus rhizosphere had diverse colonization potential between two different rootstocks in the present orchards.


2018 ◽  
Vol 156 (1) ◽  
pp. 46-58 ◽  
Author(s):  
Caixia Liu ◽  
Sabine Ravnskov ◽  
Fulai Liu ◽  
Gitte H. Rubæk ◽  
Mathias N. Andersen

AbstractDeficit irrigation (DI) improves water use efficiency (WUE), but the reduced water input often limits plant growth and nutrient uptake. The current study examined whether arbuscular mycorrhizal fungi (AMF) could alleviate abiotic stress caused by low phosphorus (P) fertilization and DI.A greenhouse experiment was conducted with potato grown with (P1) or without (P0) P fertilization, with AMF (M1+:Rhizophagus irregularisor M2+:Glomus proliferum) or AMF-free control (M−) and subjected to full irrigation (FI), DI or partial root-zone drying (PRD).Inoculation of M1+ and M2+ maintained or improved plant growth and P/nitrogen (N) uptake when subjected to DI/PRD and P0. However, the positive responses to AMF varied with P level and irrigation regime. Functional differences were found in ability of AMF species alleviating plant stress. The largest positive plant biomass response to M1+ and M2+ was found under FI, both at P1 and P0 (25% increase), while plant biomass response to M1+ and M2+ under DI/PRD (14% increase) was significantly smaller. The large growth response to AMF inoculation, particularly under FI, may relate to greater photosynthetic capacity and leaf area, probably caused by stimulation of plant P/N uptake and carbon partitioning toward roots and tubers. However, plant growth response to AMF was not related to the percentage of AMF root colonization. Arbuscular mycorrhizal fungi can maintain and improve P/N uptake, WUE and growth of plants both at high/low P levels and under FI/DI. If this is also the case under field conditions, it should be implemented for sustainable potato production.


2019 ◽  
Vol 69 (13) ◽  
pp. 1309-1327 ◽  
Author(s):  
Catarina Drumonde Melo ◽  
Christopher Walker ◽  
Claudia Krüger ◽  
Paulo A.V. Borges ◽  
Sara Luna ◽  
...  

Abstract Purpose Arbuscular mycorrhizal fungi (AMF) play important key roles in the soil ecosystems as they link plants to the root-inaccessible part of soil. The aims of this study were to investigate which environmental factors influence the spatial and temporal structuring of AMF communities associated to Picconia azorica in two Azorean islands (Terceira and São Miguel islands), and investigate the seasonal variation in AMF communities between the two islands. Methods Communities of AMF associated with P. azorica in native forest of two Azorean islands (Terceira and São Miguel) were characterised by spore morphology or molecular analysis. Results Forty-five AMF spore morphotypes were detected from the four fragments of P. azorica forest representing nine families of AMF. Acaulosporaceae (14) and Glomeraceae (9) were the most abundant families. AMF density and root colonisation varied significantly between islands and sampling sites. Root colonisation and spore density exhibited temporal patterns, which peaked in spring and were higher in Terceira than in São Miguel. The relative contribution of environmental factors showed that factors such as elevation, relative air humidity, soil pH, and soil available P, K, and Mg influenced AMF spore production and root colonisation. Conclusion Different sporulation patterns exhibited by the members of the commonest families suggested different life strategies. Adaptation to a particular climatic and soil condition and host phenology may explain seasonal differences in sporulation patterns. Cohorts of AMF associated to P. azorica are shaped by regional processes including environmental filters such as soil properties and natural disturbance.


2011 ◽  
Vol 57 (No. 11) ◽  
pp. 499-504 ◽  
Author(s):  
J.G. Zaller ◽  
F. Saccani ◽  
T. Frank

  Both earthworms and symbiotic arbuscular mycorrhizal fungi (AMF) often co-occurr in ecosystems, however very little is known on their interrelationships. Here we tested to what extent earthworms (Annelida) or AMF (Glomales) separately or in combination affect the growth of the pharmaceutical plant species, pot marigold (Calendula officinalis, Asteraceae). We conducted a greenhouse experiment using non-sterilized field soil where we manipulated the factors earthworms (addition/no addition of the vertical burrowing species Lumbricus terrestris) and AMF (addition/no addition of a mix of the four Glomus taxa G. geosporum, G. mosseae, G. intraradices, G. claroideum). Leaf length and flower stem length was significantly increased by earthworms but remained unaffected by additional AMF. The longest leaves and flower stems were observed in pots containing earthworms but no additional AMF. The number of flower buds was unaffected by earthworms but marginally significantly increased by AMF. Plant shoot biomass production was significantly higher when earthworms were present; AMF inoculation had no effect on biomass production. Root biomass production and total plant biomass production remained unaffected by earthworms or AMF. These results indicate that in soil already containing AMF earthworm addition primarily affects vegetative growth while additional AMF inoculation tended to affect reproductive plant parts.


2007 ◽  
Vol 5 (24) ◽  
pp. 773-784 ◽  
Author(s):  
A Schnepf ◽  
T Roose ◽  
P Schweiger

In order to quantify the contribution of arbuscular mycorrhizal (AM) fungi to plant phosphorus nutrition, the development and extent of the external fungal mycelium and its nutrient uptake capacity are of particular importance. We develop and analyse a model of the growth of AM fungi associated with plant roots, suitable for describing mechanistically the effects of the fungi on solute uptake by plants. The model describes the development and distribution of the fungal mycelium in soil in terms of the creation and death of hyphae, tip–tip and tip–hypha anastomosis, and the nature of the root–fungus interface. It is calibrated and corroborated using published experimental data for hyphal length densities at different distances away from root surfaces. A good agreement between measured and simulated values was found for three fungal species with different morphologies: Scutellospora calospora (Nicol. & Gerd.) Walker & Sanders; Glomus sp.; and Acaulospora laevis Gerdemann & Trappe associated with Trifolium subterraneum L. The model and findings are expected to contribute to the quantification of the role of AM fungi in plant mineral nutrition and the interpretation of different foraging strategies among fungal species.


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