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Bruno Clair - One of the best experts on this subject based on the ideXlab platform.
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Diversity of anatomical structure of Tension Wood among 242 tropical tree species
IAWA Journal, 2019Co-Authors: Barbara Ghislain, Julien Engel, Bruno ClairAbstract:Angiosperm trees produce Tension Wood to actively control their vertical position. Tension Wood has often been characterised by the presence of an unlignified inner fibre wall layer called the G-layer. Using this definition, previous reports indicate that only one-third of all tree species have Tension Wood with G-layers. Here we aim to (i) describe the large diversity of Tension Wood anatomy in tropical tree species, taking advantage of the recent understanding of Tension Wood anatomy and (ii) explore any link between this diversity and other ecological traits of the species. We sampled Tension Wood and normal Wood in 432 trees from 242 species in French Guiana. The samples were observed using safranin and astra blue staining combined with optical microscopy. Species were assigned to four anatomical groups depending on the presence/absence of G-layers, and their degree of lignification. The groups were analysed for functional traits including Wood density and light preferences. Eighty-six% of the species had G-layers in their Tension Wood which was lignified in most species, with various patterns of lignification. Only a few species did not have G-layers. We found significantly more species with lignified G-layers among shade-tolerant and shade-demanding species as well as species with a high Wood density. Our results bring up-to-date the incidence of species with/without G-layers in the tropical lowland forest where lignified G-layers are the most common anatomy of Tension Wood. Species without G-layers may share a common mechanism with the bark motor taking over the Wood motor. We discuss the functional role of lignin in the G-layer.
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Diversity in the organisation and lignification of Tension Wood fibre walls – A review
Iawa Journal, 2017Co-Authors: Barbara Ghislain, Bruno ClairAbstract:Tension Wood, a tissue developed by angiosperm trees to actively recover their verticality, has long been defined by the presence of an unlignified cellulosic inner layer in the cell wall of fibres, called the G-layer. Although it was known that some species have no G-layer, the definition was appropriate since it enabled easy detection of Tension Wood zones using various staining techniques for either cellulose or lignin. For several years now, irrespective of its anatomical structure, Tension Wood has been defined by its high mechanical internal tensile stress. This definition enables screening of the diversity of cell walls in Tension Wood fibres. Recent results obtained in tropical species with Tension Wood with a delay in the lignification of the G-layer opened our eyes to the effective presence of large amounts of lignin in the G-layer of some species. This led us to review older literature mentioning the presence of lignin deposits in the G-layer and give them credit. Advances in the knowledge of Tension Wood fibres allow us to reconsider some previous classifications of the diversity in the organisation of the fibre walls of the Tension Wood.
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diversity in the organisation and lignification of Tension Wood fibre walls a review
Iawa Journal, 2017Co-Authors: Barbara Ghislain, Bruno ClairAbstract:Tension Wood, a tissue developed by angiosperm trees to actively recover their verticality, has long been defined by the presence of an unlignified cellulosic inner layer in the cell wall of fibres, called the G-layer. Although it was known that some species have no G-layer, the definition was appropriate since it enabled easy detection of Tension Wood zones using various staining techniques for either cellulose or lignin. For several years now, irrespective of its anatomical structure, Tension Wood has been defined by its high mechanical internal tensile stress. This definition enables screening of the diversity of cell walls in Tension Wood fibres. Recent results obtained in tropical species with Tension Wood with a delay in the lignification of the G-layer opened our eyes to the effective presence of large amounts of lignin in the G-layer of some species. This led us to review older literature mentioning the presence of lignin deposits in the G-layer and give them credit. Advances in the knowledge of Tension Wood fibres allow us to reconsider some previous classifications of the diversity in the organisation of the fibre walls of the Tension Wood.
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The effect of sectioning and ultrasonication on the mesoporosity of poplar Tension Wood
Wood Science and Technology, 2017Co-Authors: Shan-shan Chang, Françoise Quignard, Bruno ClairAbstract:Increasing interest in understanding Tension stress generation in Tension Wood with fibres having a gelatinous layer (G-layer) has focused attention on the specific role of this layer. To distinguish its contribution from those of other wall layers, the G-layer of Wood sections was isolated by ultrasonication. The aim of this study was to assess the effect of sectioning and of the ultrasonic treatment on the mesoporosity of Tension Wood using nitrogen adsorption–desorption analysis. The results showed that the process of isolating the G-layer using ultrasonication strongly affects its mesoporosity. Most damage was found to occur during sectioning rather than as a result of the 15-min ultrasonic treatment.
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Multilayered structure of Tension Wood cell walls in Salicaceae sensu lato and its taxonomic significance
Botanical Journal of the Linnean Society, 2016Co-Authors: Barbara Ghislain, Eric-andré Nicolini, Raïssa Romain, Mac H. Alford, Julien Ruelle, Arata Yoshinaga, Bruno ClairAbstract:The circumscription of Salicaceae has recently been enlarged to include a majority of the species formerly placed in the polyphyletic tropical family Flacourtiaceae. Several studies have reported a peculiar and infrequently formed multilayered structure of Tension Wood in four of the tropical genera. Tension Wood is a tissue produced by trees to restore their vertical orientation, and most studies have focused on trees developing Tension Wood by means of cellulose-rich, gelatinous fibres, as is known in Populus L. and Salix L. (Salicaceae s.s.). This study aims to determine if the multilayered structure of Tension Wood is an anatomical characteristic common in other Salicaceae, and if so, how its distribution correlates to phylogenetic relationships. Therefore, we studied the Tension Wood of 14 genera of Salicaceae as well as two genera of Achariaceae, one genus of Goupiaceae, and one genus of Lacistemataceae, families closely related to Salicaceae or formerly placed in Flacourtiaceae. Opposite Wood and Tension Wood were compared with light microscopy and 3D Laser Scanning Confocal Microscopy. The results indicate that a multilayered structure of Tension Wood is common in the family except in Salix, Populus, and one of their closest relatives, Idesia polycarpa Maxim. We suggest that Tension Wood may be a useful anatomical character in understanding phylogenetic relationships in Salicaceae. Further investigation is still needed on the Tension Wood of several other putatively close relatives of Salix and Populus, in particular Bennettiodendron Merr., Macrohasseltia L.O.Williams and Itoa Hemsl.
Ryo Funada - One of the best experts on this subject based on the ideXlab platform.
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Stem gravitropism and Tension Wood formation in Acacia mangium seedlings inclined at various angles.
Annals of Botany, 2018Co-Authors: Widyanto Dwi Nugroho, Shahanara Begum, Hasnat Rahman, Satoshi Nakaba, Kayo Kudo, Yusuke Yamagishi, Sri Nugroho Marsoem, Ryo FunadaAbstract:Background and Aims: In response to a gravitational stimulus, angiosperm trees generally form Tension Wood on the upper sides of leaning stems in order to reorientate the stems in the vertical direction. It is unclear whether the angle of inclination from the vertical affects Tension Wood formation. This study was designed to investigate negative gravitropism, Tension Wood formation and growth eccentricity in Acacia mangium seedlings inclined at different angles. Methods: Uniform seedlings of A. mangium were artificially inclined at 30°, 45°, 60° and 90° from the vertical and harvested, with non-inclined controls, 3 months later. We analysed the effects of the angle of inclination on the stem recovery angle, the anatomical features of Tension Wood and radial growth. Key Results: Smaller inclination angles were associated with earlier stem recovery while stems subjected to greater inclination returned to the vertical direction after a longer delay. However, in terms of the speed of negative gravitopism towards the vertical, stems subjected to greater inclination moved more rapidly toward the vertical. There was no significant difference in terms of growth eccentricity among seedlings inclined at different angles. The 30°-inclined seedlings formed the narrowest region of Tension Wood but there were no significant differences among seedlings inclined at 45°, 60° and 90°. The 90°-inclined seedlings formed thicker gelatinous layers than those in 30°-, 45°- and 60°-inclined seedlings. Conclusion: Our results suggest that the angle of inclination of the stem influences negative gravitropism, the width of the Tension Wood region and the thickness of gelatinous layers. Larger amounts of gelatinous fibres and thicker gelatinous layers might generate the higher tensile stress required for the higher speed of stem-recovery movement in A. mangium seedlings.
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Gibberellin mediates the development of gelatinous fibres in the Tension Wood of inclined Acacia mangium seedlings.
Annals of Botany, 2013Co-Authors: Widyanto Dwi Nugroho, Shahanara Begum, Jaeheung Ko, Satoshi Nakaba, Yusuke Yamagishi, Sri Nugroho Marsoem, Ryo FunadaAbstract:†Background and Aims Gibberellin stimulates negative gravitropism and the formation of Tension Wood in tilted Acacia mangium seedlings, while inhibitors of gibberellin synthesis strongly inhibit the return to vertical growth and suppress the formation of Tension Wood. To characterize the role of gibberellin in Tension Wood formation and gravitropism, this study investigated the role of gibberellin in the development of gelatinous fibres and in the changes in anatomical characteristics of Woody elements in Acacia mangium seedlings exposed to a gravitational stimulus. †Methods Gibberellin, paclobutrazol and uniconazole-P were applied to the soil in which seedlings were growing, usingdistilledwaterasthecontrol.Threedaysafterthestartoftreatment,seedlingswereinclinedat45 8tothevertical andsampleswereharvested2monthslater.TheeffectsofthetreatmentsonWoodfibres,vesselelementsandrayparenchymacellswereanalysedinTensionWoodintheupperpartofinclinedstemsandintheoppositeWoodonthelower side of inclined stems. †Key Results Application of paclobutrazol or uniconazole-P inhibited the increase in the thickness of gelatinous layersandpreventedtheelongationofgelatinousfibresintheTensionWoodofinclinedstems.Bycontrast,gibberellin stimulated the elongation of these fibres. Application of gibberellin and inhibitors of gibberellin biosynthesis had only minor effects on the anatomical characteristics of vessel and ray parenchyma cells. †ConclusionsTheresultssuggestthatgibberellinisimportantforthedevelopmentofgelatinousfibresintheTension Wood of A. mangium seedlings and therefore in gravitropism.
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gibberellin is required for the formation of Tension Wood and stem gravitropism in acacia mangium seedlings
Annals of Botany, 2012Co-Authors: Widyanto Dwi Nugroho, Shiori Fukuhara, Shahanara Begum, Jaeheung Ko, Satoshi Nakaba, Yusuke Yamagishi, Ryo Funada, Sri Nugroho MarsoemAbstract:BACKGROUND AND AIMS: Angiosperm trees generally form Tension Wood on the upper sides of leaning stems. The formation of Tension Wood is an important response to gravitational stimulus. Gibberellin appears to be involved in the differentiation of secondary xylem, but it remains unclear whether gibberellin plays a key role in the formation of Tension Wood and plant gravitropism. Therefore, a study was designed to investigate the effects of gibberellin and of inhibitors of the synthesis of gibberellin, namely paclobutrazole and uniconazole-P, on the formation of Tension Wood and negative stem gravitropism in Acacia mangium seedlings. METHODS: Gibberellic acid (GA(3)), paclobutrazole and uniconazole-P were applied to seedlings via the soil in which they were growing. Distilled water was applied similarly as a control. Three days after such treatment, seedlings were tilted at an angle of 45° from the vertical, and samples of stems were collected for analysis 2 weeks, 2 months and 6 months after tilting. The effects of treatments on the stem recovery degree (Ro) were analysed as an index of the negative gravitropism of seedlings, together the width of the region of Tension Wood in the upper part of inclined stems. KEY RESULTS: It was found that GA(3) stimulated the negative gravitropism of tilted seedling stems of A. mangium, while paclobutrazole and uniconazole-P inhibited recovery to vertical growth. Moreover, GA(3) stimulated the formation of Tension Wood in tilted A. mangium seedlings, while paclobutrazole and uniconazole-P strongly suppressed the formation of Tension Wood, as assessed 2 weeks after tilting. CONCLUSIONS: The results suggest that gibberellin plays an important role at the initial stages of formation of Tension Wood and in stem gravitropism in A. mangium seedlings in response to a gravitational stimulus.
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PART OF A HIGHLIGHT ON TREE BIOLOGY Gibberellin is required for the formation of Tension Wood and stem gravitropism in Acacia mangium seedlings
2012Co-Authors: Widyanto Dwi Nugroho, Shiori Fukuhara, Shahanara Begum, Satoshi Nakaba, Yusuke Yamagishi, Sri Nugroho Marsoem, Hyun-o Jin, Ryo FunadaAbstract:†Background and Aims Angiosperm trees generally form Tension Wood on the upper sides of leaning stems. The formation of Tension Wood is an important response to gravitational stimulus. Gibberellin appears to be involved in the differentiation of secondary xylem, but it remains unclear whether gibberellin plays a key role in the formation of Tension Wood and plant gravitropism. Therefore, a study was designed to investigate the effects of gibberellin and of inhibitors of the synthesis of gibberellin, namely paclobutrazole and uniconazole-P, on the formation of Tension Wood and negative stem gravitropism in Acacia mangium seedlings. †Methods Gibberellic acid (GA3), paclobutrazole and uniconazole-P were applied to seedlings via the soil in which they were growing. Distilled water was applied similarly as a control. Three days after such treatment, seedlings were tilted at an angle of 458 from the vertical, and samples of stems were collected for analysis 2 weeks, 2 months and 6 months after tilting. The effects of treatments on the stem recovery degree (Ro) were analysed as an index of the negative gravitropism of seedlings, together the width of the region of Tension Wood in the upper part of inclined stems. †Key Results It was found that GA3 stimulated the negative gravitropism of tilted seedling stems of A. mangium, while paclobutrazole and uniconazole-P inhibited recovery to vertical growth. Moreover, GA3 stimulated the formation of Tension Wood in tilted A. mangium seedlings, while paclobutrazole and uniconazole-P strongly suppressed the formation of Tension Wood, as assessed 2 weeks after tilting. †Conclusions The results suggest that gibberellin plays an important role at the initial stages of formation of Tension Wood and in stem gravitropism in A. mangium seedlings in response to a gravitational stimulus.
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Gibberellin-induced formation of Tension Wood in angiosperm trees.
Planta, 2008Co-Authors: Ryo Funada, Tatsuhiko Miura, Yousuke Shimizu, Takanori Kinase, Takafumi Kubo, Satoshi Nakaba, Yuzou SanoAbstract:After gibberellin had been applied to the vertical stems of four species of angiosperm trees for approximately 2 months, we observed eccentric radial growth that was due to the enhanced growth rings on the sides of stems to which gibberellin had been applied. Moreover, the application of gibberellin resulted in the formation of Wood fibers in which the thickness of inner layers of cell walls was enhanced. These thickened inner layers of cell walls were unlignified or only slightly lignified. In addition, cellulose microfibrils on the innermost surface of these thickened inner layers of cell walls were oriented parallel or nearly parallel to the longitudinal axis of the fibers. Such thickened inner layers of cell walls had features similar to those of gelatinous layers in the Wood fibers of Tension Wood, which are referred to as gelatinous fibers. Our anatomical and histochemical investigations indicate that the application of gibberellin can induce the formation of Tension Wood on vertical stems of angiosperm trees in the absence of gravitational stimulus.
Widyanto Dwi Nugroho - One of the best experts on this subject based on the ideXlab platform.
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Stem gravitropism and Tension Wood formation in Acacia mangium seedlings inclined at various angles.
Annals of Botany, 2018Co-Authors: Widyanto Dwi Nugroho, Shahanara Begum, Hasnat Rahman, Satoshi Nakaba, Kayo Kudo, Yusuke Yamagishi, Sri Nugroho Marsoem, Ryo FunadaAbstract:Background and Aims: In response to a gravitational stimulus, angiosperm trees generally form Tension Wood on the upper sides of leaning stems in order to reorientate the stems in the vertical direction. It is unclear whether the angle of inclination from the vertical affects Tension Wood formation. This study was designed to investigate negative gravitropism, Tension Wood formation and growth eccentricity in Acacia mangium seedlings inclined at different angles. Methods: Uniform seedlings of A. mangium were artificially inclined at 30°, 45°, 60° and 90° from the vertical and harvested, with non-inclined controls, 3 months later. We analysed the effects of the angle of inclination on the stem recovery angle, the anatomical features of Tension Wood and radial growth. Key Results: Smaller inclination angles were associated with earlier stem recovery while stems subjected to greater inclination returned to the vertical direction after a longer delay. However, in terms of the speed of negative gravitopism towards the vertical, stems subjected to greater inclination moved more rapidly toward the vertical. There was no significant difference in terms of growth eccentricity among seedlings inclined at different angles. The 30°-inclined seedlings formed the narrowest region of Tension Wood but there were no significant differences among seedlings inclined at 45°, 60° and 90°. The 90°-inclined seedlings formed thicker gelatinous layers than those in 30°-, 45°- and 60°-inclined seedlings. Conclusion: Our results suggest that the angle of inclination of the stem influences negative gravitropism, the width of the Tension Wood region and the thickness of gelatinous layers. Larger amounts of gelatinous fibres and thicker gelatinous layers might generate the higher tensile stress required for the higher speed of stem-recovery movement in A. mangium seedlings.
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Gibberellin mediates the development of gelatinous fibres in the Tension Wood of inclined Acacia mangium seedlings.
Annals of Botany, 2013Co-Authors: Widyanto Dwi Nugroho, Shahanara Begum, Jaeheung Ko, Satoshi Nakaba, Yusuke Yamagishi, Sri Nugroho Marsoem, Ryo FunadaAbstract:†Background and Aims Gibberellin stimulates negative gravitropism and the formation of Tension Wood in tilted Acacia mangium seedlings, while inhibitors of gibberellin synthesis strongly inhibit the return to vertical growth and suppress the formation of Tension Wood. To characterize the role of gibberellin in Tension Wood formation and gravitropism, this study investigated the role of gibberellin in the development of gelatinous fibres and in the changes in anatomical characteristics of Woody elements in Acacia mangium seedlings exposed to a gravitational stimulus. †Methods Gibberellin, paclobutrazol and uniconazole-P were applied to the soil in which seedlings were growing, usingdistilledwaterasthecontrol.Threedaysafterthestartoftreatment,seedlingswereinclinedat45 8tothevertical andsampleswereharvested2monthslater.TheeffectsofthetreatmentsonWoodfibres,vesselelementsandrayparenchymacellswereanalysedinTensionWoodintheupperpartofinclinedstemsandintheoppositeWoodonthelower side of inclined stems. †Key Results Application of paclobutrazol or uniconazole-P inhibited the increase in the thickness of gelatinous layersandpreventedtheelongationofgelatinousfibresintheTensionWoodofinclinedstems.Bycontrast,gibberellin stimulated the elongation of these fibres. Application of gibberellin and inhibitors of gibberellin biosynthesis had only minor effects on the anatomical characteristics of vessel and ray parenchyma cells. †ConclusionsTheresultssuggestthatgibberellinisimportantforthedevelopmentofgelatinousfibresintheTension Wood of A. mangium seedlings and therefore in gravitropism.
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gibberellin is required for the formation of Tension Wood and stem gravitropism in acacia mangium seedlings
Annals of Botany, 2012Co-Authors: Widyanto Dwi Nugroho, Shiori Fukuhara, Shahanara Begum, Jaeheung Ko, Satoshi Nakaba, Yusuke Yamagishi, Ryo Funada, Sri Nugroho MarsoemAbstract:BACKGROUND AND AIMS: Angiosperm trees generally form Tension Wood on the upper sides of leaning stems. The formation of Tension Wood is an important response to gravitational stimulus. Gibberellin appears to be involved in the differentiation of secondary xylem, but it remains unclear whether gibberellin plays a key role in the formation of Tension Wood and plant gravitropism. Therefore, a study was designed to investigate the effects of gibberellin and of inhibitors of the synthesis of gibberellin, namely paclobutrazole and uniconazole-P, on the formation of Tension Wood and negative stem gravitropism in Acacia mangium seedlings. METHODS: Gibberellic acid (GA(3)), paclobutrazole and uniconazole-P were applied to seedlings via the soil in which they were growing. Distilled water was applied similarly as a control. Three days after such treatment, seedlings were tilted at an angle of 45° from the vertical, and samples of stems were collected for analysis 2 weeks, 2 months and 6 months after tilting. The effects of treatments on the stem recovery degree (Ro) were analysed as an index of the negative gravitropism of seedlings, together the width of the region of Tension Wood in the upper part of inclined stems. KEY RESULTS: It was found that GA(3) stimulated the negative gravitropism of tilted seedling stems of A. mangium, while paclobutrazole and uniconazole-P inhibited recovery to vertical growth. Moreover, GA(3) stimulated the formation of Tension Wood in tilted A. mangium seedlings, while paclobutrazole and uniconazole-P strongly suppressed the formation of Tension Wood, as assessed 2 weeks after tilting. CONCLUSIONS: The results suggest that gibberellin plays an important role at the initial stages of formation of Tension Wood and in stem gravitropism in A. mangium seedlings in response to a gravitational stimulus.
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PART OF A HIGHLIGHT ON TREE BIOLOGY Gibberellin is required for the formation of Tension Wood and stem gravitropism in Acacia mangium seedlings
2012Co-Authors: Widyanto Dwi Nugroho, Shiori Fukuhara, Shahanara Begum, Satoshi Nakaba, Yusuke Yamagishi, Sri Nugroho Marsoem, Hyun-o Jin, Ryo FunadaAbstract:†Background and Aims Angiosperm trees generally form Tension Wood on the upper sides of leaning stems. The formation of Tension Wood is an important response to gravitational stimulus. Gibberellin appears to be involved in the differentiation of secondary xylem, but it remains unclear whether gibberellin plays a key role in the formation of Tension Wood and plant gravitropism. Therefore, a study was designed to investigate the effects of gibberellin and of inhibitors of the synthesis of gibberellin, namely paclobutrazole and uniconazole-P, on the formation of Tension Wood and negative stem gravitropism in Acacia mangium seedlings. †Methods Gibberellic acid (GA3), paclobutrazole and uniconazole-P were applied to seedlings via the soil in which they were growing. Distilled water was applied similarly as a control. Three days after such treatment, seedlings were tilted at an angle of 458 from the vertical, and samples of stems were collected for analysis 2 weeks, 2 months and 6 months after tilting. The effects of treatments on the stem recovery degree (Ro) were analysed as an index of the negative gravitropism of seedlings, together the width of the region of Tension Wood in the upper part of inclined stems. †Key Results It was found that GA3 stimulated the negative gravitropism of tilted seedling stems of A. mangium, while paclobutrazole and uniconazole-P inhibited recovery to vertical growth. Moreover, GA3 stimulated the formation of Tension Wood in tilted A. mangium seedlings, while paclobutrazole and uniconazole-P strongly suppressed the formation of Tension Wood, as assessed 2 weeks after tilting. †Conclusions The results suggest that gibberellin plays an important role at the initial stages of formation of Tension Wood and in stem gravitropism in A. mangium seedlings in response to a gravitational stimulus.
Shahanara Begum - One of the best experts on this subject based on the ideXlab platform.
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Stem gravitropism and Tension Wood formation in Acacia mangium seedlings inclined at various angles.
Annals of Botany, 2018Co-Authors: Widyanto Dwi Nugroho, Shahanara Begum, Hasnat Rahman, Satoshi Nakaba, Kayo Kudo, Yusuke Yamagishi, Sri Nugroho Marsoem, Ryo FunadaAbstract:Background and Aims: In response to a gravitational stimulus, angiosperm trees generally form Tension Wood on the upper sides of leaning stems in order to reorientate the stems in the vertical direction. It is unclear whether the angle of inclination from the vertical affects Tension Wood formation. This study was designed to investigate negative gravitropism, Tension Wood formation and growth eccentricity in Acacia mangium seedlings inclined at different angles. Methods: Uniform seedlings of A. mangium were artificially inclined at 30°, 45°, 60° and 90° from the vertical and harvested, with non-inclined controls, 3 months later. We analysed the effects of the angle of inclination on the stem recovery angle, the anatomical features of Tension Wood and radial growth. Key Results: Smaller inclination angles were associated with earlier stem recovery while stems subjected to greater inclination returned to the vertical direction after a longer delay. However, in terms of the speed of negative gravitopism towards the vertical, stems subjected to greater inclination moved more rapidly toward the vertical. There was no significant difference in terms of growth eccentricity among seedlings inclined at different angles. The 30°-inclined seedlings formed the narrowest region of Tension Wood but there were no significant differences among seedlings inclined at 45°, 60° and 90°. The 90°-inclined seedlings formed thicker gelatinous layers than those in 30°-, 45°- and 60°-inclined seedlings. Conclusion: Our results suggest that the angle of inclination of the stem influences negative gravitropism, the width of the Tension Wood region and the thickness of gelatinous layers. Larger amounts of gelatinous fibres and thicker gelatinous layers might generate the higher tensile stress required for the higher speed of stem-recovery movement in A. mangium seedlings.
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Gibberellin mediates the development of gelatinous fibres in the Tension Wood of inclined Acacia mangium seedlings.
Annals of Botany, 2013Co-Authors: Widyanto Dwi Nugroho, Shahanara Begum, Jaeheung Ko, Satoshi Nakaba, Yusuke Yamagishi, Sri Nugroho Marsoem, Ryo FunadaAbstract:†Background and Aims Gibberellin stimulates negative gravitropism and the formation of Tension Wood in tilted Acacia mangium seedlings, while inhibitors of gibberellin synthesis strongly inhibit the return to vertical growth and suppress the formation of Tension Wood. To characterize the role of gibberellin in Tension Wood formation and gravitropism, this study investigated the role of gibberellin in the development of gelatinous fibres and in the changes in anatomical characteristics of Woody elements in Acacia mangium seedlings exposed to a gravitational stimulus. †Methods Gibberellin, paclobutrazol and uniconazole-P were applied to the soil in which seedlings were growing, usingdistilledwaterasthecontrol.Threedaysafterthestartoftreatment,seedlingswereinclinedat45 8tothevertical andsampleswereharvested2monthslater.TheeffectsofthetreatmentsonWoodfibres,vesselelementsandrayparenchymacellswereanalysedinTensionWoodintheupperpartofinclinedstemsandintheoppositeWoodonthelower side of inclined stems. †Key Results Application of paclobutrazol or uniconazole-P inhibited the increase in the thickness of gelatinous layersandpreventedtheelongationofgelatinousfibresintheTensionWoodofinclinedstems.Bycontrast,gibberellin stimulated the elongation of these fibres. Application of gibberellin and inhibitors of gibberellin biosynthesis had only minor effects on the anatomical characteristics of vessel and ray parenchyma cells. †ConclusionsTheresultssuggestthatgibberellinisimportantforthedevelopmentofgelatinousfibresintheTension Wood of A. mangium seedlings and therefore in gravitropism.
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gibberellin is required for the formation of Tension Wood and stem gravitropism in acacia mangium seedlings
Annals of Botany, 2012Co-Authors: Widyanto Dwi Nugroho, Shiori Fukuhara, Shahanara Begum, Jaeheung Ko, Satoshi Nakaba, Yusuke Yamagishi, Ryo Funada, Sri Nugroho MarsoemAbstract:BACKGROUND AND AIMS: Angiosperm trees generally form Tension Wood on the upper sides of leaning stems. The formation of Tension Wood is an important response to gravitational stimulus. Gibberellin appears to be involved in the differentiation of secondary xylem, but it remains unclear whether gibberellin plays a key role in the formation of Tension Wood and plant gravitropism. Therefore, a study was designed to investigate the effects of gibberellin and of inhibitors of the synthesis of gibberellin, namely paclobutrazole and uniconazole-P, on the formation of Tension Wood and negative stem gravitropism in Acacia mangium seedlings. METHODS: Gibberellic acid (GA(3)), paclobutrazole and uniconazole-P were applied to seedlings via the soil in which they were growing. Distilled water was applied similarly as a control. Three days after such treatment, seedlings were tilted at an angle of 45° from the vertical, and samples of stems were collected for analysis 2 weeks, 2 months and 6 months after tilting. The effects of treatments on the stem recovery degree (Ro) were analysed as an index of the negative gravitropism of seedlings, together the width of the region of Tension Wood in the upper part of inclined stems. KEY RESULTS: It was found that GA(3) stimulated the negative gravitropism of tilted seedling stems of A. mangium, while paclobutrazole and uniconazole-P inhibited recovery to vertical growth. Moreover, GA(3) stimulated the formation of Tension Wood in tilted A. mangium seedlings, while paclobutrazole and uniconazole-P strongly suppressed the formation of Tension Wood, as assessed 2 weeks after tilting. CONCLUSIONS: The results suggest that gibberellin plays an important role at the initial stages of formation of Tension Wood and in stem gravitropism in A. mangium seedlings in response to a gravitational stimulus.
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PART OF A HIGHLIGHT ON TREE BIOLOGY Gibberellin is required for the formation of Tension Wood and stem gravitropism in Acacia mangium seedlings
2012Co-Authors: Widyanto Dwi Nugroho, Shiori Fukuhara, Shahanara Begum, Satoshi Nakaba, Yusuke Yamagishi, Sri Nugroho Marsoem, Hyun-o Jin, Ryo FunadaAbstract:†Background and Aims Angiosperm trees generally form Tension Wood on the upper sides of leaning stems. The formation of Tension Wood is an important response to gravitational stimulus. Gibberellin appears to be involved in the differentiation of secondary xylem, but it remains unclear whether gibberellin plays a key role in the formation of Tension Wood and plant gravitropism. Therefore, a study was designed to investigate the effects of gibberellin and of inhibitors of the synthesis of gibberellin, namely paclobutrazole and uniconazole-P, on the formation of Tension Wood and negative stem gravitropism in Acacia mangium seedlings. †Methods Gibberellic acid (GA3), paclobutrazole and uniconazole-P were applied to seedlings via the soil in which they were growing. Distilled water was applied similarly as a control. Three days after such treatment, seedlings were tilted at an angle of 458 from the vertical, and samples of stems were collected for analysis 2 weeks, 2 months and 6 months after tilting. The effects of treatments on the stem recovery degree (Ro) were analysed as an index of the negative gravitropism of seedlings, together the width of the region of Tension Wood in the upper part of inclined stems. †Key Results It was found that GA3 stimulated the negative gravitropism of tilted seedling stems of A. mangium, while paclobutrazole and uniconazole-P inhibited recovery to vertical growth. Moreover, GA3 stimulated the formation of Tension Wood in tilted A. mangium seedlings, while paclobutrazole and uniconazole-P strongly suppressed the formation of Tension Wood, as assessed 2 weeks after tilting. †Conclusions The results suggest that gibberellin plays an important role at the initial stages of formation of Tension Wood and in stem gravitropism in A. mangium seedlings in response to a gravitational stimulus.
Gérard Nepveu - One of the best experts on this subject based on the ideXlab platform.
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Shiny Beech Wood is Confirmed as an Indicator of Tension Wood
IAWA Journal, 2008Co-Authors: Adelin Barbacci, Thiéry Constant, Etienne Farré, Maryline Harroué, Gérard NepveuAbstract:This study sought to develop a method to quantify Tension Wood areas in stem discs. It was suggested that the shiny appearance of beech (Fagus sylvatica L.) could provide an indication of Tension Wood. Each of 21 stem discs were digitised and the images analysed. Small areas of the discs were selected, and from these areas, anatomical sections were stained with astra-blue and safranine and the stained sections were compared with the Wood disc images. The analysis showed that the shape of shiny areas and Tension Wood were similar; moreover, the measured ratios of shiny Wood and Tension Wood were in good agreement. This confirms the assumption that in Fagus sylvatica shiny Wood corresponds to Tension Wood.
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Tension Wood occurrence in three cultivars of Populus × euramericana. Part I: Inter-clonal and intra-tree variability of Tension Wood
Annals of Forest Science, 2006Co-Authors: Miguel Angel Badia, Thiéry Constant, Frédéric Mothe, Gérard NepveuAbstract:The main Wood quality problem affecting poplar trees is Tension Wood occurrence associated to end-splits after felling, distortions of products, woolly Wood, etc. The objective of this study was to estimate the occurrence of Tension Wood by using the external shape of the stem and the 3D distribution of annual growth rings. This paper is the first of two papers and presents the inter-clonal and intra-tree Tension Wood variability. A clear clonal-effect was observed on Tension Wood area percentage (I-MC>I214>Luisa Avanzo). The clone with the best tree morphology (I-MC) showed the highest percentage of Tension Wood (15.3%). Concerning the intra-tree variability, Tension Wood extent increased significantly at the tree base (< 30-50 cm). In the radial direction of the stem, the percentage of Tension Wood showed an U-shape distribution. The first peak, close to the pith, corresponds to the "establishment growth period" during the open growth and the second peak, close to the bark corresponds to the "competition growth period
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Tension Wood occurrence in three cultivars of Populus × euramericana. Part I: Inter-clonal and intra-tree variability of Tension Wood
Annals of Forest Science, 2006Co-Authors: Miguel Angel Badia, Thiéry Constant, Frédéric Mothe, Gérard NepveuAbstract:The main Wood quality problem affecting poplar trees is Tension Wood occurrence associated to end-splits after felling, distortions of products, woolly Wood, etc. The objective of this study was to estimate the occurrence of Tension Wood by using the external shape of the stem and the 3D distribution of annual growth rings. This paper is the first of two papers and presents the inter-clonal and intra-tree Tension Wood variability. A clear clonal-effect was observed on Tension Wood area percentage (I-MC>I214>Luisa Avanzo). The clone with the best tree morphology (I-MC) showed the highest percentage of Tension Wood (15.3%). Concerning the intra-tree variability, Tension Wood extent increased significantly at the tree base (
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Assessment of Tension Wood detection based on shiny appearance for three poplar cultivars
Annals of Forest Science, 2005Co-Authors: Miguel Angel Badia, Thiéry Constant, Frédéric Mothe, Gérard NepveuAbstract:The shiny appearance of poplar Tension Wood was tested in order to detect and to quantify the amount of Tension Wood in nine cross-cut discs. These carefully sawn discs came from different poplar clones: I214, Melone Carlo (I-MC) and Luisa Avanzo, exhibiting different patterns of Tension Wood distribution. The relevancy of the results was verified by means of 80 thin sections, 15 $\mu$m thick and double stained with safranine and astra blue. Digital images of the discs and microscopic cuts were processed by image analysis to quantify the comparison. There was good agreement between both methods despite very different scales of observation. Eighty percent of the Tension Wood spots were detected by both methods and differences were mainly explained by human factors or inaccuracies in the macroscopic detection of small areas.
