scholarly journals Influence of the p-hydroxyphenyl/guaiacyl ratio on the biphenyl and β-5 contents in compression wood lignins

Holzforschung ◽  
2019 ◽  
Vol 73 (10) ◽  
pp. 923-935 ◽  
Author(s):  
Haruka Hirayama ◽  
Takuya Akiyama ◽  
Satoshi Kimura ◽  
Deded S. Nawawi ◽  
Wasrin Syafii ◽  
...  
Keyword(s):  
Aromatic Ring ◽  
Cryptomeria Japonica ◽  
Methoxy Group ◽  
Compression Wood ◽  
Lignin Biosynthesis ◽  
Cedrus Deodara ◽  
Opposite Wood ◽  
Authentic Standard ◽  
Standard Compound ◽  
Pinus Merkusii

Abstract Reaction woods of three softwoods, Pinus merkusii, Cryptomeria japonica and Cedrus deodara, were investigated by alkaline nitrobenzene oxidation (NBO) to characterize the condensed-type structures in compression wood lignins. A novel biphenyl-type NBO product carrying guaiacyl (G)- and p-hydroxyphenyl (H)-units, dehydrovanillin-p-hydroxybenzaldehyde (HG-biphenyl product), was identified using the authentic standard compound. On the basis of the yield of this novel NBO product, as well as those of GG-biphenyl-, β-5-, and uncondensed-type products [e.g. dehydrodivanillin, 5-formylvanillin, vanillin and p-hydroxybenzaldehyde], the compression wood lignins contained more HG-type biphenyl and H-type β-5 structures than the opposite wood lignins. The increase in the condensed-type structure content was largely offset by the decreases in the content of GG-biphenyl and G-type β-5 structures. Consequently, the relative yields of biphenyl, β-5 and uncondensed-type NBO products were very similar between the compression wood and the opposite wood, even though the H-unit having no methoxy group on its aromatic ring can be assumed to have a greater probability to form condensed-type structures during lignin biosynthesis than the G-unit.

Cross-field pitting characteristics of compression, lateral, and opposite wood in the stem wood of Ginkgo biloba and Pinus densiflora

IAWA Journal ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 48-60
Author(s):  
Byantara Darsan Purusatama ◽  
Nam Hun Kim
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ginkgo Biloba ◽  
Compression Wood ◽  
Pinus Densiflora ◽  
Reaction Wood ◽  
Stem Wood ◽  
Opposite Wood ◽  
The Cross ◽  
Scanning Electron

Abstract The characteristics of cross-field pitting among compression wood, lateral wood, and opposite wood, in the stem woods of Ginkgo biloba and Pinus densiflora were investigated with optical and scanning electron microscopy. In Ginkgo biloba, compression wood exhibited piceoid pits, while lateral and opposite wood exhibited cupressoid pits. The compression wood of Pinus densiflora exhibited cupressoid pits and piceoid pits, while lateral wood and opposite wood exhibited pinoid and window-like pits in the cross-field. In both species, compression wood yielded the smallest pit number among each part, while opposite wood yielded the greatest pit number per cross-field. Cross-field pitting diameters of compression wood and opposite wood were significantly smaller than lateral wood in Ginkgo biloba, while the cross-field pitting of compression wood was the smallest in Pinus densiflora. Radial tracheid diameter of compression wood was slightly smaller than lateral and opposite wood in Ginkgo biloba and significantly smaller than lateral and opposite wood in Pinus densiflora. In conclusion, the cross-field pitting type, pit number, and cross-field pitting diameter could be used to identify reaction wood in the stem wood of Ginkgo biloba and Pinus densiflora.

Strength and stiffness of the reaction wood in five Eucalyptus species

Holzforschung ◽  
2019 ◽  
Vol 73 (2) ◽  
pp. 219-222
Author(s):  
Bruno Charles Dias Soares ◽  
José Tarcísio Lima ◽  
Selma Lopes Goulart ◽  
Claudineia Olímpia de Assis
Keyword(s):  
Mechanical Behavior ◽  
Tension Wood ◽  
Compression Wood ◽  
Vertical Position ◽  
Eucalyptus Species ◽  
Reaction Wood ◽  
Opposite Wood ◽  
Average Slope ◽  
Strength And Stiffness

AbstractTree stems deviating from the vertical position react by the formation of tension wood (TW) or compression wood (CW), which are called in general as reaction wood (RW), in which the cells are modified chemically and anatomically. The focus of the present work is the mechanical behavior of TW in five 37-year-oldEucalyptusspecies, which were grown on a planting area with an average slope of 28% leading to decentralized pith in the trees, which is an unequivocal indication of the presence of RW. TW and opposite wood (OW) samples were isolated and subjected to a compression-parallel-to-grain test. It was observed that TW is less resistant and less stiff than the OW.

scholarly journals Variability in swelling of spruce (Picea abies [L.] Karst.) wood with the presence of compression wood

2008 ◽  
Vol 53 (No. 6) ◽  
pp. 243-252 ◽  
Author(s):  
V. Gryc ◽  
H. Vavrčík ◽  
P. Horáček
Keyword(s):  
Compression Wood ◽  
Longitudinal Direction ◽  
Tangential Direction ◽  
Transverse Plane ◽  
Opposite Wood ◽  
Sample Tree ◽  
Swelling Coefficient ◽  
Hygroscopic Material ◽  
The Individual ◽  
Shape Changes

Wood is a hygroscopic material that is affected by shape changes. The aim of this study was to analyse the variability of wood swelling in the individual anatomic directions. Wood swelling was examined on a sample tree containing compression wood. With regard to the presence of compression wood, the sample tree was divided into the following three zones: the compression wood zone (CW), the opposite wood zone (OW), and two side wood zones (SWL and SWR). The results show that the wood containing compression wood swells less at the transverse plane (in the radial and tangential direction). Conversely, the swelling of compression wood in the longitudinal direction is higher. The same proportion was established in the swelling coefficient that grew proportionally to the increasing wood density in all anatomic directions. The proportion of compression wood manifested its effects in different ways. Transversely (in the radial and tangential direction) the swelling coefficient decreased proportionally to the increasing percentage of compression wood, longitudinally, however, the opposite was the case.

Effect of abnormal fibres on the mechanical properties of paper made from Norway spruce, Picea abies (L.) Karst.

Holzforschung ◽  
2008 ◽  
Vol 62 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Nasko Terziev ◽  
Geoffrey Daniel ◽  
Ann Marklund
Keyword(s):  
Mechanical Properties ◽  
Picea Abies ◽  
Norway Spruce ◽  
Cell Walls ◽  
Compression Wood ◽  
Morphological Changes ◽  
Mechanical Processing ◽  
Opposite Wood ◽  
Tear Index ◽  
Control Samples

Abstract The aim of the present study was to determine the effect of a variety of abnormal fibres on the mechanical properties of paper made from Norway spruce, Picea abies (L.) Karst. Fibres representing abnormality were obtained from trees treated by irrigation and fertilisation. Moreover, fibres from compression wood and its accompanying opposite wood were isolated. The effect of dislocations on paper quality was studied on four mixtures (20, 40, 60 and 80% fibres with induced dislocations) of untreated/compressed fibres. Two more groups consisting of control untreated samples and samples with 100%-induced dislocations were also included in the test. The mechanical properties of the paper were tested and the results were compared to those of control samples. Abnormal fibres reduced the desired mechanical properties of the final paper concerning tensile strength, modulus of elasticity and tear-tensile index. Irrespective of the type of treatment, all morphological changes introduced in fibre cell walls appear to directly affect changes in the mechanical properties of the paper. Control samples had a tear index of 25 compared to 10 mN m2 g-1 of samples containing 100% dislocations. It is obvious that 20% of dislocations, an amount that is expected to be induced in pulp under mechanical processing and transport, will contribute to a decrease in tear index with an average of 3 mN m2 g-1, i.e., 10% of the total value.

Anatomical Comparison Between Compression Wood and Opposite Wood in a Branch of Korean Pine (Pinus Koraiensis)

IAWA Journal ◽  
1988 ◽  
Vol 9 (3) ◽  
pp. 275-284 ◽  
Author(s):  
Phil Woo Lee ◽  
Young Geun Eom
Keyword(s):  
Compression Wood ◽  
Pinus Koraiensis ◽  
Korean Pine ◽  
Qualitative And Quantitative ◽  
Opposite Wood

Compression wood and opposite wood formed in the branch of Korean pine (Pinus koraiensis S. et Z.) is described and compared in qualitative and quantitative anatomical aspects.

Activation energy for methoxy group relaxation

1978 ◽  
Vol 56 (13) ◽  
pp. 1800-1803 ◽  
Author(s):  
M. A. Mazid ◽  
J. P. Shukla ◽  
S. Walker
Keyword(s):  
Activation Energy ◽  
Aromatic Ring ◽  
Energy Barrier ◽  
Methoxy Group ◽  
Steric Effects ◽  
Molecular Process ◽  
Dielectric Absorption ◽  
Polystyrene Matrix ◽  
Absorption Studies ◽  
Methoxy Groups

Dielectric absorption studies hove been made on seven compounds which hove methoxy groups attached to an aromatic ring and on some related rigid molecules. The solutes hove been dispersed in a polystyrene matrix. In some cases, the absorptions due to the group and the molecular process have been separated completely, and this has permitted the estimation of more accurate Eyring enthalpies of activation for methoxy group relaxation. These values hove been compared with those in the literature and, on the whole, it would seem likely that the energy barrier to group relaxation is small and of the order of 10 kJ mol−1 for cases where there is no mutual conjugation or steric effects.

WITHIN-TREE VARIATION IN ANATOMICAL PROPERTIES OF COMPRESSION WOOD IN RADIATA PINE

IAWA Journal ◽  
2004 ◽  
Vol 25 (3) ◽  
pp. 253-271 ◽  
Author(s):  
Lloyd A. Donaldson ◽  
Jenny Grace ◽  
Geoff M. Downes
Keyword(s):  
Wall Thickness ◽  
Compression Wood ◽  
Microfibril Angle ◽  
Basic Density ◽  
Radiata Pine ◽  
Lumen Diameter ◽  
Normal Wood ◽  
Lignin Distribution ◽  
Opposite Wood ◽  
Anatomical Properties

Two trees of radiata pine, one showing severe lean, the other growing almost vertically, were assessed for the presence and anatomical properties of compression wood, including anatomy, lignin distribution, microfibril angle, basic density, radial and tangential lumen diameter and cell wall thickness. Both trees contained significant amounts of compression wood although the severity and amount of compression wood was greater in the leaning tree. Changes in lignin distribution seem to be characteristic of the mildest forms of compression wood with reduced lignification of the middle lamella representing the earliest change observed from normal wood. An increase in microfibril angle was associated with both mild and severe compression wood although examples of severe compression wood with the same or smaller microfibril angles than opposite wood, or with very small microfibril angles, were found. When segregated into mild and severe compression wood the average difference in microfibril angle was 4° and 8° respectively compared with opposite wood. Within-ring distribution of microfibril angle was different in severe compression wood compared to opposite wood with higher angles in the latewood.Severe compression wood showed a 22% increase in basic density compared to mild compression wood and opposite wood. The increased density was accounted for in terms of a 26% increase in tracheid wall thickness throughout the growth ring, offset by a 9% increase in radial lumen diameter, slightly greater in the latewood. There were no significant changes in density or cell dimensions in mild compression wood compared with opposite wood.

Lignin and carbohydrate variation with earlywood, latewood, and compression wood content of bent and straight ramets of a radiata pine clone

Holzforschung ◽  
2010 ◽  
Vol 64 (1) ◽  
Author(s):  
R. Paul Kibblewhite ◽  
Ian D. Suckling ◽  
Robert Evans ◽  
Jennifer C. Grace ◽  
Mark J.C. Riddell
Keyword(s):  
Radial Direction ◽  
Compression Wood ◽  
Juvenile Wood ◽  
Radiata Pine ◽  
Carbohydrate Content ◽  
Strongly Correlated ◽  
Growth Layer ◽  
Opposite Wood ◽  
Radial Dimension ◽  
Wood Content

Abstract Changes in lignin and carbohydrate content with radial direction, growth-layer number, compression wood (CW) severity, and earlywood (EW) and latewood (LW) origin are described for one near-ground position in each of a severely bent and a nominally straight ramet (tree) of a clone (genotype) of Pinus radiata. Bark-to-bark strips were taken through the pith and the longest radial dimension of the CW side of the discs. Separate EW and LW samples were obtained for most growth layers, yielding a total of 95 samples. Differences in lignin and carbohydrate content between EW and LW were large where CW formation was moderate and small where it was severe. Mannose content was consistently different in the EW and LW of opposite wood (OW) and CW. Results suggested that the inner juvenile wood of OW rings might contain either a galactose-rich galactoglucomannan or a β-1,4-galactan. Consideration of all 95 samples showed that although the contents of galactose, lignin, glucose, and mannose were linearly and strongly correlated with one another, their relationship with xylose and arabinose content was non-linear.

scholarly journals Transformation of 2H-1,2,3-benzothiadiazine 1,1-dioxides variously substituted at the aromatic ring, via nucleophilic substitution and demethylation reactions

2020 ◽  
Author(s):  
Imre Gyűjtő ◽  
Márta Porcs-Makkay ◽  
Ernák Ferenc Várda ◽  
Gyöngyvér Pusztai ◽  
Gábor Tóth ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
Functional Groups ◽  
Aromatic Ring ◽  
Methoxy Group ◽  
Medicinal Chemistry ◽  
Building Blocks ◽  
Chlorine Atoms ◽  
New Methods ◽  
Pharmacological Interest

2H‑1,2,3‑Benzothiadiazine 1,1-dioxides are a class of compounds of pharmacological interest. After earlier studies carried out at our laboratory on various transformations (alkylation, acylation, reduction) at the hetero ring, the present manuscript focuses on the transformation of substituents at the aromatic carbocycle, including nucleophilic substitution of chlorine atoms and demethylation of the methoxy group with amines. The new methods described here allow the introduction of versatile functional groups on the aromatic ring, making these compounds useful building blocks for organic and medicinal chemistry applications.

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