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Morphology of Norway spruce tracheids with emphasis on cell wall organisation

Brändström, Jonas (2002). Morphology of Norway spruce tracheids with emphasis on cell wall organisation. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae. Silvestria, 1401-6230 ; 237
ISBN 91-576-6321-1
[Doctoral thesis]

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Abstract

Wood from Norway spruce and other conifers consists mainly (>90%) of one cell type called tracheids. The morphology of these tracheids has a profound effect on wood industrial processes and products made from wood. A more in-depth understanding of tracheid morphology is therefore required in order to improve wood industrial processes and products derived from conifer wood. The aim of this thesis was to study the morphology of Norway spruce (Picea abies (L.) Karst) tracheids with emphasis on cell wall organisation, especially microfibril orientation in the secondary cell wall. A literature review provided an overview of the micro- and ultrastructure of Norway spruce tracheids. The use of cavities from soft rot fungi was discussed and evaluated as a way of determining microfibril angles (MFA) in the secondary cell wall of tracheids. Soft rot fungi were shown to be a useful tool for ultrastructural research and results correlated well with polarisation confocal microscopy when measuring microfibril angles of the middle layer of the secondary cell wall (S2). Both methods showed a decreasing trend in S2 microfibril angle, from the beginning of earlywood (MFA ca. 30°) and towards the end of earlywood (MFA ca. 5°). The low microfibril angles continued into the latewood. No direct correlation was found between tracheid microstructure (i.e. cell length, cell width and cell wall thickness) and the microfibril angle in the S2 layer. Several methods were used to investigate the structural organisation of the outer layer of the secondary wall (S1). It was concluded that the S1 layer is rather homogenous layer being primarily comprised of microfibrils oriented approximately perpendicular to the tracheid axis. No evidence could be found for a crossed fibrillar structure with microfibrils in alternate S and Z helices. The transition of microfibril orientation from the S1 to the S2 layer appeared abrupt. Cell wall models illustrating microfibril orientation in the cell wall layers were discussed from a historical perspective. Three new cell wall models, based on results obtained in this thesis and from the literature were presented in order to visualise the microfibril orientation in the cell wall layers of Norway spruce tracheids.

Authors/Creators:Brändström, Jonas
Title:Morphology of Norway spruce tracheids with emphasis on cell wall organisation
Year of publishing :April 2002
Volume:237
Number of Pages:39
Papers/manuscripts:
NumberReferences
ALLI. Brändström, J. 2001. Micro- and ultrastructural aspects of Norway spruce tracheids: A review. IAWA Journal 22, 333-353 II.* Brändström, J., G. Daniel, and T. Nilsson. 2002. Use of soft rot cavities to determine microfibril angles in wood; advantages, disadvantages and possibilities. Holzforschung 56, 468-472 III.* Bergander, A., J. Brändström, G. Daniel, and L. Salmén. 2002. Fibril angle variability in earlywood of Norway spruce using soft rot cavities and polarization confocal microscopy. Journal of Wood Science 48, 255-263 IV.* Brändström, J., S.L. Bardage, G. Daniel, and T. Nilsson. 2003. The structrural organisation of the S1 cell wall layer of Norway spruce tracheids. IAWA Journal 24, 27-40. * Papers II, III and IV have been published after the thesis was printed.
Place of Publication:Uppsala
ISBN for printed version:91-576-6321-1
ISSN:1401-6230
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K50 Processing of forest products
F Plant production > F50 Plant structure
Subjects:Not in use, please see Agris categories
Agrovoc terms:picea abies, wood, wood anatomy, tracheids, cell walls
Keywords:Picea abies, Norway spruce, tracheid, wood fibre, microstructure, ultrastructure, secondary cell wall, morphology, soft rot, cell wall model, microfibril angle, WURC
ID Code:236
Department:(S) > Institutionen för trävetenskap
Deposited By: Jonas Brändström
Deposited On:14 Apr 2003 00:00
Metadata Last Modified:02 Dec 2014 10:02

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