响应面优化超临界CO 2萃取大果紫檀挥发油的工艺研究

采用超临界CO2萃取大果紫檀,通过单因素试验考察萃取温度、萃取压力、萃取时间等因素对提取效果的影响;在此基础上,应用Box-Behnken中心组合进行三因素三水平响应面优化试验,并建立了影响因素和挥发油得率之间的回归方程;以气相色谱-质谱法(GC-MS)对大果紫檀挥发油化学成分进行了分离和鉴定。结果表明:超临界萃取大果紫檀挥发油适宜的工艺为萃取温度50℃,萃取压力25 MPa,萃取时间90 min,此条件下挥发油提取率为3.92%,与模型预测值接近。通过气质联用分析得出,挥发油共包含22种化学成分,主要有沉香螺醇、β-桉叶醇、7-(2-羟丙基)-1,4a-二甲基十氢萘-1-醇、桉油烯醇、3-(2,6,6-三甲基-1-环己烯-1-基)烯丙醇、1,3,3-三甲基-2-(2-甲基环丙基)-环己烯、高紫檀素、美迪紫檀素、紫檀素、3,9-二甲氧基-6H苯并呋喃[3,2-c][1]苯并吡喃等物质。     

多种名贵木材的荧光光谱特性研究

木材的荧光研究属于新兴领域，尚处于起步阶段。通过对木材荧光物质的研究以作为传统木材鉴别方法的补充具有潜力。将已知有荧光现象的紫檀属木材与未曾提及有荧光现象的黄檀属木材放在同一个试验框架与试验标准之中，以交趾黄檀、微凹黄檀、赛州黄檀、印度紫檀、大果紫檀5种常见红木木材为研究对象，通过采用不同极性的溶剂提取木材中的荧光物质，并对其进行分析，建立溶剂-荧光特征值数据库，并利用此方法区别不同的木材，特别是显微构造较为相近、传统显微切片方法不易鉴别的同属不同种木材。结果表明：交趾黄檀、印度紫檀、大果紫檀均可以利用不同溶剂提取出唯一且荧光强度较高的特征荧光物质，赛州黄檀可提取出荧光强度略低于前三种木材的特征荧光物质，而微凹黄檀并未得出可用于特征判定的溶剂-光谱组合。此外，印度紫檀的丙酮和乙醇提取溶液测的荧光参数十分相似，可能不同溶液提取了同一种特征荧光物质。     

厚朴水蒸气蒸馏和超临界CO2提取物化学成分的比较研究

采用水蒸气蒸馏和超临界CO2提取与气-质联用技术对厚朴药材中的化学成分进行了研究。结果表明超临界CO2提取的厚朴化学成分比用水蒸气蒸馏的化学成分少,而厚朴酚与和厚朴酚的相对含量却较高。超临界CO2提取的主要成分为新木脂素类化合物如厚朴酚与和厚朴酚;而水蒸气蒸馏的主要成分为倍半萜和氧化倍半萜类化合物如α-桉醇、十氢-α,,α4 a-三甲基-8-亚甲基-2-萘甲醇。水蒸气蒸馏和超临界CO2提取物中均含有咕吧烯、石竹烯、桉叶二烯、α-依兰油烯、1,2,3,5,6,8 a-六氢-4,7-二甲基-1-异丙基萘、1,2,3,4,4A,5,6,8 a-八氢-8-四甲基-2-羟甲基萘。除文献已报道的化合物外,一些化合物如桉叶二烯、1,2,3,5,6,8 a-六氢-4,7-二甲基-1-异丙基萘、α-白檀油烯醇、4-亚甲基-1-甲基-2-(2-甲基-1-丙烯)-1-乙烯基-环庚烷、4,5,6,6 a-四氢-2(1H)-并环戊二烯酮、十氢-α,,α4 a-三甲基-8-亚甲基-2-萘甲醇,β-人参烯和苍术醇也被鉴定出来。     

毛黄肉楠挥发性成分分析

采用水蒸气蒸馏法提取毛黄肉楠（Actinodaphne pilosa（Lour.）Merr.）挥发油。经气相色谱—质谱联用仪（GC/MS）分析,共鉴定出75种挥发性化合物,用气相色谱峰面积归一法测定各组分的相对质量分数。结果表明,其主要成分分别为喇叭茶烯（12.72%）、萘,1,2,3,4,4a,5,6,8a-八氢-7-甲基-4-亚甲基-1-（1-甲基乙基）-,（1a,4aa,8aa）-（12.33%）、大根香叶烯-D（11.58%）、trans-石竹烯（10.66%）和兰桉醇（5.89%）等。     

基于红外光谱的5种红木树种识别探讨

以大果紫檀、刺猬紫檀、微凹黄檀、交趾黄檀和柬埔寨黄檀5个树种的木材为试材,比较分析了抽提处理前后的木粉质量、红外光谱的变化,及其差谱中特征吸收峰所代表的化合物种类,探讨了基于红外光谱的木材树种识别的可行性.结果表明:经抽提试验后,木粉质量减少27.09％ ～40.23％;5个树种有显著不同的特征吸收峰,在烃类化合物红外光谱波段尤为明显;此外,还有脂类化合物、不饱和脂肪酸、酮类化合物、脂肪族和芳香族化合物等的变化.由此可见,基于红外光谱特征的木材树种识别是基本可行的.     

竹叶挥发油化学成分及其抗氧化特性

采用水蒸气蒸馏法从黄金间碧竹、孝顺竹、毛竹和麻竹4种竹叶中提取挥发油,用气相色谱-质谱联用技术对4种竹叶挥发油化学成分进行分析和鉴定,共获得168个色谱峰,鉴定其中132种化学成分,并运用气相色谱面积归一化法确定各组分的相对含量;以TBHQ为对照品,采用DPPH法研究4种竹叶挥发油对自由基的清除作用.结果表明:采用水蒸气蒸馏法黄金间碧竹竹叶挥发油的得率最高(0.827%),而毛竹竹叶挥发油的得率仅为0.391%.4种竹叶挥发油的化学成分在含量和组成上不同,竹叶挥发油主要化学成分是3-甲基-2-丁醇,麻竹竹叶挥发油含量最高达到46.25%;其他主要化学成分有4-乙烯基-2-甲氧基-苯酚、己-2-烯醛、橙花叔醇、植物醇、苯乙醛、天竺葵醛、植酮、二氢猕猴桃内酯和异植物醇.4种竹叶挥发油均有较强的抗氧化活性,竹叶挥发油的抗氧化活性与挥发油的浓度呈正相关(r=0.91),其中黄金间碧竹竹叶挥发油的抗氧化活性最强(IC50=2.705mg·mL-1),孝顺竹竹叶挥发油抗氧化活性较低(IC50=3.442mg·mL-1).综合研究结果表明,竹叶挥发油具有较高的应用价值,可作为食品和药品的功能性组分进一步开发和利用.     

超临界状态下松脂与甲醇反应产物的GC-MS分析

采用气相色谱-质谱联用技术(GC-MS)分别对在超临界状态下松脂与甲醇反应产物进行分析,共分离出49个峰,鉴定出45种化合物,反应产物主要为甲酯类、烯烃类化合物,还有较少量的芳香烃类、烷烃类和醇酮类等化合物.甲酯类的主要成分为脱氢枞酸甲酯、1,2,3,4,4a,9,10,10a-八氢-1,4a-二甲基-1-菲羧酸甲酯及...     

脱氢松香基偶氮化合物的合成及其紫外吸收性质

以脱氢松香酸甲酯为原料,通过对其苯环进行硝化、还原、重氮化及偶合等反应合成得到8个新的松香基偶氮化合物,分别为:(1R,4aS)-6-((E)-(4-(二甲基氨基)苯基)偶氮基)-7-异丙基-1,4a-二甲基-8-硝基-1,2,3,4,4a,9,10,10a-八氢菲-1-甲酸甲酯(2a)、(1R,4aS)-6-((E)-(5-氰基-2-羟基-1,4-二甲基-6-氧基-1,6-二氢吡啶-3-基)偶氮基)-7-异丙基-1,4a-二甲基-8-硝基-1,2,3,4,4a,9,10,10a-八氢菲-1-甲酸甲酯(2b)、(1R,4aS)-6-((E)-(5-氰基-1-乙基-2-羟基-4-甲基-6-氧基-1,6-二氢吡啶-3-基)偶氮基)-7-异丙基-1,4a-二甲基-8-硝基-1,2,3,4,4a,9,10,10a-八氢菲-1-甲酸甲酯(2c)、(1R,4aS)-7-((E)-(4-(二甲基氨基)苯基)偶氮基)-1,4a-二甲基-1,2,3,4,4a,9,10,10a-八氢菲-1-甲酸甲酯(3a)、(1R,4aS)-7-((E)-(2-羟基萘-1-基)偶氮基)-1,4a-二甲基-1,2,3,4,4a,9,10,10a-八氢菲-1-甲酸甲酯(3b)、(1R,4aS)-7-((E)-(4-(二甲基氨基)苯基)偶氮基)-1,4a-二甲基-9-氧基-1,2,3,4,4a,9,10,10a-八氢菲-1-甲酸甲酯(5a)、(1R,4aS)-7-((E)-(2-羟基萘-1-基)偶氮基)-1,4a-二甲基-9-氧基-1,2,3,4,4a,9,10,10a-八氢菲-1-甲酸甲酯(5b)和(1R,4aS)-6-溴-7-((E)-(2-羟基萘-1-基)偶氮基)-1,4a-二甲基-9-氧基-1,2,3,4,4a,9,10,10a-八氢菲-1-甲酸甲酯(5c),产率分别为57%、33%、30%、36%、39%、39%、40%和38%。产物结构经NMR、IR和元素分析进行表征。紫外测定结果显示在三氯甲烷溶液中它们的最大吸收波长分别为420、454、457、541、493、549、482和550 nm,与脱氢松香酸甲酯相比最大吸收波长分别红移了200、234、237、321、273、329、262和330 nm。     

红木家具木材种类和性质初探

根据国家标准,属于"红木"范围的树种为豆科的5属8类33种.5属是以树木学的属来命名的,即紫檀属、黄檀属、崖豆属、柿属、铁刀木属.8类是以木材商品名来命名的,即紫檀木类、花梨木类、香枝木类、黑酸枝类、红酸枝类、乌木类、条纹乌木类、鸡翅类.介绍了33个红木树种的名称、木材结构、气干密度、等级划分等.     

交趾黄檀和微凹黄檀木材构造特征及GC-MS的辨析

从构造特征和挥发性成分两方面对交趾黄檀和微凹黄檀进行了辨析,详细阐述了交趾黄檀和微凹黄檀的木材构造特征,总结了以下辨别要点:交趾黄檀黑色条纹规整,轴向薄壁组织主要为翼状和细带状;微凹黄檀黑色条纹不规整,轴向薄壁组织主要为星散-聚合状和细带状;交趾黄檀木射线为1~2列,单列较多;微凹黄檀木射线几乎单列,偶2列。用甲苯-乙醇对两种木材的粉末进行提取,GC-MS测试,结果表明:交趾黄檀和微凹黄檀的总离子流图存在一定差别,从交趾黄檀抽提液中鉴定出13种化合物,微凹黄檀中鉴定出12种化合物。微凹黄檀中的苯甲醛、肉桂醛、4-甲氧基-4-氟查耳酮挥发性成分的相对含量比交趾黄檀中的高,且前者的相对含量分别是0.803%,1.134%和0.155%;后者的相对含量分别是0.402%,0.071%和0.088%;交趾黄檀中米氏碱的相对含量比微凹黄檀中的高,前者是0.634%,后者是0.235%。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。