scholarly journals Growth model for arbuscular mycorrhizal fungi

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.

2016 ◽  
Vol 67 (10) ◽  
pp. 1116 ◽  
Author(s):  
Guangzhou Wang ◽  
Xia Li ◽  
Peter Christie ◽  
Junling Zhang ◽  
Xiaolin Li

Foraging strategies in arbuscular mycorrhizal fungi (AMF) for heterogeneously distributed resources in the soil remain to be explored. We used nylon-mesh bags of 30 μm to simulate patches of different phosphorus (P) supply levels (Expt 1) and P forms (organic v. inorganic, Expts 1 and 2). In Expt 1, host maize (Zea mays) was unfertilised; in each pot, five P-enriched bags were supplied with either Na-phytate or KH2PO4 at P rates of 0 (P0), 50 (P50), 100 (P100), 150 (P150) and 200 (P200) mg P kg–1. In Expt 2, maize plants were supplied with 20 (P20) or 50 (P50) mg P kg–1, and five P-enriched bags were supplied with different P forms (Na-phytate, lecithin, RNA, KH2PO4) and a nil-P control. Three fungal species (Funneliformis mosseae, Rhizophagus irregularis, and Glomus etunicatum) were compared in Expt 1, and the first two species in Expt 2. In Expt 1, the hyphal-length density (HLD) of G. etunicatum was not significantly different among different P levels when supplied with KH2PO4, whereas the HLD of R. irregularis tended to increase at higher P supply (above P50) in the Na-phytate treatment. The HLD of F. mosseae increased at P150 when supplied with KH2PO4, and increased at P100 and P150 in the Na-phytate treatment relative to P0. APase activity levels were more related to P supply level, in particular with F. mosseae inoculation and uninoculated control, showing that P200 significantly reduced APase relative to P0. In Expt 2, greater hyphal growth of both fungal species tended to occur with KH2PO4. At P20, the HLD of R. irregularis in treatments with KH2PO4 and lecithin, and of F. mosseae with KH2PO4, were higher than in P0. At P50, the HLD of F. mosseae was higher than of R. irregularis; but P form had no significant influence on HLD of F. mosseae, whereas the HLD of R. irregularis in the P-amended treatment (except with Na-phytate) was higher than in P0. APase activity did not differ significantly between the two fungal species. Highest APase activity generally occurred with lecithin, with no significant difference among the other P forms. Our results indicate that the response of AMF to P-enriched patches is complex, and both the form and amount of P supplied should be considered. Variations between AMF in the proliferation of hyphae to heterogeneous nutrient patches might be a mechanism by which these species can maintain diversity in intensive agricultural ecosystems.


Botany ◽  
2008 ◽  
Vol 86 (9) ◽  
pp. 1009-1019 ◽  
Author(s):  
Maria Manjarrez ◽  
F. Andrew Smith ◽  
Petra Marschner ◽  
Sally E. Smith

For the first time, the phenotypes formed in the reduced mycorrhizal colonization (rmc) Solanum lycopersicum  L. (tomato) mutant with different arbuscular mycorrhizal (AM) fungi were used to explore the potential of different fungal structures to support development of external fungal mycelium and spores. The life cycle of AM fungi with rmc was followed for up to 24 weeks. Results showed that production of external mycelium was slight and transitory for those fungi that did not penetrate the roots of rmc (Pen–) ( Glomus intraradices DAOM181602 and Glomus etunicatum ). For fungi that penetrated the root epidermis and hypodermis (Coi–, Glomus coronatum and Scutellospora calospora ) the mycelium produced varied in size, but was always smaller than with the wild-type 76R. Spores were formed by these fungi with 76R but not with rmc. The only fungus forming a Myc+ phenotype with rmc, G. intraradices WFVAM23, produced as much mycelium with rmc as with 76R. We observed lipid accumulation in hyphae and vesicles in both plant genotypes with this fungus. Mature spores were formed with 76R. However, with rmc, spores remained small and (presumably) immature for up to 24 weeks. We conclude that significant carbon transfer from plant to fungus can occur in Coi– interactions with rmc in which no cortical colonization occurs. We speculate that both carbon transfer and root signals are required for mature spores to be produced.


2003 ◽  
Vol 69 (11) ◽  
pp. 6762-6767 ◽  
Author(s):  
Ingrid M. van Aarle ◽  
Pål Axel Olsson

ABSTRACT We monitored the development of intraradical and extraradical mycelia of the arbuscular mycorrhizal (AM) fungi Scutellospora calospora and Glomus intraradices when colonizing Plantago lanceolata. The occurrence of arbuscules (branched hyphal structures) and vesicles (lipid storage organs) was compared with the amounts of signature fatty acids. The fatty acid 16:1ω5 was used as a signature for both AM fungal phospholipids (membrane constituents) and neutral lipids (energy storage) in roots (intraradical mycelium) and in soil (extraradical mycelium). The formation of arbuscules and the accumulation of AM fungal phospholipids in intraradical mycelium followed each other closely in both fungal species. In contrast, the neutral lipids of G. intraradices increased continuously in the intraradical mycelium, while vesicle occurrence decreased after initial rapid root colonization by the fungus. S. calospora does not form vesicles and accumulated more neutral lipids in extraradical than in intraradical mycelium, while the opposite pattern was found for G. intraradices. G. intraradices allocated more of its lipids to storage than did S. calospora. Thus, within a species, the fatty acid 16:1ω5 is a good indicator for AM fungal development. The phospholipid fatty acid 16:1ω5 is especially suitable for indicating the frequency of arbuscules in the symbiosis. We propose that the ratio of neutral lipids to phospholipids is more important than is the presence of vesicles in determining the storage status of AM fungi.


2016 ◽  
Vol 70 (2) ◽  
Author(s):  
Happy WIDIASTUTI ◽  
Edi GUHARDJA ◽  
Nampiah SOEKARNO ◽  
L K DARUSMAN ◽  
Didiek Hadjar GOENADI ◽  
...  

SummaryAM fungal symbiosis increase the uptake of P in oil palm seedlings. However the optimum condition of symbiosis has to be determined to get higher benefit of AM fungal symbiosis. Optimization of the symbiosis Acaulospora tuberculata and Gigaspora margarita with oil palm seedling in acid soil was determined. An experiment was conducted in polybag sized 40 x 60 cm contained sterilized Cikopomayak soil. Three factors studied were AM fungal species (A. tuberculata, G. margarita), inoculant dose (0.0; 12.5; 25.0; and 37.5% w/w), and fertilizer rate (0; 25; 50; and 100% recommended dose) and each treatment replicated three times. The result showed that optimum growth reached on the inoculant addition of 36% (w/w) in the form of infected roots, hypha, and spores and fertilizer dose of 25% for A. tuberculata, while for G. margarita was 40% (w/w) inoculant and 26% fertilizer. Efectivity of fertilizer and P uptake of oil palm seedling were significantly increased with AM fungi inoculation. P uptake of oil palm seedling inoculated with A. tuberculata increase. RingkasanSimbiosis cendawan mikoriza arbuskula (CMA) dapat meningkatkan serapan P pada pembibitan kelapa sawit. Namun, untuk mendapatkan keuntungan simbiosis yang tinggi perlu diketahui kondisi optimum simbiosis. Simbiosis CMA dengan tanaman sangat dipengaruhi tingkat hara dan dosis inokulum. Percobaan dilakukan dalam polibag berukuran 40 x 60 cm berisi tanah Cikopomayak steril. Tiga faktor yang diuji ialah spesies CMA (A. tuberculata, G. margarita), dosis inokulum campuran (0,0; 12,5; 25,0; dan 37,5% b/b), dosis pupuk (0; 25; 50; dan 100% dosis rekomendasi) dan masing masing perlakuan diulang tiga kali. Hasil percobaan menunjukkan bahwa pertumbuhan optimum dicapai pada pemberian inokulum berupa akar terinfeksi, hifa, dan spora 36% (b/b) dan pupuk 25% untuk A. tuberculata, sedangkan untuk G. margarita ialah 40% (b/b) inokulum dan pupuk 26%. Keefektifan pupuk dan serapan P meningkat secara nyata dengan inokulasi CMA


ISRN Agronomy ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Ligia Lebrón ◽  
D. Jean Lodge ◽  
Paul Bayman

Mycorrhizal symbiosis is important for growth of coffee (Coffea arabica), but differences among coffee cultivars in response to mycorrhizal interactions have not been studied. We compared arbuscular mycorrhizal (AM) extraradical hyphae in the soil and diversity of AM fungi among three coffee cultivars, Caturra, Pacas, and Borbón, at three farms in Puerto Rico. Caturra had significantly lower total extraradical AM hyphal length than Pacas and Borbón at all locations. P content did not differ among cultivars. Extraradical hyphal lengths differed significantly among locations. Although the same morphotypes of mycorrhizal fungal spores were present in the rhizosphere of the three cultivars and total spore density did not differ significantly, frequencies of spore morphotypes differed significantly among cultivars. Spore morphotypes were typical of Glomus and Sclerocystis. Levels of soil nutrients did not explain differences in AM colonzation among cultivars. The cultivar Caturra is a mutant of Borbón and has apparently lost Borbón’s capacity to support and benefit from an extensive network of AM hyphae in the soil. Widespread planting of Caturra, which matures earlier and has higher yield if fertilized, may increase dependence on fertilizers.


2018 ◽  
Vol 66 (4) ◽  
Author(s):  
Manju Gupta ◽  
Akshat Gupta ◽  
Prabhat Kumar

Increasing urbanisation is widely associated with decline in biodiversity of all forms. The aim of the present study was to answer two questions: (i) Does rapid urbanization in Delhi (India) affect biodiversity of arbuscular mycorrhizal (AM) fungi? (ii) If so, how? We measured the AM fungal diversity at nine sites located in Delhi forests, which had different types of urban usage in terms of heavy vehicular traffic pollution, littering, defecation and recreational activities. The study revealed a significant decrease in AM fungal diversity (alpha diversity) and abundance measured as spore density, biovolume, mean infection percentage (MIP) in roots, soil hyphal length and easily extractable glomalin related soluble proteins (EE-GRSP) at polluted sites. Non-metric multidimensional scaling (NMDS) and nested PERMANOVA, revealed significant differences in AM fungal community structure which could be correlated with variations in soil moisture, temperature, pH, carbon, and nitrogen and phosphorus levels. BEST (biota and environmental matching) analysis of biological and environmental samples revealed that soil temperature and moisture accounted for 47.6 % of the total variations in the samples. The study demonstrated how different forms of human activities in urban ecosystems of Delhi are detrimental to the diversity and abundance of AM fungi.


2016 ◽  
Vol 70 (2) ◽  
Author(s):  
Happy WIDIASTUTI ◽  
Edi GUHARDJA ◽  
Nampiah SOEKARNO ◽  
L K DARUSMAN ◽  
Didiek Hadjar GOENADI ◽  
...  

SummaryAM fungal symbiosis increase the uptake of P in oil palm seedlings. However the optimum condition of symbiosis has to be determined to get higher benefit of AM fungal symbiosis. Optimization of the symbiosis Acaulospora tuberculata and Gigaspora margarita with oil palm seedling in acid soil was determined. An experiment was conducted in polybag sized 40 x 60 cm contained sterilized Cikopomayak soil. Three factors studied were AM fungal species (A. tuberculata, G. margarita), inoculant dose (0.0; 12.5; 25.0; and 37.5% w/w), and fertilizer rate (0; 25; 50; and 100% recommended dose) and each treatment replicated three times. The result showed that optimum growth reached on the inoculant addition of 36% (w/w) in the form of infected roots, hypha, and spores and fertilizer dose of 25% for A. tuberculata, while for G. margarita was 40% (w/w) inoculant and 26% fertilizer. Efectivity of fertilizer and P uptake of oil palm seedling were significantly increased with AM fungi inoculation. P uptake of oil palm seedling inoculated with A. tuberculata increase. RingkasanSimbiosis cendawan mikoriza arbuskula (CMA) dapat meningkatkan serapan P pada pembibitan kelapa sawit. Namun, untuk mendapatkan keuntungan simbiosis yang tinggi perlu diketahui kondisi optimum simbiosis. Simbiosis CMA dengan tanaman sangat dipengaruhi tingkat hara dan dosis inokulum. Percobaan dilakukan dalam polibag berukuran 40 x 60 cm berisi tanah Cikopomayak steril. Tiga faktor yang diuji ialah spesies CMA (A. tuberculata, G. margarita), dosis inokulum campuran (0,0; 12,5; 25,0; dan 37,5% b/b), dosis pupuk (0; 25; 50; dan 100% dosis rekomendasi) dan masing masing perlakuan diulang tiga kali. Hasil percobaan menunjukkan bahwa pertumbuhan optimum dicapai pada pemberian inokulum berupa akar terinfeksi, hifa, dan spora 36% (b/b) dan pupuk 25% untuk A. tuberculata, sedangkan untuk G. margarita ialah 40% (b/b) inokulum dan pupuk 26%. Keefektifan pupuk dan serapan P meningkat secara nyata dengan inokulasi CMA


2010 ◽  
Vol 2 (2) ◽  
pp. 213-218 ◽  
Author(s):  
Sonika Chauhan ◽  
Aditya Kumar ◽  
Chhavi Mangla ◽  
Ashok Aggarwal

The present paper represents the positive role of Arbuscular Mycorrhizal (AM) fungi as biofertilizers in strawberry. Experiments were carried out to assess the effectiveness of Trichoderma viride and AM fungi (Glomus mosseae and Acaulospora laevis) alone or in combination, on the growth and biomass production of strawberry. After 120 days, dual inoculation of A. laevis + T. viride showed maximum increase in plant height (30.5±0.3), fresh shoot weight (10.16±0.20), dry shoot weight (2.82±0.02), fresh root weight (6.70±0.10), total chlorophyll (0.841±0.05) and phosphorus content in root (1.13±0.02) as compared to control. However root colonization and AM spore number were maximum in G. mosseae + A. lavies (90.76±1.32) and in G. mosseae (211.16±2.56) respectively as compared to uninoculated plants. Triple inoculation of G. mosseae + A. laevis + T. viride (12.33± 057) was effective in increasing the leaf area.


1993 ◽  
Vol 48 (11-12) ◽  
pp. 923-929 ◽  
Author(s):  
S. M. Boyetchko ◽  
J. P. Tewari

Abstract Three V A mycorrhizal fungal species were isolated from soils in Alberta, Canada and examined by scanning electron microscopy and energy-dispersive X-ray microanalysis. Mature spores of Glomus aggregatum developed an outer hyaline wall which contained lower levels of calcium than the middle wall. Examination of G. pansihalos spores revealed a lower level of calcium in the outer evanescent wall as compared to the ornamented wall. When spores of Entrophospora infrequens were examined, the wall of the vesicle was found to contain similar levels of calcium as the ornamented wall of the spore. The significance of the results concerning the presence of calcium in mycorrhizal spore walls is discussed, as is the occurrence of the mycorrhizal species.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Christopher Ngosong ◽  
Elke Gabriel ◽  
Liliane Ruess

Biomass estimation of arbuscular mycorrhiza (AM) fungi, widespread plant root symbionts, commonly employs lipid biomarkers, predominantly the fatty acid 16:1ω5. We briefly reviewed the application of this signature fatty acid, followed by a case study comparing biochemical markers with microscopic techniques in an arable soil following a change to AM non-host plants after 27 years of continuous host crops, that is, two successive cropping seasons with wheat followed by amaranth. After switching to the non-host amaranth, spore biomass estimated by the neutral lipid fatty acid (NLFA) 16:1ω5 decreased to almost nil, whereas microscopic spore counts decreased by about 50% only. In contrast, AM hyphal biomass assessed by the phospholipid (PLFA) 16:1ω5 was greater under amaranth than wheat. The application of PLFA 16:1ω5 as biomarker was hampered by background level derived from bacteria, and further enhanced by its incorporation from degrading spores used as microbial resource. Meanwhile, biochemical and morphological assessments showed negative correlation for spores and none for hyphal biomass. In conclusion, the NLFA 16:1ω5 appears to be a feasible indicator for AM fungi of the Glomales group in the complex field soils, whereas the use of PLFA 16:1ω5 for hyphae is unsuitable and should be restricted to controlled laboratory studies.


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