The biology of mycorrhiza in the Ericaceae

Shaw, G.; Leake, J. R.; Baker, A. J. M.; Read, David

doi:10.1111/j.1469-8137.1990.tb00450.x

Cited by 45 publications

(16 citation statements)

References 27 publications

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“…In contrast to VAM, many studies have shown that ECM and EM fungi can utilize organic N sources through the production of extracellular acid proteinases (Leake and Read, 1990;Zhu et al, 1990;Maijala et al, 1991; Fig. 1).…”

Section: Nitrogenmentioning

confidence: 95%

“…Conclusions upon the importance of siderophore production of ECM fungi for the Fe nutrition of the host plant and its adaptation to calcareous soils (Lapeyrie, 1990) are merely based on observations rather than measurements. In EM, however, experimental evidence has been presented for higher affinity of EM roots for Fe and h i g h e r u p t a k e rates at low e x t e r n a l concentrations (Shaw et al, 1990).…”

Section: P R O D U C T I O N Of S I D E R O P H O R E S Is W I D E S mentioning

confidence: 98%

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Nutrient uptake in mycorrhizal symbiosis

1994

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The role of mycorrhizal fungi in acquisition of mineral nutrients by host plants is examined for three groups of mycorrhizas. These are; the ectomycorrhizas (ECM), the ericoid mycorrhizas (EM), and the vesicular-arbuscular mycorrhizas (VAM). Mycorrhizal infection may affect the mineral nutrition of the host plant directly by enhancing plant growth through nutrient acquisition by the fungus, or indirectly by modifying transpiration rates and the composition of rhizosphere microflora.A capacity for the external hyphae to take up and deliver nutrients to the plant has been demonstrated for the following nutrients and mycorrhizas; P (VAM, EM, ECM), NH4 ÷ (VAM, EM, ECM), N0 3-(ECM), K (VAM, ECM), Ca (VAM, EM), S042-(VAM), Cu (VAM), Zn (VAM) and Fe (EM). In experimental chambers, the external hyphae of VAM can deliver up to 80% of plant P, 25% of plant N, 10% of plant K, 25% of plant Zn and 60% of plant Cu. Knowledge of the role of mycorrhiza in the uptake of nutrients other than P and N is limited because definitive studies are few, especially for the ECM. Although further quantification is required, it is feasible that the external hyphae may provide a significant delivery system for N, K, Cu and Zn in addition to P in many soils. Proposals that ECM and VAM fungi contribute substantially to the Mg, B and Fe nutrition of the host plant have not been substantiated.ECM and EM fungi produce ectoenzymes which provide host plants with the potential to access organic N and P forms that are normally unavailable to VAM fungi or to non mycorrhizal roots. The relative contribution of these nutrient sources requires quantification in the field.Further basic research, including the quantification of nutrient uptake and transport by fungal hyphae in soil and regulation at the fungal-plant interface, is essential to support the selection and utilization of mycorrhizal fungi on a commercial scale.

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Section: Nitrogenmentioning

confidence: 95%

Section: P R O D U C T I O N Of S I D E R O P H O R E S Is W I D E S mentioning

confidence: 98%

Nutrient uptake in mycorrhizal symbiosis

1994

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“…These structures provide plants with nitrogen and phosphorus and protect plants from disease (18) and heavy metal contamination (34,52). Different fungal species, and even isolates of the same species, can vary in their tolerance of harsh conditions (33,50) and in the ability to help plants grow in extreme environments, such as acidic mine tailings (51) and coal spoils (24,28).…”

mentioning

confidence: 99%

Ectomycorrhizal Fungal Associates of Pinus contorta in Soils Associated with a Hot Spring in Norris Geyser Basin, Yellowstone National Park, Wyoming

Cullings

Makhija²

2001

Appl Environ Microbiol

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Molecular methods and comparisons of fruiting patterns (i.e., presence or absence of fungal fruiting bodies in different soil types) were used to determine ectomycorrhizal (EM) associates of Pinus contorta in soils associated with a thermal soil classified as ultra-acidic to extremely acidic (pH 2 to 4). EM were sampled by obtaining 36 soil cores from six paired plots (three cores each) of both thermal soils and forest soils directly adjacent to the thermal area. Fruiting bodies (mushrooms) were collected for molecular identification and to compare fruiting body (above-ground) diversity to below-ground diversity. Our results indicate (i) that there were significant decreases in both the level of EM infection (130 ؎ 22 EM root tips/core in forest soil; 68 ؎ 22 EM root tips/core in thermal soil) and EM fungal species richness (4.0 ؎ 0.5 species/core in forest soil; 1.2 ؎ 0.2 species/core in thermal soil) in soils associated with the thermal feature; (ii) that the EM mycota of thermal soils was comprised of a small set of dominant species and included very few rare species, while the EM mycota of forest soils contained a few dominant species and several rare EM fungal species; (iii) that Dermocybe phoenecius and a species of Inocybe, which was rare in forest soils, were the dominant EM fungal species in thermal soils; (iv) that other than the single Inocybe species, there was no overlap in the EM fungal communities of the forest and thermal soils; and (v) that the fungal species forming the majority of the above-ground fruiting structures in thermal soils (Pisolithus tinctorius, which is commonly used in remediation of acid soils) was not detected on a single EM root tip in either type of soil. Thus, P. tinctorius may have a different role in these thermal soils. Our results suggest that this species may not perform well in remediation of all acid soils and that factors such as pH, soil temperature, and soil chemistry may interact to influence EM fungal community structure. In addition, we identified at least one new species with potential for use in remediation of hot acidic soil.Ectomycorrhizae (EM) are complex interactions between fungi and plant roots, are formed mainly by basidiomycete fungi (39,47), and are the dominant nutrient-gathering organ in temperate ecosystems (45). These structures provide plants with nitrogen and phosphorus and protect plants from disease (18) and heavy metal contamination (34, 52). Different fungal species, and even isolates of the same species, can vary in their tolerance of harsh conditions (33, 50) and in the ability to help plants grow in extreme environments, such as acidic mine tailings (51) and coal spoils (24, 28). Because of these abilities, EM fungi are used to aid tree growth in programs designed to reclaim habitats altered by factors such as mining, nutrient deposition, and acid rain (11, 17). Thus, it has become increasingly important to determine in situ reactions of EM fungal communities to soil modifications that could inhibit plant growth.Soil pH and temperature ca...

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“…Shoot to root ratios of Fe content (Ixg/g) of mycorrhizal plants were always lower than those of nonmycorrhizal plants, indicating that proportionally less Fe was transported to the shoots of mycorrhizal plants (Table 1). Shaw et al (1990) reported that growth of H. ericae was not inhibited in solution cultures containing an external range of 0-144 I~g/ml Fe. The present investigation showed a stimulation of fungal growth at 150 ~g/ml Fe compared to the control but a reduction in yield at higher Fe concentrations.…”

Section: Resultsmentioning

confidence: 98%

“…The role of mycorrhizas in environments containing elevated and potentially toxic levels of heavy metals has received limited attention, but there is evidence that the success of ericaceous plants in some extreme terrestrial environments may be partly attributable to their mycorrhizal partners (Bradley et al~ 1981;Burt et al 1986;Hashem 1990;Leake et al 1990;Shaw et al 1990). Shaw et al (1990) …”

Section: Introductionmentioning

confidence: 98%