Cellulose carbamates (CC) were synthesized with microcrystalline cellulose as raw materials. The Fourier transform infrared spectra of CC with different nitrogen content were recorded. The accurate results of the nitr...Cellulose carbamates (CC) were synthesized with microcrystalline cellulose as raw materials. The Fourier transform infrared spectra of CC with different nitrogen content were recorded. The accurate results of the nitrogen content for CC can be obtained by using the deconvolution method when the nitrogen content is less than 3.5%. The relationship between the nitrogen content and the absorption intensity ratio of the corresponding separated absorption peaks in FTIR spectra has been expressed bg an equation precisely.展开更多
The surface of the cotton fabric was modified using a direct current(DC)air plasma treatment and hence enhances its hydrophilicity.The Box-Behnken approach(design expert software)was used to optimise the input process...The surface of the cotton fabric was modified using a direct current(DC)air plasma treatment and hence enhances its hydrophilicity.The Box-Behnken approach(design expert software)was used to optimise the input process parameters.The sample prepared under optimized condition is subjected to ATR-FTIR and Field Emission Scanning Electron Microscopy(FESEM)studies in order to determine the changes in hydrogen bond energies(EH),Total Crystallinity Index(TCI),Hydrogen Bond Intensity(HBI),Lateral Order Index(LOI),functionalization,lattice parameters(a,b,c&β),degree of crystallinity(in%)and surface etching.The ageing of this sample has been studied by comparing the values of carboxyl content and AC-C/AC-O-C ratio calculated using data extracted from ATR-FTIR spectra of the sample recorded periodically for one month.展开更多
Stem lignin content(SLC) in common wheat(Triticum aestivum L.) contributes to lodging resistance. Caffeic acid 3-O-methyltransferase(COMT) is a key enzyme involved in lignin biosynthesis. Characterization of TaCOMT ge...Stem lignin content(SLC) in common wheat(Triticum aestivum L.) contributes to lodging resistance. Caffeic acid 3-O-methyltransferase(COMT) is a key enzyme involved in lignin biosynthesis. Characterization of TaCOMT genes and development of gene-specific markers could enable marker-assisted selection in wheat breeding. In the present study, the full-length genomic DNA(gDNA) sequences of TaCOMT genes located on chromosomes 3 A, 3 B, and 3 D were cloned by homologous cloning. Two allelic variants, TaCOMT-3 Ba and TaCOMT-3 Bb, were identified and differed by a 222-bp insertion/deletion(InDel) in the 3′-untranslated region(3′-UTR). A co-dominant gene-specific marker based on this InDel was developed and designated as Ta COMT-3 BM. A total of 157 wheat cultivars and advanced lines grown in four environments were used to validate the associations between allelic patterns and SLC. The SLC of cultivars with TaCOMT-3 Ba was significantly(P<0.01) higher than that of those with TaCOMT-3 Bb, and the marker TaCOMT-3 BM could be effectively used in wheat breeding.展开更多
One pair of near isonegic yellow/black seeded rape （Brassica napus L） were used as experimental materials to study the changes of lignin contents and enzymes activities of 4-coumarate： CoA ligase （4CL）, Cinnamyl ...One pair of near isonegic yellow/black seeded rape （Brassica napus L） were used as experimental materials to study the changes of lignin contents and enzymes activities of 4-coumarate： CoA ligase （4CL）, Cinnamyl alcohol dehydrogenase （CAD） and ferulate 5-hydroxylase （F5H） in seedcoats during the stage of seed development. The variation analysis showed that the changes of lignin contents and enzyme activities of 4CL, CAD and F5H in seed coat had significant differences between black- and yellow-seeded rapes, and also between different development stages. The correlation analysis demonstrated that the lignin contents were positively correlative to the activities of all three enzymes investigated in the study, and the interactions between them in the seed coat of the two lines. For yellow-seeded rape, the correlation coefficient （0.7262018） of lignin content and the interaction between 4CL and F5H was significant, the lignin contents were highly positively correlative to the activities of CAD and F5H, the interaction between 4CL and CAD, and the interaction between CAD and F5H. For the black-seeded rape, only the lignin content was highly positively correlative to the activity of F5H （the correlation coefficient was 0.772949）, the other correlation coefficients, i. e. lignin contents to 4CL, CAD activities, the interactions between the three enzymes were not significant although all the correlation coefficients were above 0.5000. The results suggested that 4CL, CAD and F5H regulated the biosynthesis of lignin in seedcoat of rapes, leading to the lignin contents in the seedcoats of the yellow-seeded rape much lower than that of the black-seeded line, and affecting the thickness of the developing seedcoats in rapes. Therefore, it was likely to change the seedcoat ratio by overexpressing or suppressing the activities of one of the enzymes, both of them or all of them.展开更多
A steam explosion pretreatment at various severities was applied to pure wood cellulose; the influences of steam pretreatment on the morphological structure, the hydrophilic property and viscosity-average molecular we...A steam explosion pretreatment at various severities was applied to pure wood cellulose; the influences of steam pretreatment on the morphological structure, the hydrophilic property and viscosity-average molecular weight of cellulose were evaluated. The nitration of steam-exploded cellulose was carried out in the nitrating agent medium （HNOa/organic solvent）. The performance indexes of nitrocellulose, prepared from original and steam exploded samples, were determined by using the polarized optical microscope. The results show that after pretreatment the reactivity of the three hydroxyl groups in anhydroglucose unit of cellulose is improved, and the nitrogen content and the uniformity of NC from steam exploded cellulose observably increas.展开更多
Cellulose nanofibrils(CNFs)are promising sustainable materials that can be applied to nanocomposites,as well as medical and life-sciences devices.However,methods for the preparation of these important materials are en...Cellulose nanofibrils(CNFs)are promising sustainable materials that can be applied to nanocomposites,as well as medical and life-sciences devices.However,methods for the preparation of these important materials are energy intensive because heating and mechanical disintegration are required to produce cellulose fibers below 100 nm in size.In this study,CNFs were prepared through the multi-site regioselective oxidation of cellulose with 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)and periodate at room temperature(20–25°C),without any mechanical-disintegration treatment.Transmission electron microscopy(TEM)revealed that the CNFs had the average widths of 14.1,55.4,and 81.9 nm for three different treatments.Fourier-transform infrared spectroscopy revealed that carboxyl groups were created on the surfaces of the microfibrils,while X-ray diffraction studies showed that the cellulose I structure was maintained after oxidation,and that the cellulose nanofibril crystallinity index exceeded 70%.These results demonstrate that CNFs can be prepared by multi-site regioselective oxidation at room temperature in the absence of mechanical disintegration.In addition,a model was developed to calculate the total content of carboxylate and aldehyde groups of CNFs prepared by the TEMPO mediate oxidation,the periodate oxidation,and the multi-site regioselective oxidation methods based on the particle width determined by TEM.The calculated values of the model were in good agreement with the total content(experimental value)of carboxylate and aldehyde groups of CNFs prepared by the TEMPO-mediated oxidation and the multi-site regioselective oxidation methods.However,the model was not valid for CNFs prepared by the periodate oxidation method.展开更多
The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz.Acacia mangium Willd.and Acacia auriculiformis A.Cunn.Ex Benth.and their hybrid.Acid...The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz.Acacia mangium Willd.and Acacia auriculiformis A.Cunn.Ex Benth.and their hybrid.Acid insoluble lignin content(Klason),mean stem density and fibre length differed considerably among the species and hybrids.A.mangium possessed a high percent of lignin content compared to A.auriculiformis and the Acacia hybrid.However,mean stem density of A.auriculiformis was higher than A.mangium and the hybrid.Fibre length of heartwood tissues was generally shorter than that of sapwood tissues.The hybrid had longer fibres than the parent species.Lignin was negatively correlated with mean stem density.Generally,the wood properties of the hybrid were superior to its parent species.The significant intraspecific variation observed for wood properties of Acacia species could be used in breeding superior hybrids combining desirable traits of the two species.Considering thedifficulty involved in accurately measuring the lignin content compared to mean stem density,selection for plants with low lignin content can be achieved by indirect selection of high mean stem density.展开更多
We have investigated a correlation of transcript abundances of key genes that influence the quality of wood and flavonoid biosynthesis, such as the two p-hydroxycinnamoyl-CoA:quinate shikimate p-hydroxycinnamoyl trans...We have investigated a correlation of transcript abundances of key genes that influence the quality of wood and flavonoid biosynthesis, such as the two p-hydroxycinnamoyl-CoA:quinate shikimate p-hydroxycinnamoyl transferase (HCT) and the two chalcone synthases (CHS) from Eucalyptus globulus grown in a greenhouse. The EglHCT1 and EglHCT2 transcripts accumulated in stems of all ages, but to a lesser extent in leaves. On the other hand, EglCHS3 and EglCHS4 exhibited high transcript levels in leaves, roots and shoots, but low levels in the stem. A positive correlation (R2 > 0.70) was observed between the transcript levels of the EglHCT1, EglHCT2 genes and Klason lignin (KL) content. In addition, the sum of transcript levels of EglHCT1 and EglHCT2 genes were highly correlated to KL contents (R2 > 0.85). However, there is no relationship between transcript levels of two CHS genes and, KL or flavonoid contents. This may imply that lignin biosynthesis and flavonoid biosynthesis are independently regulated in E. globulus.展开更多
Lignin is a polymer of phenylpropanoid compounds formed through a complex biosynthesis route, represented by a metabolic grid for which most of the genes involved have been sequenced in several plants, mainly in the m...Lignin is a polymer of phenylpropanoid compounds formed through a complex biosynthesis route, represented by a metabolic grid for which most of the genes involved have been sequenced in several plants, mainly in the model-plants Arabidopsis thaliana and Populus. Plants are exposed to different stresses, which may change lignin content and composition. In many cases, particularly for plant-microbe interactions, this has been suggested as defence responses of plants to the stress. Thus, understanding how a stressor modulates expression of the genes related with lignin biosynthesis may allow us to develop study-models to increase our knowledge on the metabolic control of lignin deposition in the cell wall. This review focuses on recent literature reporting on the main types of abiotic and biotic stresses that alter the biosynthesis of lignin in plants.展开更多
文摘Cellulose carbamates (CC) were synthesized with microcrystalline cellulose as raw materials. The Fourier transform infrared spectra of CC with different nitrogen content were recorded. The accurate results of the nitrogen content for CC can be obtained by using the deconvolution method when the nitrogen content is less than 3.5%. The relationship between the nitrogen content and the absorption intensity ratio of the corresponding separated absorption peaks in FTIR spectra has been expressed bg an equation precisely.
文摘The surface of the cotton fabric was modified using a direct current(DC)air plasma treatment and hence enhances its hydrophilicity.The Box-Behnken approach(design expert software)was used to optimise the input process parameters.The sample prepared under optimized condition is subjected to ATR-FTIR and Field Emission Scanning Electron Microscopy(FESEM)studies in order to determine the changes in hydrogen bond energies(EH),Total Crystallinity Index(TCI),Hydrogen Bond Intensity(HBI),Lateral Order Index(LOI),functionalization,lattice parameters(a,b,c&β),degree of crystallinity(in%)and surface etching.The ageing of this sample has been studied by comparing the values of carboxyl content and AC-C/AC-O-C ratio calculated using data extracted from ATR-FTIR spectra of the sample recorded periodically for one month.
基金supported by the National Natural Science Foundation of China(31161140346 and 31461143021)the Beijing Municipal Science and Technology Project,China(D151100004415003)+1 种基金the National Key Technology R&D Program of China(2014BAD01B05)the earmarked fund for China Agriculture Research System(CARS-3-1-3)
文摘Stem lignin content(SLC) in common wheat(Triticum aestivum L.) contributes to lodging resistance. Caffeic acid 3-O-methyltransferase(COMT) is a key enzyme involved in lignin biosynthesis. Characterization of TaCOMT genes and development of gene-specific markers could enable marker-assisted selection in wheat breeding. In the present study, the full-length genomic DNA(gDNA) sequences of TaCOMT genes located on chromosomes 3 A, 3 B, and 3 D were cloned by homologous cloning. Two allelic variants, TaCOMT-3 Ba and TaCOMT-3 Bb, were identified and differed by a 222-bp insertion/deletion(InDel) in the 3′-untranslated region(3′-UTR). A co-dominant gene-specific marker based on this InDel was developed and designated as Ta COMT-3 BM. A total of 157 wheat cultivars and advanced lines grown in four environments were used to validate the associations between allelic patterns and SLC. The SLC of cultivars with TaCOMT-3 Ba was significantly(P<0.01) higher than that of those with TaCOMT-3 Bb, and the marker TaCOMT-3 BM could be effectively used in wheat breeding.
基金The research is part of the Key Program in the National Natural Science Foundation of China(30330400)the Foundation Program in the Committee of Science and Technology of Chongqing,China(2002—7274)This work was also supported by the Rapes Engineering Laboratory of Southwest Agricultural University in Chongqing in China.
文摘One pair of near isonegic yellow/black seeded rape （Brassica napus L） were used as experimental materials to study the changes of lignin contents and enzymes activities of 4-coumarate： CoA ligase （4CL）, Cinnamyl alcohol dehydrogenase （CAD） and ferulate 5-hydroxylase （F5H） in seedcoats during the stage of seed development. The variation analysis showed that the changes of lignin contents and enzyme activities of 4CL, CAD and F5H in seed coat had significant differences between black- and yellow-seeded rapes, and also between different development stages. The correlation analysis demonstrated that the lignin contents were positively correlative to the activities of all three enzymes investigated in the study, and the interactions between them in the seed coat of the two lines. For yellow-seeded rape, the correlation coefficient （0.7262018） of lignin content and the interaction between 4CL and F5H was significant, the lignin contents were highly positively correlative to the activities of CAD and F5H, the interaction between 4CL and CAD, and the interaction between CAD and F5H. For the black-seeded rape, only the lignin content was highly positively correlative to the activity of F5H （the correlation coefficient was 0.772949）, the other correlation coefficients, i. e. lignin contents to 4CL, CAD activities, the interactions between the three enzymes were not significant although all the correlation coefficients were above 0.5000. The results suggested that 4CL, CAD and F5H regulated the biosynthesis of lignin in seedcoat of rapes, leading to the lignin contents in the seedcoats of the yellow-seeded rape much lower than that of the black-seeded line, and affecting the thickness of the developing seedcoats in rapes. Therefore, it was likely to change the seedcoat ratio by overexpressing or suppressing the activities of one of the enzymes, both of them or all of them.
文摘A steam explosion pretreatment at various severities was applied to pure wood cellulose; the influences of steam pretreatment on the morphological structure, the hydrophilic property and viscosity-average molecular weight of cellulose were evaluated. The nitration of steam-exploded cellulose was carried out in the nitrating agent medium （HNOa/organic solvent）. The performance indexes of nitrocellulose, prepared from original and steam exploded samples, were determined by using the polarized optical microscope. The results show that after pretreatment the reactivity of the three hydroxyl groups in anhydroglucose unit of cellulose is improved, and the nitrogen content and the uniformity of NC from steam exploded cellulose observably increas.
基金This research was funded by The Talents Project for Harbin Science and Technology Innovation,grant number 2016RAXXJ006China Postdoctoral Science Foundation,grant number 2017M611341.
文摘Cellulose nanofibrils(CNFs)are promising sustainable materials that can be applied to nanocomposites,as well as medical and life-sciences devices.However,methods for the preparation of these important materials are energy intensive because heating and mechanical disintegration are required to produce cellulose fibers below 100 nm in size.In this study,CNFs were prepared through the multi-site regioselective oxidation of cellulose with 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)and periodate at room temperature(20–25°C),without any mechanical-disintegration treatment.Transmission electron microscopy(TEM)revealed that the CNFs had the average widths of 14.1,55.4,and 81.9 nm for three different treatments.Fourier-transform infrared spectroscopy revealed that carboxyl groups were created on the surfaces of the microfibrils,while X-ray diffraction studies showed that the cellulose I structure was maintained after oxidation,and that the cellulose nanofibril crystallinity index exceeded 70%.These results demonstrate that CNFs can be prepared by multi-site regioselective oxidation at room temperature in the absence of mechanical disintegration.In addition,a model was developed to calculate the total content of carboxylate and aldehyde groups of CNFs prepared by the TEMPO mediate oxidation,the periodate oxidation,and the multi-site regioselective oxidation methods based on the particle width determined by TEM.The calculated values of the model were in good agreement with the total content(experimental value)of carboxylate and aldehyde groups of CNFs prepared by the TEMPO-mediated oxidation and the multi-site regioselective oxidation methods.However,the model was not valid for CNFs prepared by the periodate oxidation method.
基金funded by e-Science 02-01-02-SF0403 from the Ministry of Science,Technology and Innovation,Malaysia
文摘The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz.Acacia mangium Willd.and Acacia auriculiformis A.Cunn.Ex Benth.and their hybrid.Acid insoluble lignin content(Klason),mean stem density and fibre length differed considerably among the species and hybrids.A.mangium possessed a high percent of lignin content compared to A.auriculiformis and the Acacia hybrid.However,mean stem density of A.auriculiformis was higher than A.mangium and the hybrid.Fibre length of heartwood tissues was generally shorter than that of sapwood tissues.The hybrid had longer fibres than the parent species.Lignin was negatively correlated with mean stem density.Generally,the wood properties of the hybrid were superior to its parent species.The significant intraspecific variation observed for wood properties of Acacia species could be used in breeding superior hybrids combining desirable traits of the two species.Considering thedifficulty involved in accurately measuring the lignin content compared to mean stem density,selection for plants with low lignin content can be achieved by indirect selection of high mean stem density.
文摘We have investigated a correlation of transcript abundances of key genes that influence the quality of wood and flavonoid biosynthesis, such as the two p-hydroxycinnamoyl-CoA:quinate shikimate p-hydroxycinnamoyl transferase (HCT) and the two chalcone synthases (CHS) from Eucalyptus globulus grown in a greenhouse. The EglHCT1 and EglHCT2 transcripts accumulated in stems of all ages, but to a lesser extent in leaves. On the other hand, EglCHS3 and EglCHS4 exhibited high transcript levels in leaves, roots and shoots, but low levels in the stem. A positive correlation (R2 > 0.70) was observed between the transcript levels of the EglHCT1, EglHCT2 genes and Klason lignin (KL) content. In addition, the sum of transcript levels of EglHCT1 and EglHCT2 genes were highly correlated to KL contents (R2 > 0.85). However, there is no relationship between transcript levels of two CHS genes and, KL or flavonoid contents. This may imply that lignin biosynthesis and flavonoid biosynthesis are independently regulated in E. globulus.
文摘Lignin is a polymer of phenylpropanoid compounds formed through a complex biosynthesis route, represented by a metabolic grid for which most of the genes involved have been sequenced in several plants, mainly in the model-plants Arabidopsis thaliana and Populus. Plants are exposed to different stresses, which may change lignin content and composition. In many cases, particularly for plant-microbe interactions, this has been suggested as defence responses of plants to the stress. Thus, understanding how a stressor modulates expression of the genes related with lignin biosynthesis may allow us to develop study-models to increase our knowledge on the metabolic control of lignin deposition in the cell wall. This review focuses on recent literature reporting on the main types of abiotic and biotic stresses that alter the biosynthesis of lignin in plants.
