酚-硫酸法测定木素磺酸铵中糖含量的研究     

胡建鹏  王勇  郭明辉 《西南林学院学报》2010,30(5):65-67,71

采用酚-硫酸法测定木素磺酸铵中糖含量,以葡萄糖为对照,苯酚-硫酸作显色剂,用紫外分光光度计在490 nm处测定吸光度。结果显示：葡萄糖浓度为20～120μg/mL时线性关系显著,R2=0.995 9;精密度RSD=0.034%,稳定性RSD=0.102%,回收率98.99%,RSD=0.871%,重现性RSD=0.336%。酚-硫酸法测定木素磺酸铵中糖含量简便易行,精密度、稳定性、回收性、重现性良好。  相似文献   

竹柳材化学性质及其变异性研究     

吴向文  赵智强    王喜明  刘建霞 《西北林学院学报》2016,31(2):239-243

竹柳材因其良好的生物学特性,本世纪初被广泛引种到内蒙古西部干旱和半干旱地区。目前已进入平茬抚育期,间伐竹柳材可以作为人造板工业原材料。通过GB/T2677.2~10-1995、GB/T17660-1999、GB/T6043-2009和硝酸乙醇法,系统测试研究了不同树龄、不同部位的竹柳材的化学成分。结果表明:同一树龄不同部位竹柳材中纤维素、综纤维素、1% NaOH抽提物差异显著。不同树龄竹柳材中纤维素、酸不溶木素、苯醇抽提物和1% NaOH抽提物含量差异显著。通过对竹柳材化学性质的研究,得出竹柳材可以作为人造板材料。  相似文献   

Accumulation and composition of total organic carbon in reclaimed coal mine lands     

G. K. Ganjegunte  A. F. Wick  P. D. Stahl  G. F. Vance 《Land Degradation \u0026amp; Development》2009,20(2):156-175

Reclaimed coal mine lands have the potential to sequester atmospheric carbon (C); however, limited information exists for the western USA coalfields. This study was carried out on two chronosequences (BA‐C₃ grasses and DJ‐shrubs) of reclaimed sites at two surface coal mines to determine the effects of vegetation, soil texture, and lignin content on soil total organic carbon (TOC) accumulations. In the BA chronosequence, TOC increased over 26 years at an average rate of 0·52 Mg C ha⁻¹ yr⁻¹ in the 0–30 cm depth and was significantly correlated with clay content. Comparison between < 1 and 16‐year‐old stockpile soils indicated TOC content did not differ significantly. In the DJ chronosequence, TOC content in the 0–30 cm depth declined from 31·3 Mg ha⁻¹ in 5‐year‐old soils to 23·4 Mg ha⁻¹ in 16‐year‐old soils. The C:N ratios suggested that some (up to 2·0 per cent) of the TOC was potentially derived from coal particles in these reclaimed soils. Soil total N (TN) contents followed a similar trend as TOC with TOC and TN concentrations strongly correlated. Lignin contents in TOC of all reclaimed soils and topsoil stockpiles (TSs) were higher than that of nearby undisturbed soils, indicating the recalcitrant nature of TOC in reclaimed soils and/or possibly the slow recovery of lignin degrading organism. Results indicated that TOC accumulations in DJ were largely controlled by its composition, particular lignin content. In BA sites TOC accumulation was strongly influenced by both clay and lignin contents. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Susceptibility evaluation of Picea abies and Cupressus lusitanica to the pine wood nematode (Bursaphelenchus xylophilus)     

M. Nunes da Silva  M. R. M. Lima  M. W. Vasconcelos 《Plant pathology》2013,62(6):1398-1406

Pine wilt disease (PWD), recently introduced into Europe, is caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus and is a devastating illness that affects mainly pine trees. It is known that the PWN is capable of infecting other conifers; however, there is currently no information on which other plant species may be susceptible to PWD. In this study, the potential susceptibility of two common species of European forests, Picea abies and Cupressus lusitanica, to PWN was assessed through the monitoring of visual external symptoms, dimension and localization of the nematode population in stems, quantification of total chlorophyll, total soluble phenolics and lignin, at 7, 14, 21 and 28 days after inoculation. The degree of susceptibility was established through the comparison of symptoms with Pinus pinaster, a well‐known PWN host. Furthermore, the stem ultrastructure of P. abies, C. lusitanica and Pn. pinaster was analysed by scanning electron microscopy. The results suggest that P. abies and C. lusitanica are resistant to PWN, and that lignin biosynthesis in these species is affected at an early stage of the infestation. Nevertheless, P. abies seems to be a compatible host that could act as a repository for PWN.  相似文献   

油茶籽壳的化学成分分析与扫描电镜观察     

周建平  杨俊换  胡尧超 《湖南农业大学学报(自然科学版)》2013,39(5):554-558

用化学分析法测定油茶籽壳的主要成分,并用不同方法处理油茶籽壳后测定其主要成分,同时利用扫描电镜对处理后油茶籽壳的细胞微观结构进行观察。结果表明,油茶籽壳中水分占11.07%,灰分占1.02%,粗脂肪占2.53%,粗蛋白占2.70%,还原糖占1.59%,茶皂素占10.68%,半纤维素占22.00%,纤维素占17.32%,木质素占31.35%,油茶籽壳的成分处理前、后有所变化;油茶籽壳的细胞壁主要由半纤维素、纤维素、木质素组成,且每部分都呈层状结构,半纤维素分布于细胞壁的内层,纤维素分布于细胞壁的中层,木质素分布于纤维素和半纤维素的层状结构之间和细胞壁的外层。  相似文献   

甲醛交联碱木质素-聚乙烯醇薄膜的透光性和透气性   总被引：7，自引：1，他引：6  

苏玲  方桂珍 《农业工程学报》2014,30(4):239-246

为了提高工业碱木质素的利用价值,扩大碱木质素的应用范围,以工业碱木质素和聚乙烯醇为原料,以甲醛为交联剂,利用流延法制备了碱木质素-聚乙烯醇交联反应膜。通过单因素实验探索了碱木质素加入量、甲醛加入量、溶液pH值对碱木质素-聚乙烯醇(PVA,poly vinyl alcohol)反应膜透光性和透气性的影响。采用紫外可见分光光度计分析了薄膜的光学性能,压差法测定薄膜的透气性。采用SEM(scanning electron microscopy)和FTIR(Fourier transform infrared spectroscopy)方法分析反应膜的表面形貌和化学结构,利用静态接触角测量仪测定薄膜的接触角。结果表明:碱木质素加入后,在紫外光区200～400 nm薄膜的透过率为零,对紫外线全吸收,在可见光区400～800 nm薄膜透过率降低,当碱木质素与PVA质量比为1:4时,在600 nm处薄膜的透过率为16.12%;随着甲醛加入量的提高,薄膜可见光区的透光率逐渐增大;随着pH值增大,木质素逐渐溶解,pH值为9时,薄膜600 nm处薄膜透过率为20.85%。与纯PVA薄膜相比较,碱木质素加入后薄膜二氧化碳和氧气的透气性都减小;经甲醛交联后,薄膜的氧气和二氧化碳的透过量都增大;pH值由小到大变化时,碱木质素-聚乙烯醇反应薄膜对二氧化碳和氧气的透气量先增大后减小。FT-IR表征说明碱木质素-聚乙烯醇薄膜结构中有醚键生成,碱木质素和PVA发生了交联反应;电镜图片显示碱木质素-聚乙烯醇反应薄膜表面较光滑;接触角分析说明碱木质素的加入增大了薄膜与水的接触角,薄膜表面亲水性降低,并且交联反应薄膜的接触角大于共混薄膜的接触角,交联提高了薄膜的耐水性。与戊二醛相比甲醛做交联剂时碱木质素和PVA之间的交联反应程度更大,交联薄膜在可见光区的透光性更大。薄膜对紫外线吸收主要是受碱木质素的影响。碱木质素-聚乙烯醇反应膜可作为良好的紫外吸收材料,应用于地膜中。  相似文献   

竹材草酸预水解过程木质素的溶出规律     

曹石林  马晓娟  林玲  黄六莲  陈礼辉 《农业工程学报》2014,30(5):277-284

为了探索用草酸预处理竹材制备溶解浆,该文用不同用量的草酸对竹材进行预水解,测定预水解过程竹材木质素含量的变化,用场发射扫描电镜(field emission scanning electron microscope,FE-SEM)观察水解后假木质素在竹纤维表面的分布状况,用核磁共振技术(cross polarisation/magic angle spinning carbon-13 nuclear magnetic resonance,CP/MAS 13C-NMR)分析木质素的结构变化。研究结果表明,在竹片草酸预水解过程中,竹片预水解得率将随着预水解时间的延长而下降,并且,草酸用量越大,得率下降越多。基于水解后竹材基质的木质素含量会随着预水解时间的延长而逐渐升高,并且,草酸用量越大,木质素含量升高越多;而基于竹材原料的木质素含量则随着预水解时间的延长先下降再增加,并且,草酸用量越大,增加的速率也越大。竹材木质素由于芳基醚键(β-O-4)断裂,酚型木质素含量提高。纤维素和半纤维素降解产物在预水解过程形成的假木质素类物质会以微球的形式附着在竹片表面。该研究可为探索竹材快速高选择性去除半纤维素的预水解方法提供参考。  相似文献   

Impact of plant cell wall network on biodegradation in soil: Role of lignin composition and phenolic acids in roots from 16 maize genotypes     

Gaylord Erwan Machinet  Isabelle Bertrand  Yves Barrière  Sylvie Recous 《Soil biology & biochemistry》2011,43(7):1544-1552

Residue quality is a key factor governing biodegradation and the fate of C in soil. Most investigations of relationships existing between crop residue quality and soil decomposition have been based on determining the relative proportions of soluble, cellulose, hemicellulose and lignin components. However, cell wall cohesion is increased by tight interconnections between polysaccharides and lignin that involve cross-linking agents (phenolic acids). The aim of this study was to determine the role of lignin composition and phenolic acids on short- to medium-term decomposition of maize roots in soil. Sixteen maize genotypes, presenting a range of chemical characteristics related to root lignin and phenolic acids, were used. The main components were characterized by Van Soest (VS) extraction and cell wall acid hydrolysis, and the non-condensed Syringyl and Guaicyl lignin monomers, esterified phenolic acids and etherified phenolic acids were determined. Maize roots were then incubated in soil under controlled conditions (15 °C, −80 kPa moisture) for 796 days. Results showed that VS extraction over-estimated the structural hemicellulose content and that VS lignin was more recalcitrant than Klason lignin. The tremendous effect of cell wall chemical characteristics was shown by marked variations (almost two-fold differences in C mineralization), between the 16 maize roots. Decomposition was controlled by soluble residue components in the short term whereas lignin and the interconnections between cell wall polymers were important in the long-term. Notably the cell wall domain rich in non-condensed lignin and esterified phenolic acids was prone to decomposition whereas the presence of etherified ferulic acids seemed to hamper cell wall decomposition.  相似文献   

氨化木质素在丸粒化种衣剂中应用研究初报   总被引：4，自引：0，他引：4  

运广荣  刘奎彬  马文荷  刘秋娟 《天津农业科学》2001,7(4):37-38

以造纸工业废料——氨化木质素作为丸粒化种子包衣剂的辅料包衣花椰菜和豇豆种子,研究其应用效果,探索再生资源重复利用的新途径。结果表明,氨化木质素Ls-1能促进蔬菜幼苗生长发育和增产,可以在种子丸粒化包衣剂生产中充分利用。  相似文献   

黄孢原毛平革菌对玉米秸秆木质素的降解研究   总被引：1，自引：0，他引：1  

黄慧  申源源  陈宏 《西南大学学报(自然科学版)》2011,33(7)

农作物秸秆还田是目前合理利用秸秆资源的有效方法之一,但不经预处理直接还田存在着许多不足之处.笔者通过分析玉米秸秆在黄孢原毛平革菌处理条件下木质素的降解情况,筛选出黄孢原毛平革菌对玉米秸秆木质素降解的最佳粒度与时间,为今后经济高效的还田产业提供理论基础.研究结果表明,黄孢原毛平革菌对大粒度的玉米秸秆(4~5和1~3 cm)较小粒度(0.5 cm)的降解效果好.在动态降解过程中,玉米秸秆的降解速率出现了两个高峰期,但不同粒度高峰期出现的时间略有不同.3种粒度的玉米秸秆分别在接菌35,40和35 d后累计降解率达到最大,其值分别为21.6%,35.6%和45.2%.综合比较,粒度为4~5 cm的玉米秸秆接种黄孢原毛平革菌35 d后,玉米秸秆达到最佳降解效果.  相似文献