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Tree carbon partitioning, respiratory efficiency, and nitrogen acquisition

Henriksson, Nils (2017). Tree carbon partitioning, respiratory efficiency, and nitrogen acquisition. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2017:95
ISBN 978-91-7760-080-0
eISBN 978-91-7760-081-7
[Doctoral thesis]

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Tree growth in boreal systems is frequently limited by nitrogen (N) availability, and a significant portion of photosynthetically assimilated carbon (C) is partitioned to N-acquisition by roots and mycorrhizal fungi.
A new method for reversibly halting tree belowground C flux was developed. The method, termed stem compression, consists of applying pressure around the stem to collapse the conducting phloem and was shown to efficiently stop belowground C transport in Scots pine trees. Stem compression reduced tree N uptake by 32%, but N uptake of uncompressed trees also suffered - if they were surrounded by compressed trees. Conversely, a single compressed tree did not significantly affect N uptake by nearby uncompressed trees. This indicates that belowground C transport mediates N uptake, but also that within-community C status influences competition for N.
In the second part of the thesis, a method using the oxygen isotope discrimination technique for partitioning between the cytochrome oxidase (COX) and alternative oxidase (AOX) respiration was developed and applied to Scots pine roots from two forest stands. All plants examined to date contain AOX, as well as many other organisms. Its energy yield is only 1/3 of what is gained from COX, and pathway partitioning can shift in response to stress, such as nutrient deficiency.
Alternative oxidase partitioning was measured at two temperatures (6°C and 20°C). At 6°C significant fraction of fine root respiration (c. 20%) occurred via the AOX pathway. This fraction was found to decrease to c. 12% in response to elevated temperature and improved soil N availability. The potential influence of AOX on C sequestration coupled with responsiveness to environmental conditions make AOX relevant in light of changes in climate and forest management.
Taken together, the results point toward two feedback systems where C and N acquisition can act to reinforce each other: One mechanism where belowground C partitioning mediates uptake of soil/mycorrhizal N; and another where high soil N availability can trigger a shift in AOX partitioning, leading to increased biosynthetic efficiency of roots, potentially allowing more efficient use of the belowground C flux.

Authors/Creators:Henriksson, Nils
Title:Tree carbon partitioning, respiratory efficiency, and nitrogen acquisition
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2017
Depositing date:20 October 2017
Number of Pages:48
IHenriksson, N., Tarvainen, L., Lim, H., Tor-Ngern, P., Palmroth, S., Oren, R., Marshall, J., Näsholm, T. (2015). Stem compression reversibly reduces phloem transport in Pinus sylvestris trees. Tree Physiology 35 (10), 10751085
IIHenriksson, N., Marshall, J. D., Tarvainen, L., Näsholm, T. Tree nitrogen acquisition in response to community level patterns in belowground C partitioning (manuscript).
IIIHenriksson, N., Marshall, J., Lundholm, J., Boily, Å., Boily, J-F., Näsholm, T. Improved in vivo measurement of alternative oxidase respiration in fieldcollected pine roots. (under revision for Physiologia Plantarum).
1VHenriksson, N., Marshall, J., Tarvainen, L., Näsholm, T. Shifting alternative oxidase partitioning in response to nitrogen addition has the potential to change carbon use efficiency (manuscript).
Place of Publication:Umeå
Publisher:Department of forest ecology and management, Swedish university of agricultural sciences
ISBN for printed version:978-91-7760-080-0
ISBN for electronic version:978-91-7760-081-7
Additional Information:This study was supported by: The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas), The Kempe Foundations, The Swedish University of Agricultural Sciences (TC4F and Bio4E) and the Knut and Alice Wallenberg Foundation
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F40 Plant ecology
F Plant production > F60 Plant physiology and biochemistry
U Auxiliary disciplines > U30 Research methods
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Cell Biology
(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 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Agrovoc terms:Pinus sylvestris, carbon sequestration, nitrogen, photosynthesis, use efficiency, boreal forests, oxidoreductases, respiration
Keywords:carbon partitioning, nitrogen, stem compression, strangling, girdling, carbon use efficiency, AOX, alternative oxidase, stable isotope, pinus sylvestris, scots pine, respiration, nitrogen uptake, isotopic discrimination
Permanent URL:
ID Code:14643
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Forest Ecology and Management
External funders:Bio4energy and FORMAS and Kempe Foundations and Knut and Alice Wallenberg Foundation and TC4F (Trees and Crops for the Future) and Swedish Research Council
Deposited By: Nils Henriksson
Deposited On:23 Oct 2017 10:19
Metadata Last Modified:09 Sep 2020 14:17

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