The microfibril angle of seven poplar clones was determined by using X-ray diffraction technique. Microfibril angle, wood basic density, fiber length, fiber width and cellulose content were assessed for every growth r...The microfibril angle of seven poplar clones was determined by using X-ray diffraction technique. Microfibril angle, wood basic density, fiber length, fiber width and cellulose content were assessed for every growth ring at breast height for all sample trees. Significant variation in microfibril angle was observed among growth rings. Mean microfibril angle (MFA) at breast height varied from 7.8?to 28?between growth rings with cambial age and showed a consistent pith-to-bark trend of decline an-gles. Analysis of variance also indicated that there were significant differences in wood basic density, fiber length, fiber width and cellulose content between the growth rings, which had an increasing tendency from pith to bark. Correlations between MFA and examined wood properties were predominantly large and significant negative (?0.01), and the coefficients were -0.660 for cellulose content, -0.586 for fiber length, -0.516 for fiber width and -0.450 for wood basic density, respectively. Regression analysis with linear and curve estimation indicated that a quadratic function showed the largest R2 and the least standard error for describing the relationships between microfibril angle and measured wood properties, and the correlation coefficients were over -0.45 (n=125). The results from this study suggested that microfibril angle would be a good characteristic for improvement in the future breeding program of poplars.展开更多
The microfibril angle of fiber walls is an ultra-mieroscopic feature affecting the performance of wood products. It is therefore essential to get more definitive information to improve selection and utilization. X-ray...The microfibril angle of fiber walls is an ultra-mieroscopic feature affecting the performance of wood products. It is therefore essential to get more definitive information to improve selection and utilization. X-ray diffraction is a rapid method for measuring microfibril angles. In this paper, the variability of microfibril angle in plantation-grown Masson pine was investigated by peak-fitting method. This method was compared with the traditional hand-drawn method, 40% peak height method and half peak height method. X-ray diffraction measurements indicated that the microfibril angle changed as a function of the position in the tree. The mean microfibril angle decreased more gradually as the distance increased from the pith and reached the same level in mature wood. The microfibril angle also seemed to decrease clearly from the base upward. Differences of angle-intensity curves between heartwood and sapwood were also examined.展开更多
The first objective of this study was to investigate the variation of microfibril angle (Mfa), tracheid morphology and shrinkage within China-fir (Cunninghamia lanceolata) plantation tree. The second objective was to ...The first objective of this study was to investigate the variation of microfibril angle (Mfa), tracheid morphology and shrinkage within China-fir (Cunninghamia lanceolata) plantation tree. The second objective was to discuss the relationship between Mfa and tracheid morphology, and the influence of Mfa on longitudinal and tangential shrinkage. The results showed that the mean value of Mfa decreased from the 2nd (30.8°) to 26th growth ring (7.7°); the radial variation of latewood tracheid length ranged f...展开更多
Microfibril angle (MFA) in Chinese fir was tested by X-ray diffraction apparatus and calculated by computer software. The results were as follows: MFA was controlled strongly by inheritance, and there was no signif...Microfibril angle (MFA) in Chinese fir was tested by X-ray diffraction apparatus and calculated by computer software. The results were as follows: MFA was controlled strongly by inheritance, and there was no significant difference in MFA among interspecies, juvenile and mature wood. In the longitudinal, MFA reduces with the height rising from 0 to 5.5 m, especially in the heights from 0 to 1.5 m. The values of MFA are nearly consistence from 1.5 to 7.5 m. The variation range was between 10.82°and 12.57°from 1.5 to 7.5 m, R2 of power equation achieved 0.932 1, and analysis of variance indicated that the variation of MFA was not significant from 1.5 to 7.5 m, The age of the trees had an important influence on MFA, consequently, the difference in MFA was significant among annual rings in radial, which was maximal in near pith and reduced rapidly from the pith to sapwood, and its decline tendency was slow beyond the ninth annual ring. MFA reached minimum value at the 15th annual ring, and the difference reached more than 20° and R^2 of binomial equation achieved 0.755 6.展开更多
Near infrared (NIR) spectroscope and X-ray diffractometry have been used for rapid prediction of the microfibril angle (MFA) which is one of the important factors affecting wood properties. Wood property evaluation in...Near infrared (NIR) spectroscope and X-ray diffractometry have been used for rapid prediction of the microfibril angle (MFA) which is one of the important factors affecting wood properties. Wood property evaluation in breeding and resource evaluation requires effective and rapid analysis methods for thousands of samples. In the experiment, all samples from increment cores with moisture content of 60% to 150% were used for measuring MFA by X-ray scanning diffractometry. Then, a partial least squares regression (PLS) model was built based on NIR data and MFA measured. As a result, a strong linear relationship was found between NIR spectroscope fitted and X-ray measured with coefficient of calibration 0.95 and prediction model rate 0.88. NIR estimating is in consist with X-ray determining closely, which indicates that NIR spectroscopy can be successfully used to estimate MFA of increment cores of Chinese fir.展开更多
Collapse-type shrinkage is one of highly refractory drying defects inlow-medium density plantation-grown eucalypt wood used as solid wood products. Basic density (BD),microfibril angle (MFA), double fibre cell wall th...Collapse-type shrinkage is one of highly refractory drying defects inlow-medium density plantation-grown eucalypt wood used as solid wood products. Basic density (BD),microfibril angle (MFA), double fibre cell wall thickness (DWT), proportion of ray parenchyma (RP),unit cell wall shrinkage, total shrinkage and residual collapse, which are associated withcollapse-type shrinkage characteristics, were investigated by using simple regression method forthree species of collapse-susceptible Eucalyptus urophyll,, E. grandis and E. urophyllaxE.grandis,planted at Dong-Men Forest Farm in Guangxi autonomous region, China. The results indicated that:unit cell wall shrinkage had a extremely strong positive correlation with BD, moderately strongpositive correlation with DWT, and a weakly or moderately negative correlation with RP and MFA;total shrinkage was positively correlated with BD, DWT and RP and negatively related to MFA, but notable to be predicted ideally by any examined factors alone owing to lower R^2 value (R^2≤0.5712);residual collapse was negatively correlated with BD and DWT, linearly positively correlated withMFA, and had strongly positive linear correlation with RP. It is concluded that BD can be used assingle factor (R^2≥ 0.9412) to predicate unit cell wall shrinkage and RP is the relatively soundindicator for predicting residual collapse展开更多
We studied in detail the mean micro fibril angle and the width of cellulose crystals from the pith to the bark of a 15-year-old Maidenhair tree(Ginkgo biloba L.). The orientation of cellulose micro fibrils with resp...We studied in detail the mean micro fibril angle and the width of cellulose crystals from the pith to the bark of a 15-year-old Maidenhair tree(Ginkgo biloba L.). The orientation of cellulose micro fibrils with respect to the cell axis and the width and length of cellulose crystallites were determined using Xray diffraction. Raman microscopy was used to compare the lignin distribution in the cell wall of normal/opposite and compression wood, which was found near the pith. Ginkgo biloba showed a relatively large mean micro fibril angle,varying between 19° and 39° in the S2 layer, and the average width of cellulose crystallites was 3.1–3.2 nm. Mild compression wood without any intercellular spaces or helical cavities was observed near the pith. Slit-like bordered pit openings and a heavily lignified S2 L layer con firmed the presence of compression wood. Ginkgo biloba showed typical features present in the juvenile wood of conifers. The micro fibril angle remained large over the 14 annual rings. The entire stem disc,with a diameter of 18 cm, was considered to consist of juvenile wood. The properties of juvenile and compression wood as well as the cellulose orientation and crystalline width indicate that the wood formation of G. biloba is similar to that of modern conifers.展开更多
基金This research was supported by National Natural Science Foundation of China (Grant No. 30070616).
文摘The microfibril angle of seven poplar clones was determined by using X-ray diffraction technique. Microfibril angle, wood basic density, fiber length, fiber width and cellulose content were assessed for every growth ring at breast height for all sample trees. Significant variation in microfibril angle was observed among growth rings. Mean microfibril angle (MFA) at breast height varied from 7.8?to 28?between growth rings with cambial age and showed a consistent pith-to-bark trend of decline an-gles. Analysis of variance also indicated that there were significant differences in wood basic density, fiber length, fiber width and cellulose content between the growth rings, which had an increasing tendency from pith to bark. Correlations between MFA and examined wood properties were predominantly large and significant negative (?0.01), and the coefficients were -0.660 for cellulose content, -0.586 for fiber length, -0.516 for fiber width and -0.450 for wood basic density, respectively. Regression analysis with linear and curve estimation indicated that a quadratic function showed the largest R2 and the least standard error for describing the relationships between microfibril angle and measured wood properties, and the correlation coefficients were over -0.45 (n=125). The results from this study suggested that microfibril angle would be a good characteristic for improvement in the future breeding program of poplars.
基金This study was financially supported by the National Natural Science Foundation of China (Grant Nos. 30371125 and 30400337).
文摘The microfibril angle of fiber walls is an ultra-mieroscopic feature affecting the performance of wood products. It is therefore essential to get more definitive information to improve selection and utilization. X-ray diffraction is a rapid method for measuring microfibril angles. In this paper, the variability of microfibril angle in plantation-grown Masson pine was investigated by peak-fitting method. This method was compared with the traditional hand-drawn method, 40% peak height method and half peak height method. X-ray diffraction measurements indicated that the microfibril angle changed as a function of the position in the tree. The mean microfibril angle decreased more gradually as the distance increased from the pith and reached the same level in mature wood. The microfibril angle also seemed to decrease clearly from the base upward. Differences of angle-intensity curves between heartwood and sapwood were also examined.
基金the State Key Basic Research and Development Plan of China (G1999016001)Sino-Japan project "Sino-Japanese Cooperation Project-Research on Chinese Plantation Wood
文摘The first objective of this study was to investigate the variation of microfibril angle (Mfa), tracheid morphology and shrinkage within China-fir (Cunninghamia lanceolata) plantation tree. The second objective was to discuss the relationship between Mfa and tracheid morphology, and the influence of Mfa on longitudinal and tangential shrinkage. The results showed that the mean value of Mfa decreased from the 2nd (30.8°) to 26th growth ring (7.7°); the radial variation of latewood tracheid length ranged f...
文摘Microfibril angle (MFA) in Chinese fir was tested by X-ray diffraction apparatus and calculated by computer software. The results were as follows: MFA was controlled strongly by inheritance, and there was no significant difference in MFA among interspecies, juvenile and mature wood. In the longitudinal, MFA reduces with the height rising from 0 to 5.5 m, especially in the heights from 0 to 1.5 m. The values of MFA are nearly consistence from 1.5 to 7.5 m. The variation range was between 10.82°and 12.57°from 1.5 to 7.5 m, R2 of power equation achieved 0.932 1, and analysis of variance indicated that the variation of MFA was not significant from 1.5 to 7.5 m, The age of the trees had an important influence on MFA, consequently, the difference in MFA was significant among annual rings in radial, which was maximal in near pith and reduced rapidly from the pith to sapwood, and its decline tendency was slow beyond the ninth annual ring. MFA reached minimum value at the 15th annual ring, and the difference reached more than 20° and R^2 of binomial equation achieved 0.755 6.
文摘Near infrared (NIR) spectroscope and X-ray diffractometry have been used for rapid prediction of the microfibril angle (MFA) which is one of the important factors affecting wood properties. Wood property evaluation in breeding and resource evaluation requires effective and rapid analysis methods for thousands of samples. In the experiment, all samples from increment cores with moisture content of 60% to 150% were used for measuring MFA by X-ray scanning diffractometry. Then, a partial least squares regression (PLS) model was built based on NIR data and MFA measured. As a result, a strong linear relationship was found between NIR spectroscope fitted and X-ray measured with coefficient of calibration 0.95 and prediction model rate 0.88. NIR estimating is in consist with X-ray determining closely, which indicates that NIR spectroscopy can be successfully used to estimate MFA of increment cores of Chinese fir.
基金This work was supported by both the project ( No. 30170754)from Chinese National Natural Science Fund and the national significant fundamental research 'Ascending Plan' program (No.95- 07) authorized by Ministry of Science and Technology, China. And was partly presented at the 54th Annual Meeting of the Japan Wood Research Society in Hokkaido, Japan and at the 7th Pacific Rim Bio-based Composites Symposium in Nanjing, P. R. China.
文摘Collapse-type shrinkage is one of highly refractory drying defects inlow-medium density plantation-grown eucalypt wood used as solid wood products. Basic density (BD),microfibril angle (MFA), double fibre cell wall thickness (DWT), proportion of ray parenchyma (RP),unit cell wall shrinkage, total shrinkage and residual collapse, which are associated withcollapse-type shrinkage characteristics, were investigated by using simple regression method forthree species of collapse-susceptible Eucalyptus urophyll,, E. grandis and E. urophyllaxE.grandis,planted at Dong-Men Forest Farm in Guangxi autonomous region, China. The results indicated that:unit cell wall shrinkage had a extremely strong positive correlation with BD, moderately strongpositive correlation with DWT, and a weakly or moderately negative correlation with RP and MFA;total shrinkage was positively correlated with BD, DWT and RP and negatively related to MFA, but notable to be predicted ideally by any examined factors alone owing to lower R^2 value (R^2≤0.5712);residual collapse was negatively correlated with BD and DWT, linearly positively correlated withMFA, and had strongly positive linear correlation with RP. It is concluded that BD can be used assingle factor (R^2≥ 0.9412) to predicate unit cell wall shrinkage and RP is the relatively soundindicator for predicting residual collapse
基金the National Natural Science Foundation (31370562) for financial support
文摘We studied in detail the mean micro fibril angle and the width of cellulose crystals from the pith to the bark of a 15-year-old Maidenhair tree(Ginkgo biloba L.). The orientation of cellulose micro fibrils with respect to the cell axis and the width and length of cellulose crystallites were determined using Xray diffraction. Raman microscopy was used to compare the lignin distribution in the cell wall of normal/opposite and compression wood, which was found near the pith. Ginkgo biloba showed a relatively large mean micro fibril angle,varying between 19° and 39° in the S2 layer, and the average width of cellulose crystallites was 3.1–3.2 nm. Mild compression wood without any intercellular spaces or helical cavities was observed near the pith. Slit-like bordered pit openings and a heavily lignified S2 L layer con firmed the presence of compression wood. Ginkgo biloba showed typical features present in the juvenile wood of conifers. The micro fibril angle remained large over the 14 annual rings. The entire stem disc,with a diameter of 18 cm, was considered to consist of juvenile wood. The properties of juvenile and compression wood as well as the cellulose orientation and crystalline width indicate that the wood formation of G. biloba is similar to that of modern conifers.