Phosphorus solubilization and pH changes as a result of the interactions between soil bacteria and arbuscular mycorrhizal fungi on a medium containing NO3-as nitrogen source

2002 ◽  
Vol 80 (5) ◽  
pp. 571-576 ◽  
Author(s):  
J Villegas ◽  
J A Fortin

The interactions between arbuscular mycorrhizal fungi and bacteria may affect the nutrient dynamics in the environment. To study these changes, assays were conducted in a two-compartment Petri plate system. A NO3--N medium containing an insoluble phosphate (P) source was used to evaluate the effect of Glomus intraradices (Schenck & Smith) external mycelium, mycorrhizal, and nonmycorrhizal transformed carrot roots (Daucus carrota L.), alone or in interaction with Pseudomonas aeruginosa (Schroeter) Migula, Pseudomonas putida (Trevisan) Migula, or Serratia plymuthica (Dyar) Bergey et al., on phosphorus solubilization and pH changes of the medium. In the NO3--containing medium, G. intraradices external mycelium as well as the three bacterial species studied were rather inefficient P solubilizers when growing individually. However, when G. intraradices external mycelium interacted with either P. aeruginosa or P. putida, the levels of soluble P in the medium significantly increased (P [Formula: see text] 0.05). These improvements were closely related to changes in the pH of the medium.Key words: Glomus intraradices, P solubilization, external mycelium, Pseudomonas aeruginosa, Pseudomonas putida, Serratia plymuthica.

2001 ◽  
Vol 79 (8) ◽  
pp. 865-870 ◽  
Author(s):  
J Villegas ◽  
J A Fortin

This paper reports the effects of Glomus intraradices (Schenck & Smith) external mycelium, mycorrhizal, and nonmycorrhizal transformed carrot roots (alone or in interaction with Pseudomonas aeruginosa (Schroeter) Migula, Pseudomonas putida (Trevisan) Migula, or Serratia plymuthica (Dyar) Bergey et al.) on phosphorus solubilization and pH changes of the medium. All experiments were conducted in a two-compartment Petri plate system with a NH4+medium containing an insoluble source of phosphorus (P). In interaction with P. aeruginosa, G. intraradices mycorrhizal roots and G. intraradices external mycelium enhanced solubilization of sparingly soluble sources of phosphates above the levels reached with each culture alone. These improvements were correlated with changes in the pH of the media.Key words: Glomus intraradices, P solubilization, external mycelium, Pseudomonas aeruginosa, Pseudomonas putida, Serratia plymuthica.


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.


1998 ◽  
Vol 28 (1) ◽  
pp. 150-153
Author(s):  
J N Gemma ◽  
R E Koske ◽  
E M Roberts ◽  
S Hester

Rooted cuttings of Taxus times media var. densiformis Rehd. were inoculated with the arbuscular mycorrhizal fungi Gigaspora gigantea (Nicol. & Gerd.) Gerd. & Trappe or Glomus intraradices Schenck and Smith and grown for 9-15 months in a greenhouse. At the completion of the experiments, leaves of inoculated plants contained significantly more chlorophyll (1.3-4.1 times as much) than did noninoculated plants. In addition, mycorrhizal plants had root systems that were significantly larger (1.3-1.4 times) and longer (1.7-2.1 times) than nonmycorrhizal plants, and they possessed significantly more branch roots (1.3-2.9 times). No differences in stem diameter and height or shoot dry weight were evident at the end of the experiments, although the number of buds was significantly greater in the cuttings inoculated with G. intraradices after 15 months.


2012 ◽  
Vol 14 (4) ◽  
pp. 692-699 ◽  
Author(s):  
M.C. Arango ◽  
M.F. Ruscitti ◽  
M.G. Ronco ◽  
J. Beltrano

This study evaluated the effects of inoculation with the arbuscular mycorrhizal fungi Glomus mosseae, Glomus intraradices A4 and Glomus intraradices B1 and two phosphorus levels (10 and 40 mg kg-1) on root colonization, plant growth, nutrient uptake and essential oil content in Mentha piperita L. The experiment was carried out in a greenhouse, in 4x2 factorial arrangement, in completely randomized design. At sixty days after transplanting, the mycorrhizal plants had significantly higher fresh matter, dry matter and leaf area compared to non-mycorrhizal plants. The inoculation increased P, K and Ca levels in the shoot which were higher under 40 mg P kg-1 of soil. Plants grown with 40 mg P kg-1 soil increased the essential oil yield per plant by about 40-50% compared to those cultivated with 10 mg P kg-1, regardless of the mycorrhizal treatment. Among the studied fungal species, inoculation with G. intraradices A4 and a high level of P significantly increased plant growth and essential oil yield, compared to the other studied mycorrhizal fungal species. In conclusion, inoculation of arbuscular mycorrhizal fungi into peppermint plants is a feasible alternative to increase the essential oil production and reduce the use of fertilizers required to obtain economic production of peppermint under phosphorus-deficient soil condition.


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.


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.


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