Fundamental Factors Causing Formation of Compression Wood

Timell, T. E.

doi:10.1007/978-3-642-61616-7_11

Cited by 11 publications

(23 citation statements)

References 82 publications

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“…It is a matter of long debate whether reaction wood (a collective name for TW and its corresponding phenomenon in gymnosperms, compression wood) is a gravitational or a mechanical response. Experimental treatments normally induce both cues, and experiments excluding the influence of the gravity vector have yielded conflicting results (42,43). However, it is beyond doubt that leaning and reaction wood formation have additional components besides purely mechanical ones; reaction wood is always induced unilaterally and develops at the side of the stem, which creates a force that counters its displacement, independent of tension or compression forces (43).…”

Section: Do Responses To Gravitational and Mechanical Loads Convergementioning

confidence: 99%

“…Experimental treatments normally induce both cues, and experiments excluding the influence of the gravity vector have yielded conflicting results (42,43). However, it is beyond doubt that leaning and reaction wood formation have additional components besides purely mechanical ones; reaction wood is always induced unilaterally and develops at the side of the stem, which creates a force that counters its displacement, independent of tension or compression forces (43). Little is known about gravitational sensing in secondary stems, but the hypothesis holds that there may be a convergence of this signaling with that derived from mechanical perturbationsboth acting through the induction of ethylene, and hence a stimulation of cambial cell division and diameter growth (2).…”

Section: Do Responses To Gravitational and Mechanical Loads Convergementioning

confidence: 99%

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Ethylene is an endogenous stimulator of cell division in the cambial meristem of Populus

Love

Björklund

Vahala

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

208

189

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The plant hormone ethylene is an important signal in plant growth responses to environmental cues. In vegetative growth, ethylene is generally considered as a regulator of cell expansion, but a role in the control of meristem growth has also been suggested based on pharmacological experiments and ethylene-overproducing mutants. In this study, we used transgenic ethylene-insensitive and ethylene-overproducing hybrid aspen (Populus tremula ؋ tremuloides) in combination with experiments using an ethylene perception inhibitor [1-methylcyclopropene (1-MCP)] to demonstrate that endogenous ethylene produced in response to leaning stimulates cell division in the cambial meristem. This ethylenecontrolled growth gives rise to the eccentricity of Populus stems that is formed in association with tension wood.plant hormones ͉ secondary xylem ͉ tension wood ͉ vascular cambium ͉ wood development T he vascular cambium is the meristem that produces secondary xylem and phloem by periclinal cell divisions, and it is responsible for wood production and stem diameter growth in trees. Cambial growth rate along the trunk is correlated with leaf biomass and crown structure (1). Superimposed on this intrinsic control, cambial growth is also strongly influenced by environment, where mechanical and gravitational loads imposed by wind and leaning are important (2). Wind sway induces increased diameter growth that protects against stem breakage (3), whereas a static lean results in a localized growth response known as tension wood (TW) in dicotyledonous angiosperms. TW is formed on the upper side of the leaning stem, resulting in characteristic asymmetric growth, and it serves to correct the stem position (4). In addition to the striking increase in cambial cell divisions, TW has an altered anatomy, and the fibers form an additional inner, cellulose-rich, gelatinous secondary cell wall layer (G layer) (5).Experiments with ethylene applications have revealed that this volatile plant hormone has the potential to both inhibit and stimulate growth (6). Its synthesis from S-adenosylmethionine through the action of 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) and ACC oxidase (ACO) is triggered in vegetative tissues in response to many environmental cues. To date, concepts of ethylene function in vegetative growth have mainly implicated its role in primary tissue and cell expansion (6). However, ethylene biosynthesis increases during TW formation because of an asymmetric induction of ACO (7,8), and application of ethylene has been shown to stimulate cambial growth both in trees and herbaceous species (9, 10). Additional observations also support a potential role for ethylene in cell division. Applied ethylene stimulated endoreduplication in cucumber hypocotyls and growth of the intercalary meristem in deepwater rice (11-13). Moreover, the ethylene-overproducing Arabidopsis mutant eto1 exhibits aberrant cell divisions in the quiescent center of the root (14). However, experiments where ethylene homeostasis is artificially manipulated by a...

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Section: Do Responses To Gravitational and Mechanical Loads Convergementioning

confidence: 99%

Section: Do Responses To Gravitational and Mechanical Loads Convergementioning

confidence: 99%

Ethylene is an endogenous stimulator of cell division in the cambial meristem of Populus

Love

Björklund

Vahala

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

208

189

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“…Compression wood is characterized by short, rounded tracheids that have thick walls with increased lignin content and increased microfibril angles (Timell, 1969). The formation of reaction wood is often (but not always) accompanied by a stimulation of cambial cell division, whereas the cell division at the opposite side is more or less inhibited.The physiology and development of reaction wood formation has been extensively explored (particularly in gymnosperms) and reviewed in great detail by Timell (1986). The induction of reaction wood by gravistimuli rather than by mechanical stimulation has been deduced from a large number of bending, leaning, and clinostat experiments.…”

mentioning

confidence: 99%

“…This response is unilateral and beneficial for the tree in that it creates physical strains in the wood that force the stem or branch back toward its original orientation in space (Scurfield, 1973;Wilson and Archer, 1977;Timell, 1986). Angiosperm and gymnosperm trees differ in their nature of reaction wood.…”

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Patterns of Auxin Distribution during Gravitational Induction of Reaction Wood in Poplar and Pine

2004

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Gravistimulation of tree stems affects wood development by unilaterally inducing wood with modified properties, called reaction wood. Commonly, it also stimulates cambial growth on the reaction wood side. Numerous experiments involving applications of indole-3-acetic acid (IAA) or IAA-transport inhibitors have suggested that reaction wood is induced by a redistribution of IAA around the stem. However, in planta proof for this model is lacking. Therefore, we have mapped endogenous IAA distribution across the cambial region tissues in both aspen (Populus tremula, denoted poplar) and Scots pine (Pinus sylvestris) trees forming reaction wood, using tangential cryosectioning combined with sensitive gas chromatographymass spectrometry analysis. Moreover, we have documented the kinetics of IAA during reaction wood induction in these species. Our analysis of endogenous IAA demonstrates that reaction wood is formed without any obvious alterations in IAA balance. This is in contrast to gravitropic responses in roots and shoots where a redistribution of IAA has been documented. It is also of interest that cambial growth on the tension wood side was stimulated without an increase in IAA. Taken together, our results suggest a role for signals other than IAA in the reaction wood response, or that the gravitational stimulus interacts with the IAA signal transduction pathway.Displacement of stems and branches by wind or mechanical stress in woody species results in the formation of reaction wood. This response is unilateral and beneficial for the tree in that it creates physical strains in the wood that force the stem or branch back toward its original orientation in space (Scurfield, 1973;Wilson and Archer, 1977;Timell, 1986). Angiosperm and gymnosperm trees differ in their nature of reaction wood. In angiosperm trees, such as poplar, reaction wood is called tension wood and forms on the upper side of stems that have been displaced. Tension wood characteristically has few, small vessels, and fibers with an inner gelatinous cell wall layer (the G-layer) that consists of almost pure cellulose with microfibrils that are parallel to the long cell axis (Haygreen and Bowyer, 1996;Jourez et al., 2001). In gymnosperm trees, such as pine, reaction wood is called compression wood and forms at the lower side of displaced stems. Compression wood is characterized by short, rounded tracheids that have thick walls with increased lignin content and increased microfibril angles (Timell, 1969). The formation of reaction wood is often (but not always) accompanied by a stimulation of cambial cell division, whereas the cell division at the opposite side is more or less inhibited.The physiology and development of reaction wood formation has been extensively explored (particularly in gymnosperms) and reviewed in great detail by Timell (1986). The induction of reaction wood by gravistimuli rather than by mechanical stimulation has been deduced from a large number of bending, leaning, and clinostat experiments. Reaction wood can also be induced by int...

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ACC Oxidase and ACC Synthase Expression Profiles after Leaning of Young Radiata (P. radiata D. Don) and Maritime Pine (P. pinaster Ait.) Seedlings

Ramos

Valenzuela

Provost

et al. 2011

J Plant Growth Regul

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Fundamental Factors Causing Formation of Compression Wood

Cited by 11 publications

References 82 publications

Ethylene is an endogenous stimulator of cell division in the cambial meristem of Populus

Ethylene is an endogenous stimulator of cell division in the cambial meristem of Populus

Patterns of Auxin Distribution during Gravitational Induction of Reaction Wood in Poplar and Pine

ACC Oxidase and ACC Synthase Expression Profiles after Leaning of Young Radiata (P. radiata D. Don) and Maritime Pine (P. pinaster Ait.) Seedlings

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