碱液处理对改善竹束液体渗透性能的研究

竹材液体渗透性是影响竹材改性处理效果的重要因素。采用碱液处理(80℃,质量分数1%～4%,处理时间1～4 h)竹束,分析工艺参数对竹束质量损失率、染液质量增加率的影响,解析处理前后竹材微观构造、孔隙结构参数的变化情况,揭示碱液处理改善竹材液体渗透性的机理。结果显示,碱液质量分数及处理时间对竹束质量损失率影响显著。碱液质量分数2%、处理时间1 h条件下,可以在保证竹束液体渗透性改善效果和处理效率的同时,使竹束质量损失率较小。扫描电镜观察发现,碱液处理后竹束导管等细胞产生明显皱缩,导管壁上规则的网状孔隙结构产生破坏,竹材部分闭塞孔隙结构重新打开,竹纤维产生剥离现象。压汞测试分析发现,碱液处理后竹材显微构造变化会导致竹束内部孔体积增大;细胞壁内部孔径40 nm左右的孔隙增多,孔径增大。竹束纤维细胞剥离可增加液体渗透通道,缩短液体渗透路径,降低液体渗透压,提升液体渗透效率。孔体积的增大导致流体在竹束内部的渗透量增大,孔径增大导致流体在竹束内部渗透的效率提高。竹束细胞壁内部小尺寸孔隙的增加,使流体有更多的渗透路径向细胞壁内部渗透,易于实现深度均匀渗透。     

不同预处理对竹纤维束提取及其结构的影响

采用3种不同的预处理工艺提取获得竹纤维束,利用光学显微镜和X射线衍射法分别比较3种工艺下竹纤维束的微观形态和结晶结构。研究结果表明,低碱处理可分离提取竹纤维束,提取的竹纤维束为黄褐色丝状,直径为100～200μm。微观形态下,竹纤维束横截面呈蜂窝状,纵面呈多根柱形紧密排列状。3种工艺中,10%碱常温处理分离竹纤维最易,分离效果最好,残留基质黏附最少。由竹材经3种工艺提取的竹纤维束,结晶结构未改变,但相对结晶度均较原竹材有所提高。     

Effect of alkali extraction on the lignin monomeric composition inEucalyptus

The effect of alkali extraction on the lignin monomeric composition was examined inEucalyptus camaldulensis andE. globulus by thioacidolysis using extractive-free samples as a control. Results showed that the effect onEucalyptus is different among species and among sample positions in the trunk, although a small amount of lignin is solubilized during the extraction in all samples. In addition, it was proved that lignin extracted by the alkali extraction is not always guaiacyl-rich, probably relating to the original lignin monomeric composition, which depends on the sample species or the sample position in the trunk.     

Effect of different drying methods on liquid penetration of Chinese fir plantation wood

Chinese fir plantation sapwood and heartwood boards were treated by three drying methods: radio frequency-vacuum drying (RFVD), conventional kiln drying (KD) and high temperature drying (HTD). The maximum amount of dyeing solution uptake by the capillary rising method was used to evaluate the liquid penetration of the treated wood. The pit aspiration ratio was determined by a semithin section method. Changes in wood microstructure were investigated using scanning electron microscopy. The results show that liquid penetration of Chinese fir sapwood after RFVD is significantly higher than that after KD and HTD. Liquid penetration of Chinese fir heartwood after RFVD is higher than that after HTD. Liquid penetration of Chinese fir sapwood is significantly higher than that of heartwood after three drying treatments. Low pit aspiration ratio and cracks of some bordered pits are the main reasons for the increase in liquid penetration after RFVD treatment. __________ Translated from Scientia Silvae Sinicae, 2006, 42(10): 85–90 [译自: 林业科学]     

Purification of four strains of endophytic fungi from Astragalus and their optimized liquid fermentations

This study was designed to isolate endophytic fungi from A. mongholicus(growing in northeast China) to determine whether they can produce bioactive metabolites. Four strains of endophytic fungi(strains 16, 17, 23 and 75) were successfully isolated from A. mongholicus using the surface disinfection method. According to ITS-rDNA sequences analysis, strains 16 and 75 were identified as Fusarium oxysporum, and strains 17 and 23 were identified as Bionectria ochroleuca. We applied the Box-Behnken design(BBD) to optimize the liquid fermentation conditions and obtain the maximum cell dry weight(CDW) yield. Optimal parameters were obtained under the following experimental conditions: temperature of 28°C, potato dextrose agar(PDA) liquid medium of 80 mL and rotation speed of 150 rpm. The four isolated endophytic fungi did not produce astragalosides I–IV, flavonoids or polysaccharides. Isolation of additional species of endophytic fungi from A. mongholicus and determination of their capacity to produce biologically active substances are subjects in need of further research.     

Liquid penetration of precompressed wood VII: combined treatment of precompression and extraction in hot water on the liquid penetration of wood

The object of this study was to determine the cause of differences in the improvement in liquid penetration of precompressed wood species. The maximum amount of water uptake by the capillary rise method and changes in the aspirated pits seen with scanning electron microscopy before and after of preextraction and precompression were investigated using heartwood samples of four softwoods. The height of penetration and the weight by the capillary rise method for preextractive wood powders are discussed. Three wood species andLarix leptolepis showed marked increases in the amount of solution uptake after precompressed treatment only.Larix leptolepis wood required compression after extraction by boiling in water. These differences among wood species were caused by the accumulation of extractive material. It was also recognized that the accumulative material inLarix wood has plasticity and that inPseudotsuga is brittle. Based on these results it was found that it is difficult to destroy aspirated pits in the former and easy in the latter. On the other hand, the difference in penetration of each wood species was caused by the quantity and quality of the extraction material in addition to the extent of the wettability of the surface of the cell cavity as well as aspirated pit.Part of this report was presented at the 46th annual meeting of the Japan Wood Research Society, Kumamoto, April 1996     

四种桉树青枯菌DNA提取方法及PCR检测灵敏度比较

以带有青枯菌Ralstonia solanacearum的桉树组织为材料,采用4种不同的提取方法抽提青枯菌DNA,同时利用青枯菌的特异性引物进行PCR扩增,比较了4种DNA的提取方法及PCR检测的灵敏度。结果表明,煮沸法和热裂解法操作相对简单,但检测灵敏度较低,检测限分别为104CFU/mL和103CFU/mL;简化提取法和试剂盒法检测效果较好,均可检测到102CFU/mL的青枯菌;简化提取法比试剂盒法操作更简单,检测成本低,具有更高的应用价值。     

Agroforestry on alkali soils: Effect on some management practices on initial growth,biomass accumulation and chemical composition of selected tree species

This field study started in July 1982 on a typical alkali soil (Aquic Natrustalf, ESP 99.7) examined the growth responses to some management practices in a unified system planned to establish agroforestry. The planting of 3 salt tolerant tree species with two methods: on flat natural surface (FSPB) without rainwater conservation and on ridges (0.6 m high, 1.5 m at top and 2.5 m at base) having parallel trenches of the same section to store 300 mm of monsoon rainwater; constituted the main plot treatments. The tree planting with and without forage grassDiplachne fusca linn. in the inter-row space and planting in shallow (15 × 60 cm) and deep (15 × 180 cm to cross hard pan) augerholes filled with amendment treated soil (2 kg gypsum, 8 kg FYM, 50 g N, 10 g zinc sulphate and original soil) formed the sub and sub-plot treatments replicated 4 times in a split-split plot design.The mean plant height ofEucalyptus tereticornis smith;Acacia nilotica L; andParkinsonia aculeata L. in 2 years period was 273 and 328, 240 and 240 and 211 and 199 cm respectively with and without rainwater conservation. The corresponding height of the 3 tree species was 314 and 287, 250 and 231 and 207 and 203 cm with and without grass in the inter-row space. Similarly the plant height was 247 and 354, 182 and 298, 172 and 238 in shallow and deep augerholes respectively. The tree height and basal diameter differences with and without rainwater conservation and grass growth remained non-significant but deep augerhole planting was markedly superior to the shallow augerhole planting. The 2 year biomass accumulation also followed the same trend. The grass competed with trees for moisture during hot dry summer months and increased plant mortality particularly in the shallow augerholes and more so on ridges. The plant roots, essentially, remained confined to the amended soil of the augerholes in FSPB but proliferated in the loose soil of ridges or grass and submergence ameliorated surface soil of trenches.Acacia nilotica accumulated low sodium and had the lowest Na:Ca and Na:K ratio. It was found more promising than eucalyptus and parkinsonia as it experienced low mortality and had better chemical constitution to tolerate adverse alkali soil environment. The rainwater conservation system needed further evaluation before drawing final conclusions.     

三种不同萃取方法对印楝种子活性物提取率的影响

印楝作为植物源木材防腐剂活性物提取的重要来源深受研究人员的重视,对其活性物的萃取工艺也多种多样。本文采用了超声波震荡法、微波萃取法及水浴搅拌法对印楝种子粉末进行提取,在不同物液比（1∶8、1∶10、1∶12）、不同温度（30、40、50℃）下,对比分析三种工艺的粗提率。结果表明,三种提取工艺的提取率均随着温度的升高而增大,随着物液比（印楝种子粉末与乙醇-水之比）的降低而增大;在对印楝种子活性成分粗提取时的三种方法比较,温度控制在50℃,物液比为1∶12时,微波萃取法的提取率最高。     

不同提取方法的铁线莲属叶片总DNA提取效果

以铁线莲属植物的叶片为材料,采用CTAB-SDS法、简易CTAB法、改良CTAB法等3种提取方法,比较耗时、纯度、得率、浓度和质量等指标,以期为铁线莲属植物叶片总DNA的提取筛选适宜方法.结果表明,在纯度和浓度方面CTAB-SDS法＞简易CTAB法＞改良CTAB法,在节省提取时间方面改良CTAB法＞CTAB-SDS法＞简易CTAB法.以CTAB-SDS法所提取的9种铁线莲DNA为模板,进行PCR扩增,CTAB-SDS法提取的DNA得率高、质量好,PCR扩增成功率也较高.综合比较,采用CTAB-SDS法进行铁线莲属叶片总DNA提取效果更佳.     

辊压预处理条件对蒙古栎干燥速率及纹孔结构的影响

[目的]针对木材干燥耗时长、效率低的问题,以改变司职水分疏导功能的木材分子关键部位的微观结构为手段,通过改善木材的渗透性和水分的流动性,建立易于水分移动的新路径,达到缩短木材干燥时间的目的.在描述蒙古栎导管分子细胞壁构造变异的形态、数量和程度以及表征处理材在常规蒸汽干燥全程和各阶段干燥速率变动的基础上,探索并建立辊压预处理工艺条件、构造特征变异与干燥速率三者的相关关系.[方法]依托木材的黏弹性和水分移动机制,以蒙古栎为试材,对其含水率47％～55％、900 mm(长)×100 mm(宽)×30 mm(厚)的径切板和弦切板施行2个压缩方向(径向和弦向)、3种压缩率(10％,20％和30％)和3种压缩次数(1,4和9次)的辊压预处理,使用环境扫描电子显微镜(Fei Quanta 200)观察研究辊压处理材的导管分子微观构造特征变异,并在常规蒸汽干燥全程和各阶段测试和分析处理木材的干燥速率变动规律.[结果]环境扫描电镜观察表明,辊压压缩预处理使蒙古栎导管分子纹孔膜破裂和细胞壁出现裂隙,可形成水分移动的微观新路径;随着压缩率增大、压缩次数增加,纹孔膜破裂的数量和程度、细胞壁破坏的规模和尺寸增加,木材的渗透性和水分的流动性得到改善,缩短木材干燥时间.在常规蒸汽干燥的6个阶段和干燥全程,辊压预处理材的干燥速率均大于未处理材;压缩率和压缩方向相同时,干燥速率随压缩次数的增加而增大;压缩方向和压缩次数相同时,干燥速率随压缩率的增加面加快;压缩率和压缩次数相同时,径向压缩的弦切板干燥速率快于弦向压缩的径切板.[结论]以试材初含水率50％、终含水率15％计算,辊压预处理材的全程干燥时间均少于未处理材,弦向压缩径切板干燥时间缩短6.67％～23.64％,径向压缩弦切板缩短4.55％ ～ 13.02％.辊压预处理可在蒙古栎试材内部形成微观的水分移动新路径,改善水分的渗透性和流动性,缩短木材干燥时间.     

木聚糖酶处理对麦草化学组成及其纸浆纤维长度的影响

研究了木聚糖酶预处理对麦草的化学组成及其化学浆纤维长度的影响。结果表明,木聚糖酶酶处理后原料的热水抽出物和1%NaOH抽出物含量增加,乙醇-苯酚(苯-醇)抽出物含量有所降低,酶处理对原料中酸不溶木质素含量影响很小,但聚戊糖含量降低。延长酶处理时间,对酶处理最终结果影响不大。酶处理后的稀碱抽提可以有效地降低原料中的木质素和聚戊糖含量。与对照样品相比,酶处理后麦草化学浆的纤维长度有所增加。上述结果从理论上解释了酶法制浆过程中出现的一些现象。     

Effects of different N sources on growth, nutrient uptake and ionic balance ofLarlix gmelini seedlings

The effect of different sources and levels of N on dry matter production, nutrient uptake and ionic balance ofLarlix gmelini was studied. The results showed that the growth of the plants fertilized with ammonium was not as good as the control treatment. The growth of the plants fertilized with ammonium nitrate did not differ significantly from that in control or nitrate treatment, but was better than that in the ammonium treatment. Total cation concentrations in shoots varied little with N level in the ammonium and ammonium nitrate treatments, while those in the shoot increased with N level in the nitrate treatment. The treatments had little effect on the anion concentrations in the shoot. In the roots, the concentrations of both cations and anions changed little except for SO₄ ²⁻ and Ca²⁺. There existed a higher carboxylate production in the plants fertilized with nitrate. The ratio between the production of carboxylate and the production of organic N Δ(C-A)/ΔN_org was constant with N supply in the plants receiving nitrate, but obviously declined with N supply for ammonium-fed plants. Δ (C-A)/ΔN_org values were intermediate between those of the nitrate and the ammonium-fed plants as for the mixed N source. Foundation item: This paper was supported by “Hundred Scientists” Project of Chinese Academy of Sciences. Biography: CHEN Yong-liang (1969-), male, Ph. Doctor, lecture of Northeast Forestry University, Harbin 150040, Post-doctor in Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P.R. China. Responsible editor: Song Fuman     

不同N源对兴安落叶松苗木生长,养分吸收及离子平衡的影响(英文)

本文研究了不同N源对落叶松苗木干物重、养分吸收及离子平衡的影响。结果表明:施铵态N的苗木干物重小于对照处理;施硝铵态N的苗木生长与对照和施硝态N的苗木差别不大,但较施铵态N的苗木生长要好。铵态N与硝铵态N处理苗木地上部的阳离子总浓度受N水平的影响很小,而硝态N处理时则阳离子浓度增加;各处理对地上部阴离子浓度的影响均不大。在根部除硫酸根与钙离子外,阳离子与阴离子浓度均变化不大。硝态N处理的苗木具有较高的C-A值;△(C-A)/△Norg值在硝态N处理的苗木中随N供应量的增加而略有变化,但铵态N处理则明显下降;硝铵态N处理苗木的△(C-A)/△Norg值界于铵态N处理与硝态N处理之间。     

超临界CO2萃取杉木根化感物质对杉木的化感效应

采用正交试验及超临界CO_2流体萃取技术萃取杉木根化感物质,并通过杉木种子发芽试验进行杉木根化感物质对杉木的化感作用进行评价。结果表明:就化感物质萃取得率而言,在众多萃取因素当中,萃取压力和萃取温度是两个最主要的因素;经纯CO2及乙醇和CO2混和萃取的杉木根化感物质对杉木存在不同的化感效应,其中经乙醇和CO2混和萃取的杉木根化感物质对杉木种子发芽的抑制效应强于纯CO2萃取的化感物质。表3参20。     

Effect of Allelochemicals of Chinese—fir root extracted by supercritical CO2 extraction on Chinese fir

Allelochemicals of Chinese-fir root was extracted by technology of supercritical CO2 extraction under orthogonal experiment design, and it was used to analyze allelopathic activity of Chinese-fir through bioassay of seed germination, The results showed that as to the available rate of allelochemicals, the pressure and temperature of extraction were the most im-portant factors, The allelochemicals of Chinese-fir root extracted by pure CO2 and ethanol mixed with CO2 have different al-lelopathic activities to seed germination, and the allelochemicals extracted by ethanol mixed with CO2 had stronger inhibitory effects on seed Qermination than that extracted by pure CO2.     

4种药剂对杜鹃冠网蝽的药效试验和毒力测定

为有效防治杜鹃主要害虫杜鹃冠网蝽,选择37%高氯·马、1.8%阿维菌素、5%吡虫啉·氯氰菊酯复配乳油以及10%吡虫啉4种药剂,进行室内毒力测定及药效试验。结果表明:4种药剂对杜鹃冠网蝽均有较好的防治效果,药后5天的防治效果均达到100%,其中5%吡虫啉·氯氰菊酯复配乳油1 000倍液,药后1天、2天和3天对杜鹃冠网蝽的防效分别达到93.3%、98.9%、100%。4种药剂的毒力排序为5%吡虫啉·氯氰菊酯复配乳油37%高氯·马1.8%阿维菌素10%吡虫啉。     

羟丙基化碱木质素的制备及其对纤维素酶水解的影响

以碱木质素(AL)为原料制备羟丙基化碱木质素(HL),研究HL对纤维素酶的非生产性吸附性能的影响机制,并进一步探讨其对纤维素的酶水解得率的影响。Zeta电位滴定、X射线光电子能谱以及疏水性的测试结果表明:AL经过羟丙基化改性后表面特性发生改变,表面负电荷增加(Zeta电位由+35.0 mV降至-44.8 mV);表面元素分布及化学键组成发生了较大的变化,C—O和■键强度增加,疏水性减弱(疏水度由106.60 L/g减小为4.30 L/g),使得木质纤维素底物对纤维素酶的非生产性吸附减弱,进而显著提高纤维素酶水解效率。以10 U/g纤维素酶水解0.4 g/L微晶纤维素72 h,添加4 g/L的HL时游离酶蛋白质量分数为11.65%,相比4 g/L的AL提高152%;添加4 g/L的HL时酶水解得率为54.38%,相比4 g/L的AL提高32.09%。     

酸碱处理对制备再生桉木颗粒板的影响

废弃人造板中的胶黏剂影响人造板的回收利用。笔者利用化学法对废弃桉木颗粒板中的胶黏剂进行处理,分别探究不同浓度的硫酸、甲酸、硝酸、氢氧化钾分解废弃木颗粒板中脲醛树脂的最佳条件。结果表明,在90℃,水浴处理2 h条件下,甲酸浓度大于60%,硫酸浓度大于25%,或硝酸浓度大于25%可完全分解固化后的脲醛胶黏剂;对酸处理后的木颗粒的颜色、形貌、化学性质进行分析,甲酸对木颗粒的形态、颜色影响较小。用酸处理后制得的再生木颗粒板,力学性能相对于未经处理的再生木颗粒板得到显著提高。     

天然产物活性成分提取分离研究进展

从动物、植物、微生物体内分离得到的某些天然成分,具有结构的多样性和生物活性的多样性,在新药和药物先导化合物的开发中起着重要作用。传统分离技术分离效率低而成本高,新技术的出现将有效改善这一不利局面。为给天然产物活性成分的开发应用提供参考依据,综述了近年来国内外天然产物活性成分提取分离技术的研究进展,并对天然产物活性成分提取分离中存在的问题进行了探讨,还对天然产物活性成分的利用前景进行了展望。