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1.
利用直接碳复型和超薄切片技术，在透射电镜下观察了我国４５种（隶２８属、１５科）阔叶树材的纹孔超微构造。其中有１０种（隶８属、４科）木材维管间具绷纹孔膜具纹孔塞，其余不具纹孔塞。纹孔膜上微纤丝排列有３种类型：随机排列、辐射状排列、平行排列。维管间具缘纹孔室内有５种具附物，１９种具瘤状物。以上特征有木材识别价值。在新鲜材和部分脱木素的试样中１７种木材的管间具缘纹孔膜和半具缘纹孔膜有明显开孔，直径０．０ 相似文献
2.
利用直接碳复型和超薄切片技术，在透射电镜下观察了我国与种（隶２８属、１５科）阔叶树材的纹孔超微构造。其中有１０种（隶８属、４科）木材维管间具缘纹孔膜具纹孔塞，其余不具纹孔塞。纹孔膜上微纤丝排列有３种类型：随机排列、辐射状排列、平行排列。维管间具缘纹孔室内有５种具附物，１９种具瘤状物。以上特征有木材识别价值。在新鲜材和部分脱木素的试样中１７种木材的管间具缘纹孔膜和半具缘纹孔膜有明显开孔，直径０．０４—０．１９μｍ。新鲜村单纹孔的纹孔膜有胞间连丝存在，膜上有微孔。还讨论了阔叶树材具缘纹孔在系统发育中的变化。 相似文献
3.
国产主要阔叶树材导管和纤维瘤状层的电镜观察和研究 总被引：3，自引：1，他引：2
对我国１８２种（４８科１３５属）阔叶树材导管和纤维壁的内表面进行扫描和透射电镜观察，其中５０种（隶１７科３２属）有瘤状层存在，其余不见或罕见。就这５０种木材的瘤状层有无及其形态和分布进行深入的观察与探讨。并对２种木材的超薄切片进行透射电镜观察和分析，认为瘤状物与次生壁的电子密度不同，说明两者化学成分不同。此外，还讨论了瘤状层的分布与穿孔板类型和在生长轮的位置关系。未发现瘤状层的出现和木质部进化趋势 相似文献
4.
国产阔叶树材晶体的研究 总被引：1，自引：0，他引：1
用扫描电镜和光学显微镜观察了国产阔叶树材６２０种（隶７６科２６２属）木材的构造特征。其中含晶体的有２３１种（隶４４科１１１属），占所观察树种的３７％。晶体的主要形态为菱形，其它为针晶体，针晶束，柱状晶体，晶砂，晶簇等。晶体的形态，分布及其方式与树种有关，品体在木材识别与分类上具有一定的意义。晶体可以视为区分阔叶树材属或种的辅助特征。 相似文献
5.
6.
柳树杂种木材基本密度的遗传变异 总被引：5，自引：2，他引：5
利用柳属和钻天柳属种间、属间杂交１５个杂种３９个杂交组合１５１个无性系材料，对木材基本密度的遗传变异情况进行了研究。结果表明，杂种间和无性系间，在木材基本密度上存在极显著（α＝０．０１）差异，其中属间杂种（旱柳×钻天柳）×旱柳平均木材基本密度达到０．４８８，显著（α＝０．０５）超过各杂种平均值；柳树杂种及无性系木材基本密度是受强遗传控制的，被研究群体的广义遗传力达到０．９２￣０．９８，遗传变异系数 相似文献
7.
在多次野外实地调查的基础上，对龙泉山城市森林公园野生维管植物的数量特点、区系成分进行了探究。结果表明：（1）该区共有野生维管植物138科442属628种，国家Ⅱ级保护植物7种，其生活型以草本植物种类最为丰富，共392种，占全部种类的62.42%。（2）在科属组成上，科组成以寡种科和单种科占优势，两者共占总科数的78.26%；属组成以寡种属和单种属占优势，两者共占总属数的98.87%。（3）分布区类型多样，科级水平上有10个类型和5个变型，热带成分占明显优势；属级水平上有14个类型和18个变型，热带成分略多于温带成分，具有明显的亚热带特性。 相似文献
8.
本文中，确认了杨亚科中的胡杨属，产于北美洲的墨杨被改隶于该属。胡杨属包含３个现代种，即胡杨，东非杨，墨杨（新组合）和一些古代种，目前间断分布于热非洲，古地中海地区和墨西哥，该属被认为是代表了杨亚科植物系统发育中的一个谱系分枝。 相似文献
9.
中国西南地区濒危植物的区系地理研究 总被引：1，自引：0，他引：1
根据《中国植物红皮书》第一册，中国西南地区共有濒危植物(除去稀有和渐危植物)28科，41属，52种。文章对这些植物的生活型、分布区类型、地理分布和植物区系分区的特征进行了分析。主要结果表明，从属的分布来看，西南地区37属濒危种子植物中，热带分布型属有16属，占种子植物属的43．3％，温带分布型属有19属，占51．4％，中国特有分布型属只有2属，其中1属为西南地区有属，说明属的特有分布现象不明显；从西南地区52种濒危植物的水平分布来看，有33种为西南地区特有种，占63．5％，说明种的特有分布现象明显；西南地区跨越了我国仅有的两大植物区，5个地区，植物区系成分复杂。 相似文献
10.
芳香植物具有净化空气、驱除蚊虫、美化环境、调节身心健康等功能，在公园绿化中占据重要地位。对广州10个公园的芳香植物种类、生活型、芳香类型、香气来源、观赏期及应用频率等进行调查，结果显示：共出现芳香植物109种，隶属54科95属；乔木的种类最多，占比51%，其次为灌木；芳香类型覆盖芳香型、浓香型、淡香型、清香型和木香型5种；花是芳香植物主要的散香部位。运用层次分析法（AHP）和最优解法（TOPSIS）对芳香植物资源进行综合评价，其中最重要的准则层指标为康养性，其次为芳香性、观赏性；舒适性、愉悦感是芳香植物最重要的指标。根据评价结果，将109种芳香植物分为I级“很好”、II级“好”、III级“中等”3个等级，分别有31种、37种、41种。 相似文献
11.
We developed a novel method for preparation of microcasts of wood with silicone elastomer (polydimethylsiloxane; PDMS). PDMS
was so flexible and elastic that it was possible to isolate the microcasts by simply pulling them out of the mold without
digesting the cell wall after the resin was cured for 2 days at room temperature. The casts of some cell wall sculptures,
such as spiral thickenings and bordered pits, had high fidelity. By contrast, the casts of distinctly bordered pits and tails
of vessel elements were often deformed or broken. Bars of scalariform perforation plates were always torn and remained in
the resin casts. The microcast preparation using PDMS is useful for easy investigation of cell wall sculptures. It might be
also useful for microfractography of bars of scalariform perforation plates. 相似文献
12.
An improved fibril angle measurement method for wood fibres 总被引：3，自引：0，他引：3
H. H. Wang J. G. Drummond S. M. Reath K. Hunt P. A. Watson 《Wood Science and Technology》2001,34(6):493-503
A rapid, reliable technique for the observation and measurement of the fibril angle in wood cell walls has been developed.
Sonication in the presence of solutions of certain cobalt and copper salts (5%, wt/vol) was found to be most effective in
facilitating fibril angle visualisation. Latewood fibre fibril angle, which previously had been difficult to measure, was
also visible, though less frequently. This method has been successfully applied to a number of softwood species including
coastal Douglas-fir whose prominent spiral thickenings make it difficult to determine the fibril angle by other methods. The
method was also used to determine the fibril angle of some hardwood species as well as a non-woody material, flax straw. It
can also be used to determine the microfibril angle of pulp fibres although this procedure is less convenient than with wood
sections.
Received: 24 June 1999 相似文献
13.
T. E. Timell 《Wood Science and Technology》1978,12(1):1-15
Summary The longitudinal tracheids in compression wood of Taxus baccata contain helical thickenings but no helical cavities. The thickenings are as frequent and well developed and have the same ropelike appearance as in normal wood of this species. They are an integral part of the S3 in normal and of the S2 in compression wood and have the same orientation as the innermost microfibrils in these layers. Except for the absence of cavities and presence of thickenings, compression wood tracheids of Taxus baccata possess all the anatomical features typical of such cells, including a rounded outline, intercellular spaces, a thick S1 layer, a highly lignified S2 (L) layer, and no S3 layer. Pronounced compression wood of Pseudotsuga menziesii contains helical cavities but no helical thickenings. Thickenings and cavities seem to be mutually exclusive in Pseudotsuga and Taxus.This investigation was carried out under the McIntire-Stennis Program, Cooperative State Research Service. I am indebted to Mr. A. Rezanowich of the Pulp and Paper Research Institute of Canada for kindly providing the scanning electron micrographs. 相似文献
14.
FURUKAWA Ikuo 《中国林业科技(英文版)》2006,5(2):22-27
INTRODUCTION The larger genus in Polygonaceae is Calligonum, which includes about 100 species of shrubs that grow in central Asia. It is well suited to arid climates with drought resistance, and grows more on clay, sandy and gravel grounds. These plants are often cultivated as ornamentals and a stabilizer of mobile sand dunes. There was published information on the wood anatomy of all the examined genera in Polygonaceae (Ma 1994), but the selected species have not yet been described. Ad… 相似文献
15.
《Wood material science & engineering》2013,8(3-4):118-129
Abstract Twist in wood, being closely related to spiral grain, may cause serious problems in building structures, furniture and joinery. It is therefore of great interest to sort out, at an early stage in the manufacturing process, trees, logs and boards that have an excess of spiral grain. The spiral grain pattern is described by a helical deviation of the fibre direction in relation to the longitudinal direction of a living tree or a log and seems to be an indicator for other defects such as compression wood. Remote microwave sensing of spiral grain has received a lot of interest during the past two decades. Its development has been impeded by the large variation with moisture content of the microwave properties of wood and by the complexity in modelling the electromagnetic field in a log with spiral grain. A review is presented of a direct method with no requirement for information on moisture content for boards. This procedure has recently been generalized to cylindrical logs and trees having a constant slope of the grain. A further generalization is presented here to allow for the normal spiral grain pattern with radially changing slope of grain in wood under bark. Based on this theory, a measurement procedure is proposed for the detection of wood grain angle with radial dependence, requiring no information on moisture content in the sapwood, which is also applicable to completely or partially frozen wood. A suitable application would be an instrument to use in the forest for measurements on living trees or logs. 相似文献
16.
Paul Sepúlveda 《Journal of Wood Science》2001,47(4):289-293
Spiral grain is a feature of wood that affects the shape of the sawn timber. Boards sawn from logs with a large spiral grain have a tendency to twist when the moisture content changes. In sawmills the spiral grain in logs is judged manually. For research purposes the spiral grain in stems and logs is normally measured by destructive methods. In this study the spiral grain of the stems was measured nondestructively with a computed tomography (CT) scanner. Twelve Norway spruce (Picea abies) stems from two stands in Sweden were scanned with a CT scanner with one cross-sectional scan every 10mm along the stem. Concentric surfaces at various distances from the pith were reconstructed from the stack of CT images. In these concentric-surface images, which show various internal features of the log. the spiral grain angle was measured at different distances from the pith and at different heights in the stem. The destructive measurements of the spiral grain were carried out on disks from the top ends of the logs. On these disks the spiral grain was measured at different distances from the pith with a protractor. Finally, the results from the destructive method were compared with the results from analysis of the CT images. The nondestructive and destructive measurements were compared in pairs with the same radial and approximately the same height position in each pair. The correlations (r) between the two methods were 0.81 and 0.71. respectively, for the two stands. It was concluded that it is possible to measure the spiral grain angle nondestructively with a CT scanner.An outline of this study was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto 相似文献
17.
中国蒺藜科3种旱生植物的木材解剖适应性 总被引：2，自引：0，他引：2
从木材次生木质部特性和径向变异两方面,对中国西部区的蒺藜科的3种旱生植物(Zygophyllumxanthoxylon,Nitrariatangutorum,Tetraenamongolica)进行了对比研究。3树种具有的共同特点为:生长轮分界明显,但是霸王和四合木的年轮有时不连续,半环孔到环孔材,具单穿孔,穿孔板倾斜,导管壁间纹孔互列,木纤维无横隔膜,联合傍管轴向薄壁组织,导管壁上呈现螺纹加厚和异型射线。所选树种明显区别是导管排列方式和导管的数量化指标:四合木导管直径较小,长度较短,频率较大,水分传导安全性增加。其他2种树种之间导管指标没有多大差别,但均比沙冬青的值大。树种导管要素长和纤维要素长的水平变动不规律,树种间和同一树种个体间差异显著。并且对该树种的解剖学特征和沙漠环境的适应性进行了讨论。图19表2参24。 相似文献
18.
YANG Shu-min FURUKAWA Ikuo 《林业研究》2006,17(3):247-251
Secondary xylem characteristics and horizontal variations were described in three xerophytic species, Zygophyllum xanthoxylon, Nitraria tangutorum, Tetraena mongolica of Zygophyllaceae native to western China. All the species have obvious growth ring boundaries except sometimes discontinuous in T. mongolica and Z xanthoxylum ring to semi-ring-porosity; simple perforation plate; alternate intervessel pitting; non-septate fibres; paratracheal confluent axial parenchyrna; helical thickenings and heterocellular rays. However the vessel arrangement and quantitative features of vessels were different. Vessel elements tend to be shorter and narrower and more frequent in T. mongolica than in other two species that are hardly different could lead to greater conductive safety. The variation of vessel element length and fibre length along radial direction showed irregular tendency. There was significant difference in both fibre length and vessel element length among-tree and within-tree. Furthermore, the relationships between anatomical features and adaptability to desert environments were also discussed. 相似文献
19.
螺旋齿圆柱铣刀在高速切削木材时会出现崩刃和折断等现象,且小直径长铣刀此类问题尤为明显,为此对螺旋齿圆柱铣刀铣削加工时的运动力学特性进行分析研究。建立螺旋齿圆柱铣刀的矩阵方程,获得铣刀铣削运动轨迹,并明确了铣削加工方式;利用ADAMS分析不同铣削参数对螺旋齿圆柱铣刀切入过程的影响,得到不同铣削参数下螺旋齿圆柱铣刀所受冲击载荷随时间的变化曲线;运用ANSYS Workbench瞬态动力学分析,明确了铣削切入工件时螺旋齿圆柱铣刀的瞬时应力大小和分布情况,为螺旋圆柱铣削加工确定最佳铣削参数提供理论依据。 相似文献
20.
从生态学角度对沙棘和沙枣的木材结构进行对比研究.两树种具有的共同特点为 :生长轮明显,半环孔材,具单穿孔,导管间纹孔交互排列,无分隔木纤维,导管较窄, 环管管胞和纤维状管胞具螺纹加厚,轴向薄壁组织缺失或很少.所选树种明显区别是射线类型、宽度和叠生排列方式:沙棘射线,轴向薄壁组织细胞和导管分子具有明显的叠生排列方式,但沙枣的叠生排列不规则;沙棘射线为异型,1～2列,沙枣射线为同型,2～5列;并且二者之间数量化指标有差异,沙棘导管频率较大,导管分子较短及导管管孔较小,因此V和M值也较小,更能适应干旱环境.两树种导管分子长和纤维长的水平变动不规律,并且树种间和同一树种个体间差异显著.本文最后对该树种的解剖学特征和沙漠环境的适应性进行了讨论 . 相似文献