Infection Unit Method of Vesicular‐Arbuscular Mycorrhizal Propagule Determination

Franson, Raymond L.; Bethlenfalvay, Gábor J.

doi:10.2136/sssaj1989.03615995005300030020x

Cited by 40 publications

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“…Soil AM propagule densities were determined by the infection‐unit (IU) method ( Franson & Bethlenfalvay 1989), growing sorghum in the soils collected from the 20 sites (two samples per site in 80‐mL tapered growth tubes). We measured root and shoot dry weight, root length ( Giovanetti & Mosse 1980), and the number of IU in the entire root system, sampled roots and IU daily from day 10 on, and assayed at 14 days when the root tips reached the bottom of the tube and discrete IUs (Fig.…”

Section: Methodsmentioning

confidence: 99%

Nurse Plants, Mycorrhizae, and Plant Establishment in a Disturbed Area of the Sonoran Desert

Carrillo‐Garcia

Luz

Bashan

et al. 1999

Restoration Ecology

167

104

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Arbuscular-mycorrhizal (AM) fungi stabilize the soil and enhance plant growth by alleviating nutrient and drought stress. Their contributions to agriculture are well known, but their role in desert ecosystems has received less attention. The AM status of perennial plants in disturbed and undisturbed plots were investigated in the Sonoran Desert near La Paz, Baja California Sur, Mexico to determine if AM fungi contribute to resource-island stability and plant establishment. All perennial plants (46 species) in the study plots were AM, but root colonization varied widely ( Ͻ 10 to Ͼ 70%). Roots of plants that established in greatest numbers in plant-free zones (colonizers) of disturbed areas were highly AM. Plants with trace ( Ͻ 10%) root colonization (cacti of the tribe Pachycereae : Pachycereus pringlei , Machaerocereus gummosus , and Lemaireocereus thurberi ; and Agave datilyo ) established preferentially in association with nurse trees. The pachycereid cacti grew under Prosopis articulata and A. datilyo under Olneya tesota canopies. Of the nine species of trees and arborescent shrubs in the area, the mature ( Ͼ 20 yr) nurse-legumes P. articulata and O. tesota supported the largest number of under-story plants. Younger plants had only occasional associates. AM propagule densities in plant-free areas were lower than under plant canopies (40 vs. 280 propagules/kg soil). Occurrence of soil mounds (islands) under plants owing to soil deposition was related to the nature of the canopies and to the AM status of the roots. Island soils were enmeshed with AM-fungal hyphae, especially in the upper layer (approximately 10 cm). Seedlings of P. pringlei , growing in a screenhouse for six months in soil collected under P. articulata , had a biomass ten times greater than plants growing in bare-area soil. The results are consistent with the proposition that AM fungi contributed to the plant-soil system of our study area by: (1) helping to stabilize windborne soil that settles under dense plant canopies; (2) enhancing the establishment of colonizer plants in bare soils of disturbed areas; and (3) influencing plant associations through differences in the mycotrophic status of the associates. . 1996. A framework for tackling drought and land degradation. Journal of Arid Environments 33:309-320.

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Section: Methodsmentioning

confidence: 99%

Nurse Plants, Mycorrhizae, and Plant Establishment in a Disturbed Area of the Sonoran Desert

Carrillo‐Garcia

Luz

Bashan

et al. 1999

Restoration Ecology

167

104

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“…The relative change in survival capacity of the soil inoculum was measured by comparing the colonization potential in natural and sieved soil (through a 5-mm sieve) for each sampling date. The colonization potential was quantified by following the protocol of the infection unit method described by Franson and Bethlenfalvay (1989). This technique is based on the quantification of the infection units established by AM fungi in the roots of a bait plant (Sorghum vulgare Pers.)…”

Section: Characterization Of the Am Fungal Soil Inoculummentioning

confidence: 99%

The interactions between plant life form and fungal traits of arbuscular mycorrhizal fungi determine the symbiotic community

2014

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Arbuscular mycorrhizal (AM) fungi have traditionally been considered generalist symbionts. However, an increasing number of studies are pointing out the selectivity potential of plant hosts. Plant life form, determined by plant life history traits, seems to drive the AM fungal community composition. The AM fungi also exhibit a wide diversity of functional traits known to be responsible for their distribution in natural ecosystems. However, little is known about the role of plant and fungal traits driving the resultant symbiotic assemblages. With the aim of testing the feedback relationship between plant and fungal traits on the resulting AM fungal community, we inoculated three different plant life forms, i.e. annual herbs, perennial herbs and perennial semi-woody plants, with AM fungal communities sampled in different seasons. We hypothesized that the annual climate variation will induce changes in the mean traits of the AM fungal communities present in the soil throughout the year. Furthermore, the association of plants with different life forms with AM fungi with contrasting life history traits will show certain preferences according to reciprocal traits of the plants and fungi. We found changes in the AM fungal community throughout the year, which were differentially disrupted by disturbance and altered by plant growth form and plant biomass. Both plant and fungal traits clearly contributed to the resultant AM fungal communities. The revealed process can have implications for the functioning of ecosystems since changes in dominant plant life forms or climatic variables could influence the traits of AM fungal communities in soil and hence ecosystem processes.

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“…of Florida Agronomy Farm). The isolates were cultured on Sorghum bicolor L. Inoculum potentials of the soil cultures (inocula) were determined by the infection unit method (Franson and Bethlenfalvay, 1989) based on a microscopic count of successful encounters (infection units) between fungus and root. Inocula of each isolate, in amounts calculated to produce the same number of infection units [10()0 units(g root FW) '] after 14 days of growth, were mixed into the soil prior to planting.…”

Section: Biological Materialsmentioning

confidence: 99%

The Glycine‐Glomus‐Bradyrhizobium symbiosis. IX. Nutritional, morphological and physiological responses of nodulated soybean to geographic isolates of the mycorrhizal fungus Glomus mosseae.

Bethlenfalvay

Franson

Brown

et al. 1989

Physiologia Plantarum

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1989. The Glycirte-Glorrtus-Bradyrhizobium symbiosis. IX. Nutritional, morphological and physiological responses of nodulated soybean to geographic isolates of the mycorrhizal fungus Glomus mosseae. -Physiol. Plant. 76: 226-232.The objective of the work was to determine differences in plant response to geographic isolates of a vesicular-arbuscular mycorrhizal (VAM) fungus, and to demonstrate the need for such determinations in the selection of desirable host-endophyte combinations for practical applications. Soybean {Glycine max (L.) Merr.) plants were inoculated with Bradyrhizoblum japonlcum and isolates of the VAM-fungal morphospecies Glomus mosseae (Nicol. & Gerd.) Gerd. and Trappe, collected from an arid (AR), semiarid (SA) or mesic (ME) area. Inoculum potentials of the VAMfungal isolates were determined and the inocula equalized, achieving the same level of root colonization (41%, /'>0.05) at harvest (50 days). Plants of the three VAM treatments (AR, SA and ME) were evaluated against nonVAM controls. Significant differences in plant response to colonization were found in dry mass, leaf K, N and P concentrations, and in root/shoot, nodule/root, root length/leaf area and root length/ root mass ratios. The differences were most pronounced and consistent between the AR and all other treatments. Photosynthesis and nodule activity were higher (P<0.05) in all VAM treatments, but only the AR plants had higher (P<0.05) photosynthetic water-use efficiency than the controls. Nodule activity, evaluated by HT evolution and CjH, reduction, differed significantly between treatments. The results are discussed in terms of nutritional and non-nutritional effects of VAM colonization on the development and physiology of the tripartite soybean association in the light of intraspecific variability within the fungal endophyte.

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Infection Unit Method of Vesicular‐Arbuscular Mycorrhizal Propagule Determination

Cited by 40 publications

References 0 publications

Nurse Plants, Mycorrhizae, and Plant Establishment in a Disturbed Area of the Sonoran Desert

Nurse Plants, Mycorrhizae, and Plant Establishment in a Disturbed Area of the Sonoran Desert

The interactions between plant life form and fungal traits of arbuscular mycorrhizal fungi determine the symbiotic community

The Glycine‐Glomus‐Bradyrhizobium symbiosis. IX. Nutritional, morphological and physiological responses of nodulated soybean to geographic isolates of the mycorrhizal fungus Glomus mosseae.

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