杉木根干馏油提取杉木精油及化学成分分析

本实验先通过水蒸气蒸馏后减压蒸馏法,从杉木根干馏油中分段提取出杉木精油,并用GC、GC-MS对提取物进行了定性定量分析.分离出30个色谱峰,共鉴定出25个化合物.其中,水蒸气蒸馏部分的精油中主要含α-蒎烯11.88%、α-松油醇3.97%、α-柏木烯35.03%、β-柏木烯8.62%、柏木脑11.76%;减压蒸馏部分的精油中主要含α-柏木烯18.02%、β-柏木烯15.04%、柏木脑52.51%,精油经重结晶提纯得柏木脑,并对其进行了红外光谱和核磁共振氢谱分析.     

杉木根精油得油率和柏木醇含量比较分析

为筛选得油率和柏木醇含量高的杉木(Cunninghamia lanceolata)种质,对25年生杉木不同部位和不同单株根精油进行提取,采用GC和GC-MS法对提取的精油进行定性和定量分析。结果表明,杉木不同部位根精油的得油率和柏木醇含量差异较大,精油几乎全部集中在心材部位,在以含油量为目标进行品种选育时,应采用心材得油率为主要参考指标;不同单株根精油的得油率和柏木醇含量差异也较大,根精油的绝干得油率和柏木醇含量最大可相差7.71和8.94倍,在资源丰富的杉木群体中筛选出含油率和柏木醇含量高的品系存在可能。     

陈山红心杉乙醇抽提物化学成分研究

采用GC-MS检测方法分别研究了20年生、30年生红心杉和普通杉木中边材及心材乙醇抽提物化学成分组成. 研究表明,醇提物中主要化学成分为:柏木脑和香紫苏醇. 醇提物中柏木脑百分含量范围:29.11%~52.54%,香紫苏醇百分含量范围:3.57%~24.77%. 红心杉和普通杉木心材中柏木脑含量均高于边材中柏木脑含量. 红心杉边材和心材中柏木脑含量均随着树龄的增加而增加,且柏木脑在木材中的横向分布,随树龄的增加呈同步增长趋势.红心杉和普通杉木,心材中香紫苏醇含量均高于边材中香紫苏醇含量.红心杉边材和心材中香紫苏醇含量均随树龄的增加而增加,且心材中香紫苏醇含量约为边材中含量5倍.     

桦木醇提取及纯化工艺的研究

以白桦树皮为原料,研究了桦木醇提取和纯化的工艺,确定了适宜的提取工艺条件:树皮原料30 g,树皮颗粒大小为0.42~1.16 mm,采用氯仿为溶剂,用索氏抽提器抽提7 h,得到粗桦木醇黄色固体,得率为38.5%。通过重结晶对桦木醇进行纯化,确定了适宜的重结晶条件:以异丙醇为重结晶用溶剂,粗提物与异丙醇的比为1∶20(g∶mL),结晶温度-5℃,结晶时间1 h,在此条件下桦木醇的结晶得率41.4%,产品熔点为245~254℃,纯度为95.4%。     

气相色谱内标法测定柏木醇含量

本实验选用茴脑为内标物,对杉木油及杉木油经减压精馏收集的高沸点馏分中柏木醇进行了定量分析。结果表明,柏木醇在5.036 6～40.292 8μg呈良好的线性关系,回归方程为:Y=0.949 4X+0.000 8,r=0.999 9。并用内标法与面积归一法分别对样品进行了定量分析。     

天然冰片的精制工艺优化研究

以湖南省新晃县天然冰片（龙脑）粗品为原料，研究其结晶方法的精制工艺。结果表明：以120^#汽油为溶剂结晶的产品晶型最好，得率及纯度都较高；最佳精制工艺条件为：结晶时间6d，结晶温度9℃，结晶固液配比为1：1。经气相色谱检测，结晶产品的纯度可达95％以上，得率可达90％以上。     

杉木屑干馏及干馏产物组成的研究

以杉木屑为原料,采用干馏法制备杉木油,分别得到干馏油、木醋液、焦油和木炭,产率分别为4.0%、38.0%、14.3%、28.8%,除此之外还得到不凝性可燃气,产率为15.0%。对杉木屑干馏油、木醋液和不凝性气体的性质、组成进行研究,结果发现:杉木屑的固液产品总转化率达到了80%以上;杉木干馏油的主要组成为α-柏木烯29.36%、β-柏木烯11.87%、柏木醇12.10%等;木醋液的主要成分为1-甲基亚乙基环己烷24.07%、乙酸19.77%、4-乙基愈创木酚11.71%、糠醛8.06%等;不凝性可燃气主要由H_2、CO和CH_4组成。     

墨西哥柏精油的提取及成分分析

以墨西哥柏的枝、叶为原料,研究水蒸气蒸馏法和溶剂法提取精油工艺,并采用GC-MS分析茎叶油与枝干油的化学成分,以及水蒸气蒸馏法与溶剂提取法所得精油成分的差异。研究表明,水蒸气蒸馏法较佳工艺条件为:茎叶原料粒度1.0 mm,提取时间4 h,渗透剂Na Cl 6%,料液比1∶6,在此条件下精油得率为1.17%;溶剂提取法以石油醚、乙醇为溶剂,提取所得浸膏得率(去除石油醚和乙醇溶剂后的得率)分别为16.06%和28.79%。成分分析结果表明,茎叶油中含有36种成分,其中单萜类物质12种;枝干油中含有24种成分,其中7种为单萜类物质;溶剂提取浸膏中有42种成分,含倍半萜类20种。此外,墨西哥柏木油中石竹烯、Α-毕橙茄醇、(+)-柠檬烯含量明显高于其他品种柏木油。     

杉木精油化学成分的GC—MS分析

采用GC—MS法对杉木精油进行了定性定量分析,共分离出68个色谱峰,鉴定出50种化合物,占精油总量的97.77%。该精油中含有28.99%柏木醇、21.83%α—柏木烯、9.52%β—柏木烯、3.49%α—松油醇、3.33%香叶烯、2.33%β—榄香烯、2.19%α—花柏烯、2.01%罗汉柏烯等。     

三聚氰胺包合法分离不饱和脂肪酸

采用三聚氰胺包合法从混合脂肪酸中分离不饱和脂肪酸(UFAs),探讨了三聚氰胺/脂肪酸质量比、晶化包合温度、包合时间对包合效果的影响,并采用傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)和核磁共振(NMR)对三聚氰胺包合物进行了表征。研究结果表明:饱和脂肪酸可以在低温下被三聚氰胺包合;当脂肪酸20 g,96 mL 95%乙醇溶液,三聚氰胺/脂肪酸(M/F)质量比为0.9∶1,在75℃条件下溶解,并在9℃下晶化包合7 h,脂肪酸得率60.83%、不饱和脂肪酸纯度为93.75%、包合率为87.23%。采用气相色谱(GC)分析发现:与尿素包合法相比,经三聚氰胺包合后分离获得的不饱和脂肪酸纯度、包合率均较高,且可将单不饱和与多不饱和脂肪酸同时分离。结构分析表明:与三聚氰胺晶体相比,饱和脂肪酸的三聚氰胺包合物晶体结构未发生改变,饱和脂肪酸能够进入三聚氰胺晶体片层之间形成稳定的结晶包合物,且三聚氰胺包合后可回收再利用,其分离不饱和脂肪酸的纯度仍可达86.28%。     

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.     

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.     

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。     

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.     

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.     

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.