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1.
Summary The distribution of lignin in normal and compression wood of loblolly pine (Pinus taeda L.) has been studied by the technique of lignin skeletonizing. Hydrolysis of the wood carbohydrates with hydrofluoric acid left normal wood tracheids with a uniform distribution of lignin in the S1 and S2 cell wall layers. However, the S3 region of both earlywood and latewood tracheids consistently retained a dense network of unhydrolyzable material throughout, perhaps lignin.Lignin content in compression wood averaged about 7% more than in normal wood and appears to be concentrated in the outer zone of the S2 layer. The inner S2 region, despite helical checking, is also heavily lignified. The S1 layer, although thicker than normal in compression wood tracheids, contains relatively little lignin.Ray cells, at least in normal wood, appear to be lignified to the same extent, if not more so in certain cases, than the longitudinal tracheids. Other locations where lignin may be concentrated include initial pit border regions and the membranes of bordered pits.This report is a detailed excerpt from the Ph. D. dissertation of R. A. P. Financial support provided by the College of Forestry at Syracuse University and the National Defense Education Act is hereby gratefully acknowledged.  相似文献   

2.
Summary The formation of lignin in the cell wall of compression wood of Pinus thunbergii was examined by selective radio-labeling of specific structural units in the lignin and visualization of the label in the different morphological regions by microautoradiography. Deposition of lignin in the tracheid cell wall of compression wood occurred in the order: p-hydroxyphenyl, guaiacyl and syringyl lignin, which is the same order as observed in normal wood. However, the period of lignification in the compression wood was quite different from those of normal and opposite woods. The p-hydroxyphenyl units were deposited mainly in the early stage of cell wall formation in compound middle lamella in normal and opposite woods, while in compression wood, they were formed in both the compound middle lamella and the secondary wall. The most intensive lignification was observed during the formation of the S2 layer, proceeding from the outer to inner S2 layers for a long period in compression wood. In the normal or opposite woods, in contrast, the lignification became active after formation of S3 had begun, then proceeded uniformly in the secondary wall and ended after a short period.A part of this report was originally presented at the 1989 International Symposium on Wood and Pulping Chemistry at Raleigh, NC, U.S.A.  相似文献   

3.
Summary Opposite wood, normal side wood, and compression wood were isolated from leaning stems of Abies balsamea, Larix laricina, Picea mariana, Pinus resinosa, and Tsuga canadensis and were subjected to analyses for lignin and relative carbohydrate composition. There were no statistically significant differences between the data obtained for opposite wood and side wood. Contrary to some earlier reports, opposite wood has exactly the same content of lignin, cellulose, and hemicelluloses as has corresponding normal wood.This paper is dedicated to Dean Edwin C. Jahn in honor of his 70th birthday.  相似文献   

4.
ABSTRACT

The connection between chemical composition and anatomy of wood is poorly studied. Abiotic and biotic growth conditions affect the synthesis of structural compounds and the anatomy of wood at the same time as they affect growth. In this study, the wood chemical composition, and connections between wood chemistry and anatomy were studied in downy birch (Betula pubescens Ehrh.) grown on four growth sites possessing mineral and peat soils. Lignin, holocellulose, extractive and ash contents, and effective heating value were analysed and compared with libriform fibre double wall thickness and lumen diameter, vessel size and number, and ray and axial parenchyma numbers. Measured lignin and extractive contents were exceptionally high and holocellulose content low. Correlations between wood anatomy and effective heating value were partly different on different soils. Correlations between holocellulose and anatomy were the opposite of the correlations between other chemical compounds and anatomy. The significant correlations between chemical composition and anatomy were commonly opposite in trees grown on peat than in trees grown on mineral soil. Particularly, vessel characteristics and fibre wall thickness correlated significantly with wood chemistry in trees grown on mineral soil. The connections between wood anatomy and chemistry proved to be soil-dependent.  相似文献   

5.
Scanning UV-microspectrophotometry was used to investigate the topochemistry of lignin removal from pine wood (Pinus taeda and P. elliottii) chips during biopulping involving wood treatment with Ceriporiopsis subvermispora (Pilát) Gilbn. & Ryv. followed by alkaline sulfite/anthraquinone delignification. A delignification front starting from the lumen towards the compound middle lamella was clearly observed in micrographs recorded from individual cell wall layers of wood samples biotreated for 30 days. Lignin was removed without cell wall erosion. UV-micrographs of wood samples cooked for a short time (90 min pulping) showed that the S2 of biotreated samples are more homogeneously delignified compared to the S2 of the undecayed controls. Similarly, the compound middle lamella and cell corners are also more delignified in biotreated samples. On the other hand, UV-micrographs of samples cooked for a long time (150 min pulping at 170°C) showed that there are no significant differences in the contents of residual lignin retained in the S2 of undecayed and biotreated wood samples.  相似文献   

6.
To clarify the behavior of whole lignins in wood cell walls during alkaline nitrobenzene oxidation, the delignification process from cell walls in normal and compression woods of Chamaecyparis obtusa Endl. (Cupressaceae) was observed using ultraviolet and transmission electron microscopies. The lignin content conspicuously decreased to around 10% after 35min in normal wood. The lignin content in compression wood finally leveled off at aroumd 10% after 50min. In gel filtration of oxidation products in ethyl acetate, a high molecular weight fraction was prominent in extracts from the early stage of the reaction. As the oxidation progressed, the high molecular weight fraction became less prominent in both normal and compression wood. Changes in the weights of cell wall residues during reaction indicated that approximately half of the components other than lignin were also removed from the cell walls. This shows that the majority of lignin with relatively high molecular weight is removed from the cell walls together with polysaccharides in the early stage of the reaction and that further oxidative degradation occurs in solution in later stages. Only a small amount of the lignin with low molecular weight could be analyzed by gas chromatography.Parts of this report were presented at the 47th (Kochi, April 1997) and 48th (Shizuoka, April 1998) Annual Meetings of the Japan Wood Research Society, and at the Lignin Symposium, Sapporo, October 1997  相似文献   

7.
Summary To elucidate biochemical features leading to p-hydroxyphenyl-rich lignin in gymnosperm reaction wood the activities of the following five enzymes involved in the biosynthesis of p-hydroxyphenyl lignin were compared in reaction and opposite woods: phenylalanine ammonialyase (EC 4.3.1.5), cinnamate 4-hydroxylase (EC 1.14.13.11), p-hydroxycinnamate: CoA ligase (EC 6.2.1.12), cinnamyl alcohol dehydrogenase (EC 1.1.1.-) and peroxidase (EC 1.11.1.7). The enzyme activities in the reaction woods of Thuja orientalis and Metasequoia glyptostroboides were remarkably higher than those in the opposite woods, reflecting the higher contents of p-hydroxyphenyl lignin in reaction wood.This work was partly supported by the Grant-in-Aid for Scientific Research (548047) from the Ministry of Education, Science and Culture of Japan. We thank the Ministry of Education for the support  相似文献   

8.
Summary The distribution of lignin has been studied in tracheids and ray cells of normal and compression wood of tamarack [Larix laricina (Du Roi) K. Koch]. The three layers in the secondary wall of normal wood tracheids are lignified to approximately the same extent, and previous evidence that the S 3 layer should contain a higher proportion of lignin than the other regions has not been confirmed. The lignin follows closely the orientation of the cellulose microfibrils in all three layers. Compared to the tracheids, the ray cells contain a denser network of lignin in their secondary wall.Only a small proportion of the total lignin in compression wood tracheids is present in the compound middle lamella. The thick S 1 layer is only slightly lignified; the orientation of the lignin in this region is that of the transversely oriented, lamellated microfibrils. The outer portion of S 2 consists largely of lignin but also contains lamellae of cellulose microfibrils which probably have the same helical orientation as the microfibrils in the inner part of S 2. The latter region, which contains the helical cavities, consists of lamellae of cellulose microfibrils which are uniformly encrusted with lignin. The ray cells in compression wood appear to be lignified to the same extent as in normal wood. Transverse sections of the cells reveal a lateral orientation of the lignin. The orientation of the cellulose microfibrils in the S 2 layer of the first-formed springwood tracheids of compression wood is the same as in the cells which are formed later. It is suggested that for ease of reference, the outer, lignin-rich layer in compression wood tracheids be referred to as the S 2(L) layer.
Zusammenfassung Im Druckholz und im normalen Holz von Tamarack (Larix laricina (Du Roi) K. Koch) wurde die Verteilung des Lignins in Tracheiden und Markstrahlzellen untersucht. Die drei Schichten der Sekundärwand in den Tracheiden normalen Holzes werden in nahezu demselben Umfange lignifiziert. Frühere Feststellungen, daß die S 3-Schicht einen höheren Ligningehalt erreicht als andere Zellwandbereiche, konnten also nicht bestätigt werden. Das Lignin folgt sehr genau der Orientierung der Cellulose-Mikrofibrillen aller drei Schichten. Im Vergleich zu den Tracheiden erfahren die Sekundärwände der Markstrahlzellen eine stärkere Ligninauskleidung.Nur ein geringer Prozentsatz des gesamten Lignins der Druckholztracheiden befindet sich in der Mittellamelle. Die dicke S 1-Schicht ist nur wenig lignifiziert. Die Orientierung des Lignins in diesem Bereich entspricht den transversal orientierten, lamellierten Mikrofibrillen. Der äußere Teil der S 2-Schicht enthält sehr viel Lignin, daneben aber auch Lamellen von Cellulose-Mikrofibrillen, die wahrscheinlich dieselbe spiralige Orientierung besitzen wie die Mikrofibrillen des inneren Teiles der S 2-Schicht. Der letzterwähnte Bereich, der spiralige Kavitäten enthält, weist Lamellen von Cellulose-Mikrofibrillen auf, in welche gleichmäßig Lignin eingelagert ist. Die Markstrahlzellen des Druckholzes erscheinen ebenso stark lignifiziert wie die Markstrahlzellen des Normalholzes. Querschnitte durch diese Zellen lassen die laterale Orientierung des Lignins erkennen. Die Orientierung der Cellulose-Mikrofibrillen in der S 2-Schicht der zuerst gebildeten Frühholztracheiden des Druckholzes ist dieselbe wie in jenen Zellen, die später ausgeformt werden. Es wird vorgeschlagen, daß zur eindeutigeren Kennzeichnung die äußere ligninreiche Schicht der Druckholztracheiden als S 2(L)-Schicht bezeichnet wird.

The authors wish to express their gratitude to Messrs. A. K. Bentum, D. C. Jones, and B. W. Simson for technical assistance. They are also thankful to Dr. D. A. I. Goring, McGill University, Montreal, Canada, for valuable discussions and for making available to them important, unpublished information. This investigation was supported by the United States Department of Agriculture, Forest Service, through Forest Service Research Grant No. 1, which is hereby gratefully acknowledged.  相似文献   

9.
Analysis on residue formation during wood liquefaction with polyhydric alcohol   总被引：12，自引：0，他引：12  
Liquefactions of cellulose powder, steamed lignin, alkali lignin, and their mixtures were carried out to analyze the reaction process of wood using polyhydric alcohol. The liquefaction of wood proceeded immediately and wood components were converted to N,N-dimethylformamide (DMF)-soluble components. After that, the condensation reaction occurred with increasing reaction time. However, none of cellulose powder, steamed lignin, and alkali lignin condensed by themselves during their liquefaction. The mixture of cellulose and lignin was also liquefied, and condensed after a long reaction time. The results of analysis showed that the behavior of the mixture resembled that of wood with respect to molecular weight distribution and the main functional groups. Lignin was converted to DMF-soluble compounds in the initial stage of wood liquefaction, followed by cellulose gradually being converted into soluble compounds. After that, condensation reactions took place among some parts of depolymerized and degraded compounds from cellulose and lignin, and were converted into DMF-insoluble compounds. It was concluded that the rate-determining step of wood liquefaction was the depolymerization of cellulose. Furthermore, it was suggested that the condensation reaction was due to the mutual reaction among depolymerized cellulose and degraded aromatic derivatives from lignin or due to the nucleophilic displacement reaction of cellulose by phenoxide ion.Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002  相似文献   

10.
Seedlings ofEucalyptus viminalis were grown for 50 days with their stems bent so tension wood would form. Every 10 days the lignin content, monomeric composition, and peroxidase activity in the tension wood were compared with those in the lower side (opposite wood) and in vertically grown controls. The lignin content in the developing tension wood started to decrease after 10 days of bending and kept decreasing for 50 days, whereas those in control plants and opposite wood remained almost unchanged. The yields of syringaldehyde from tension wood by nitrobenzene oxidation increased, and consequently the syringyl/ guaiacyl ratio of the lignin was higher in tension wood than in opposite wood and control plants. The peroxidase ionically bound to the cell walls (IPO) catalyzed oxidation of guaiacol and syringaldazine. The syringaldazineoxidizing activity of IPO from tension wood increased, whereas the activities of IPO from opposite wood and control plants did not show any marked change. In tension wood the increase in syringaldazine-oxidizing activity of IPO was consistent with an increase in the syringaldehyde yield. This suggests that IPO contributes to syringyl lignin deposition as other enzymes involved in the monolignol biosynthesis do in tension wood formation.This study was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000  相似文献   

11.
Condensation of lignin during heating of wood   总被引：3，自引：0，他引：3  
Summary The structural change of lignin during heating of wood was investigated quantitatively by a method combining nucleus exchange and nitrobenzene oxidation. Lignin modification during heating was mainly a diphenylmethane type condensation. About 40 and 75% of noncondensed units in protolignins were converted to diphenylmethane type units by heating of dry and wet wood meals up to 220 °C, respectively. On the other hand, during heating of modified lignin (dioxane lignin) various types of modifications in addition to diphenylmethane type condensation occurred. Lignin modification via the diphenylmethane type condensation was proposed as a new route for its utilization.  相似文献   

12.
Lignin deposition at consecutive secondary wall thickening stages of early and late xylem cells during annual ring wood formation in Scots pine (Pinus sylvestris L.) stems was studied. Lignin patterns, isolated by thioglycolic acid method, consisted of alcohol-soluble (LTGA-I) and alkali-soluble (LTGA-II) fractions. The sum of two fractions, being the total lignin content, gradually increased in the course of lignification. However, the increments of lignin amount at each development stage of early and late tracheids were different. The intensity of lignin deposition increased in the course of earlywood tracheid maturation and decreased toward the end of latewood cell differentiation. The deposition of two lignin fractions in each layer of forming wood also occurred oppositely. The increment of LTGA-I descended, whereas that of LTGA-II increased from the beginning to the end of early xylem lignification. In contrast, LTGA-I increment dropped, whereas LTGA-II rose during late xylem lignification. Gel permeation chromatography showed that the lignins, formed at the beginning of lignification, were more homogeneous and had higher molecular weight compared with the lignins at the end of cell differentiation. Besides, the content of cellulose, estimated as the residue after lignin isolation, and of cell wall substances, presented as cell wall cross-section areas, at consecutive maturation stages of early and late xylem cells have been found to be different. The data show that lignin deposition occurred in different conditions and with opposite dynamics during early and late xylem formation.  相似文献   

13.
Lignin and cellulose contents and wood basic density were related to diameter at breast height (DBH) in six fast-growing and five slow-growing families from a combined progeny test and seedling seed orchard of Eucalyptus urophylla grown for 10 years in northern Vietnam. The mean cellulose content of the fast-growing families was significantly higher than that of the slow growing-families (40.0 and 37.1%, respectively), and for individual trees cellulose content was significantly correlated phenotypically with DBH. Wood basic density was significantly lower in the fast-growing group than in the slow-growing group (0.506 and 0.535 g cm−3, respectively), and was significantly negatively correlated phenotypically with DBH. The lignin contents were not significantly different between groups. Cellulose content and wood basic density were not correlated. The main conclusion is that there is no obstacle to combining high growth rate with high cellulose content, for plantation of forests intended mainly for pulpwood.  相似文献   

14.
Summary The ultrastructure of steam-exploded wood from the softwood Pinus radiata D. Don was examined by electron microscopy in order to determine the reasons for increased porosity and enhanced susceptibility to enzymatic hydrolysis. Ultrastructural changes were observed in the form of lignin redistribution and swelling of the cellulose framework. Lignin showed evidence of melting, having contracted into well defined agglomerates suspended in a web of cellulose. Using lanthanum and gold tracers of known particle size the pores in the microfibrillar cell wall have been examined. Cellulose regions were shown to contain numerous pores greater than 2 nm, while lignin agglomerates did not contain such pores. Treatment with NaOH resulted in lignin being smeared over the porous cell wall material — hence blocking pores and reducing digestibility.The authors gratefully acknowledge the assistance of T. A. Clark and K. F. Deverell during the course of this work  相似文献   

15.
Fibre morphology, anatomy and ultrastructure in cell wall of Salix gordejecii normal wood were examined by transmission electron microscopy (TEM). S. gordejecii tension wood can be recognized anatomically by the presence of gelatinous (G) fibres, which contain a conspicuously thickened inner cell wall layer. TEM images showed that cell wall of S. gordejecii normal wood was typically divided into three layers including the primary wall (P), the middle lamellar (ML) and the secondary wall (S1, S2 and S3). Lignin distribution was determined by using confocal laser scanning microscopy (CLSM) and transmission electron microscopy with energy dispersive X-ray analysis (TEM-EDXA). Confocal images (530 nm) of S. gordejecii normal wood showed strongly lignified CCML, and weakly lignified ML and S2 layer. Weakly lignified fibres (F) and strongly lignified vessels (V) were also detected by using CLSM. Results obtained from confocal microscopy were further confirmed by using TEM-EDXA, indicating that the ratio of lignin concentration in CCML, ML and S2 is 1.72 (1321):1.31 (1006):1 (768). Lignin distribution in tension wood is similar to that in normal wood, except for the non-lignified G layer.  相似文献   

16.
《Southern Forests》2013,75(3):215-220
The infection and association between the wood wasp Sirex noctilio and the fungus Amylostereum areolatum is responsible for large-scale tree mortality in the Midlands of the KwaZulu-Natal province in South Africa. An exploratory investigation on the effect of the infestation of trees by the wood wasp and its associated fungus on the chemical composition of Pinus patula pulpwood was undertaken. Various tree classes representing different levels of physiological growth stress from this infestation were compared. Together with the above stress agents, fire damage to P. patula trees was also considered as a possible cause of changes in pulpwood chemical composition. Chemical analyses to determine the Seifert cellulose and Klason lignin contents as well as the levels of water- and solvent-soluble extractives were conducted using published Tappi standard methods. The results indicated only negligible differences between infestation levels (tree classes) with respect to Seifert cellulose and Klason lignin contents. In contrast, highly significant differences were observed for solvent- and water-borne extractives. It is evident from the results that P. patula trees engage a defence strategy to counter the effects of the infestation and the resulting physiological stress. The results of the chemical analyses suggest that trees should not be harvested any younger than the intended rotation age of 12 years and at the time of harvesting all the biomass, including the infected wood, should be sent to the pulp mill. Fire-damaged trees can be utilised in the same way as healthy trees when applying the TMP process provided the charcoal on the outer bark is removed. The usefulness of a biplot to simultaneously display the various tree classes and their chemical composition is illustrated.  相似文献   

17.
Summary Cell wall lignin distribution was assessed in Pinus radiata wood using quantitative interference microscopy. Three groups of trees were examined. Five trees, offspring of NZ clone 850-55, and five trees of NZ 850-55 crossed with several parents of the Guadelupe provenance, were compared with five trees of unselected P. radiata. Lignin concentration in the cell corner middle lamella region was significantly lower in both offspring groups of NZ 850-55 when compared with the unselected control trees. No difference in S2 lignin concentration was observed among the three groups. This result represents the first indication that variations in lignin distribution are genetically controlled in pines.The author gratefully acknowledges the assistance of Dr. C. J. A. Shelbourne, Mr. G. D. Young, FRI, and Mr. R. S. Foster, Papro (NZ), during the course of this work  相似文献   

18.
采用紫外光谱、红外光谱、核磁共振波谱、凝胶渗透色谱和有机元素分析对从马尾松正常木与应压木中提取的纤维素酶酶解木素的结构进行比较研究。结果表明:马尾松正常木与应压木木素的芳香环结构主要以愈创木基为主,有少量的对羟基苯基;都含有较多的脂肪族羟基;与正常木木素相比,应压木木素含有较多的对羟基苯基单元和酚羟基,其中缩合酚羟基和对羟基酚羟基较多,还含有少量的紫丁香基酚羟基;应压木木素中的甲氧基、羧基、β-O-4键、β-5键,β-β键和β-1键较少;正常木与应压木木素的经验式分别为C9H7.27O1.53(OH)0p.H19(OH)1A.118(OCH3)1.23和C9H7.28O1.54(OH)0p.H20(OH)1A.117(OCH3)1.13。  相似文献   

19.
Summary A new lignin isolation method has been developed. Wood and pulp were subjected to ball milling, swelled in an organic solvent, and then treated with a cellulase. The enzyme digestion time could be shortened to 1 day with this method. The lignin obtained has been named Swelled Enzyme Lignin (SEL). Swelling and enzyme digestion conditions and their effects on lignins were investigated. The SEL's from wood could be directly washed with water, while those from pulp had to be washed with aqueous acetic acid because they were water soluble. The purification of crude SEL's was accomplished by extracting them with dioxane-water, and then precipitating and washing with ethyl ether. Lignin yields were 24–67% based on the total amount of lignin present. The characteristics of the SEL's were further investigated by gel-permeation chromatography (GPC), infrared and 13C nuclear magnetic resonance (NMR) spectroscopy.Symbols SUKP Softwood Unbleached Kraft Pulp - BUKP Birch Unbleached Kraft Pulp - TD Todomatsu (Abies sachalinensis) wood - MWL Milled Wood Lignin - MWLS (BK, TD) Milled Wood Lignin of SUKP (BUKP, TD) - SEL-C Swelled Enzyme Lignin (crude) - SELS-C SEL-C of SUKP, other materials named in the same way - SELS-90 SEL-C of SUKP and extracted with 90% dioxane-water - SELS-96 SEL-C of SUKP and extracted with 96% dioxane-water, other materials named in the same way  相似文献   

20.
To analyze the structural features of lignin in the vicinity of lignin–carbohydrate linkages, water-soluble lignin–carbohydrate complex (LCC) with low lignin content was prepared from residual birch wood meal after the extraction of milled wood lignin (MWL). The molecular weight distribution of lignin in this LCC appeared together with carbohydrate in the relatively high molecular weight region of the gel permeation chromatogram. This result was consistent with our previous results obtained for the same fraction of Japanese cedar (sugi); however, after treatment with polysaccharide-degrading enzyme, the molecular weight distribution of carbohydrate and that of lignin shifted significantly to the lower region. These results demonstrated that molecular size of this LCC is determined by carbohydrates while lignin is present as a minor fragment in this fraction. The syringyl/guaiacyl (S/V) ratio of this LCC was higher than other lignin fractions. Ozonation analysis implied that this LCC has a relatively high number of β-1 structures. It is likely that lignin that exists near lignin–carbohydrate linkages has more endwise-type features than other lignin fractions.This paper was presented in part at the 48th Lignin Symposium, Fukui, Japan, October 2003 and at the 12th International Symposium on Wood and Pulping Chemistry, Madison, USA, June 2003  相似文献   

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