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Malcolm K, Dighton J, Barkay T. Mercury affects the phylloplane fungal community of blueberry leaves to a lesser extent than plant age. Mycology 2017; 9:49-58. [PMID: 30123661 PMCID: PMC6059040 DOI: 10.1080/21501203.2017.1397063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 10/20/2017] [Indexed: 11/20/2022] Open
Abstract
Mercury (Hg) is a toxic heavy metal pollutant that is globally distributed due to atmospheric deposition to non-point source locations. Leaf surfaces directly sequester atmospheric Hg. Little is known of how phylloplane (leaf surface) fungi are influenced by Hg pollution. Through culture-based methodology, this study analysed fungal phylloplane community identity following a single-dose response to HgCl2 concentrations between 0 and 20 times ambient levels for New Jersey. Time passed following the Hg addition had a strong influence on the fungal phylloplane community, associated with natural successional changes. Mercury, however, did not significantly affect the phylloplane community identity. Notably, the control group was not significantly different than any of the Hg treatments. How the phylloplane functional group responds to Hg pollution has not been previously investigated and more research is needed to fully understand how Hg influences fungal phylloplane ecology.
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Affiliation(s)
- Katalin Malcolm
- Graduate Program in Ecology and Evolution, Rutgers University, New Brunswick, NJ, USA
- Rutgers Pinelands Field Station, New Lisbon, NJ, USA
| | - John Dighton
- Graduate Program in Ecology and Evolution, Rutgers University, New Brunswick, NJ, USA
- Rutgers Pinelands Field Station, New Lisbon, NJ, USA
| | - Tamar Barkay
- Graduate Program in Ecology and Evolution, Rutgers University, New Brunswick, NJ, USA
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA
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2
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Dighton J. Chapter 34 Fungal Degradation of Our Cultural Heritage. Mycology 2017. [DOI: 10.1201/9781315119496-35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Malcolm K, Dighton J. Chapter 11 Ecology of Fungal Phylloplane Epiphytes. Mycology 2017. [DOI: 10.1201/9781315119496-12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Caplan JS, Stone BWG, Faillace CA, Lafond JJ, Baumgarten JM, Mozdzer TJ, Dighton J, Meiners SJ, Grabosky JC, Ehrenfeld JG. Nutrient foraging strategies are associated with productivity and population growth in forest shrubs. Ann Bot 2017; 119:977-988. [PMID: 28119293 PMCID: PMC5604599 DOI: 10.1093/aob/mcw271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 12/07/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND AND AIMS Temperate deciduous forest understoreys are experiencing widespread changes in community composition, concurrent with increases in rates of nitrogen supply. These shifts in plant abundance may be driven by interspecific differences in nutrient foraging (i.e. conservative vs. acquisitive strategies) and, thus, adaptation to contemporary nutrient loading conditions. This study sought to determine if interspecific differences in nutrient foraging could help explain patterns of shrub success and decline in eastern North American forests. METHODS Using plants grown in a common garden, fine root traits associated with nutrient foraging were measured for six shrub species. Traits included the mean and skewness of the root diameter distribution, specific root length (SRL), C:N ratio, root tissue density, arbuscular mycorrhizal colonization and foraging precision. Above- and below-ground productivity were also determined for the same plants, and population growth rates were estimated using data from a long-term study of community dynamics. Root traits were compared among species and associations among root traits, measures of productivity and rates of population growth were evaluated. KEY RESULTS Species fell into groups having thick or thin root forms, which correspond to conservative vs. acquisitive nutrient foraging strategies. Interspecific variation in root morphology and tissue construction correlated with measures of productivity and rates of cover expansion. Of the four species with acquisitive traits, three were introduced species that have become invasive in recent decades, and the fourth was a weedy native. In contrast, the two species with conservative traits were historically dominant shrubs that have declined in abundance in eastern North American forests. CONCLUSIONS In forest understoreys of eastern North America, elevated nutrient availability may impose a filter on species success in addition to above-ground processes such as herbivory and overstorey canopy conditions. Shrubs that have root traits associated with rapid uptake of soil nutrients may be more likely to increase in abundance, while species without such traits may be less likely to keep pace with more productive species.
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Affiliation(s)
- Joshua S. Caplan
- Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ 08901, USA
- Department of Biology, Bryn Mawr College, 101 North Merion Avenue, Bryn Mawr, PA 19010, USA
| | - Bram W. G. Stone
- Department of Biology, University of Mississippi, 30 University Avenue, University, MS 38677, USA
| | - Cara A. Faillace
- Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ 08901, USA
| | - Jonathan J. Lafond
- Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ 08901, USA
| | - Joni M. Baumgarten
- Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ 08901, USA
- Rutgers Pinelands Field Station, PO Box 206, New Lisbon, NJ 08064, USA
| | - Thomas J. Mozdzer
- Department of Biology, Bryn Mawr College, 101 North Merion Avenue, Bryn Mawr, PA 19010, USA
| | - John Dighton
- Rutgers Pinelands Field Station, PO Box 206, New Lisbon, NJ 08064, USA
| | - Scott J. Meiners
- Department of Biological Sciences, Eastern Illinois University, 600 Lincoln Avenue, Charleston, IL 61920, USA
| | - Jason C. Grabosky
- Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ 08901, USA
| | - Joan G. Ehrenfeld
- Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ 08901, USA
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Luo J, Walsh E, Miller S, Blystone D, Dighton J, Zhang N. Root endophytic fungal communities associated with pitch pine, switchgrass, and rosette grass in the pine barrens ecosystem. Fungal Biol 2017; 121:478-487. [PMID: 28390505 DOI: 10.1016/j.funbio.2017.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/26/2017] [Accepted: 01/28/2017] [Indexed: 11/27/2022]
Abstract
Almost all plants in nature harbour fungi in their roots but the knowledge on distribution and the underlying principles of assemblage is still poorly developed for the root-associated fungi. In this study we analysed the root endophytic fungal communities associated with switchgrass, rosette grass, and pitch pine in the acidic, oligotrophic pine barrens ecosystem. A total of 434 fungal isolates were obtained from 600 root segments of 60 plant samples. DNA barcoding and morphological analyses identified 92 fungal species, which belong to 39 genera in six classes. Compared to other ecosystems, the pine barrens has a higher proportion of Leotiomycetes. The fungal community associated with pitch pine was significantly different from those associated with the grasses, while less difference was found between those associated with the two grasses. Our results suggest that edaphic factors and host specificity play a role in shaping root endophytic fungal community. This study also corroborates our previous finding that plant roots in the pine barrens are a rich reservoir of novel fungi.
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Affiliation(s)
- Jing Luo
- Department of Plant Biology, 201 Foran Hall, 59 Dudley Road, Rutgers University, New Brunswick, NJ 08901, USA
| | - Emily Walsh
- Department of Plant Biology, 201 Foran Hall, 59 Dudley Road, Rutgers University, New Brunswick, NJ 08901, USA
| | - Stephen Miller
- Department of Plant Biology, 201 Foran Hall, 59 Dudley Road, Rutgers University, New Brunswick, NJ 08901, USA
| | - David Blystone
- Department of Plant Biology, 201 Foran Hall, 59 Dudley Road, Rutgers University, New Brunswick, NJ 08901, USA
| | - John Dighton
- Rutgers Pinelands Field Station, DEENR, SEBS and Biology, Camden, PO Box 206, 501 Four Mile Road, New Lisbon, NJ 08064, USA
| | - Ning Zhang
- Department of Plant Biology, 201 Foran Hall, 59 Dudley Road, Rutgers University, New Brunswick, NJ 08901, USA; Department of Biochemistry and Microbiology, 76 Lipman Drive, Rutgers University, New Brunswick, NJ 08901, USA.
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Tugay T, Zhdanova NN, Zheltonozhsky V, Sadovnikov L, Dighton J. The influence of ionizing radiation on spore germination and emergent hyphal growth response reactions of microfungi. Mycologia 2017. [DOI: 10.1080/15572536.2006.11832654] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - Nelli N. Zhdanova
- Institute of Microbiology & Virology National Academy of Sciences of Ukraine, Kiev 25214, Ukraine
| | | | - Leonid Sadovnikov
- Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kiev 03028, Ukraine
| | - John Dighton
- Rutgers University Pinelands Field Station, New Lisbon, New Jersey 08064
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Crane S, Barkay T, Dighton J. The effect of mercury on the establishment of Pinus rigida seedlings and the development of their ectomycorrhizal communities. FUNGAL ECOL 2012. [DOI: 10.1016/j.funeco.2011.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Wang Y, Boyd E, Crane S, Lu-Irving P, Krabbenhoft D, King S, Dighton J, Geesey G, Barkay T. Environmental conditions constrain the distribution and diversity of archaeal merA in Yellowstone National Park, Wyoming, U.S.A. Microb Ecol 2011; 62:739-752. [PMID: 21713435 DOI: 10.1007/s00248-011-9890-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 06/04/2011] [Indexed: 05/31/2023]
Abstract
The distribution and phylogeny of extant protein-encoding genes recovered from geochemically diverse environments can provide insight into the physical and chemical parameters that led to the origin and which constrained the evolution of a functional process. Mercuric reductase (MerA) plays an integral role in mercury (Hg) biogeochemistry by catalyzing the transformation of Hg(II) to Hg(0). Putative merA sequences were amplified from DNA extracts of microbial communities associated with mats and sulfur precipitates from physicochemically diverse Hg-containing springs in Yellowstone National Park, Wyoming, using four PCR primer sets that were designed to capture the known diversity of merA. The recovery of novel and deeply rooted MerA lineages from these habitats supports previous evidence that indicates merA originated in a thermophilic environment. Generalized linear models indicate that the distribution of putative archaeal merA lineages was constrained by a combination of pH, dissolved organic carbon, dissolved total mercury and sulfide. The models failed to identify statistically well supported trends for the distribution of putative bacterial merA lineages as a function of these or other measured environmental variables, suggesting that these lineages were either influenced by environmental parameters not considered in the present study, or the bacterial primer sets were designed to target too broad of a class of genes which may have responded differently to environmental stimuli. The widespread occurrence of merA in the geothermal environments implies a prominent role for Hg detoxification in these environments. Moreover, the differences in the distribution of the merA genes amplified with the four merA primer sets suggests that the organisms putatively engaged in this activity have evolved to occupy different ecological niches within the geothermal gradient.
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Affiliation(s)
- Yanping Wang
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA
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11
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Karpati AS, Handel SN, Dighton J, Horton TR. Quercus rubra-associated ectomycorrhizal fungal communities of disturbed urban sites and mature forests. Mycorrhiza 2011; 21:537-547. [PMID: 21287207 DOI: 10.1007/s00572-011-0362-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Accepted: 01/17/2011] [Indexed: 05/30/2023]
Abstract
The presence and quality of the belowground mycorrhizal fungal community could greatly influence plant community structure and host species response. This study tests whether mycorrhizal fungal communities in areas highly impacted by anthropogenic disturbance and urbanization are less species rich or exhibit lower host root colonization rates when compared to those of less disturbed systems. Using a soil bioassay, we sampled the ectomycorrhizal fungal (EMF) communities associating with Quercus rubra (northern red oak) seedlings in soil collected from seven sites: two mature forest reference sites and five urban sites of varying levels of disturbance. Morphological and polymerase chain reaction-restriction fragment length polymorphism analyses of fungi colonizing root tips revealed that colonization rates and fungal species richness were significantly lower on root systems of seedlings grown in disturbed site soils. Analysis of similarity showed that EMF community composition was not significantly different among several urban site soils but did differ significantly between mature forest sites and all but one urban site. We identified a suite of fungal species that occurred across several urban sites. Lack of a diverse community of belowground mutualists could be a constraint on urban plant community development, especially of late-successional woodlands. Analysis of urban EMF communities can add to our understanding of urban plant community structure and should be addressed during ecological assessment before pragmatic decisions to restore habitats are framed.
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Affiliation(s)
- Amy S Karpati
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, NJ, 08901, USA.
| | - Steven N Handel
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, NJ, 08901, USA
| | - John Dighton
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Thomas R Horton
- Department of Environmental and Forest Biology, SUNY-ESF, Syracuse, NY, 13210, USA
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Stanwood JM, Dighton J. Seasonality and management, not proximity to highway, affect species richness and community composition of epiphytic phylloplane fungi found on (wild and cultivated) Vaccinium spp. FUNGAL ECOL 2011. [DOI: 10.1016/j.funeco.2011.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Landesman WJ, Dighton J. Shifts in microbial biomass and the bacteria: fungi ratio occur under field conditions within 3 h after rainfall. Microb Ecol 2011; 62:228-236. [PMID: 21360141 DOI: 10.1007/s00248-011-9811-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 01/17/2011] [Indexed: 05/30/2023]
Abstract
Increases in the frequency of soil drying and extreme precipitation projected by climate models may have important consequences for soil microbial community composition. However, the microbial response may occur over short time scales not captured by traditional sampling methods. Following a 2-year rainfall exclusion experiment in a pine forest ecosystem, we used phospholipid fatty acid profiling to measure the hourly, daily, and weekly-scale response of soil microbial biomass and the bacteria/fungi ratio to a precipitation event. We compared this response to the rewetting of un-manipulated plots. Within 3 h of watering, we detected increases in fungal and bacterial biomass of 125% and 66%, respectively, in un-manipulated plots, but only small increases in biomass within drought plots. We detected a decrease in the bacteria/fungi ratio in un-manipulated plots and an increase in this ratio in the drought plots. This surprising result was likely caused by root mortality (resulting from the previous 2-year rain exclusion) and an increase in ammonium pools in the drought plots, both of which could have suppressed fungal growth. Whereas past research suggests that soil microbes are resistant to drying-rewetting stress and to changes in annual precipitation patterns, here we show that microbes are sensitive to soil drying, but highly resilient, recovering within hours or days of a rain event. We propose that more emphasis be placed on hourly-scale field measurements of soil microbial community structure in future climate change studies.
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Affiliation(s)
- William J Landesman
- Graduate Program in Ecology and Evolution, Rutgers University, New Brunswick, NJ 08901, USA.
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14
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DiLeo K, Donat K, Min-Venditti A, Dighton J. A correlation between chytrid abundance and ecological integrity in New Jersey pine barrens waters. FUNGAL ECOL 2010. [DOI: 10.1016/j.funeco.2009.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Crane S, Dighton J, Barkay T. Growth responses to and accumulation of mercury by ectomycorrhizal fungi. Fungal Biol 2010; 114:873-80. [PMID: 20943197 DOI: 10.1016/j.funbio.2010.08.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Revised: 07/21/2010] [Accepted: 08/12/2010] [Indexed: 11/18/2022]
Abstract
Heavy metals have been shown to negatively affect the growth of ectomycorrhizal fungi (ECMF). In addition, ECMF have been shown to accumulate heavy metals and to protect host trees from metal toxicity. However, specific literature on the interactions between ECMF and mercury (Hg) is scant. This paper describes the responses of ECMF to Hg in axenic culture conditions. Six ECMF from an area with no known history of direct Hg contamination were tested to determine their sensitivity to Hg. ECMF were incubated on solid medium amended with Hg (0-50μM) as HgCl₂ and the effect of Hg on radial growth was determined. The effect of preexposure cultivation on Hg sensitivity, the effect of Hg on biomass production, and the ability to accumulate Hg were determined for four of the ECMF. At micromolar concentrations, Hg significantly inhibited the radial growth rate of ECMF. This inhibitory effect was lessened in some ECMF when an established colony was exposed to Hg. Mercury lowered biomass production by some ECMF, and ECMF accumulate Hg from a solid growth substrate in direct relation to the amount of Hg added to the media. Possible implications for ECMF communities in Hg-impacted areas are discussed.
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Affiliation(s)
- Sharron Crane
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, USA.
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Abstract
Radionuclides in the environment are one of the major concerns to human health and ecotoxicology. The explosion at the Chernobyl nuclear power plant renewed interest in the role played by fungi in mediating radionuclide movement in ecosystems. As a result of these studies, our knowledge of the importance of fungi, especially in their mycorrhizal habit, in long-term accumulation of radionuclides, transfer up the food chain and regulation of accumulation by their host plants was increased. Micro-fungi have been found to be highly resilient to exposure to ionizing radiation, with fungi having been isolated from within and around the Chernobyl plant. Radioresistance of some fungal species has been linked to the presence of melanin, which has been shown to have emerging properties of acting as an energy transporter for metabolism and has been implicated in enhancing hyphal growth and directed growth of sensitized hyphae towards sources of radiation. Using this recently acquired knowledge, we may be in a better position to suggest the use of fungi in bioremediation of radioactively contaminated sites and cleanup of industrial effluent.
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Affiliation(s)
- John Dighton
- Rutgers University Pinelands Field Station, New Lisbon, NJ 08064, USA.
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Nix-Stohr S, Moshe R, Dighton J. Effects of propagule density and survival strategies on establishment and growth: further investigations in the phylloplane fungal model system. Microb Ecol 2008; 55:38-44. [PMID: 17436116 DOI: 10.1007/s00248-007-9248-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 02/13/2007] [Accepted: 03/12/2007] [Indexed: 05/14/2023]
Abstract
This work builds on an earlier culture study where we determined that species diversity of competing saprotrophic phyllpolane fungi had only a negligible effect on the establishment and coexistence of a target fungus, Pestalotia vaccinii. Here, we explore preliminary evidence suggesting that spore density is a more important contributing factor to colonization and coexistence. We examine the influence of propagule density in vitro on establishment and growth of select members of the phylloplane of Vaccinium macrocarpon (American cranberry). To evaluate the response of the weak pathogen P. vaccinii to changes in competitors spore density, we chose saprotrophs from the previous investigation that had the greatest inhibitory effect on the establishment of P. vaccinii (Curvularia lunata), an intermediate inhibitory effect (Alternaria alternata) and the least inhibitory effect (Penicillium sp.). A constant target spore concentration of 50 viable spores of P. vaccinii was pit against densities of the three individual competitors ranging between 12 and 200 spores. As viable propagule density increased, establishment and coexistence of P. vaccinii significantly decreased, with C. lunata and A. alternata decreasing the growth of P. vaccinii more than Penicillium sp. Concomitantly, both C. lunata and Penicillium sp. were not significantly affected by overall spore density but were significantly affected by the presence of P. vaccinii. A. alternata, on the other hand, was not significantly influenced by the presence of P. vaccinii but was significantly affected by overall spore density. An in vitro investigation into the effect of interspecific competition on mycelial growth suggests how different survival strategies and community assembly rules might influence both growth and development. Growth of P. vaccinii was significantly less when interacting with C. lunata than when interacting with either A. alternata or Penicillium sp. Conversely, P. vaccinii had the greatest effect on the growth of C. lunata, less of an effect on the growth of A. alternata, and the least effect on Penicillium sp.
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Affiliation(s)
- Shannon Nix-Stohr
- Department of Plant Pathology, University of Georgia, Griffin, GA 30223-1797, USA.
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Tugay T, Zhdanova NN, Zheltonozhsky V, Sadovnikov L, Dighton J. The influence of ionizing radiation on spore germination and emergent hyphal growth response reactions of microfungi. Mycologia 2006; 98:521-7. [PMID: 17139845 DOI: 10.3852/mycologia.98.4.521] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The accident at the Chernobyl Atomic Energy Station resulted in radiation contamination of large tracts of land and particularly the reactor building itself. Sustained exposure of microfungi to radiation appears to have resulted in formerly unknown adaptive features, such as directed growth of fungi to sources of ionizing radiation. We evaluate here spore germination and subsequent emergent hyphal growth of microfungi in the presence of pure gamma or mixed beta and gamma radiation of fungi isolated from a range of long term background radiation levels. Conidiospore suspensions were exposed to collimated beams of radiation and percent spore germination and length of emergent hyphae were measured. All fungal species isolated from background radiation showed inhibition or no response in germination when irradiated. Isolates from sites with elevated radiation showed a stimulation in spore germination (69% mixed radiation and 46% for gamma irradiation). Most isolates from low background radiation sites showed a significant reduced or no response to exposure to either source of radiation, whereas the stimulatory effect of experimental exposure to radiation appeared to increase in magnitude as prior exposure to radiation increased. We propose that the enhanced spore germination and hyphal growth seen in the exposure trials is induced by prior long term exposure to radiation and these factors could be important in controlling the decomposition of radionuclide-bearing resources in the environment.
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Affiliation(s)
- Tatyana Tugay
- Institute of Microbiology & Virology National Academy of Sciences of Ukraine, Kiev 25214, Ukraine
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Karpenko YV, Redchitz TI, Zheltonozhsky VA, Dighton J, Zhdanova NN. Comparative responses of microscopic fungi to ionizing radiation and light. Folia Microbiol (Praha) 2006; 51:45-9. [PMID: 16821711 DOI: 10.1007/bf02931449] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Microscopic fungi of 47 species and 24 genera isolated from radioactive soil and other radioactive substrates of a 10-km alienation zone from Chernobyl Nuclear Power Plant were investigated. Only 19 % of such fungi showed toward the ionizing irradiation source positive radiotropism. Strains with best-defended radiotropism responded to the influence of weak white light. Both of these responses (radiotropism and photostimulation) were of an adaptive nature, were found in both dark-colored and light-colored micromycetes and were probably a strain-related feature.
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Affiliation(s)
- Y V Karpenko
- Department of Physiology and Taxonomy of Fungi, Institute of Microbiology and Virology, Kiev, Ukraine.
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Baxter JW, Dighton J. Phosphorus source alters host plant response to ectomycorrhizal diversity. Mycorrhiza 2005; 15:513-523. [PMID: 15809869 DOI: 10.1007/s00572-005-0359-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Accepted: 02/25/2005] [Indexed: 05/24/2023]
Abstract
We examined the influence of phosphorus source and availability on host plant (Pinus rigida) response to ectomycorrhizal diversity under contrasting P conditions. An ectomycorrhizal richness gradient was established with equimolar P supplied as either inorganic phosphate or organic inositol hexaphosphate. We measured growth and N and P uptake of individual P. rigida seedlings inoculated with one, two, or four species of ectomycorrhizal fungi simultaneously and without mycorrhizas in axenic culture. Whereas colonization of P. rigida by individual species of ectomycorrhizal fungi decreased with increasing fungal richness, colonization of all species combined increased. Plant biomass and N content increased across the ectomycorrhizal richness gradient in the organic but not the inorganic P treatment. Plants grown under organic P conditions had higher N concentration than those grown under inorganic P conditions, but there was no effect of richness. Phosphorus content of plants grown in the organic P treatment increased with increasing ectomycorrhizal richness, but there was no response in the inorganic P treatment. Phosphorus concentration was higher in plants grown at the four-species richness level in the organic P treatment, but there was no effect of diversity under inorganic P conditions. Overall, few ectomycorrhizal composition effects were found on plant growth or nutrient status. Phosphatase activities of individual ectomycorrhizal fungi differed under organic P conditions, but there was no difference in total root system phosphatase expression between the inorganic or organic P treatments or across richness levels. Our results provide evidence that plant response to ectomycorrhizal diversity is dependent on the source and availability of P.
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Affiliation(s)
- James W Baxter
- Rutgers Pinelands Field Station, Rutgers University, New Lisbon, NJ 08064, USA.
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Dighton J, White J, Oudemans P. Introduction. Mycology 2005. [DOI: 10.1201/9781420027891.ch0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Abstract
During the last 15 years, about 2000 strains of 200 species of 98 genera of fungi have been isolated from around the Chernobyl Atomic Energy Station. Many of these microfungi are capable of growing into and decomposing 'hot particles'; carbon based radioactive graphite from the reactor and there are suggestions that some fungi actively direct their growth toward sources of radioactivity, possibly attracted to the carbon skeleton of these structures. In our experiments, we eliminated the confounding effects of carbon as a fungal resource, by developing experimental protocols that expose fungal spores and their germinating hyphae to directional sources of ionizing radiation allowing us to measure fungal response to ionizing radiation per se. We show that both beta and gamma radiation promote directional growth of hyphae towards the source of ionizing radiation.
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Affiliation(s)
- Nelli N Zhdanova
- Institute of Microbiology & Virology, National Academy of Sciences of the Ukraine, Kiev 25214, Ukraine
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McHugh JM, Dighton J. Influence of Mycorrhizal Inoculation, Inundation Period, Salinity, and Phosphorus Availability on the Growth of Two Salt Marsh Grasses, Spartina alterniflora Lois. and Spartina cynosuroides (L.) Roth., in Nursery Systems. Restor Ecol 2004. [DOI: 10.1111/j.1061-2971.2004.03109.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Stohr SN, Dighton J. Effects of species diversity on establishment and coexistence: a phylloplane fungal community model system. Microb Ecol 2004; 48:431-438. [PMID: 15692863 DOI: 10.1007/s00248-003-1064-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2003] [Accepted: 12/04/2003] [Indexed: 05/24/2023]
Abstract
A model system was devised, evaluating the influence that species diversity (species richness) has on fungal establishment and coexistence. Seven members of the fungal phylloplane community of Vaccinium macrocarpon (American cranberry) were selected to assess how species diversity affected development and coexistence of another community member, Pestalotia vaccinii. Pestalotia was engaged in competitive interactions on 1% Malt Extract Agar (MEA) petri dishes with each of the seven individual saprotrophs (two-way interaction), in random combinations with three of the seven saprotrophs (four-way interaction), and in random combinations with five of the seven saprotrophs (six-way interaction). The saprotrophic fungi used in this study were Aspergillus sp., Alternaria alternata, Cladosporium cladosporoides, Curvularia lunata, Epicoccum purpuracens, Penicillium sp., and Pithomyces chartarum. We hypothesized that species diversity would have a significant impact on the establishment and coexistence of Pestalotia vaccinii in culture. In an effort to minimize density-dependent effects, the number of viable spores employed in the three types of interactions was kept constant. Target spore concentrations of 50 viable spores of P. vaccinii and 50 saprotroph spores were used, regardless of the number of species involved in the interaction. This proved to be a very important factor in the experiment. As our results show, species diversity had little or no effect on the establishment and coexistence of Pestalotia vaccinii; however, spore density played an extremely important role in the establishment and development of fungal propagules in our model.
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Affiliation(s)
- S N Stohr
- Rutgers University Pinelands Field Station, P.O. Box 206, New Lisbon, NJ, 08064, USA.
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Baxter JW, Dighton J. Ectomycorrhizal diversity alters growth and nutrient acquisition of grey birch (Betula populifolia) seedlings in host-symbiont culture conditions. New Phytol 2001; 152:139-149. [PMID: 35974479 DOI: 10.1046/j.0028-646x.2001.00245.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
• The influence of ectomycorrhizal fungal diversity on plant performance was investigated by establishing a gradient of ectomycorrhizal diversity on Betula populifolia (grey birch) seedlings. • We measured growth, as well as N and P uptake, of individual B. populifolia seedlings inoculated with replicate one, two and four species 'communities' of ectomycorrhizal fungi simultaneously and without mycorrhizas in axenic culture. • Colonization of B. populifolia by individual species of ectomycorrhizal fungi decreased with increasing fungal diversity although total colonization increased. Shoot biomass decreased with increasing ectomycorrhizal diversity and mycorrhizal root biomass increased. Plant biomass did not differ with individual mycorrhizal species or composition. Shoot N concentration showed a small increase with increasing ectomycorrhizal diversity. Whole plant P content and concentration increased across the ectomycorrhizal diversity gradient. Despite higher mycorrhizal colonization rates with increasing fungal diversity, plant growth and nutrient responses were best explained by changes in ectomycorrhizal diversity. • Greater ectomycorrhizal diversity per se, rather than colonization or composition, increased mycorrhizal root biomass at the expense of shoot biomass and increased P uptake of B. populifolia seedlings.
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Affiliation(s)
- James W Baxter
- Rutgers Pinelands Field Station, Rutgers University, PO Box 206, New Lisbon, NJ 08064 USA
| | - John Dighton
- Rutgers Pinelands Field Station, Rutgers University, PO Box 206, New Lisbon, NJ 08064 USA
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Abstract
Abstract
The growth of Aphelenchoides sp. populations was investigated in vitro with
17 different fungal species as food source. Nematode mass cultures were
obtained with saprophytic (Agrocybe, Chaetomium) and especially with
mycorrhizal fungi (Cenococcum, Hymenoscyphus, Laccaria). Mitosporic species,
like Alternaria, Monocillium or Penicillium, were generally meagre or
non-hosts. This poor host suitability is likely due to the release of toxic
metabolites (e.g. antibiotics) and/or to morphological differences (e.g.,
forming of conidiophores) by the fungi. Frequent grazing of nematodes on
mycorrhizal mycelia may be of major significance for the establishment and
maintenance of mycorrhizal associations in the field. Food preference of
Aphelenchoides sp. was tested in choice chamber experiments. Nematodes
showed a marked preference for particular fungal species. They changed food
source with time, indicating a “mixed diet” selection, probably a strategy
to avoid the concentration of toxic metabolites. The attractiveness of a
fungus was not necessarily correlated with its suitability as a host. That a
poor fungal host can be a strong nematode attractant and influence their
spatial distribution in the soil has implications for nematode populations
in the field. In Laborexperimenten wurde die Vermehrung des Nematoden
Aphelenchoides sp. mit 17 verschiedenen Pilzspezies als Nahrungsgrundlage
untersucht. Neben saprophytischen Arten (Agrocybe, Chaetomium) eigneten sich
insbesondere Mykorrhizapilze (Cenococcum, Hymenoscyphus, Laccaria) für eine
Massenvermehrung. Eine schlechte Nahrungsquelle stellten mitosporische
Arten, wie Alternaria, Monocillium oder Penicillium, dar. Dies dürfte auf
toxische Stoffwechselprodukte (z.B., Antibiotika) und/oder auf
morphologische Unterschiede (z.B., Sporenbildung) zurückzuführen sein. Die
gute Vermehrung der Nematoden an Mykorrhizapilzen ist von weitreichender
Bedeutung für das Freiland. Negative Auswirkungen auf die Ausbildung und
Funktion von Mykorrhiza im Boden sind zu erwarten. In
Nahrungswahlexperimenten zeigte Aphelenchoides sp. eine ausgeprägte
Präferenz für bestimmte Pilzarten. Das Wechseln zwischen den einzelnen
Pilzspezies weist auf die Bevorzugung von “Mischnahrung” hin. Dies dürfte
eine Strategie zur Vermeidung von hohen Konzentrationen toxischer
Nahrungsbestandteile sein. Präferenz und Nahrungsqualität standen nur in
geringem Zusammenhang. Somit können auch Pilze, die eine schlechte
Nahrungsquelle darstellen, attraktiv auf Nematoden wirken und deren
Verbreitung in Boden und Rhizosphäre beeinflussen.
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Baxter JW, Pickett STA, Carreiro MM, Dighton J. Ectomycorrhizal diversity and community structure in oak forest stands exposed to contrasting anthropogenic impacts. ACTA ACUST UNITED AC 1999. [DOI: 10.1139/b99-039] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We compared the ectomycorrhizal community structure of oak forest stands located in either an urban or a rural area. Urban stands had higher N deposition rates, soil heavy metal levels, and earthworm counts than rural stands. Ectomycorrhizal types were quantified on roots of mature oak (Quercus) in soil cores and on Quercus rubra L. seedlings grown in soil cores in the glasshouse. Twenty-six ectomycorrhizal types were distinguished on mature oak in rural soils versus 16 in urban soils. Nine ectomycorrhizal types were distinguished on Q. rubra seedlings grown in rural soils versus seven in urban soils. Despite fewer ectomycorrhizal types in urban soils, richness of ectomycorrhizal types per centimetre fine root of mature oak or Q. rubra seedlings did not differ between urban and rural soils. Ectomycorrhizal colonization (ectomycorrhizal tips/m fine root) was lower in urban than rural soil cores but higher on Q. rubra seedlings grown in urban versus rural soils. Fine root length per unit soil volume was higher in urban than rural stands. No difference in fine root length was observed between Q. rubra seedlings grown in urban and rural soils. These differences in ectomycorrhizal community structure between the urban and rural stands are likely due to anthropogenic impacts.Key words: air pollution, anthropogenic impacts, community structure, diversity, ectomycorrhiza, Quercus rubra.
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Baxter JW, Pickett ST, Carreiro MM, Dighton J. Ectomycorrhizal diversity and community structure in oak forest stands exposed to contrasting anthropogenic impacts. ACTA ACUST UNITED AC 1999. [DOI: 10.1139/cjb-77-6-771] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Jones DR, Eason WR, Dighton J. Foliar leaching of 137Cs from Eriophorum vaginatum L., Scirpus caespitosus L. and Erica tetralix L. Environ Pollut 1998; 99:247-254. [PMID: 15093318 DOI: 10.1016/s0269-7491(97)00171-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/1997] [Accepted: 10/15/1997] [Indexed: 05/24/2023]
Abstract
Evidence of extensive leaching losses of nutrients, particularly of K, suggest that loss of 137Cs by foliar leaching could be considerable and could stimulate further root uptake and redistribution of 137Cs in plants. This study investigated the foliar leaching of 137Cs from two deciduous graminoid species, Eriophorum vaginatum and Scirpus caespitosus and one evergreen shrub, Erica tetralix. Plants were labelled with 137Cs via the roots and subjected to a leaching treatment in August and November and changes in both leachate and plant 137Cs activity were determined. Leaching losses were significantly reduced in November compared with August in the deciduous species, but not in the evergreen E. tetralix. A reduction in the total activity of 137Cs of leached plants was observed not only in leaves but also in stems and roots in some instances, suggesting that 137Cs from these organs had been redistributed to replenish that lost by leaching from the leaves. The data suggest that leaching losses were greater from older and senescent leaves than from younger leaves of E. vaginatum. The extent to which this is an accurate representation of foliar leaching of field-grown plants by rainfall, and the likely fate of 137Cs lost by foliar leaching are discussed.
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Affiliation(s)
- D R Jones
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion, Wales, UK
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Halley JM, Robinson CH, Comins HN, Dighton J. Predicting Straw Decomposition by a Four-Species Fungal Community: A Cellular Automaton Model. J Appl Ecol 1996. [DOI: 10.2307/2404979] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Gray SN, Dighton J, Jennings DH. The physiology of basidiomycete linear organs: III. Uptake and translocation of radiocaesium within differentiated mycelia of Armillaria spp. growing in microcosms and in the field. New Phytol 1996; 132:471-482. [PMID: 26763643 DOI: 10.1111/j.1469-8137.1996.tb01867.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Autoradiography and quantitative image analysis were used to measure (137) Cs distribution and translocation through mycelia of A. gallica Marxmuller & Romagn. and A. ostoyae (Romagn.) Herink growing in small microcosms in the laboratory. Rhizomorphs of A. gallica were labelled with (134) Cs in the field, and the translation of radiolabel measured after excavation and destructive harvesting. The flux of radiocaesium through rhizomorphs was estimated to be greater than through undifferentiated hyphae, and greater through rhizomorphs growing in the field than through rhizomorphs grown across homogeneous media in the laboratory'. Differentiation within mycelia resulting in melanization or rhizomorph formation cave rise to increased heterogeneity in the (137) Cs distribution through laboratory microcosms compared with that through microcosms containing undifferentiated mycelia. Radiocaesium leaked from undifferentiated hyphae into the surrounding medium, but melanized regions of the mycelium appeared to be conservative for radiocaesium. These findings provide further evidence for the importance of filamentous fungi in determining the distribution and rate of release of radiocaesium currently present in the environment as a result of weapons testing and the accident at the Chernobyl nuclear reactor.
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Affiliation(s)
- S N Gray
- Institute of Terrestrial Ecology, Merlewood Research Station, Winder mere Road, Grange-over-Sands, Cumbria LA 11 6JU UKDepartment of Genetics & Microbiology, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, UK
| | - J Dighton
- Institute of Terrestrial Ecology, Merlewood Research Station, Winder mere Road, Grange-over-Sands, Cumbria LA 11 6JU UKDepartment of Genetics & Microbiology, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, UK
| | - D H Jennings
- Institute of Terrestrial Ecology, Merlewood Research Station, Winder mere Road, Grange-over-Sands, Cumbria LA 11 6JU UKDepartment of Genetics & Microbiology, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, UK
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Abstract
Comparisons are made between nutrient cycling systems of arctic tundra, temperate forest, tropical forest, grassland, arable, and desert ecosystems. Detailed nutrient budgets are not given, but general differences between ecosystems are discussed primarily in relation to the role of soil fungi. General discussion reviews the impact of anthropogenic factors, including land management, pollution, and climate change on the role of fungi in nutrient cycling. Areas where further research is needed to complete our understanding of the functional aspects of fungi and nutrient cycling are highlighted and some of the techniques that may be employed are discussed. Key words: nutrient cycling, ecosystems, fungi.
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Hopkins DW, Ritz K, Dighton J, Giller KE. Beyond the Biomass. J Appl Ecol 1995. [DOI: 10.2307/2405115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Shaw T, Dighton J, Sanders F. Interactions between ectomycorrhizal and saprotrophic fungi on agar and in association with seedlings of lodgepole pine (Pinus contorta). ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0953-7562(09)80880-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Michelsen A, Schmidt IK, Jonasson S, Dighton J, Jones HE, Callaghan TV. Inhibition of growth, and effects on nutrient uptake of arctic graminoids by leaf extracts - allelopathy or resource competition between plants and microbes? Oecologia 1995; 103:407-418. [PMID: 28306988 DOI: 10.1007/bf00328678] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/1994] [Accepted: 04/03/1995] [Indexed: 11/25/2022]
Abstract
Previous research has shown that plant extracts, e.g. from boreal dwarf shrubs and trees, can cause reduced growth of neighbouring plants: an effect known as allelopathy. To examine whether arctic and subarctic plants could also be affected by leaching of phytochemicals, we added extracts from the commonly occurring arctic dwarf shrubs Cassiope tetragona and Empetrum hermaphroditum, and from mountain birch, Betula pubescens ssp. tortuosa to three graminoid species, Carex bigelowii, Festuca vivipara and Luzula arcuata, grown in previously sterilized or non-sterilized arctic soils. The graminoids in non-sterilized soil grew more slowly than those in sterilized soil. Excised roots of the plants in non-sterilized soil had higher uptake rate of labelled P than those in sterilized soil, demonstrating larger nutrient deficiency. The difference in growth rate was probably caused by higher nutrient availability for plants in soils in which the microbial biomass was killed after soil sterilization. The dwarf shrub extracts contained low amounts of inorganic N and P and medium high amounts of carbohydrates. Betula extracts contained somewhat higher levels of N and much higher levels of P and carbohydrates. Addition of leaf extracts to the strongly nutrient limited graminoids in non-sterilized soil tended to reduce growth, whereas in the less nutrient limited sterilized soil it caused strong growth decline. Furthermore, the N and P uptake by excised roots of plants grown in both types of soil was high if extracts from the dwarf shrubs (with low P and N concentrations) had been added, whereas the P uptake declined but the N uptake increased after addition of the P-rich Betula extract. In contrast to the adverse extract effects on plants, soil microbial respiration and soil fungal biomass (ergosterol) was generally stimulated, most strongly after addition of the Betula extract. Although we cannot exclude the possibility that the reduced plant growth and the concomitant stimulation of microbial activity were caused by phytochemicals, we believe that this was more likely due to labile carbon in the extracts which stimulated microbial biomass and activity. As a result microbial uptake increased, thereby depleting the plant available pool of N and P, or, for the P-rich Betula extract, depleting soil inorganic N alone, to the extent of reducing plant growth. This chain of events is supported by the negative correlation between plant growth and sugar content in the three added extracts, and the positive correlation between microbial activity, fungal biomass production and sugar content, and are known reactions when labile carbon is added to nutrient deficient soils.
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Affiliation(s)
- Anders Michelsen
- Merlewood Research Station, Institute of Terrestrial Ecology, LA11 6JU, Grange-over-Sands, Combria, UK
- Department of Plant Ecology, University of Copenhagen, Oester Farimagsgade 2 D, DK-1353, Copenhagen K, Denmark
| | - Inger K Schmidt
- Department of Plant Ecology, University of Copenhagen, Oester Farimagsgade 2 D, DK-1353, Copenhagen K, Denmark
| | - Sven Jonasson
- Department of Plant Ecology, University of Copenhagen, Oester Farimagsgade 2 D, DK-1353, Copenhagen K, Denmark
| | - John Dighton
- Merlewood Research Station, Institute of Terrestrial Ecology, LA11 6JU, Grange-over-Sands, Combria, UK
| | - Helen E Jones
- Merlewood Research Station, Institute of Terrestrial Ecology, LA11 6JU, Grange-over-Sands, Combria, UK
| | - Terry V Callaghan
- Sheffield Centre for Arctic Ecology, University of Sheffield, P.O. Box 601, S10 2UQ, Sheffield, UK
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Dighton J, Poskitt JM, Brown TK. Phosphate influx into ectomycorrhizal and saprotrophic fungal hyphae in relation to phosphate supply; a potential method for selection of efficient mycorrhizal species. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/s0953-7562(09)81136-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Dighton J, Clint G, Poskitt J. Uptake and accumulation of 137Cs by upland grassland soil fungi: a potential pool of Cs immobilization. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/s0953-7562(09)80545-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Harrison AF, Taylor K, Hatton JC, Dighton J, Howard DM. Potential of a Root Bioassay for Determining P-Deficiency in High Altitude Grassland. J Appl Ecol 1991. [DOI: 10.2307/2404129] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
Changes in research emphasis from pollution towards the effects of climate change have resulted from shifts in political and public interests. Information gained from research on the effects of pollutants as a perturbation on mycorrhizae and mycorrhizae-mediated processes may be an appropriate starting point from which to launch into climate change studies. However, the effects of pollution on mycorrhizae are not clear cut as there are many conflicting results. The methods used in experiments, levels of pollutants used and relationships between studies on seedling trees to the mature forest do not suggest unifying models of pollution effects. Some areas of work still lacking in the pollution field are highlighted. These include well replicated experiments at currently ambient pollutant levels, and areas for potential development in the global climate change arena, e.g. the interaction between C supply and nutrient uptake.
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Affiliation(s)
- J Dighton
- Institute of Terrestrial Ecology, Merlewood Research Station, Grange-over-Sands, Cumbria LA11 6JU, UK
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Jones KC, Watts SA, Harrison AF, Dighton J. The distribution of metals in the forest floor of aged conifer stands at a plantation in Northern England. Environ Pollut 1988; 51:31-47. [PMID: 15092637 DOI: 10.1016/0269-7491(88)90237-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/1987] [Revised: 09/02/1987] [Accepted: 09/07/1987] [Indexed: 05/24/2023]
Abstract
The distribution of the elements Cd, Cr, Cu, Mn, Ni, Pb, Sr, V and Zn has been examined in the horizons of soils under aged Sitka spruce (Picea sitchensis (Bong.) Carr.) stands at a plantation in Northern England. The stands are under first-generation cultivation and are up to 33 years old. Cadmium, Mn, Pb and Zn concentrations were consistently higher in the organic layers than in the underlying mineral soil. This contrasted with the situation for Sr and V. Cadmium, Pb and Zn all showed an increase in concentration in the L + F horizons with stand age and a corresponding increase in the difference between L + F horizon concentrations. Soil pH declined with increasing stand age. Cadmium, Cr, Pb and Zn were all present at higher concentrations in the F horizon than in any other, while Cu and Ni were relatively constant through all the horizons studied. For all nine elements, the H horizon was the largest store of the three organic layers. Calculated rates of accumulation of Cd, Pb and Zn in the L + F horizons gave good agreement with estimated regional atmospheric deposition rates. In comparison to atmospheric deposition, biological mobilisation and deposition of Cd, Pb and Zn make a relatively minor contribution to the surface soil metal burden. Cadmium appeared to be the most readily leached of these three metals from the forest floor, although some transfer of atmospherically-derived Pb to the H+ soil horizons was indicated.
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Affiliation(s)
- K C Jones
- Department of Environmental Science, University of Lancaster, Bailrigg, Lancaster LA1 4YQ, Great Britain
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Dighton J, Poskitt JM, Howard DM. Changes in occurrence of basidiomycete fruit bodies during forest stand development: with specific reference to mycorrhizal species. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/s0007-1536(86)80017-1] [Citation(s) in RCA: 115] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Dighton J, Cooke RC, Rayner ADM. Ecology of Saprotrophic Fungi. (1984). J Appl Ecol 1985. [DOI: 10.2307/2403197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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