ACCUMULATION OF CALCIUM OXALATE IN THE MANTLE OF ECTOMYCORRHIZAL ROOTS OF <i>PINUS RADIATA</i> AND <i>EUCALYPTUS MARGINATA</i>

Malajczuk, N.; Cromack, Kermit

doi:10.1111/j.1469-8137.1982.tb03411.x

Cited by 103 publications

(39 citation statements)

References 14 publications

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“…Although the preservation of these older root nodules does not provide visual evidence of mycorrhizal fungi, the presence of calcium in only the root nodules offers some chemical evidence that fungi were once there. In extant plants, mycorrhizal fungi often contain a large amount of calcium oxalate, which is used to break down soil into usable minerals (4,29).…”

Section: Discussionmentioning

confidence: 99%

Morphological and functional stasis in mycorrhizal root nodules as exhibited by a Triassic conifer

Schwendemann

Decombeix

Taylor

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Mycorrhizal root nodules occur in the conifer families Araucariaceae, Podocarpaceae, and Sciadopityaceae. Although the fossil record of these families can be traced back into the early Mesozoic, the oldest fossil evidence of root nodules previously came from the Cretaceous. Here we report on cellularly preserved root nodules of the early conifer Notophytum from Middle Triassic permineralized peat of Antarctica. These fossil root nodules contain fungal arbuscules, hyphal coils, and vesicles in their cortex. Numerous glomoid-type spores are found in the peat matrix surrounding the nodules. This discovery indicates that mutualistic associations between conifer root nodules and arbuscular mycorrhizal fungi date back to at least the early Mesozoic, the period during which most of the modern conifer families first appeared. Notophytum root nodules predate the next known appearance of this association by 100 million years, indicating that this specialized form of mycorrhizal symbiosis has ancient origins.

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Section: Discussionmentioning

confidence: 99%

Morphological and functional stasis in mycorrhizal root nodules as exhibited by a Triassic conifer

Schwendemann

Decombeix

Taylor

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…These deposits varied in size and number and, although there was some variation in distribution, most of them occurred either at the mantle surface or among loosely organized outer mantle hyphae. Crystals have been noted previously in ectomycorrhizas formed by Rhizopogon species and the closely related genus Suillus with several genera of Pinaceae (Malajczuk & Cromack, 1982 ;Agerer, 1990 ;Treu, 1990 ;Massicotte et al, 1992Massicotte et al, , 1994Agerer et al, 1996) and it has been suggested that these deposits might be partially responsible for the various colours displayed by fungal mantles (Massicotte et al, 1994). It is possible that these deposits are of calcium oxalate, a common extracellular substance localized along hyphae of many fungal species (O'Connell et al, 1983 ;Whitney & Arnott, 1987).…”

Section: mentioning

confidence: 99%

Biology of the ectomycorrhizal fungal genus, Rhizopogon

et al. 1999

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The morphology and anatomy of ectomycorrhizas of Rhizopogon arctostaphyli, R. ellenae, R. flavofibrillosus, R. occidentalis, R. rubescens, R. smithii, R. subcaerulescens and R. truncatus synthesized on Ponderosa pine (Pinus ponderosa) in glasshouse conditions using spore slurries, are described and compared. All species produced a well‐developed Hartig net, and a well‐developed fungal mantle. The mantles of R. arctostaphyli, R. smithii and R. subcaerulescens ectomycorrhizas were two‐layered with outer mantle hyphae of wider diameter than inner mantle hyphae. The mantle of R. subcaerulescens ectomycorrhizas also had distinctive peg‐like structures (cystidia) along peripheral hyphae. Rhizopogon truncatus ectomycorrhizas were tuberculate in morphology and had a rind‐like mantle enclosing adjacent roots. In addition, several species exhibited crystal inclusions in the outer mantle, presumably at the interface between mantle and soil.

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“…If, in addition to their large surface area mycorrhizas are associated with chemical activity, the significance for nutrient cycling is immense. There are reports of exudation of organic acids by fungi and mycorrhizas (Graustein, Cromack & Sollins, 1977;Malajczuk & Cromack, 1982;Jurinak et al, 1986), of the accumulation of phosphorus as polyphosphate by mycorrhizas ) and of increased phosphatase activity at the mycorrhizal surface (although the latter are rather variable -see Antibus et al, 1981;Dighton, 1983 ;Dodd et al, 1987). The further definition of this potentially active role of mycorrhizas in forests, particularly where mycorrhizas are concentrated as a root mat or in the litter layers, seems to us to be a high research priority (and see also Hetrick, 1989;Bolan, 1991).…”

Section: Nutrientsmentioning

confidence: 99%

Nutrient cycling in forests

1993

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SUMMARY Studies of nutrient cycling in forests span more than 100 yr. In earlier years, most attention was given to the measurement of the pools of nutrients in plants and soil and of the return of nutrients from plant to soil in litterfall. The past 20 yr or so have seen a major concentration on the processes of nutrient cycling, with particular emphasis on those processes by which the supply of nutrients to the growing forest is sustained. In the more highly productive forests, up to 10 tonnes of litter of low nutritional quality is deposited annually on the forest floor. The decomposition of this litter, the mineralization of the nutrients it holds, and the uptake of nutrients by tree roots in the carbon‐rich environment which results are the themes of this review. Studies of decomposition of litter in forests have been dominated by the role of nitrogen as a limiting factor, a domination which reflects the preponderance of studies of temperate forests in the Northern Hemisphere. For many forests of the world growing on soils of considerable age, it seems more probable that growth and nutrient cycling are limited by phosphorus (or some other element). There is increasing evidence for a number of forests that phosphorus is immobilized in the first stages of decomposition to a significantly greater extent than is nitrogen. Advances in research will depend, as with studies of soil organic matter, in denning and developing analytical techniques for studying biologically active forms of potentially limiting nutrients, rather than total elemental concentrations. The availability of phosphorus in forests is sustained by phosphorus cycling. More than 50% of the total phosphorus in the surface soils is in organic forms and much of the more labile phosphorus is in the form of diesters. Phosphorus availability is determined by competition between biological and geochemical sinks, and it is clear that the sinks in the rhizosphere (plant roots, microorganisms, soil mineral and organic components) are extensively modified by active processes (e.g. production of exudates, nutrient storage in a variety of organic or polymeric forms and nutrient transport away from sites of uptake). There is abundant evidence that roots of many species exude compounds which have the ability to solubilize sources of phosphorus of otherwise low availability. The significance of root exudates (for example, phosphatases, organic acids) in the functioning of perennial ecosystems has yet to be quantified and there are conflicting reports as to the effects of simple organic acids on phosphorus availability. The distribution of phosphorus sinks and their relative competitiveness and their modification are topics of fundamental importance for future research. In contrast to the mineralization of phosphorus, our knowledge of transformations and availability of nitrogen in forest soils is well‐developed. Net nitrogen mineralization rates approximate rates of nitrogen return in litterfall but the contribution of nitrification is variable. Nitrification is ...

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ACCUMULATION OF CALCIUM OXALATE IN THE MANTLE OF ECTOMYCORRHIZAL ROOTS OF PINUS RADIATA AND EUCALYPTUS MARGINATA

Cited by 103 publications

References 14 publications

Morphological and functional stasis in mycorrhizal root nodules as exhibited by a Triassic conifer

Morphological and functional stasis in mycorrhizal root nodules as exhibited by a Triassic conifer

Biology of the ectomycorrhizal fungal genus, Rhizopogon

Nutrient cycling in forests

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