Impact of arbuscular mycorrhizal fungi on N and P cycling in the root zone

2004 ◽  
Vol 84 (4) ◽  
pp. 383-395 ◽  
Author(s):  
Chantal Hamel

The influence of arbuscular mycorrhizal fungi (AMF) on soil processes is difficult to define, in part because it varies with the plant and fungal geno types as well as with environmental conditions. The influence of AMF on N cycling is just being discovered. This short review examines areas of knowledge related to the nature of the mycorrhizosphere, AMF-microbe interactions, and N and P mobilization in the root zone. The role AMF could play in the root zone in N and P dynamics is presented. The spatial organization of roots and hyphae in soil suggests that AMF may enhance the reabsorption of nutrients lost through root exudation. These fungi influence soil microorganisms and, hence, they may influence biochemical reactions in soil including mineralization of organic matter and nitrification. AMF seem to improve the capacity of their host plant to use organic sources of P and N. AMF might improve the ability of plants to compete with saprotrophs for the uptake of P and N. The impact from this latter effect of AMF could exceed that stemming from their possible direct use of amino-acid-N, their production of phosphatase enzymes and possibly of organic anions. Better competitive ability of mycorrhizal plants under conditions of low soil P and N levels could reduce saprotrophic populations and, if this occurs, regulate soil organic matter turnover rate. The management of biological soil resources, in truly sustainable cropping systems, may be the largest challenge in crop production. Key words: Arbuscular mycorrhizal fungi, soil functioning, nitrogen cycling, phosphorus cycling, soil fertility, soil microbial community

2021 ◽  
Vol 12 ◽  
Author(s):  
Hassan Etesami ◽  
Byoung Ryong Jeong ◽  
Bernard R. Glick

Phosphorus (P) availability is usually low in soils around the globe. Most soils have a deficiency of available P; if they are not fertilized, they will not be able to satisfy the P requirement of plants. P fertilization is generally recommended to manage soil P deficiency; however, the low efficacy of P fertilizers in acidic and in calcareous soils restricts P availability. Moreover, the overuse of P fertilizers is a cause of significant environmental concerns. However, the use of arbuscular mycorrhizal fungi (AMF), phosphate–solubilizing bacteria (PSB), and the addition of silicon (Si) are effective and economical ways to improve the availability and efficacy of P. In this review the contributions of Si, PSB, and AMF in improving the P availability is discussed. Based on what is known about them, the combined strategy of using Si along with AMF and PSB may be highly useful in improving the P availability and as a result, its uptake by plants compared to using either of them alone. A better understanding how the two microorganism groups and Si interact is crucial to preserving soil fertility and improving the economic and environmental sustainability of crop production in P deficient soils. This review summarizes and discusses the current knowledge concerning the interactions among AMF, PSB, and Si in enhancing P availability and its uptake by plants in sustainable agriculture.


2019 ◽  
Vol 113 (2) ◽  
pp. 321
Author(s):  
Mazen IBRAHIM

The impact of indigenous arbuscular mycorrhizal fungi (AMF) on agronomic characteristics of sunflower (<em>Helianthus annuus</em> L.) was evaluated in a pot experiment. The indigenous AMF, including <em>Glomus intraradices, Glomus mosseae</em>, and <em>Glomus viscosum</em>, were isolated from an agricultural field in which cotton and sunflower plants were grown. The most abundant species (<em>G. viscosum</em>) was multiplied in a monospecific culture. Sunflower plants were inoculated with the mixture of three selected AMF species or solely with <em>G. viscosum</em>. The number of leaves, shoot length, head diameter, above ground biomass, and seeds mass were significantly higher in the plant inoculated with AMF mixture followed by individual inoculation with <em>G. viscosum</em> followed by the control. AMF mixture outperformed the <em>G. viscosumby</em> increasing mycorrhizal dependency and mycorrhizal inoculation effect of sunflower. The results indicate that AMF mixture could be considered as a good inoculum for improving growth and yield of sunflower in sustainable agriculture.


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.


2012 ◽  
Vol 77 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Anna Lisek ◽  
Lidia Sas Paszt ◽  
Beata Sumorok

Summary In organic farming, mineral fertilizers are replaced by various preparations to stimulate plant growth and development. Introduction of new biopreparations into horticultural production requires an assessment of their effects on the growth and yielding of plants. Among the important indicators of the impact on plants of beneficial microorganisms contained in bioproducts is determination of their effectiveness in stimulating the growth and yielding of plants. Moreover, confirmation of the presence of arbuscular mycorrhizal (AM) fungi in the roots and plant growth promoting rhizobacteria (PGPR) in the rhizosphere is also necessary. In addition to conventional methods, molecular biology techniques are increasingly used to allow detection and identification of AM fungi in plant roots. The aim of this study was identification and initial taxonomic classification of AM fungi in the roots of ‘Elkat’ strawberry plants fertilized with various biopreparations using the technique of nested PCR. Tests were performed on DNA obtained from the roots of ‘Elkat’ strawberry plants: not fertilized, treated with 10 different biopreparations, or fertilized with NPK. Amplification of the large subunit of ribosomal gene (LSU rDNA) was carried out using universal primers, and then, in the nested PCR reaction, primers specific for the fungi of the genera Glomus, Acaulospora, and Scutellospora were used. Colonization of strawberry roots by arbuscular mycorrhizal fungi was determined on the basis of the presence of DNA fragments of a size corresponding to the types of the fungi tested for. As a result of the analyses, the most reaction products characterizing AM fungi were found in the roots of plants treated with the preparation Florovit Eko. The least fragments characteristic of AM fungi were detected in the roots of plants fertilized with NPK, which confirms the negative impact of mineral fertilizers on the occurrence of mycorrhizal fungi in the roots of strawberry plants. The roots of plants fertilized with Tytanit differed from the control plants by the presence of one of the clusters of fungi of the genus Glomus and by the absence of a cluster of fungi of the genus Scutellospora. In the roots of plants treated with other biopreparations there were reaction products indicating the presence of fungi of the genera Glomus, Scutellospora and Acaulospora, like in the roots of the control plants. The results will be used to assess the suitability of microbiologically enriched biopreparations in horticultural production.


2017 ◽  
Vol 42 (6) ◽  
pp. 793-802 ◽  
Author(s):  
PIL U. RASMUSSEN ◽  
TARIQUE AMIN ◽  
ALISON E. BENNETT ◽  
KRISTINA KARLSSON GREEN ◽  
SARI TIMONEN ◽  
...  

2005 ◽  
Vol 85 (1) ◽  
pp. 31-40 ◽  
Author(s):  
C. Plenchette ◽  
C. Clermont-Dauphin ◽  
J. M. Meynard ◽  
J. A. Fortin

Market globalization, demographic pressure, and environmental degradation have led us to reconsider many of our current agricultural systems. The heavy use of chemical inputs, including fertilizers and pesticides, has resulted in pollution, decreased biodiversity in intensively-farmed regions, degradation of fragile agro-ecosystems, and prohibitive costs for many farmers. Low input sustainable cropping systems should replace conventional agriculture, but this requires a more comprehensive understanding of the biological interactions within agro-ecosystems. Mycorrhizal fungi appear to be the most important telluric organisms to consider. Mycorrhizae, which result from a symbiosis between these fungi and plant roots, are directly involved in plant mineral nutrition, the control of plant pathogens, and drought tolerance. Most horticultural and crop plants are symbiotic with arbuscular mycorrhizal fungi. Mycorrhizal literature is abundant, showing that stimulation of plant growth can be mainly attributed to improved phosphorous nutrition. Although the mycorrhizal potential of its symbiosis to improve crop production is widely recognized, it is not implemented in agricultural systems. There is an urgent need to improve and widely apply analytical methods to evaluate characteristics such as, relative field mycorrhizal dependency, soil mycorrhizal infectivity, and mycorrhizal receptivity of soil. Decreased use of fertilizers, pesticides, and tillage will favour arbuscular mycorrhizal fungi. However, shifting from one system to a more sustainable one is not easy since all components of the cropping system are closely linked. Different cases, from actual agricultural practices in different countries, are analyzed to highlight situations in which mycorrhizae might or might not play a role in developing more sustainable agriculture. Key words: Cropping systems, mycorrhizae, sustainability, technical itineraries, rotation


2011 ◽  
Vol 354 (1-2) ◽  
pp. 335-345 ◽  
Author(s):  
Christine Vos ◽  
Sofie Claerhout ◽  
Rachel Mkandawire ◽  
Bart Panis ◽  
Dirk De Waele ◽  
...  

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