The 'most probable number' method for enumerating infective propagules of vesicular arbuscular mycorrhizal fungi in soil

Estimates of the number of infective propagules of vesicular-arbuscular (VA) endophytes in two soils were obtained using a most probable number (MPN) method. These estimates were compared with counts of the number of spores in the same soils obtained using a conventional wet sieving method. In one soil, there was good agreement between the number of coarse endophyte propagules, estimated by the MPN technique, and the number of germinable spores extracted using the wet sieving technique. However, a large population of fine endophyte propagules (more than 230 per 50 g soil) could only be enumerated using the MPN technique. In the second soil, fewer coarse endophyte propagules were found using the wet sieving technique than when using the MPN technique. The MPN technique appears to give a more realistic estimate of the number of infective propagules of VA endophytes in field soils than the conventional method.

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Factors affecting the estimation of numbers of infective propagules of vesicular arbuscular mycorrhizal fungi by the most probable number method

Soil Research ◽

10.1071/sr9830073 ◽

1983 ◽

Vol 21 (1) ◽

pp. 73 ◽

Cited By ~ 38

Author(s):

JM Wilson ◽

MJ Trinick

Keyword(s):

Arbuscular Mycorrhizal Fungi ◽

Mycorrhizal Fungi ◽

Arbuscular Mycorrhizal ◽

Most Probable Number ◽

Probable Number ◽

Vesicular Arbuscular Mycorrhizal Fungi ◽

Factors Affecting ◽

Soil Inoculum ◽

Vesicular Arbuscular ◽

Time Of Harvest

Factors affecting the estimation of the number of infective propagules of vesicular arbuscular mycorrhizal fungi by the most probable number (MPN) method were investigated. The value obtained was shown to be dependent on the conditions of the experiment. Both temperature and time of harvest changed the result because of their effects on the growth of both roots and propagules, and hence on their interception. Other factors which must be taken into account in order to optimize the MPN estimate are discussed. The number of infective propagules in a dried root/soil inoculum was shown to be affected by both the amount of infection in the pot culture from which it was formed and by its age.

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Communities of arbuscular mycorrhizal fungi in maize (Zea mays L.) crops along an edaphoclimatic gradient in Northeast Brazil

Botany ◽

10.1139/cjb-2018-0084 ◽

2018 ◽

Vol 96 (11) ◽

pp. 767-778 ◽

Cited By ~ 2

Author(s):

Catarina Maria Aragão de Mello ◽

Gladstone Alves da Silva ◽

Fritz Oehl ◽

Iolanda Ramalho da Silva ◽

Inácio Pascoal do Monte Junior ◽

...

Keyword(s):

Species Richness ◽

Arbuscular Mycorrhizal Fungi ◽

Mycorrhizal Fungi ◽

Zea Mays L ◽

Arbuscular Mycorrhizal ◽

Most Probable Number ◽

Probable Number ◽

Structural Differences ◽

Amf Communities ◽

Original Area

The objective of this study was to determine the species richness, diversity, and communities of arbuscular mycorrhizal fungi (AMF), based on the morphology of their spores, in maize plantations along an edaphoclimatic gradient going from a humid zone (original area of Atlantic rainforest), to a transition zone and a drier zone (original area of Caatinga), to increase the understanding of the ecology of AMF in tropical agroecosystems. We extracted glomerospores from soil samples from maize plantations in each mesoregion and analysed AMF propagules and community structure. A total of 57 AMF taxa were identified, of which two are new to science. The most probable number of AMF infective propagules did not differ among the three areas. A greater number of glomerospores was obtained from the transition site, whereas species richness for AMF differed between the high humidity and transition sites. The composition of AMF communities differed among sites, with edaphic attributes significantly associated with AMF community composition. The environmental conditions of each mesoregion contribute to the structural differences of AMF assemblages in soils cultivated by the same host plant (maize).

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CHARACTERIZATION OF RHIZOBIA AND ARBUSCULAR MYCORRHIZAL FUNGI IN AREAS IMPACTED BY GRAVEL MINING IN BRAZIL

Revista Caatinga ◽

10.1590/1983-21252019v32n416rc ◽

2019 ◽

Vol 32 (4) ◽

pp. 995-1004

Author(s):

FELIPE FERREIRA DA SILVA ◽

THAINÁ ALVES DOS SANTOS ◽

EDERSON DA CONCEIÇÃO JESUS ◽

GUILHERME MONTANDON CHAER

Keyword(s):

Arbuscular Mycorrhizal Fungi ◽

Mycorrhizal Fungi ◽

Base Material ◽

Arbuscular Mycorrhizal ◽

Most Probable Number ◽

Semiarid Region ◽

Oil Exploration ◽

Probable Number ◽

Gravel Mining ◽

The Impact

ABSTRACT On-shore oil exploration is one of the main economic activities in the semiarid region (Caatinga biome) of the state of Rio Grande do Norte (RN), Brazil. Gravel mining is an activity associated with oil exploration that causes environmental impacts. Gravel is a base-material for constructions, such as roads and pumpjack bases. The areas of gravel mining and other decommissioned areas where the gravel has been deposited must be revegetated with species native to the biome at end of the activity in the site. An efficient strategy for revegetation of degraded areas has been the planting of leguminous species that can associate with rhizobia and arbuscular mycorrhizal fungi (AMF). Nevertheless, the impact of mining activities on the autochthonous populations of these microorganisms is unknown. The objective of the present work is to characterize the density of rhizobia and AMF spores in four areas impacted by the oil exploration in RN when compared to non-impacted adjacent areas. Gravel samples were collected in dry and rainy seasons in two mining areas: one in a pumpjack base, and one in a waste disposal area. Surface soil (topsoil) samples were collected in adjacent areas with native Caatinga vegetation. Assays were carried out to evaluate the most probable number (MPN) of rhizobia and to identify the type and density of arbuscular mycorrhizal fungi (AMF), using rhizobia trap plants Mimosa tenuiflora (Mart.) Benth. and Mimosa caesalpiniifolia Benth. The MPN of rhizobia was low in all areas, but higher in the rainy season. The highest amount and diversity of AMF spores were found in the dry season. Among the symbiotic microorganisms studied, the AMF presented lower densities in the evaluated areas when compared to those in the adjcent native vegetation areas, denoting the impact of this activity.

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