The role of absorbed hemicelluloses on final paper properties and printability

Hemicelluloses isolated from eucalyptus wood were adsorbed onto both bleached eucalyptus kraft pulp and pine kraft pulp as part of a general strategy to investigate their role on final sheet mechanics and physical properties. The tensile indices increased upon hemicelluloses addition and respectively reached a maximum at 9 mg/g and 10 mg/g hemicelluloses adsorption for bleached eucalyptus kraft pulp and pine kraft pulp, whereas the tear index increased depending on the pulp type. The air permeability and surface roughness of the bleached eucalyptus kraft pulp slightly decreased, however, brightness and opacity did not changed. SEM analysis shows that hemicelluloses adsorption increases bleached eucalyptus kraft pulp fibers interaction, whereas the effect of hemicelluloses addition on the beaten pine kraft pulp is unclear. The hemicelluloses adsorption also affected printability. It was found that print through for the bleached eucalyptus kraft pulp hand sheet slightly decreased, but for the bleached pine kraft pulp hand sheet it was unaffected. Print densities were not influenced.     

橡胶无性系木材比重的遗传变异

海南农垦橡胶研究所24个参试橡胶无性系,平均木材比重为0.455～0.526,总平均为0.492。品系间差异高度显著,据品系平均估算的广义遗传力为0.90。橡胶树木材比重径向变异趋势是自髓心向外增大,存在一定的早一晚期相关性。木材比重与茎围之间表现为正的但属弱的表型相关和遗传相关。     

Upgrading of hemp core for papermaking purposes by means of organosolv process

Non-wood raw materials for paper production have been maintained constant during last decade. In Europe, fibres from non-wood resources proceed mainly from flax and hemp crops. Hemp core is considered a by-product of the process, mainly used in equestrian sector. The application of these fibres for papermaking process gives a significant added value to the sector.New technologies in cooking processes like organosolv pulping gives advantages compared with traditional Kraft cooking. Hemp fibres obtained by means of organosolv process have been compared with eucalyptus Kraft pulp to determine if physical and mechanical properties of final pulps are similar.Efficiency of the organosolv cooking experiments was evaluated by means of yield, percentage of uncooked sample, kappa number and viscosity.To analyze the suitability of pulp samples for papermaking applications, different evaluation of mechanical properties as morphological characterization were done. Controlling cooking conditions of hemp core, similar properties of eucalyptus Kraft fibres are obtained.     

Antioxidant activity and phenolic content of chestnut (Castanea sativa) shell and eucalyptus (Eucalyptus globulus) bark extracts

Chestnut (Castanea sativa) shell and eucalyptus (Eucalyptus globulus) bark, waste products of the food and wood industries, respectively, were analysed as potential sources of antioxidant compounds. The extraction yield, the antioxidant activity and total phenols content of the extracts were greater in chestnut shell than in eucalyptus bark for most of the extraction conditions essayed. Extraction of chestnut shell with a 2.5% Na₂SO₃ aqueous solution led to the highest extraction yield, 25.6%, total phenols, 13.4 g gallic acid equivalent/100 g oven-dried shell, and FRAP antioxidant activity, 80.7 mmol ascorbic acid equivalent/100 g oven-dried shell. Extraction with methanol:water (50:50, v/v) provided the best results for eucalyptus bark. The antioxidant activity and the total phenols content of the extracts had a positive linear correlation. FTIR spectroscopy confirmed the higher content of phenolic compounds in chestnut shell extracts compared to eucalyptus bark extracts. Chestnut shell extracts were characterized by the presence of high molecular weight species whereas lower molecular weight species were predominant in eucalyptus bark extracts.     

Low Mw-lignin fractions together with vegetable oils as available oligomers for novel paper-coating applications as hydrophobic barrier

Lignin residues are available in large amounts as kraft lignin from chemical pulping processes. This lignin is mainly incinerated in recovery boilers. The recovery boilers are often the bottle-necks in the overall pulping process when pulp production increases are desired. Through cross-flow nano-filtration of the black liquor from kraft pulping, a low-molecular weight lignin fraction can be removed thus decreasing the organic load on the recovery boilers. The low-molecular weight lignin fraction furthermore exhibit different characteristics compared to other commercial kraft lignins and represents a new raw material source in novel applications.The low-molecular weight lignin was used together with a vegetable oil to produce a new hydrophobic lignin derivative similar to suberin. The lignin and the lignin derivative was analysed with FT-IR, UV–vis and SEC. The ability of the product to make paper surfaces hydrophobic was also evaluated.The results demonstrate the possibility to make a suberin-like lignin derivative that is potentially of interest in paper-coating applications due to its capability to interact well with wood fibres and make paper hydrophobic.     

Comparison of various pulping processes for producing pulp from vine shoots

The results of characterization for four different vine shoot varieties, grown using two different methods, revealed no significant differences in composition among vine varieties or between growing methods. The holocellulose content of vine shoots (67.14%) is lower than those of other non-wood raw materials (e.g. wheat straw, sunflower stalks, cotton stalks, etc.), but similar to those of pine and higher to those of olive trimmings. On the other hand, their lignin content (20.27%) is similar to those of eucalyptus and the non-wood raw materials. Also, their contents in cold-water, hot-water and 1% soda solubles, and ethanol–benzene extractables, are higher than for pine and eucalyptus.Soda, kraft, ethanol and ethylene–glycol pulping processes have low yields (29–47%) relative to the pulping processes applied to olive trimmings and wheat straw. Kraft pulp is that exhibiting the best properties, including a higher α-cellulose content (73.74%) than pulp from wheat straw or olive trimmings, but a higher lignin content (17.18%). Also, kraft pulp provides paper with the highest breaking length, burst index and tear index (viz. 1316 m, 1.63 kN/g and 1.59 mN m²/g, respectively); these values, which are intermediate among those for olive trimmings, wheat straw and sunflower seeds, are low and can be substantially improved by appropriate refining of the pulp.     

Chemical constituents and physical properties of guayule wood and bark

About 15 Parthenium species grow in the North American continent with Parthenium argentatum (guayule) as the only species containing harvestable amounts of the rubber latex. The predicted commercialization of the guayule plant for its hypoallergenic latex will result in a significant amount of waste fiber or bagasse biomass that can also be put to use for making wood, paper, and other chemical products, as well as in energy production. Thus, the guayule wood and bark fibers can be considered a new source of plant biomass that may be used as a direct substitute for forest-based wood fiber. However, little information is available on the chemical composition of the wood and bark tissues of guayule (P. argentatum). The objectives of this study were to determine the chemical and fiber composition of guayule and to compare it with other wood fiber sources.Three germplasm lines of mature guayule (Cal-6, AZ-101, and G7-15) and another species of Parthenium (P. tomentosum, PT), juvenile soft maple (Acer rubrum), a deciduous tree, and milkweed (Asclepias syriaca L.) that has long fibers were the plant sources. Separate wood and bark tissues were analyzed for hot water, 1% sodium hydroxide, and alcohol–toluene extracts. In addition, the lignin, holocellulose, alpha-cellulose, and pentosan contents were determined.All the chemical components in the wood fibers for the Partheniums were equal to or greater than the juvenile maple tree. Milkweed had higher alpha-cellulose and lower alcohol–toluene extract contents than both the guayule and soft maple. The guayule bark fibers had more chemical extracts than the wood fibers. The specific gravity of guayule wood was greater than the deciduous wood species. However, the fiber lengths of soft maple wood, guayule wood, and milkweed are similar. Based on the chemical composition, P. argentatum and P. tomentosum could serve as raw materials for the paper and chemical industries as well as for energy production.     

酶处理对芒果原浆性质的影响

在分析芒果原浆酶处理前后的理化性质的基础上,选用合适的配方,结合酶处理技术,改进芒果打浆工艺,生产出质量稳定的芒果原浆产品,提高了芒果打浆的得浆率。      

高效液相色谱法检测防腐橡胶木中的碘代丙炔基丁基氨基甲酸酯

橡胶木中淀粉含量远高于其他树种,易发霉、蓝变。碘代丙炔基丁基氨基甲酸酯（3-iodo-2-propynyl butyl carbamate,IPBC）绿色环保,对霉菌、蓝变菌有特效,尤其适用于橡胶木保护。目前橡胶木中IPBC分析方法的研究报道较少,其防腐处理材的质量监督尚缺乏有效手段。为了准确分析防腐橡胶木中的IPBC,建立了一种高效液相色谱（high-performance liquid chromatography,HPLC）方法,检验了该方法的检出限、加标回收率等性能,并比较了不同提取方法、提取溶剂、木粉粒径等因素对防腐橡胶木中IPBC提取效果的影响。建立的HPLC方法使用C18反相色谱柱,乙腈-水（55︰45,V/V）为流动相,流速1.0 mL/min,检测波长204 nm,IPBC保留时间约6.45 min。在2~80 mg/L浓度范围内,线性关系良好,相关系数0.9998;检出限0.2 mg/L,平均加标回收率99.61%。超声法提取的效果显著优于索氏抽提器法;以甲醇或甲醇-水（9︰1, V/V）混合液为溶剂超声提取的效果较好,乙酸乙酯和石油醚不适于提取木材中的IPBC。以甲醇-水（9︰1, V/V）混合液为溶剂制备样品可改善色谱峰形,有助于提高分析方法的准确性。木粉粒径差异对IPBC超声提取的影响较小。高温条件会导致IPBC降解,严重影响分析结果准确性,因此在整个分析过程中应避免高温条件。本方法检出限低、重现性好,准确性高,适于分析防腐木材中微量的IPBC。     

Kinetics of organosolv delignification of fibre crop Arundo donax L

Kinetics of ethanol–alkali delignification of fibre crop Arundo donax L. (giant reed) has been studied. The improved approach for determination of the reaction rate constants by accurate quantification of lignin fractions with different reactivity during standard procedure of graphical differentiation was applied. Following to a simplified model, the delignification process was considered as a complex of n-parallel irreversible first-order reactions with similar final product and analysed as a multi-component reaction system. Three kinetically distinguishable lignin fractions of A. donax were revealed and quantified in proportion of approximately 61, 23 and 16% (as initial, bulk and residual lignin, respectively) and their effective degradation rate constants were determined for different pulping conditions. The proportion of lignin fractions was different from that reported for wood, but close to another crop—wheat straw, where the initial lignin fraction was also found as a major fraction (about 90%). The values of apparent activation energy were estimated respectively as 64, 89 and 96 kJ mol⁻¹, and were generally within the range of those reported for wood kraft and organosolv pulping. The simulation of ethanol–alkali delignification using found kinetic parameters showed the high reproducibility of experimental data on lignin removal, providing thereby the adequate test on validation of the suggested kinetic approach. The data reproducibility was substantially higher in comparison with conventional consecutive kinetic model (sum of square residuals (SQR) 0.0036 versus 0.0856).     

Wettability and roughness characteristics of modified wood boards using a hot-press

The aim of this study was to investigate the effect of the thermal modification process by hot-press on the wettability and surface roughness characteristics of the eucalyptus wood boards. The roughness measurements, average roughness (R_a), and maximum roughness (R_max) were taken both parallel and perpendicular to the grain using a fine stylus tracing technique. Contact angle measurements were obtained using a goniometer system connected to a digital camera and computer system. The results showed that surface roughness values of the modified wood boards using a hot-press significantly decreased with increasing press pressure and with decreasing temperature. The contact angle measurements indicated that the thermal modification had a significant influence on the surface wettability of the wood boards. Statistical analyses showed significant differences in the surface roughness and contact angle values of the wood boards following thermal modification. The results acquired in this work provide important information for future research and utilization of the thermally modified wood boards.     

栽培奇楠的显微结构研究

为探究不同栽培奇楠树所结沉香的显微结构特征,收集15份栽培奇楠树所结沉香样品,通过木材切片和显微观察的方法进行解剖学研究,对其三切面的显微结构特征进行观测、描述、统计、对比和分析,并与普通白木香所结沉香进行对比。结果表明,栽培奇楠树所结沉香样品在显微结构方面有共性特征,其树脂均主要分布于内涵韧皮部、木射线及导管中,树脂丰富且有向木纤维扩散的趋势,在千里香中表现明显,而与之相比,普通白木香所结沉香样品中树脂主要集中于导管中且含量较少,二者差异较大,就树脂富集面积与含量而言,栽培奇楠树所结沉香样品明显优于普通白木香所结沉香样品;此外,部分栽培奇楠所结沉香样品内涵韧皮部与髓心中可见大量草酸钙棱晶,晶体作为树木抵御外界伤害的一种方式,推测其有利于奇楠树受到创伤开始结香后结香面积的扩展与树脂含量的增加;对沉香样品部分特征的定量数据进行统计研究,结果表明部分栽培奇楠树所结沉香样品间有较大差别,如金丝油的管孔密度、直径,内涵韧皮部宽度、密度,射线宽度、间距等与其他样品差异较大,聚类分析结果表明,栽培奇楠树所结沉香金丝油与乌身圆叶较为特殊,位于分支树的根部,千里香、张勺子、透顶绿及凹身木聚为一类,其余9个样品绿油王、‘热科2号'、樱桃叶、糖结、紫棋、蓝宝石、西瓜叶、指天椒及油叶子聚为一类。本研究可为栽培奇楠的树种选育、资源利用、检测鉴定和市场规范化提供依据,尽快完善相关研究才能不断推进沉香产业良性发展。     

Chemical composition and pulp characterization of Tunisian vine stems

In this study, the valorisation of Tunisian vine stem wastes was investigated. The chemical composition of the vine stems was studied, and it was found that when compared to non-wood plants, they contain greater amounts of extractives, lignin, and comparable holocellulose content. An elementary analysis of the ashes showed that the major constituents were mineral elements (K and Ca). Soda pulping of vine stems led to a yield of about 35% after the bleaching step. This amount is lower than that obtained for wood plants and similar to that observed for annual plants. The morphological properties, Kappa number, and degree of polymerization of the resulting pulp were determined. Finally, paper handsheets were prepared from the pulp, and their physical properties were investigated. The breaking length, Young's modulus, and burst index of the produced paper presents quite acceptable values. Further, the silica content of the stems is low, which is advantageous for the pulping process. Experimental results obtained for both the pulp and paper show that this agricultural residue has the potential to be used for papermaking applications.     

刚果12号桉叶片水抽提物对4种植物幼苗生长的影响

采用盆栽法研究了刚果12号桉叶片水抽提物在水分胁迫（水渍与干旱）和养分缺乏与丰足的环境条件下对4种植物生长的影响。结果表明，植物种类与盆栽基质的肥力是影响植物幼苗生长的关键因素，而桉叶水抽提物与土壤水分对植物幼苗的生长虽有影响，但与前二相比作用较小。因此，在退化的桉树人工林地重建林下植被，首先应选择耐瘠薄、耐旱性强和对化感作用不敏感的植物，如柱花草等豆科植物，既能自身固氮，又能通过循环增加土壤养分，当然应该注意豆科与禾本科搭配。结果还表明，在逆境条件下，桉树的化感作用会增强，并与其它因素互相作用，抑制林下植被生长。     

海南桉树人工林林下植物多样性特征研究

为探究海南桉树人工林林下植物多样性特征,对不同区域桉树人工林进行植被调查,采用标准木法和收获法相结合的方法,测定样方内地上部分的生物量,再结合灌木层、草本层α多样性指数与地上部分生物量构建综合功能指数,并比较新指数与α多样性指数。结果显示：（1）桉树人工林林下植物共101种,其中灌木层植物共49种,隶属31科45属,草本层植物共52种,隶属28科48属。（2）不同区域桉树人工林林下灌木层多样性指数差异不显著,仅临高的草本层α多样性指数显著大于其他区域,说明灌木层多样性水平相近,而草本层多样性水平更易受环境影响。（3）不同区域桉树人工林下灌木层、草本层的地上生物量分配差异显著,灌木层大于草本层,但是分配比例波动范围较大。（4）不同区域桉树人工林灌木层综合功能指数（Yd）无显著差异,临高和定安的草本层Yd指数显著大于屯昌和东方,表明不同区域桉树林灌木层的综合功能相近,草本层的综合功能则是临高和定安明显较强。（5）灌木层Yd指数与α多样性指数的相关性很强;草本层Yd指数与α多样性指数的相关性一般,与地上生物量相关性很强。结果表明,桉树林下植物多样性特征受区域环境影响,其中草本层比灌木层更易受...     

桉树林取代马尾松树林后土壤动物组成变化研究

为深入了解不同林龄桉树林下土壤动物的多样性及相似性，客观评价桉树取代马尾松林后的生态效益，利用建立的标准养地，对比研究了广西柳州不同林龄桉树林和马尾松土壤动物群落结构特征。大型土壤动物采用野外分层手捡记数，中小型土壤动物采用取土器分层取土，带回实验室采用干漏斗分离并镜检。结果表明，桉树取代马尾松后，土壤动物物种丰富度增加了，但土壤动物的多样性指数、优势度指数和均匀度指数均下降，导致群落的稳定性变差。炼山导致生境的改变，影响了土壤动物的数量。随着桉树的持续经营，土壤动物相似程度增加，但与马尾松林下土壤动物的     

不同林龄桉树人工林的土壤理化性质及脲酶活性

为探明桉树林地土壤理化因子和土壤脲酶活性随林龄的动态变化规律,以及脲酶活性与土壤主要理化因子之间的深层关系,采用时空互代法和通径分析方法对海南儋州地区不同林龄桉树林土壤主要理化因子和脲酶活性进行了研究。结果表明:随林龄的增加,桉树林下土壤理化因子及脲酶活性大致呈现递减趋势且存在显著差异,其中2年生林地脲酶活性最高为0.901 mg/g,4年生和6年生林地土壤脲酶活性分别为0.533 mg/g和0.499 mg/g。通过进一步的相关分析和通径分析发现,土壤各因子对脲酶活性影响(按绝对值大小)的大小顺序为:全磷(0.719)水溶性有机氮(0.519)全氮(0.508)土壤含水量(0.463)总有机碳(0.170)土壤容重(0.154)水溶性有机碳(0.143)。综合各因子的直接作用和间接作用得出,土壤全氮以及水溶性有机氮(WSON)是制约脲酶活性的直接相关因子,而水溶性有机碳(WSOC)通过强烈的间接效应也对脲酶活性产生重要影响。     

Effects of trees planted on levees on rice yields in rain-fed paddy fields of northeast Thailand

Trees are increasingly being planted on the levees of paddy fields of rice (Oryza sativa L.) in northeast Thailand. We investigated and compared the yields of rice grown in rain-fed paddies under and far from canopies of three different tree species: eucalyptus (Eucalyptus spp.), mango (Mangifera indica L.), and the indigenous neem tree (Azadirachta indica A. Juss). Rice yields tended to decrease near trees of all types at five sites, but there was no change in yields at the remaining 11 sites during the 3-year study. The reduced yields likely resulted from lower aboveground biomass, leading to fewer rice panicles and spikelets, particularly near trees with a dense canopy. Extremely low yields were observed near eucalyptus in paddy fields suffering from severe drought. These results, as well as information provided by farmers’, suggest that eucalyptus trees may have detrimental effects on rice and should not be planted on the levees of paddy fields with relatively low productivity.     

Lignin modification improves the biofuel production potential in transgenic Populus tomentosa

Lignin has been recognized for its negative impact on forage digestibility, tree pulping properties, and cellulosic biofuel production, although it is the major structural component of the secondarily thickened cell walls of vascular plants. Earlier studies have demonstrated that lignin modification improves forage digestibility and poplar pulping properties. To determine whether lignin modification has beneficial effect on saccharification of lignocellulosic biomass, we pretreated and then enzymatically hydrolyzed the mature wood from transgenic poplar plants that expressed the antisense transgenes of monolignol biosynthesis genes 4-coumarate: CoA ligase (4CL) or caffeoyl CoA 3-O-methyltransferase (CCoAOMT). Firstly, a long-term field trial was set up for the transgenic plants. Over five years, the reduced trend of lignin content remained stable in all transgenic lines. And a total lignin reduction of up to 10% did not alter the growth rate or biomass yield of the transgenic poplars. In the mature wood, suppression of CCoAOMT increased saccharification potential, but 4CL down-regulation had no significantly positive effect on saccharification. Sugar yield were negatively correlated with soluble lignin content of dried, extractive-free stem biomass. These results imply that lignin modification can facilitate the process of saccharification for biofuel production in tree crops.     

Toxicity of cultured bullseye puffer fish Sphoeroides annulatus

The toxin content in various life cycle stages of tank-cultivated bullseye puffer (Sphoeroides annulatus) were analyzed by mouse bioassay and ESI-MS spectrometry analysis. The presence of toxin content was determined in extracts of sperm, eggs, embryo, larvae, post-larvae, juvenile, pre-adult, and adult fish, as well as in food items used during the cultivation of the species. Our findings show that only the muscle of juveniles, the viscera of pre-adults, and muscle, liver, and gonad of adult specimens were slightly toxic (<1 mouse unit). Thus, cultivated S. annulatus, as occurs with other cultivated puffer fish species, does not represent a food safety risk to consumers. This is the first report of toxin analysis covering the complete life stages of a puffer fish under controlled conditions.