The Significance of X-Rays in Studying the Orientation of Cellulose in the Secondary Wall of Tracheids

Bailey, I. W.; Berkley, Earl E.

doi:10.2307/2437675

Cited by 28 publications

(18 citation statements)

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“…These follow the direction of the microfibrils in the S2 layer (Preston, 1947 ;Marts, 1955;Huang, 1995). Others have infiltrated the cell wall with iodine which forms crystals in the checks or splits between microfibrils and thereby reveals their orientation (Bailey & Vestal, 1937 ;Senft & Bendtsen, 1985). The orientation of the longer axis of the oval aperture of cross-field pits has also been used (Pillow, Terrell & Hiller, 1953;Cockrell, 1974;Donaldson, 1998) although as Huang et al (1998) point out, the orientation of adjacent pits within the same cell wall may differ.…”

Section: Microfibril Anglementioning

confidence: 99%

Cellulose microfibril angle in the cell wall of wood fibres

2004

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The term microfibril angle (MFA) in wood science refers to the angle between the direction of the helical windings of cellulose microfibrils in the secondary cell wall of fibres and tracheids and the long axis of cell. Technologically, it is usually applied to the orientation of cellulose microfibrils in the S2 layer that makes up the greatest proportion of the wall thickness, since it is this which most affects the physical properties of wood. This review describes the organisation of the cellulose component of the secondary wall of fibres and tracheids and the various methods that have been used for the measurement of MFA. It considers the variation of MFA within the tree and the biological reason for the large differences found between juvenile (or core) wood and mature (or outer) wood. The ability of the tree to vary MFA in response to environmental stress, particularly in reaction wood, is also described. Differences in MFA have a profound effect on the properties of wood, in particular its stiffness. The large MFA in juvenile wood confers low stiffness and gives the sapling the flexibility it needs to survive high winds without breaking. It also means, however, that timber containing a high proportion of juvenile wood is unsuitable for use as high-grade structural timber. This fact has taken on increasing importance in view of the trend in forestry towards short rotation cropping of fast grown species. These trees at harvest may contain 50% or more of timber with low stiffness and therefore, low economic value. Although they are presently grown mainly for pulp, pressure for increased timber production means that ways will be sought to improve the quality of their timber by reducing juvenile wood MFA. The mechanism by which the orientation of microfibril deposition is controlled is still a matter of debate. However, the application of molecular techniques is likely to enable modification of this process. The extent to which these techniques should be used to improve timber quality by reducing MFA in juvenile wood is, however, uncertain, since care must be taken to avoid compromising the safety of the tree.

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Section: Microfibril Anglementioning

confidence: 99%

Cellulose microfibril angle in the cell wall of wood fibres

2004

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“…4). According to studies on various conifer species by using light microscopy and electron microscopy, the microfibrils of the S1 layer are oriented nearly perpendicular to the cell axis (Bailey and Vestal 1937;Brändström et al 2003). According to Donaldson and Xu (2005), MFA of layers S1 and S3 varied from 40°t o 120°with mean values around 90°in tracheids of Pinus radiata.…”

Section: Mfa Distributionsmentioning

confidence: 99%

“…Many methods have been used to characterise MFA, such as light microscopy (Preston 1934;Bailey and Vestal 1937;Preston 1946;Manwiller 1966;Page 1969;Cousins 1972;Senft and Bendtsen 1985;Donaldson 1991;Mott et al 1996;Batchelor et al 1997;Anagnost et al 2000), electron microscopy (Wardrop and Harada 1965;Abe et al 1991) and X-ray diffraction (XRD) (Preston 1934(Preston , 1945Cave 1966;Paakkari and Serimaa 1984;Evans 1999;Lichtenegger et al 1999a;Peura et al 2005). The advantage of XRD is that the X-ray beam probes the entire cell wall at once, not only the surface of a single exposed cell wall layer such as in electron microscopy.…”

Section: Introductionmentioning

confidence: 99%

X-ray microdiffraction reveals the orientation of cellulose microfibrils and the size of cellulose crystallites in single Norway spruce tracheids

Peura

Müller

Vainio

et al. 2007

Trees

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The microfibril angle (MFA) distribution and the size of cellulose crystallites in isolated double cell walls of Norway spruce (Picea abies [L.] Karst.) tracheids were determined by synchrotron X-ray microdiffraction using the reflections 200 and 004. Samples were 25 lm thick longitudinal sections of earlywood from annual rings 6-18 of several stems. The asymmetric MFA distributions extended from -20°to 90°. The mean MFA of tangential cell walls decreased from an average of 24°into 19°from the pith to the bark. The mode of the MFA distribution was about 10°smaller than the mean MFA. The standard deviation of the MFA distribution varied between 18°and 25°. The mean MFA and the mode of the MFA distribution were larger in radial than in tangential cell walls. MFA distributions of mature wood samples exhibited a separate small peak at around 90°. The average width and length of cellulose crystallites varied between 28.9-30.9 Å and 192-284 Å , respectively. Both increased slightly as a function of annual ring number from the pith up to the 15th annual ring. An irrigation-fertilisation treatment of some of the stems resulted in longer cellulose crystallites compared to the untreated stems.

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“…), double refraction (up to 0.07), and very conspicuous dichroism when stained with suitable dyes (13,57). The x-ray analysis yields interference spots revealing a high degree of orien tation of cellu l ose within the secondary wall (3,43,44,53).…”

mentioning

confidence: 99%

Physiology of Cell Wall Growth

Frey‐Wyssling¹

1950

Annu. Rev. Plant. Physiol.

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The Significance of X-Rays in Studying the Orientation of Cellulose in the Secondary Wall of Tracheids

Cited by 28 publications

References 0 publications

Cellulose microfibril angle in the cell wall of wood fibres

Cellulose microfibril angle in the cell wall of wood fibres

X-ray microdiffraction reveals the orientation of cellulose microfibrils and the size of cellulose crystallites in single Norway spruce tracheids

Physiology of Cell Wall Growth

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