Xylogénèse chez les Dicotylédones arborescentes. V. Formation du bois de tension et transport de l'acide indole acétique tritié chez le Hêtre

1987 ◽  
Vol 65 (6) ◽  
pp. 1253-1258 ◽  
Author(s):  
Suzanne Lachaud
Keyword(s):  
Tension Wood ◽  
Indole Acetic Acid ◽  
Auxin Transport ◽  
Lower Side ◽  
Preferential Direction ◽  
Axial Parenchyma ◽  
Gelatinous Fibers ◽  
Fagus Silvatica ◽  
Normal Transport ◽  
Bois De Tension

Upper stems of young beeches (Fagus silvatica L.) were bent into Jaccard loops in May. If they stayed on the tree, they produced a wide arc of extreme tension wood on the upper side of the loop, which contained numerous gelatinous fibers, few vessels, and little axial parenchyma. On the lower side of these loops, xylogenesis was nearly stopped. If bent stems were removed from the tree, xylogenesis was far less asymmetric: the wood formed on the upper side contained normal vessels and axial parenchyma, but also gelatinous fibers; on the lower side, the wood was normal. Transport and metabolism of 3H-labelled indole acetic acid was studied in both models. In intact loops left on the trees, lateral auxin transport took place mainly towards the lower half of the stem. In isolated loops, no preferential direction could be detected for lateral auxin transport. Extreme tension wood differentiation on the upper side of a bent stem requires the intervention of correlative factors, not only from buds, but also from the base of the tree, which particularly influence lateral downward transport of auxin.

scholarly journals ANATOMICAL CHARACTERIZATION OF TENSION WOOD IN Hevea brasiliensis (Willd. ex A. Juss.) Mull. Arg.

2016 ◽  
Vol 40 (6) ◽  
pp. 1099-1107
Author(s):  
Letícia Maria Alves Ramos ◽  
João Vicente de Figueiredo Latorraca ◽  
Thayanne Caroline Castor Neto ◽  
Letícia Souza Martins ◽  
Elias Taylor Durgante Severo
Keyword(s):  
Hevea Brasiliensis ◽  
Fiber Length ◽  
Tension Wood ◽  
Rubber Tree ◽  
Microfibril Angle ◽  
Vessel Diameter ◽  
Longitudinal Distribution ◽  
Axial Parenchyma ◽  
Gelatinous Fibers ◽  
Gelatinous Fiber

ABSTRACT Tension wood is an important anatomical structure for its participation in the orientation of the trunk and the architecture of the branches as a function of structural reinforcement. However, its presence in large amounts significantly affects the technological properties of wood, just as in the rubber tree. Nevertheless, there is still demand for information about the origin, distribution and structural features in this species. Thus, this study aims to characterize the cellular structures in tension and opposite wood in Hevea brasiliensis (rubber tree), as well as its radial and longitudinal distribution. Discs at the base and the middle of the commercial logs were collected from three trees in a commercial plantation located in Tabapoã - SP. Tangential diameter of vessels, fiber length (gelatinous and non-gelatinous fibers), microfibril angle and proportionality of cellular elements (vessels, axial parenchyma, ray, gelatinous fibers and non-gelatinous fibers) were measured, and influence of gelatinous fiber presence in vessel diameter was observed. Gelatinous fibers were observed in the two types of wood and in the two trunk heights. Both types of wood were distinguished by gelatinous fiber length and the proportion of axial parenchyma. The tension wood in mid-trunk was the most different, with long gelatinous fibers and less abundant, larger vessel diameter and vessel proportion. Moreover, smaller vessel diameter was observed in the regions with a high proportion of gelatinous fibers, suggesting that the plant invests more support than in liquid transport.

ROLES OF AUXIN AND GIBBERELLIN IN GRAVITY-INDUCED TENSION WOOD FORMATION IN AESCULUS TURBINATA SEEDLINGS

IAWA Journal ◽  
2004 ◽  
Vol 25 (3) ◽  
pp. 337-347 ◽  
Author(s):  
Sheng Du ◽  
Hiroki Uno ◽  
Fukuju Yamamoto
Keyword(s):  
Tension Wood ◽  
Auxin Transport ◽  
Histological Analysis ◽  
Synergistic Effects ◽  
Wood Formation ◽  
Wood Fibers ◽  
Lower Side ◽  
Inhibitory Effects ◽  
Auxin Action ◽  
Ga Biosynthesis

The lowest nodes of 6-week-old Aesculus turbinata seedlings were treated with uniconazole-P, an inhibitor of gibberellin (GA) biosynthesis, or a mixture of uniconazole-P and GA3 in acetone solution. To the seedling stems, an inhibitor of auxin transport (NPA) or inhibitors of auxin action (raphanusanin or MBOA) were applied in lanolin paste. The seedlings were tilted at a 45° angle and kept for 10 weeks before histological analysis. Decreases in both normal and tension wood formation followed the application of uniconazole-P. The application of GA3 together with uniconazole-P partially negated the effect of uniconazole-P alone. The application of NPA inhibited tension wood formation at, above, and below the lanolin-treated portions. The treatment of raphanusanin or MBOA also resulted in decreases in tension wood formation at the treated portions. The inhibitory effects of these chemicals applied on the upper side of tilted stems or around the entire stem were greater than on the lower side. The application of uniconazole-P in combination with raphanusanin, MBOA or NPA showed synergistic effects on the inhibition of tension wood formation. The results suggest that both auxin and GA regulate the quantitative production of tension wood fibers and are essential to tension wood formation.

scholarly journals Prognostic of the Using Wood of Erythroxylum myrsinites Mart. Under the Anatomic Prism

2019 ◽  
Vol 12 (1) ◽  
pp. 188
Author(s):  
Rossana Cortelini da Rosa ◽  
Dione Dambrós Raddatz ◽  
Paulo Fernando dos Santos Machado ◽  
Mario Lima dos Santos ◽  
Alexandro Dias Martins Vasconcelos ◽  
...  
Keyword(s):  
Wood Properties ◽  
Anatomical Structure ◽  
Specific Mass ◽  
Wood Technology ◽  
Mechanical Loads ◽  
Axial Parenchyma ◽  
Thin Walls ◽  
Gelatinous Fibers ◽  
Vascular Elements ◽  
High Flexibility

The composition of the wood and its elements are considered determinants in the wood properties, standing out the fibers, axial parenchyma, number of vessels and rays. In this context, we aimed to investigate and describe the wood anatomical structure of the Erythroxylum myrsinites Mart. and identify its potential uses in the area of wood technology. From the tree, were removed three wood samples for the confection of anatomical slides, witch 3 × 3 × 3 cm, oriented we plans transversal, longitudinal and tangential longitudinal. For the preparation of histological blades, the method of Burger and Richter was adopted; the anatomical description was based on IAWA Committee recommendations. The species presents vessels numerous, solitary, composing 19% of the volume of wood. Diffuse porosity of polygonal contour and thin walls. Mean vascular elements, axial parenchyma representing 3% of the volume of the wood, in a paratracheal vasicentric arrangement. The rays are numerous, occupying 23% of the volume of the wood, narrow and heterogeneous, consisting of procumbent, square and erect cells. The fibers are libriform, of length medium and thick walls, occupying 55% of the volume of the wood, have spiral thickening and septate fibers, absent tracheids, and gelatinous fibers abundant. The characteristics presented give high flexibility to the stem and branches, and the wood with low specific mass, permeable and resistant to mechanical loads has potential for use in energy generation.

scholarly journals Deletion in the Promoter of PcPIN-L Affects the Polar Auxin Transport in Dwarf Pear (Pyrus communis L.)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaodong Zheng ◽  
Haiyue Zhang ◽  
Yuxiong Xiao ◽  
Caihong Wang ◽  
Yike Tian
Keyword(s):  
Indole Acetic Acid ◽  
Auxin Transport ◽  
Dominant Gene ◽  
Polar Auxin Transport ◽  
Shoot Tips ◽  
Dwarf Phenotype ◽  
Standard Type ◽  
Pyrus Communis L ◽  
Transgenic Lines ◽  
Dwarf Type

AbstractDwarf cultivars or dwarfing rootstocks enable high-density planting and are therefore highly desirable in modern pear production. Previously, we found that the dwarf growth habit of pear is controlled by a single dominant gene PcDw. In this study, PcPIN-L (PCP021016) was cloned from dwarf-type and standard-type pears. PcPIN-L expression was significantly lower in the dwarf-type pears than in standard-type pears, which was caused by the CT repeat deletion in the promoter of dwarf-type pears. PcPIN-L overexpression in tobacco plants enhanced the growth of the stems and the roots. Notably, the indole acetic acid (IAA) content decreased in the shoot tips and increased in the stems of transgenic lines compared with wild type, which is consistent with the greater IAA content in the shoot tips and lower IAA content in the stems of dwarf-type pears than in standard-type pears. The CT repeat deletion in the promoter that causes a decrease in promoter activity is associated with lower PcPIN-L expression in the dwarf-type pears, which might limit the polar auxin transport and in turn result in the dwarf phenotype. Taken together, the results provide a novel dwarfing molecular mechanism in perennial woody plants.

Comparison of basic density and longitudinal shrinkage in tension wood and opposite wood in young stems of Populus euramericana cv. Ghoy when subjected to a gravitational stimulus

2001 ◽  
Vol 31 (10) ◽  
pp. 1676-1683 ◽  
Author(s):  
B Jourez ◽  
A Riboux ◽  
A Leclercq
Keyword(s):  
Physical Properties ◽  
Tension Wood ◽  
Basic Density ◽  
Small Samples ◽  
Longitudinal Shrinkage ◽  
Wood Tissue ◽  
Populus Euramericana ◽  
Opposite Wood ◽  
Gelatinous Fibers ◽  
Poplar Cuttings

In a greenhouse, under controlled conditions, young shoots, taken from poplar cuttings (Populus euramericana (Dole) Guinier cv. Ghoy), were artificially bent to quantify the modifications of physical properties induced by a gravitational stimulus. At the end of the growing season, basic density and longitudinal shrinkage were measured on very small samples taken from pure tension wood tissue observed on the upper face of the inclined axis and compared with opposite wood tissue, free of gelatinous fibers, developed on the opposite lower face. In a second step, shoots bent at two different lean intensities were analyzed. In young poplar wood, gravitational stimulus was found to have a significant effect on physical properties. Relations between basic density and longitudinal shrinkage are different depending on the types of wood considered. Shrinkage appears more sensitive to lean intensity in the range considered here.

scholarly journals Localization of xyloglucan epitopes in the gelatinous layer of developing and mature gelatinous fibers of European aspen (Populus tremula L.) tension wood

BioResources ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 7675-7686
Author(s):  
Jong Sik Kim ◽  
Geoffrey Daniel
Keyword(s):  
Tension Wood ◽  
Developmental Changes ◽  
Immunogold Localization ◽  
Gelatinous Layer ◽  
Gelatinous Fibers ◽  
Transmission Electron ◽  
European Aspen ◽  
Innermost Layer ◽  
Specific Localization ◽  
Populus Spp

There is controversy concerning the presence of xyloglucans in gelatinous (G) layers of Populus spp. tension wood, particularly in mature G-fibers. Transmission electron microscopy (TEM) immunogold localization combined with LM15 antibody (recognizes XXXG-motif of xyloglucans, heptasaccharide) was used to investigate the distribution of xyloglucan epitopes in both transverse and radial sections of P. tremula tension wood. Results provided clear evidence for the presence of xyloglucans in both mature and developing G-layers. Developmental decrease of LM15 epitope localization in G-layers was also detected during G-fiber maturation. High magnification TEM observations showed specific localization of LM15 epitopes on newly synthesized cellulose macrofibrils present in the innermost layer of developing G-layers adjacent to the cell lumen, suggesting linkage between xyloglucans and cellulose macrofibrils. Possible mechanisms were discussed for developmental changes of xyloglucan with respect to the different results reported in the literature.

Effect of exogenous IAA on tension wood formation by facilitating polar auxin transport and cellulose biosynthesis in hybrid poplar (Populus deltoids × Populus nigra) wood

Holzforschung ◽  
2017 ◽  
Vol 71 (2) ◽  
pp. 179-188 ◽  
Author(s):  
Min Yu ◽  
Kai Liu ◽  
Shengquan Liu ◽  
Haiyan Chen ◽  
Liang Zhou ◽  
...  
Keyword(s):  
Tension Wood ◽  
Auxin Transport ◽  
Hybrid Poplar ◽  
Wood Formation ◽  
Polar Auxin Transport ◽  
Fiber Formation ◽  
Pcr Analysis ◽  
Cellulose Content ◽  
Cellulose Biosynthesis ◽  
Exogenous Iaa

Abstract Auxins as phytohormons, responsible for coordination of growing processes, also contribute to the formation of tension wood (TW) in trees, but the mechanism of this process is still unclear. In this study, it has been tried to induce TW formation in erect hybrid poplar trees (in opposite to inclined or bended trees) by treatment with exogenous indole-3-acetic acid (IAA, as one of the auxins) or N-1-naphthylphthalamic acid (NPA) as an auxin transport inhibitor. The treatment with IAA resulted in TW formation and, as expected, NPA treatment did not. The gelatinous fiber formation and higher cellulose content in the cell wall were unambiguous indicators for TW formation. Real-time polymerase chain reaction (PCR) analysis revealed that genes of PIN1, ABCB1, and AUX2 involved in polar auxin transport were highly expressed in trees treated with exogenous IAA. Moreover, expressions of cellulose biosynthesis related genes of UGP1, UGP2 and CesA13 were strongly up-regulated. These observations indicate that the accelerated intercellular polar auxin transport caused by exogenous IAA is accounted for TW formation, i.e. the signal transduction of auxin is affected, which then facilitates cellulose biosynthesis. In contrast, the transcript abundances of PIN1 and all selected cellulose synthases (CesAs) were decreased after NPA treatment via inhibiting the cellular auxin efflux with negative effects on plant’s primary growth. These results are interpreted that TW formation is closely associated with the acceleration of intercellular polar auxin transport.

scholarly journals GROWTH STRAINS AND RELATED WOOD STRUCTURES IN THE LEANING TRUNKS AND BRANCHES OF TROCHODENDRON ARALIOIDES - A VESSEL-LESS DICOTYLEDON

IAWA Journal ◽  
2007 ◽  
Vol 28 (2) ◽  
pp. 211-222 ◽  
Author(s):  
Ling-Long Kuo-Huang ◽  
Shin-Shin Chen ◽  
Yan-San Huang ◽  
Shiang-Jiuun Chen ◽  
Yi-In Hsieh
Keyword(s):  
Microfibril Angle ◽  
Wall Layer ◽  
Growth Stress ◽  
Lower Side ◽  
Wood Structures ◽  
Opposite Wood ◽  
Gelatinous Fibers ◽  
Percentage Area ◽  
Gelatinous Fiber ◽  
The Difference

Leaning trunks and branches of Trochodendron aralioides Sieb. & Zucc., a primitive vessel-less dicotyledon, show increased radial growth and gelatinous fibers on the upper side similar to the features found in dicotyledons with vessels. The patterns of peripheral longitudinal growth strain are variable among trees but similar at different heights within the same leaning trunk. Growth strains on the lower side of the trunks are very small but they are relatively large on the lower side of the branches. Growth stress in the branches is partly affected by the gravitational bending stress, which would be exerted mostly on the lower side. Large spring back strains of branches are associated with large surface strains. Both the microfibril angle (MFA) and the percentage area of gelatinous fiber show positive relationships with the measured strains. The MFA of the S2 wall layer in tracheids in the opposite wood is 24.6 ± 2.2°, whereas the MFA of gelatinous layer in the tension wood is only 14.2 ± 2.7°. The difference of MFA between the gelatinous fibers and the opposite wood is one of the factors accounting for the large contracting force for reorientation.

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