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1.
水曲柳枝桠材应力木的年轮偏向性分析 总被引：1，自引：0，他引：1
运用SEM显微观察技术,对比分析了水曲柳枝桠材断面应拉区和对应区木质部在微观构造上的异同,并在此基础上讨论了水曲柳应力木的年轮偏向性问题。结论如下:水曲柳应力木的髓心偏向断面上侧,在此区域有大量胶质木纤维形成,干燥时开裂较明显,而下侧的宽年轮区域仅有极少量厚壁纤维存在,基本无开裂。说明在水曲柳应力木中,应拉木主要存在于断面上侧的年轮较窄区域,胶质木纤维的大量存在是其典型特征。 相似文献
2.
该实验的目的是观察栎木枝条的年轮偏向性和应拉木的显微及化学特性。结果表明,栎木枝桠木髓心偏向上侧,即下侧的生长比上侧迅速。双染色法和SEM的观察发现,胶质层同时发生于枝桠木上下侧的纤维细胞,但上侧的应拉程度比下侧稍显严重。化学分析结果显示,枝桠上下侧的a-纤维素含量仅比正常木高2%~3%,木质素含量仅比正常木低2%~4%。该实验的结论是,栎木枝桠木中反应木同时发生在上下两侧,只是应拉程度有差异,而枝桠木下侧生长迅速造成髓心偏向上侧。 相似文献
3.
Sha Jiang Ikuo Furukawa Tamaki Honma Miho Mori Teruko Nakamura Fukuju Yamamoto 《Journal of Wood Science》1998,44(5):385-391
The present study deals with the effects of gibberellins (GA3 GA4) and uniconazole-P, an inhibitor of gibberellin biosynthesis, on negative gravitropism and xylem formation in the stems of horizontally positioned, 2-year-oldFraxinus mandshurica Rupr. var.japonica Maxim. seedlings. Each growth regulator (100 g) dissolved in 5 l acetone (50%) was applied to the basal node of the current shoot on May 24, 1995. The same treatment was repeated five times weekly until June 28. Five seedlings were used for each treatment. The seedlings were positioned horizontally 24h after the first application on May 25. Within 5 weeks the horizontal stem of control and GA-treated seedlings exhibited negative gravitropism. In contrast, the application of uniconazole-P inhibited negative gravitropic stem bending. The application of GAs increased the number of gelatinous fibers having thickened cell walls on the upper side of stems. The uniconazole-P application decreased xylem cell formation but did not inhibit the formation of gelatinous fibers. These results indicate that not only the differentiation of gelatinous fibers but also xylem increment is important in the negative gravitropism of horizontally positionedF. mandshurica seedlings. These results also suggest that GAs may be involved in xylem cell :formation rather than the differentiation of gelatinous fibers in this species.Part of this research was reported at the 23rd annual meeting of the Plant Growth Regulation Society of America, Calgary, Canada, July 1996 相似文献
4.
Chang-Hua Fang Daniel Guibal Bruno Clair Joseph Gril Ya-Mei Liu Sheng-Quan Liu 《Annals of Forest Science》2008,65(3):307-307
Six inclined poplar I-69 (Populus deltoids cv. I-69/55) trees were collected for studying the influence of growth stress level on wood properties. Growth stress indicator (GSI) was measured at eight positions around the periphery of each trunk at breast height and corresponding wood samples were obtained. Wood anatomical, physico-mechanical and chemical characteristics were measured, including cell diameter, fibre length, double wall thickness excluding the gelatinous layer, lumen diameter after gelatinous layer removal, proportion of wood tissues, basic density, FSP, MOE, compressive strength, shrinkage and chemical composition. Each property was regarded and discussed in relation to the growth stress level. 相似文献
5.
Laguncularia racemosa wood is commonly used in north-western Mexico and harvested without the knowledge of whether environmental conditions affect wood quality.
Laguncularia racemosa anatomy variation was evaluated to identify which cell features, mainly fibre features, are related to an environmental gradient and how this variation affects wood quality. Trees were sampled in six sites along the river where different flooding periods and levels occur. Analyses revealed that in sites with high salinity and flooding levels, there are more abundant vessels and axial parenchyma although the fibres and vessel elements are shorter, suggesting a water stress effect. Correlation analysis confirmed that the higher the percentage of gelatinous fibres, the longer the fibres. This occurred in L. racemosa trees growing in those sites with a high sand particle percentage and a lower flooding level. Anova (analysis of variance) revealed non-significant differences among sites for flexibility, rigidity and Peteri coefficients as well as for Runkel ratio, however the rigidity coefficient is affected by occurrence of gelatinous fibres. L. racemosa wood harvesting should avoid those sites with high flooding level, high sand particle percentage and high salinity that may modify wood quality. 相似文献
6.
7.
Summary Pronounced tension wood from four North-American hardwood species has been examined by light and electron microscopy. Delignified fibers were also studied. The gelatinous layer was in all cases loosely attached to S2 but varied considerably in thickness within each species and was in one case terminated towards the lumen by a layer resembling S3. A terminal lamella was not observed. After considering both earlier evidence and the present results, it was concluded that the gelatinous layer has neither a honeycomb nor a homogeneous texture, as has been suggested, but that it consists of concentric lamellae of cellulose microfibrils. In the absence of hemicelluloses and lignin, the microfibrils are probably bound together less firmly than they are in other cell wall layers. The gelatinous layer is more readily separated from the remainder of the cell wall by mechanical forces than by chemical reagents.
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
Zusammenfassung Zugholz von vier nordamerikanischen Laubbäumen wurde im Licht-und im Elektronenmikroskop ebenso wie entlignifizierte Fasern untersucht. Die gelatinöse Schicht war überall locker an die S2 gebunden, zeigte aber sehr verschiedene Dicken und war in einem Fall gegen das Lumen von einer Schicht, die der S3 ähnlich sah, begrenzt. Eine Abschlußlamelle konnte nicht beobachtet werden. Frühere und die eigenen Resultate zeigten, daß die gelatinöse Schicht weder eine Wabenstruktur noch eine homogene Struktur besitzt, sondern daß sie aus konzentrischen Lamellen von Cellulosemikrofibrillen besteht. Da Hemicellulosen und Lignin nicht vorhanden sind, sind die Mikrofibrillen wahrscheinlich nicht so fest aneinander gebunden wie in den anderen Zellwandschichten. Die gelatinöse Schicht läßt sich von der übrigen Zellwand durch mechanische Kräfte leichter als durch chemische Reagenzien trennen.
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
8.
This study examined how boiling and drying treatments influenced various physical properties of the tension wood with gelatinous
fibers (G-fibers) of a 29-yearold Zelkova branch. By boiling treatment, tension wood with numerous G-fibers contracted considerably in the longitudinal direction and
the longitudinal Young’s modulus decreased in spite of the water-saturated condition. The drying treatment caused green tension
wood and boiled tension wood with numerous G-fibers to shrink longitudinally and increased their longitudinal Young’s moduli.
These specific behaviors in tension wood were highly correlated with the proportion of G-fibers in a specimen and were probably
caused by the microscopic behavior of cellulose microfibril (CMF) in the gelatinous layers (G-layers). The longitudinal shrinkage
of tension wood due to drying suggests the existence of a hygro-sensible, noncrystalline region in the CMF, which is abundant
in the G-layer. Furthermore, the noncrystalline region in the CMF softens during boiling treatment, resulting in the reduction
of the longitudinal Young’s modulus in tension wood. The longitudinal contraction of tension wood with G-fibers by boiling
might be caused by the tensile growth stress remaining in green G-layers. However, no changes were detected in the 004 d-spacing of cellulose crystal in tension wood from the boiling and drying treatments, regardless of the proportion of G-fibers. 相似文献
9.
The involvement of microfilaments and microtubules in the development of the radial and axial components of secondary xylem (wood) in hybrid aspen (Populus tremula L. x P. tremuloides Michx.) was studied by indirect immunofluorescent localization techniques. In addition to cambial cells, the differentiated cell types considered were early- and late-wood vessel elements, axial parenchyma, normal-wood fibers and gelatinous fibers, and contact and isolation ray cells. Microfilaments were rare in ray cambial cells, but were abundant and axially arranged in their derivatives once cell elongation had begun, and persisted in that orientation in mature ray cells. Microfilaments were axially arranged in fusiform cambial cells and persisted in that orientation in all xylem derivatives of those cells. Microtubules were randomly oriented in ray and fusiform cells of the cambial zone. Dense arrays of parallel-aligned microtubules were oriented near axially in the developing gelatinous fibers, but at a wide range of angles in normal-wood fibers. Ellipses of microfilaments were associated with pit development in fiber cells and isolation ray cells. Rings of co-localized microtubules and microfilaments were associated with developing inter-vessel bordered pits and vessel-contact ray cell contact pits, and, in the case of bordered pits, these rings decreased in diameter as the over-arching pit border increased in size. Although only microtubules were seen at the periphery of the perforation plate of vessel elements, a prominent meshwork of microfilaments overlaid the perforation plate itself. A consensus view of the roles of the cytoskeleton during wood formation in angiosperm trees is presented. 相似文献
10.
Two new species of Colpoma are described from China. Colpoma intermedium on Pinus armandii is macroscopically similar to species of Colpoma while asci and ascospores are similar to those of species of Therrya. Colpoma sinense on Rhododendron sp. differs from other Colpoma species by conspicuous lip cells embedded in a gelatinous matrix. 相似文献
11.
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. 相似文献
12.
Both of straight and inclining poplar clone 107 tree were selected for studying materials in this paper.The optimal pulping conditions was established by orthogonal experimental design both for normal wood and tension wood,and the quality of pulping and paper-making between normal wood and tension wood was compared with each other. Finally,potential application for improving paper quality of tension wood through increasing beating revolutions was discussed.The result showed that the optimal cooking condition for normal wood was alkali concentration 15%,the highest temperature 164℃,time at highest temperature 75 min,and for tension wood it was alkali concentration 13%,the highest temperature 160℃,time at highest temperature 40 min.Path coefficient of effect of alkali concentration both on pulp yield and kappa value was significant at different levels.By comparison between average result of normal wood and tension wood in quality of pulping and paper-making,it was found that tension wood had higher pulping yield and lower kappa value than normal wood. Furthermore,for all mechanical properties of paper, normal wood hold higher value than tension wood, and even near two times than tension wood,such as burst index and tensile index.However,difference of tear index was quite narrow.Result of one way ANOVA showed that difference of burst index and tear index between normal wood and tension wood was significant at the 0.001 level,of tear index was significant at the 0.05 level.Based on observation of cross surface of paper,it was assumed that contribution of gelatinous layer to rigidity of single fiber had hampered collapse and compression of fiber during paper formation,which is essential for exerting combination between fibers in paper.So, mechanical properties of tension wood paper were decreased accordingly.However,owing to high cellulose content of gelatinous layer,tension wood was easier to pulping than normal wood.Mechanical properties of tension wood paper could be improved by increasing beating revolutions, 相似文献
13.
S. C. Chafe 《Wood Science and Technology》1977,11(1):59-77
Summary Microscopical examination of the xylem of straight Eucalyptus regnans trees of high growth stress revealed the presence of radial dislocations in the secondary wall of many of the fibres. These features were characterized by a localized disruption in the microfibrillar orientation of the cellulose and were evident in both unlignified and lignified cell walls. Dislocations were not detected in trees having low peripheral growth stress. The origin of these features was suggested to lie in the expansion of the cell wall during the relaxation of longitudinal growth stresses following removal of the sample from the tree. A similar origin of the typically convoluted form of the gelatinous layer of tension wood fibres is discussed.The author expresses his appreciation to Dr. J. D. Boyd for helpful discussions. 相似文献
14.
Asghar Tarmian Romain Remond Hadi Dashti Patrick Perré 《Wood Science and Technology》2012,46(1-3):405-417
The moisture diffusion coefficient of compression wood in spruce (P. abies) and tension wood in beech (F. sylvatica) was examined. The results indicated that the diffusion coefficient measured under steady-state condition (cup method) could well characterize the drying kinetics of the reaction woods. The compression wood offered more resistance to the moisture diffusivity when compared with the corresponding normal wood. The thick cell wall rich in lignin explains the small mass diffusivity in compression wood. In contrast, the mass diffusivity in beech is almost always higher in tension wood than in normal wood, in spite of similar density values. The high moisture diffusion in tension wood can be explained by the ease of bound water diffusion in the gelatinous layers (G-layers). 相似文献
15.
欧美杨107杨正常木与应拉木制浆造纸性能比较 总被引：1，自引：0，他引：1
选取直立和倾斜欧美杨107杨为研究材料,根据正交试验确定正常木和应拉木最佳制浆条件,比较正常木和应拉木的制浆造纸性能,通过提高打浆转数对应拉木纸张性能的提高进行探讨。结果表明:正常木的最佳制浆条件为用碱量15%、最高温度164℃、最高温度保温时间75min;而应拉木最佳制浆条件为用碱量13%、最高温度160℃、最高温度保温时间40min。用碱量对正常木和应拉木制浆得率和卡伯值影响的通径系数在不同水平上显著。通过对正常木和应拉木制浆造纸性能比较发现,应拉木比正常木制浆得率高、卡伯值低、纸张力学性能均低,且抗张指数和耐破指数差距较大(约2倍),而撕裂指数差距较小。正常木和应拉木之间卡伯值、制浆得率、抗张指数、耐破指数均在0.001水平上差异显著,撕裂指数在0.05水平上差异显著。结合纸张断口形貌分析认为,胶质层的存在使得应拉木纤维成纸时不容易扁平坍陷,极大地阻碍了成纸时纤维之间的结合,因此降低了纸张力学性能;但是,由于其胶质层纤维素含量很高,因此其制浆性能优于正常木。随着打浆转数的提高,应拉木纸张力学性能增强,且接近正常木纸张水平,但过高会降低纸张力学性能。 相似文献
16.
探索海绵胶煤炱菌子实体形成的培养条件,研究该菌的子实体发育规律,为规模化生产这种新型食用蕈菌提供技术方案。在浙江、四川、江苏等地共采集到100多份野生子实体标本,经组织分离得到纯培养菌株,在多种琼脂、液体、固体培养基上进行纯培养。在琼脂和固体培养基上,菌丝体直接分泌胶质物质形成胶质的小型子实体;在液体培养基上只形成菌丝和胶质菌丝球,不形成子实体。该菌的形态发育过程:分生孢子萌发→菌丝→胶质组织→子实体分枝→小型子实体→形成分生孢子器和分生孢子→释放孢子。海绵胶煤炱菌在纯培养条件下难以形成大型子实体。 相似文献
17.
Summary Fine structure of cellulose microfibrils in poplar (Populus euramericana) gelatious layer and Valonia cell walls was observed in the electron microscope by using disintegration and ultrathin section techniques with various electron stains. Staining of the gelatinous layer in poplar showed that the microfibrils had a paracrystalline region surrounding a crystalline core, but such a region was negligible in Valonia. From the facts that kinks and shortened microfibrils were observed after mechanical and hydrolysis treatments, respectively, and that the microfibrils were unaffected by negative staining, it was concluded that the microfibril core is uniformly crystalline in the longitudinal direction although there may be some crystalline dislocations.The authors are indebted to Dr. Y. Yokohama (Marine Biological Laboratory, Tokyo University of Education) for supplying the samples and to Mr. Y. Tachida (Sanyo-Kokusaku Pulp Co.) for the technical assistance of the glow discharge apparatus. 相似文献
18.
杨木应拉木微区结构可视化及化学成分分析 总被引：1，自引：0，他引：1
木材微区结构与木材宏观性质密切相关,杨木应拉木与对应木宏观性质存在较大差别,探究杨木应拉木和对应木微区结构和化学成分,可为了解杨木应力木的宏观性质提供理论根据。借助光学显微镜、荧光显微镜、显微拉曼成像光谱仪、透射电镜对杨木应拉木微区结构进行可视化研究,并借助X射线衍射技术和美国可再生能源实验室方法,分析杨木应拉木的微晶尺寸、结晶度以及化学成分。结果表明:杨木应拉木中应拉区和对应区纤维细胞微区结构差异显著。光学显微镜下显示应拉区木纤维中胶质层清晰可见,荧光显微镜和拉曼显微镜下显示胶质层的木质素浓度比对应区低。透射电镜下显示应拉区木纤维细胞壁结构由初生壁、次生壁和胶质层组成,未见次生壁外层,各层的平均厚度分别为0.61,1.22和2.53μm。对应区木纤维为典型的初生壁和次生壁结构,次生壁各层平均厚度分别为0.33,2.28和0.14μm。杨木应拉区纤维素含量(58.91%)比对应区(41.53%)高,木质素含量和半纤维素含量均比对应区的低,应拉区木质素和半纤维素含量分别为21.99%和12.01%,对应区分别为28.10%和17.08%。杨木应拉区结晶度(48.06%)比对应区(41.01%)高,应拉区晶区宽度为2.66 nm,长度为8.84 nm;对应区晶区宽度为2.65 nm,长度为9.87 nm。 相似文献
19.
Arend M 《Tree physiology》2008,28(8):1263-1267
The occurrence and distribution of (1,4)-beta-galactan in wood cells of poplar (Populus trichocarpa Torr. & A. Gray x P. koreana Rehder) were studied by immunolabeling with a monoclonal antibody (LM5) specific to this carbohydrate epitope. Immunofluorescence microscopy revealed exclusive binding of the LM5 antibody to tension wood fibers, indicating the specific presence of (1,4)-beta-galactan in cell walls of this wood cell type. Higher magnifications achieved with the fluorescence microscope and additional immunogold electron microscopy showed that the binding of the LM5 antibody was mainly restricted to a narrow cell wall area between the gelatinous G-layer and the secondary cell wall. This labeling pattern strongly suggests a role of (1,4)-beta-galactan in cross-linking the G-layer and secondary cell wall. Furthermore, the exclusive localization of (1,4)-beta-galactan in tension wood strengthens the view that this carbohydrate epitope can be considered a highly specific marker of reaction wood formation in mechanically stressed trees. 相似文献
20.
To discuss the role of the gelatinous layer (G-layer) on the origins of the physical properties peculiar to the tension wood fiber (TW fiber), the deformation process of an isolated TW fiber caused by a certain biomechanical state change was formulated mathematically. The mechanical model used in the present formulation is a four-layered hollow cylinder having the compound middle lamella (CML), the outer layer of the secondary wall (S1) and its middle layer (S2), and the G-layer (G) as an innermost layer. In the formulation, the reinforced matrix mechanism was applied to represent the mechanical interaction between the cellulose microfibril (CMF) as a framework bundle and the amorphous substance as a matrix skeleton in each layer. The model formulated in the present study is thought to be useful to investigate the origins of extensive longitudinal drying shrinkage, large tensile growth stress, and a high axial elastic modulus, which are rheological properties peculiar to the TW. In this article, the detailed process of the mathematical formulation is described. In a subsequent article, some TW properties from a 70-year-old Kohauchiwakaede (Acer sieboldianum Miq.) will be analyzed using the newly developed model. 相似文献