Publikationsdatum:
2012-07-05
Beschreibung:
X-ray scattering and microtomography (μCT) are useful techniques to reveal the structure of wood at the nano- and micrometer scales. The nanostructure of xylem in greenhouse-grown 2.5- to 3.5-month-old Populus tremula L. × tremuloides Michx. trees was characterized using wide-angle X-ray scattering (WAXS), and the cellular structure was investigated using μCT. For comparison, the nanostructure of wood in 2-year-old silver birch, Norway spruce and Scots pine saplings was determined. Based on the μCT results, the lengths of fiber lumina of the hybrid aspen saplings were shorter than any previous results on the lengths of wood fibers. The mean microfibril angles of the hybrid aspen saplings were significantly lower (8°–14°) than those of the birch, spruce and pine saplings (27°–35°) implicating that cellulose microfibrils were oriented nearly parallel to the cell axis in the young hybrid aspen saplings. Hybrid aspen saplings were found to contain tension wood based on the histochemical analysis and μCT images. However, typical tension wood properties, i.e. larger crystallite width and higher crystallinity than in normal wood, were detected only in a few hybrid aspen samples, while in most of the hybrid aspen saplings, the crystallite widths (3.0 ± 0.1 nm) and the crystallinities (30 ± 5 %) corresponded to those of normal wood. The deformations of cellulose crystallites were determined using WAXS in situ upon dehydration of the never-dried samples. In all the species studied, the cellulose unit cell dimension decreased and disorder of cellulose chains increased parallel to the chains upon drying. Also, the transverse disorder of chains increased in birch, spruce and pine, while no changes were detected in this direction in hybrid aspen. The crystallite widths and drying deformation results might indicate that the gelatinous layer has not fully developed in the young hybrid aspen saplings. Content Type Journal Article Category Original Paper Pages 1-12 DOI 10.1007/s00468-012-0748-x Authors Kirsi Svedström, Department of Physics, University of Helsinki, P.O.B. 64, 00014 University of Helsinki, Finland Jessica Lucenius, Department of Physics, University of Helsinki, P.O.B. 64, 00014 University of Helsinki, Finland Jan Van den Bulcke, UGCT-WOODLAB, Department of Forest and Water Management, Ghent University, Coupure Links 653, 9000 Ghent, Belgium Denis Van Loo, UGCT, Department of Physics and Astronomy, Ghent University, Proeftuinstraat 86, 9000 Ghent, Belgium Peter Immerzeel, Department of Forest Genetics and Plant Physiology, SLU, Umeå Plant Science Centre, 90183 Umeå, Sweden Jussi-Petteri Suuronen, Department of Physics, University of Helsinki, P.O.B. 64, 00014 University of Helsinki, Finland Loes Brabant, UGCT, Department of Physics and Astronomy, Ghent University, Proeftuinstraat 86, 9000 Ghent, Belgium Joris Van Acker, UGCT-WOODLAB, Department of Forest and Water Management, Ghent University, Coupure Links 653, 9000 Ghent, Belgium Pekka Saranpää, Finnish Forest Research Institute, P.O.B. 18, 01301 Vantaa, Finland Kurt Fagerstedt, Department of Biosciences, University of Helsinki, P.O.B. 65, 00014 University of Helsinki, Finland Ewa Mellerowicz, Department of Forest Genetics and Plant Physiology, SLU, Umeå Plant Science Centre, 90183 Umeå, Sweden Ritva Serimaa, Department of Physics, University of Helsinki, P.O.B. 64, 00014 University of Helsinki, Finland Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890
Print ISSN:
0931-1890
Digitale ISSN:
1432-2285
Thema:
Biologie
,
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
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