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The role of biological processes in base cation supply in boreal forest podzols

Fahad, Zaenab Adnan (2017). The role of biological processes in base cation supply in boreal forest podzols. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2017:23
ISBN 978-91-576-8819-4
eISBN 978-91-576-8820-0
[Doctoral thesis]

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Abstract

This thesis describes experiments designed to improve understanding of biological processes contributing to supply of base cations and other nutrients in boreal forest podzols. We used microcosms containing tree seedlings growing in natural substrates, a combination of direct measurements, modelling, stable Mg isotope analysis, and 13CO2 pulse-labelling. Addition of 13C-labelled fungal necromass to soil resulted in rapid decomposition and active incorporation of 13C into RNA of Burkholderia, Streptacidophilus, Dyella, Herminiimonas, Granulicella and fungal species belonging mainly to the genera Mortierella and Umbelopsis. There was no evidence of 13C incorporation into RNA of ectomycorrhizal fungi supporting the idea that ectomycorrhizal fungi primarily play an active role in organic matter decomposition by releasing N from recalcitrant substrates, but do not use organic matter as a source of metabolic C. Selected ectomycorrhizal and nonmycorrhizal fungi were examined for their capacity to fractionate and assimilate stable Mg isotopes in vitro. Ectomycorrhizal fungi mobilised and accumulated significantly higher concentrations of Mg, K and P than nonmycorrhizal fungi, when grown on granite particles. Mycorrhizal fungi were significantly depleted in heavy isotopes compared with nonmycorrhizal fungi and there was a highly significant statistical relationship between δ26Mg tissue signature and mycelial concentration of Mg. Pinus sylvestris seedlings were grown in compartmentalised microcosms allowing their mycorrhizal mycelium, but not roots, to access different substrates, including granite particles. Root biomass and contents of Ca, K, Mg, and P in plants in granite treatments were significantly higher than in control roots. Carbon allocation by the ectomycorrhizal mycelium to soil solution was significantly and positively correlated with base cation and P content of the plants. A final experiment (using reconstructed boreal forest podzol layers) was conducted in which the relative amounts of organic and mineral substrates were manipulated to simulate different levels of intensification of the removal of organic matter. All plants were deficient in K and P but had above optimal levels of Ca and Mg. Total plant and fungal mycelial biomass was positively related to the amount of organic soil in each treatment. The δ26Mg values of soil solution samples in B horizon soil increased successively with increasing plant and fungal mycelial biomass, suggesting increased uptake of Mg from the B horizon, with discrimination against the heavier isotope resulting in higher enrichment of 26Mg.

Authors/Creators:Fahad, Zaenab Adnan
Title:The role of biological processes in base cation supply in boreal forest podzols
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :14 February 2017
Depositing date:14 February 2017
Volume:2017:23
Number of Pages:90
Papers/manuscripts:
NumberReferences
IFahad, Z.A., Mahmood, S., Mikusinska, A., Ekblad, A., Fransson, P., Lindahl, B., Finlay, R.D. Decomposition of fungal mycelium in podzol horizons of boreal forest – a 13C-RNA stable isotope probing study (manuscript).
IIFahad, Z.A., Bolou-Bi EB, Ekblad, A., Köhler SJ, Finlay RD, Mahmood, S. 2016. Fractionation and assimilation of Mg isotopes by fungi is species dependent. Environmental Microbiology Reports 8, 956-965.
IIIFahad, Z.A., Mahmood, S., Bolou-Bi, E.B., Ekblad, A., Köhler, S.J., Bishop, K., Finlay, R.D. Patterns of mycelial colonisation, base cation mobilisation, carbon allocation and Mg isotope fractionation in compartmentalised microcosms containing mineral and organic substrates (manuscript).
IVFahad, Z.A., Mahmood, S., Bolou-Bi, E.B., Ekblad, A., Köhler, S.J., Bishop, K., Finlay, R.D. Nutrient mobilisation from, and carbon allocation to, different soil horizons in a reconstructed boreal forest podzol – effects of organic matter depletion (manuscript).
Place of Publication:Uppsala
Publisher:Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences.
ISBN for printed version:978-91-576-8819-4
ISBN for electronic version:978-91-576-8820-0
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K01 Forestry - General aspects
P Natural resources > P30 Soil science and management
P Natural resources > P34 Soil biology
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 104 Chemical Sciences > Analytical Chemistry
(A) Swedish standard research categories 2011 > 1 Natural sciences > 105 Earth and Related Environmental Sciences > Geochemistry
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Ecology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Other Biological Topics
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Soil Science
Agrovoc terms:podzols, ectomycorrhizae, fungi, environmental degradation, isotopes, forestry biology, fertilizers
Keywords:Base cations, Mineral weathering, Organic matter decomposition, Ectomycorrhizal fungi, Podzol, Magnesium isotopes, Nutrient mobilisation
URN:NBN:urn:nbn:se:slu:epsilon-e-3951
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-3951
ID Code:14046
Faculty:S - Faculty of Forest Sciences
Department:(NL, NJ) > Dept. of Forest Mycology and Plant Pathology
(S) > Dept. of Forest Mycology and Plant Pathology
External funders:FORMAS
Deposited By: Ms Zaenab Adnan Fahad
Deposited On:16 Feb 2017 08:55
Metadata Last Modified:20 Feb 2017 18:57

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