Toward identifying molecules responsible for the peculiar properties of the G-layer in tension wood fibres

The cell wall organization, the cell wall texture, and the degree of lignification of tension wood fibres have been investigated in a wide variety of temperate and tropical species. Following earlier work describing the cell wall structure of tension wood fibres, two additional types of cell wall organization have been observed. In one of these, the inner thick "gelatinous" layer which is typical of tension wood fibres exists in addition to the normal three-layered structure of the secondary wall; in the other only the outer layer of the secondary wall and the thick gelatinous layer are present. In all the tension wood examined the micellar orientation in the inner gelatinous layer has been shown to be nearly axial and the cellulose of this layer found to be in a highly crystalline state. A general argument is presented as to the meaning of differences in the degree, of crystallinity of cellulose. The high degree of crystallinity of cellulose in tension wood as compared with normal wood is attributed to a greater degree of lateral order in the crystalline regions of tension wood, whereas the paracrystalline phase is similar in both cases. The degree of lignification in tension wood fibres has been shown to be extremely variable. However, where the degree of tension wood development is marked as revealed by the thickness of the gelatinous layer the lack of lignification is also most marked. Severity of tension wood formation and lack of lignification have also been correlated with the incidence of irreversible collapse in tension wood. Such collapse can occur even when no whole fibres are present, e.g. in thin cross sections. Microscopic examination of collapsed samples of tension wood has led to the conclusion that the appearance of collapse in specimens containing tendon wood can often be attributed in part to excessive shrinkage associated with the development of fissures between cells, although true collapse does also occur. Possible explanations of the irreversible shrinkage and collapse of tension wood fibres are advanced.

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REACTION TISSUES IN GNETUM GNEMON A PRELIMINARY REPORT

IAWA Journal ◽

10.1163/22941932-90000385 ◽

2001 ◽

Vol 22 (4) ◽

pp. 401-413 ◽

Cited By ~ 8

Author(s):

P. B. Tomlinson

Keyword(s):

Cell Walls ◽

Tension Wood ◽

Secondary Xylem ◽

Secondary Phloem ◽

Outer Cortex ◽

Cortical Cells ◽

Wood Fibres ◽

Developmental Feature ◽

Gnetum Gnemon ◽

Clear Differentiation

Gnetum gnemon exhibits Rouxʼs model of tree architecture, with clear differentiation of orthotropic from plagiotropic axes. All axes have similar anatomy and react to displacement in the same way. Secondary xylem of displaced stems shows little eccentricity of development and no reaction anatomy. In contrast, there is considerable eccentricity in extra-xylary tissue involving both primary and secondary production of apparent tension-wood fibres (gelatinous fibres) of three main kinds. Narrow primary fibres occur concentrically in all axes in the outer cortex as a normal developmental feature. In displaced axes gelatinous fibres are developed abundantly and eccentrically on the topographically upper side, from pre-existing and previously undetermined primary cortical cells. They are wide with lamellate cell walls. In addition narrow secondary phloem fibres are also differentiated abundantly and eccentrically on the upper side of displaced axes. These gelatinous fibres are narrow and without obviously lamellate cell walls. Eccentric gelatinous fibres thus occupy a position that suggests they have the function of tension wood fibres as found in angiosperms. This may be the first report in a gymnosperm of fibres with tension capability. Gnetum gne-mon thus exhibits reaction tissues of unique types, which are neither gymnospermous nor angiospermous. Reaction tissues seem important in maintaining the distinctive architecture of the tree.

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Persistence of the gelatinous layer within altered tension-wood fibres of beech degraded by Ustulina deusta

New Phytologist ◽

10.1046/j.1469-8137.2000.00706.x ◽

2000 ◽

Vol 147 (2) ◽

pp. 347-355 ◽

Cited By ~ 10

Author(s):

S. BAUM ◽

F. W. M. R. SCHWARZE ◽

S. FINK

Keyword(s):

Tension Wood ◽

Gelatinous Layer ◽

Wood Fibres

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Microfibril Angle Distribution of Poplar Tension Wood

IAWA Journal ◽

10.1163/22941932-90000105 ◽

2012 ◽

Vol 33 (4) ◽

pp. 431-439 ◽

Cited By ~ 7

Author(s):

Silke Lautner ◽

Cordt Zollfrank ◽

Jörg Fromm

Keyword(s):

Electron Microscopy ◽

Tension Wood ◽

Microfibril Angle ◽

Cellulose Microfibrils ◽

Normal Wood ◽

Angle Distribution ◽

Transmission Electron ◽

Wood Fibres ◽

Characteristic Features ◽

Fibril Angle

Tension wood of poplar (Populus nigra) branches was studied by lightand electron microscopy. The characteristic features of tension wood such as wider growth rings, reduced vessel density and higher gross density were confirmed by our results. Based on a novel combination of transmission electron microscopy (TEM) imaging and image analysis, involving Fourier transformation, the orientation of cellulose microfibrils in the S2- and G-layer was determined. Within the G-layer microfibril angle (MFA) was parallel to the growth axis (0°). However, in the S2 it was 13° in tension wood fibres and 4° in normal wood fibres. With the exception of the relatively low fibril angle in the S2 of tension wood fibres (13°) the results are in good agreement with those of the literature.

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The Nature of Reaction Wood

Australian Journal of Biological Sciences ◽

10.1071/bi9480003 ◽

1948 ◽

Vol 1 (1) ◽

pp. 3 ◽

Cited By ~ 12

Author(s):

AB Wardrop ◽

HE Dads Well

Keyword(s):

Tensile Strength ◽

Tension Wood ◽

Reaction Wood ◽

Fibre Structure ◽

Longitudinal Shrinkage ◽

High Tensile Strength ◽

Wood Fibres

The structure of tension wood fibres is ofconsiderahle academic and practicalinterest, both in relation to considerations of the stimuli which produce them,and to studies of the influence of fibre structure on the properties of the wood asa whole. As is well known, the chief abnormal properties of tension wood lie inits unusually high longitudinal shrinkage, its high tensile strength, and its lowcompressive strength .

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Decay of oak Wood provoked by fungus Stereum hirsutum (Willd. ex Fr.) S. F. Gray. and its' essential physiological requirements

Glasnik Sumarskog fakulteta ◽

10.2298/gsf0591179m ◽

2005 ◽

pp. 179-192

Author(s):

Milenko Miric

Keyword(s):

Cell Walls ◽

Tension Wood ◽

White Rot Fungi ◽

White Rot ◽

Pedunculate Oak ◽

Nitrogen And Phosphorus ◽

Wood Fibres ◽

Parenchyma Cells ◽

Stereum Hirsutum ◽

Mycelial Mass

White rot fungi usually decompose cell walls of attacked wood destroying tissue elements (i.e. parenchyma cells, wood fibres, tension wood, tracheas etc) in different amount, depending to wood-species as well as to its' zones. Different fungi secrete specific enzymes that are responsible for certain damages. As consequence, the wood structure use to be significantly and unfixable decomposed and changed. Microscopical analyses that have been run provided clear and indicative information relating to effects of fungal activity on wood tissue. Physiological requirements of fungi are for shore of the highest importance in understanding of mechanism of decaying process in the wood. The most important factors as like temperature and concentration of H ions, as well as main nutrients as sources of carbon, nitrogen and phosphorus can affect the behaviour of wood decaying fungi. The impacts of these factors on the growth and production on mycelial mass of Stereum hirsutum (Willd. ex Fr.) S.F. Gray., have been investigated. This fungus is one of the most frequent appearing on the Sessile- and Pedunculate Oak weakened trees or felled logs, behaving as parasite as well as saprophyte. As a causer of Oak sapwood white rot S. hirsutum causes significant damages of wood at forest- as well as at industrial storages.

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Regulation by Uniconazole-P and Gibberellins of Morphological and Anatomical Responses of Fraxinus Mandshurica Seedlings to Gravity

IAWA Journal ◽

10.1163/22941932-90001537 ◽

1998 ◽

Vol 19 (3) ◽

pp. 311-320 ◽

Cited By ~ 8

Author(s):

Sha Jiang ◽

Tamaki Honma ◽

Teruko Nakamura ◽

Ikuo Furukawa ◽

Fukuju Yamamoto

Keyword(s):

Tension Wood ◽

Wood Formation ◽

Inhibitory Effect ◽

Fraxinus Mandshurica ◽

Wood Fibres

The present study deals with roles of gibberellins (GAs) in gravitropic responses of woody sterns of horizontally-positioned, 2-year-old seedling of Fraxinus mandshurica Rupr. var.japonica Maxim. The application of uniconazole-P, an inhibitor of GAs biosynthesis, to stern nodes at various concentrations significantly inhibited not only righting the sterns but also wood formation. The application of GAs (GA3 and GA4) in combination with uniconazole-P negated the inhibitory effect of the treatment of uniconazole-P alone. The GAs alone did not affect wood formation, however, both GAs increased wood formation on both the upper and lower sides of horizontal sterns with an increase in the concentration of combined uniconazole-P. In all of the seedlings, tension wood was formed on the upper side of sterns. The application of uniconazole-P alone at various concentrations did not inhibit the formation of tension wood fibres.

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Orientation of microfibrils and microtubules in developing tension-wood fibres of Japanese ash (Fraxinus mandshurica var. japonica)

Planta ◽

10.1007/bf00203659 ◽

1995 ◽

Vol 196 (3) ◽

Cited By ~ 28

Author(s):

A.K.M.A. Prodhan ◽

R. Funada ◽

J. Ohtani ◽

H. Abe ◽

K. Fukazawa

Keyword(s):

Tension Wood ◽

Fraxinus Mandshurica ◽

Wood Fibres

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Precautions for the Structural Analysis of the Gelatinous Layer in Tension Wood

IAWA Journal ◽

10.1163/22941932-90000110 ◽

2005 ◽

Vol 26 (2) ◽

pp. 189-195 ◽

Cited By ~ 32

Author(s):

Bruno Clair ◽

Joseph Gril ◽

Kei'ichi Baba ◽

Bernard Thibaut ◽

Junji Sugiyama

Keyword(s):

Tension Wood ◽

Solid Wood ◽

Mechanical Function ◽

Serial Sections ◽

Border Effect ◽

Anatomical Features ◽

Living Tree ◽

Gelatinous Layer ◽

Embedding Technique ◽

Wood Fibres

The gelatinous layer (G-layer) of tension wood fibres in hardwood contributes to the mechanical function of the living tree and has significant consequences on properties of solid wood. Its size, shape and structure observed by optical or electron microscopy exhibits characteristic anatomical features. However, we found that sectioning of non-embedded wood samples results in an uncontrolled swelling of the G-layer. In order to assess this artefact, the shape and thickness of the G-layer was monitored by serial sections from an embedded wood sample, from its trimmed transverse face to that located several hundreds of micrometres deep. The results revealed that the initial cutting before embedding produced a border effect responsible for the swollen nature, which is similar to sections from non-embedded material. After a conventional embedding technique was applied, a section of at least 30 micrometres below the trimming surface is required to observe an un-swollen G-layer.

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Zeitliche Einordnung der G-Schicht-Auflagerung in den Prozess der Zellwandbildung bei Zugholzfasern in Zitterpappeln | On the chronology of g-layer formation during cell wall differentiation in tension wood fibres of poplars

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2004.0523 ◽

2004 ◽

Vol 155 (12) ◽

pp. 523-527 ◽

Cited By ~ 2

Author(s):

Daniel Keunecke ◽

Sebastian Baum

Keyword(s):

Cell Wall ◽

Tension Wood ◽

Early Stage ◽

Wall Layer ◽

Deciduous Trees ◽

Layer Formation ◽

Cell Wall Layer ◽

Wood Fibres ◽

Additional Cell ◽

Secondary Wall Formation

The tension wood of some deciduous trees is characterised by fibres that form an additional cell wall layer, the so-called «gelatinous layer» (g-layer). The chronology of g-layer formation in the process of cell wall differentiation and lignification was investigated using two-year old poplars (Populus tremula L.). For this purpose the pinning-method was applied. The results show that the g-layer formation probably takes place at an early stage of secondary wall formation.

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