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Journal ArticleDOI

Tension wood and opposite wood in 21 tropical rain forest species : 1. Occurence and efficiency of the G-layer

01 Jan 2006-Iawa Journal-Vol. 27, Iss: 3, pp 329-338
TL;DR: Wood samples were taken from the upper and lower sides of 21 naturally tilted trees from 18 families of angiosperms in the tropical rain forest in French Guyana and showed that the G-layer is not a key factor in the production of high tensile stressed wood.
Abstract: SUMMARY Wood samples were taken from the upper and lower sides of 21 naturally tilted trees from 18 families of angiosperms in the tropical rain forest in French Guyana. The measurement of growth stresses ensured that the two samples were taken from wood tissues in a different mechanical state: highly tensile stressed wood on the upper side, called tension wood, and lower tensile stressed wood on the lower side, called opposite wood. Eight species had tension wood fibres with a distinct gelatinous layer (G-layer). The distribution of gelatinous fibres varied from species to species. One of the species, Casearia javitensis (Flacourtiaceae), showed a peculiar multilayered secondary wall in its reaction wood. Comparison between the stress level and the occurrence of the G-layer indicates that the G-layer is not a key factor in the production of high tensile stressed wood.
Citations
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Journal ArticleDOI
TL;DR: This work investigates the structural and compositional basis of a sophisticated plant movement mechanism--the hydration-dependent unfolding of ice plant seed capsules--the reversible origami-like folding pattern proceeds via a cooperative flexing-and-packing mechanism actuated by a swellable cellulose layer filling specialized plant cells.
Abstract: Hydro-responsive plant movements have provided inspiration for the design of adaptive materials. Harrington et al. investigate the hydration-dependent unfolding of ice plant seed capsules and find an origami-like folding pattern, which could aid the development of biomimetic folding structures.

237 citations

Journal ArticleDOI
TL;DR: Measurements show that mesoporosity is high in tension wood with a typical thick G-layer while it is much less with a thinner G- layer, sometimes no more than normal wood.
Abstract: The mechanism for tree orientation in angiosperms is based on the production of high tensile stress on the upper side of the inclined axis. In many species, the stress level is strongly related to the presence of a peculiar layer, called G-layer, in the fibre wall. The structure of G-layer has been recently described as a hydrogel thanks to N2 adsorption-desorption isotherms of supercritically dried samples showing a high mesoporosity (pores size from 2 to 50 nm). This led us to revisit the concept of G-layer that was until now only described from anatomical observation. Adsorption isotherms of both normal wood and tension wood have been measured on six tropical species. Measurements show that mesoporosity is high in tension wood with typical thick G-layer while it is much less with thinner G-layer, sometimes no more than normal wood. The mesoporosity of tension wood species without G-layer is as low as in normal wood. Not depending on the amount of pores, the pore sizes distribution are always centred around 6-12 nm. These results suggest that, among species producing fibres with G-layer, large structural differences of G-layer exist between species

196 citations


Cites background from "Tension wood and opposite wood in 2..."

  • ...Different anatomical patterns of TW exist, from fibres with a typical G-layer to fibres exhibiting no difference at the fibre level (Clair et al., 2006; Ruelle et al., 2006, 2007)....

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  • ...However, it is known that many species (Onaka, 1949; Fisher and Stevenson, 1981; Clair et al., 2006) are able to produce tensile stress without forming a typical G-layer....

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  • ...As already shown earlier (Clair et al., 2006; Ruelle et al., 2006), the general relations between tensile stress level in tension wood and macroscopic anatomical variations are not visible, while observation at an ultrastructural level allows some common features in cellulose organization to be…...

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Journal ArticleDOI
TL;DR: It is proposed that XET activity is essential for G-fiber shrinking by repairing xyloglucan cross-links between G- and S(2)-layers and thus maintaining their contact.
Abstract: Tension wood is a specialized tissue of deciduous trees that functions in bending woody stems to optimize their position in space. Tension wood fibers that develop on one side of the stem have an increased potency to shrink compared with fibers on the opposite side, thus creating a bending moment. It is believed that the gelatinous (G) cell wall layer containing almost pure cellulose of tension wood fibers is pivotal to their shrinking. By analyzing saccharide composition and linkage in isolated G-layers of poplar, we found that they contain some matrix components in addition to cellulose, of which xyloglucan is the most abundant. Xyloglucan, xyloglucan endo-transglycosylase (XET) activity and xyloglucan endo-transglycosylase/hydrolase (XTH) gene products were detected in developing G-layers by labeling using CCRC-M1 monoclonal antibody, in situ incorporation of XXXG-SR and the polyclonal antibody to poplar PttXET16-34, respectively, indicating that xyloglucan is incorporated into the G-layer during its development. Moreover, several XTH transcripts were altered and were generally up-regulated in developing tension wood compared with normal wood. In mature G-fibers, XTH gene products were detected in the G-layers while the XET activity was evident in the adjacent S 2 wall layer. We propose that XET activity is essential for G-fiber shrinking by repairing xyloglucan cross-links between G- and S 2 -layers and thus maintaining their contact. Surprisingly, XTH gene products and XET activity persisted in mature G-fibers for several years, suggesting that the enzyme functions after cell death repairing the cross-links as they are being broken during the shrinking process.

177 citations


Cites background from "Tension wood and opposite wood in 2..."

  • ...Strain measurement on the stem surface in hardwood species indicated that the TW has up to 20 times higher tensile stress than the OW or NW (Fournier et al. 1994, Clair et al. 2006a, Clair et al. 2006b, Clair et al. 2006c)....

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  • ...Recent studies showed that cellulose microfibrils of the G-layer accumulate residual strain of the same order of magnitude as that observed in TW, pointing to the major role of cellulose microfibrils in generation of growth strains (Clair et al. 2006b)....

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  • ...It has been shown recently that the stress relaxation observed macroscopically on the stem surface corresponds to that observed at the nano level in cellulose microfibrils of the G-layer (Clair et al. 2006b)....

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  • ...…that the structural differences between the reaction wood and the wood on the opposite side (so-called opposite wood, OW) induce different residual growth stresses of both sides of the stem, resulting in a bending moment (Fournier et al. 1994, Bamber 2001, Almeras et al. 2005, Clair et al. 2006a)....

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Journal ArticleDOI
TL;DR: This review will focus on two different aspects, the lignification process and the control of microfibril angle in the cell wall of wood fibres, as they are both key features of wood material properties.

131 citations

Journal ArticleDOI
TL;DR: Recent studies of plant biomechanics highlighting several current research themes in the field are summarized, including expulsion of high-speed reproductive projectiles, generation of slow movements by shrinking and swelling cell walls, effects of ontogenetic shifts in mechanical properties of stems, flexible reconfiguration and material properties of seaweeds under crashing waves, and the development of botanically-inspired commercial products.
Abstract: Plant and animal biomechanists have much in common. Although their frame of reference differs, they think about the natural world in similar ways. While researchers studying animals might explore airflow around flapping wings, the actuation of muscles in arms and legs, or the material properties of spider silk, researchers studying plants might explore the flow of water around fluttering seaweeds, the grasping ability of climbing vines, or the material properties of wood. Here we summarize recent studies of plant biomechanics highlighting several current research themes in the field: expulsion of high-speed reproductive projectiles, generation of slow movements by shrinking and swelling cell walls, effects of ontogenetic shifts in mechanical properties of stems, flexible reconfiguration and material properties of seaweeds under crashing waves, and the development of botanically-inspired commercial products. Our hope is that this synopsis will resonate with both plant and animal biologists, encourage cross-pollination across disciplines, and promote fruitful interdisciplinary collaborations in the future.

110 citations


Cites background from "Tension wood and opposite wood in 2..."

  • ...This ‘‘G-layer’’ consists of almost pure cellulose, oriented parallel to the cell axis....

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  • ...Interestingly, fibers containing a G-layer have been found also in other species that generate relatively slow moving organs, such as tendrils (Bowling and Vaughn 2009) or contractile roots of perennial plants (Fisher 2008, Schreiber et al. 2010), possibly pointing to a general principle of tensile stress generation by this stiff and highly expansible inner cell-wall layer (Goswami et al. 2008)....

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  • ...Although the specific function of the G-layer in the generation of stress is still debated (Clair et al. 2008, Goswami et al. 2008, Mellerowicz et al. 2008), it is well established that the parallel orientation of the cellulose fibrils plays a crucial role and that very high tensile stresses in tension wood are associated with formation of the G-layer (Fang et al. 2008) (Fig....

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  • ...Tropical tree species have recently been shown to possess several distinct types of reaction wood, with and without specialized cells containing a G-layer (Clair et al. 2006)....

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References
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Journal ArticleDOI
01 Oct 1975-Nature

308 citations

Book
12 Mar 2014
TL;DR: In this article, the authors present a more quantitative approach to the effect of growth stresses than might have been the case in the past, by taking a more qualitative approach to evaluate the relationship between growth stress and wood properties.
Abstract: Although over 40 years have passed since Jacobs (1945) convincingly established the basic radial pattern of residual growth stress in growing trees, yet this phenomenon is still not widely appreciated in wood science and technology circles. This is in spite of the fact that the presence of these stresses of sizeable magnitudes has long been recognized as a primary cause of shakes and splits in logs as well as the warping of lumber sawn in the green condition. The presentation of the subject of growth stresses in trees presents some special problems due to the wide range of specialists who potentially might have an interest in the subject. For example, tree physiologists interested in questions such as the relation of mechanical stress to stem taper and the role of reaction wood and gravity forces in determining tree crown form encounter growth stress models. Silvi culturists interested in the relation ofthinning practices to wood quality find that wood properties are correlated with growth stress levels which are in turn significantly changed by cutting practices. Wood techno logists interested in the relation of residual growth stress gradients in green logs to the dimensional quality of sawn and seasoned lumber are forced to take a more quantitative approach to the effect of growth stresses than might have been the case in the past."

261 citations


"Tension wood and opposite wood in 2..." refers background in this paper

  • ...lignification and formation of the secondary cell wall (Archer 1986; Fournier et al. 1994a)....

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  • ...opposite to the external one induced by gravity and growth in mass (Wilson & Archer 1979; Archer 1986; Fournier et al. 1994b)....

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Journal ArticleDOI
TL;DR: It is hypothesize that the advantage of maintaining assimilative area in present height is diminished in a habitat with higher growth rate and/or steeper vertical light gradient such as in.
Abstract: Differences in allometric relationships of understorey saplings (60-300 cm tall) between nine common shade-tolerant species of subcanopy, canopy and emergent trees were examined in an old-growth foothill rain forest in West Sumatra, Indonesia. Interspecific variation was found in the intercept of the regression line between logarithmic dimensions but not in the slope. Detected interspecific differences could be interpreted as a result of a trade-off between height growth (for future exploitation of better-lit conditions at higher levels in the canopy) and leaf area extension (for current exploitation of poor light nearer the base of the canopy). Saplings of emergent Swintonia schwenkii Teijsm. & Binn. ex Hook. f. favoured height growth rather than expansion of assimilative area. Trends of interspecific differences in sapling allometry in tropical rain forest were similar to those in warm-temperate rain forest. Tropical saplings had more slender trunks and greater total leaf area at a given height than warm-temperate saplings, but dry weight proportions among organs were similar. We hypothesize that the advantage of maintaining assimilative area in present height is diminished in a habitat with higher growth rate and/or steeper vertical light gradient such as in

194 citations

Journal ArticleDOI
TL;DR: In this article, different organic solvents were passed through green cylindric samples of sapwood of Abies alba Miller and Picea abies Karst, at a pressure equal to 5 cm water column.
Abstract: On the Longi tudinal Permeabi l i ty of Green Sapwood of Abies alba Miller and Piceaabies Karst. to Organic Solvents Summary Different organic solvents were passed through green cylindric samples of sapwood of Abies alba Miller and Picea abies Karst, at a pressure equal to 5 cm water column. By this means the factors influencing the rate of flow could be determined. 1. The rate of flow of an organic solvent is essentially dependent on its viscosity. 2. Although viscosity of the solvent influences the rate of flow especially at the onset of filtration, a high surface tension of the solvent can cause a continuous decrease of the rate of flow with the progress of the experiment. On the contrary a low surface tension effects only a small decrease in the rate of flow. 3. Hydrophobie solvents cannot be filtrated through untreated green sapwood even under application of a higher pressure. 4. For the solvents used here, no influence of the molecular size on the rate of flow is detectable.

156 citations

Journal ArticleDOI
06 Apr 2004-Planta
TL;DR: Immunochemical labelling provides the first visualization in planta of lignin structures within the G-layer of tension wood fibres, and patterns of distribution of syringyl epitopes indicate thatSyringyl lignIn is deposited more intensely in the later phase of fibre secondary wall assembly, and is under specific spatial and temporal regulation targeted differentially throughout cell wall layers.
Abstract: The occurrence of lignin in the additional gelatinous (G-) layer that differentiates in the secondary wall of hardwoods during tension wood formation has long been debated. In the present work, the ultrastructural distribution of lignin in the cell walls of normal and tension wood fibres from poplar (Populus deltoides Bartr. ex Marshall) was investigated by transmission electron microscopy using cryo-fixation-freeze-substitution in association with immunogold probes directed against typical structural motifs of lignin. The specificity of the immunological probes for condensed and non-condensed guaiacyl and syringyl interunit linkages of lignin, and their high sensitivity, allowed detection of lignin epitopes of definite chemical structures in the G-layer of tension wood fibres. Semi-quantitative distribution of the corresponding epitopes revealed the abundance of syringyl units in the G-layer. Predominating non-condensed lignin sub-structures appeared to be embedded in the crystalline cellulose matrix prevailing in the G-layer. The endwise mode of polymerization that is known to lead to these types of lignin structures appears consistent with such an organized cellulose environment. Immunochemical labelling provides the first visualization in planta of lignin structures within the G-layer of tension wood. The patterns of distribution of syringyl epitopes indicate that syringyl lignin is deposited more intensely in the later phase of fibre secondary wall assembly. The data also illustrate that syringyl lignin synthesis in tension wood fibres is under specific spatial and temporal regulation targeted differentially throughout cell wall layers.

142 citations


"Tension wood and opposite wood in 2..." refers background in this paper

  • ...However, recent studies demonstrated the presence of lignins (Joseleau et al. 2004) in the G-layer....

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