Cellulose microfibril aggregates and their size variation with cell wall type

Donaldson, Lloyd

doi:10.1007/s00226-006-0121-6

Cited by 203 publications

(179 citation statements)

References 44 publications

Supporting

Mentioning

162

Contrasting

Order By: Relevance

“…Unlignified developing compression wood secondary walls were considerably less compact than the corresponding cell walls of normal wood, suggesting that b(1,4)-galactan may have some role in controlling the organization of the cell wall prior to lignification, but this organization presumably affects cell wall physiology in a way unrelated to lignin deposition per se. Such differences in secondary cell wall organization have been observed in fully lignified compression wood using high-resolution field emission scanning electron microscopy (Donaldson, 2007). A robust, compression wood-specific GalT activity was identified in microsomes derived from developing wood, which implies that b(1,4)-galactan biosynthesis in pine is associated with Golgi vesicles, as it is in other species.…”

Section: B(14)-galactan Is An Integral Component Of the S2 Cell Wallmentioning

confidence: 67%

Exploring the Ultrastructural Localization and Biosynthesis of β(1,4)-Galactan in Pinus radiata Compression Wood

et al. 2009

Self Cite

View full text Add to dashboard Cite

Softwood species such as pines react to gravitropic stimuli by producing compression wood, which unlike normal wood contains significant amounts of b(1,4)-galactan. Currently, little is known regarding the biosynthesis or physiological function of this polymer or the regulation of its deposition. The subcellular location of b(1,4)-galactan in developing tracheids was investigated in Pinus radiata D. Don using anti-b(1,4)-galactan antibodies to gain insight into its possible physiological role in compression wood. b(1,4)-Galactan was prominent and evenly distributed throughout the S2 layer of developing tracheid cell walls in P. radiata compression wood. In contrast, b(1,4)-galactan was not detected in normal wood. Greatly reduced antibody labeling was observed in fully lignified compression wood tracheids, implying that lignification results in masking of the epitope. To begin to understand the biosynthesis of galactan and its regulation, an assay was developed to monitor the enzyme that elongates the b(1,4)-galactan backbone in pine. A b(1,4)-galactosyltransferase (GalT) activity capable of extending 2-aminopyridine-labeled galacto-oligosaccharides was found to be associated with microsomes. Digestion of the enzymatic products using a b(1,4)-specific endogalactanase confirmed the production of b(1,4)-galactan by this enzyme. This GalT activity was substantially higher in compression wood relative to normal wood. Characterization of the identified pine GalT enzyme activity revealed pH and temperature optima of 7.0 and 20°C, respectively. The b(1,4)-galactan produced by the pine GalT had a higher degree of polymerization than most pectic galactans found in angiosperms. This observation is consistent with the high degree of polymerization of the naturally occurring b(1,4)-galactan in pine.

show abstract

Section: B(14)-galactan Is An Integral Component Of the S2 Cell Wallmentioning

confidence: 67%

Exploring the Ultrastructural Localization and Biosynthesis of β(1,4)-Galactan in Pinus radiata Compression Wood

et al. 2009

Self Cite

View full text Add to dashboard Cite

show abstract

“…Xylan is also localized to the inner S2 region where the ultrastructural organization of the wall changes relative to the outer S2 region ( Fig. 7B; Donaldson, 2007). Xylans are also detected in abundance at pit borders and the dentations of ray tracheids, both areas where microfibril orientation shows complex changes (Figs.…”

Section: Colocalization Of Cellulose and Other Polysaccharidesmentioning

confidence: 93%

“…This pattern is not obvious with xylan epitopes. Cellulose in this region of the secondary wall is known to also show such a radial organization (Donaldson, 2007), suggesting that mannan and cellulose may be more closely associated than xylan and cellulose in compression wood secondary walls. We also found evidence for an association between mannan and cellulose in delignified wood, where mannan was preferentially retained following delignification treatment, compared to galactan and xylans.…”

Section: Colocalization Of Cellulose and Other Polysaccharidesmentioning

confidence: 96%

Localization of Cell Wall Polysaccharides in Normal and Compression Wood of Radiata Pine: Relationships with Lignification and Microfibril Orientation

Donaldson

Knox²

2011

Plant Physiology

123

View full text Add to dashboard Cite

The distribution of noncellulosic polysaccharides in cell walls of tracheids and xylem parenchyma cells in normal and compression wood of Pinus radiata, was examined to determine the relationships with lignification and cellulose microfibril orientation. Using fluorescence microscopy combined with immunocytochemistry, monoclonal antibodies were used to detect xyloglucan (LM15), b(1,4)-galactan (LM5), heteroxylan (LM10 and LM11), and galactoglucomannan (LM21 and LM22). Lignin and crystalline cellulose were localized on the same sections used for immunocytochemistry by autofluorescence and polarized light microscopy, respectively. Changes in the distribution of noncellulosic polysaccharides between normal and compression wood were associated with changes in lignin distribution. Increased lignification of compression wood secondary walls was associated with novel deposition of b(1,4)-galactan and with reduced amounts of xylan and mannan in the outer S2 (S2L) region of tracheids. Xylan and mannan were detected in all lignified xylem cell types (tracheids, ray tracheids, and thickwalled ray parenchyma) but were not detected in unlignified cell types (thin-walled ray parenchyma and resin canal parenchyma). Mannan was absent from the highly lignified compound middle lamella, but xylan occurred throughout the cell walls of tracheids. Using colocalization measurements, we confirmed that polysaccharides containing galactose, mannose, and xylose have consistent correlations with lignification. Low or unsubstituted xylans were localized in cell wall layers characterized by transverse cellulose microfibril orientation in both normal and compression wood tracheids. Our results support the theory that the assembly of wood cell walls, including lignification and microfibril orientation, may be mediated by changes in the amount and distribution of noncellulosic polysaccharides.

show abstract

“…In addition to the proposed short-range coalescence of softwood microfibrils, where the crystal lattice is continuous across the interface, they are known to be aggregated into bundles about 10-20 nm across without continuity of crystalline structure between individual microfibrils (Fahlen and Salmen 2003;Donaldson 2007;Fernandes et al 2011). The majority of the hemicellulose and lignin content of softwoods is likely to be situated outside these microfibril bundles (Fahlen and Salmen 2003;Xu et al 2007;Fernandes et al 2011;Terashima et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Structure and spacing of cellulose microfibrils in woody cell walls of dicots

et al. 2014

View full text Add to dashboard Cite

There may be differences between this version and the published version. You are advised to consult the publisher's version if you wish to cite from it.http://eprints.gla.ac.uk/105070/ Key words: WAXS; WANS; SANS; crystallinity; Scherrer; wood AbstractThe structure of cellulose microfibrils in situ in wood from the dicotyledonous (hardwood) species cherry and birch, and the vascular tissue from sunflower stems, was examined by wide-angle X-ray and neutron scattering (WAXS and WANS) and small-angle neutron scattering (SANS). Deuteration of accessible cellulose chains followed by WANS showed that these chains were packed at similar spacings to crystalline cellulose, consistent with their inclusion in the microfibril dimensions and with a location at the surface of the microfibrils. Using the Scherrer equation and correcting for considerable lateral disorder, the microfibril dimensions of cherry, birch and sunflower microfibrils perpendicular to the [200] crystal plane were estimated as 3.0, 3.4 and 3.3 nm respectively. The lateral dimensions in other directions were more difficult to correct for disorder but appeared to be 3 nm or less. However for cherry and sunflower, the microfibril spacing estimated by SANS was about 4 nm and was insensitive to the presence of moisture. If the microfibril width was 3 nm as estimated by WAXS, the SANS spacing suggests that a non-cellulosic polymer segment might in places separate the aggregated cellulose microfibrils. Abbreviations:NMR -Nuclear magnetic resonance; WAXS -Wide angle X-ray scattering; WANS -Wide angle neutron scattering; SANS -Small angle neutron scattering 2

show abstract

Cellulose microfibril aggregates and their size variation with cell wall type

Cited by 203 publications

References 44 publications

Exploring the Ultrastructural Localization and Biosynthesis of β(1,4)-Galactan in Pinus radiata Compression Wood

Exploring the Ultrastructural Localization and Biosynthesis of β(1,4)-Galactan in Pinus radiata Compression Wood

Localization of Cell Wall Polysaccharides in Normal and Compression Wood of Radiata Pine: Relationships with Lignification and Microfibril Orientation

Structure and spacing of cellulose microfibrils in woody cell walls of dicots

Contact Info

Product

Resources

About