髯毛樟叶和樟叶精油化学成分的研究

用毛细管气相色谱法和色谱—质谱—计算机联用技术对四川省的髯毛樟叶和樟叶的精油化学成分进行了研究.从髯毛樟叶精油中鉴定出45个成分,其主要成分是1.8—桉叶油素36.28%、香叶醛12.16%、橙花醛0.06%、香桧烯10.79%等,从樟叶精油中鉴定出49个成分,其主要成分是樟脑37.36%、β—橙花叔醇22.28%等.前者为第一次研究,后者可能是樟树的一个新的生化类型.这一研究为植物分类和资源利用提供了依据.     

4种樟属植物鲜叶精油成分分析

采用水蒸气蒸馏法对樟属(Cinnamomum)的樟(C.camphora)、阳春樟(C.purpureum)、肉桂(C.cassia)和阴香(C.burmannii)4种植物鲜叶的精油进行提取,并采用色谱/质谱/计算机联用技术(GC-MS-DS)对精油样品进行分离和鉴定。共鉴定出111种成分:樟鉴定出44种成分,其主要成分是吉马酮(27.95%)、橙花叔醇(18.94%)和芳樟醇(16.36%),特有成分有26种,占其精油成分的42.54%;阳春樟鉴定出40种成分,其主要成分是芳樟醇(33.76%)和苯甲酸苄酯(24.54%),特有成分有21种,占其精油成分的31.19%;肉桂鉴定出30种成分,其主要成分是肉桂醛(62.72%)和香豆素(12.50%),特有成分有15种,占其精油成分的71.50%;阴香鉴定出38种成分,其主要成分是龙脑(40.90%)和1,8-桉叶油素(10.42%),特有成分有17种,占其精油成分的19.86%。4种樟属植物精油中均出现的成分是芳樟醇、橙花叔醇、龙脑和反式石竹烯,表明4种樟属植物精油相同成分较少,种间精油成分差异较大,各植物特有精油成分突出。因此,可根据植物特有精油来鉴别这4种植物,也可为化工产业选择植物和植物器官提取精油提供参考。     

江西吉安右旋芳樟醇型黄樟鲜枝叶油的质量标准研究

用水蒸汽蒸馏提取d-芳樟醇型黄樟鲜枝叶油。用芳樟油对其进行主成分对照,并采用气相色谱测定不同立地条件的精油主成分,提出右旋芳樟醇型黄樟鲜枝叶油的质量标准建议,黄樟鲜枝叶油芳樟醇含量大于90%,樟脑含量小于1.5%。     

细毛樟实生苗同工酶的初步研究

细毛樟(Cinnamomum tenuipilum Kostern)系樟科樟属植物,根据精油主成分的不同将细毛樟分为不同的化学型,如细毛香樟(香叶醇geraniol为精油主成分)、细毛芳樟(芳樟醇linanol为精油主成分)等。在引种驯化的过程中发现细毛樟种子苗精油主成分变化相当大,一般解释为遗传分离的结果。本文以细毛香樟和细毛芳樟的种子苗为材料,研究樟叶在生化实验中的一些内源干扰问题,探讨子代精油变异与同工酶的关系,为系统地研究细毛樟精油的生物合成控制打下基础。     

不同月份柠檬醛型樟树叶精油变化规律及最佳采叶时间

为了开发柠檬醛型樟树(Cinnamomum camphora)资源,以柠檬醛型樟树叶为研究对象,采用水蒸气蒸馏法提取叶精油,并采用毛细管气相色谱法(GC)和气相色谱-质谱联用技术(GC-MS)对其得油率和精油主成分含量的变化规律进行分析。结果表明,叶得油率在1-5月上升较明显,5-7月平稳上升,7月达到最高值,从单株精油得油率考虑,7月为最佳采收时间。主成分橙花醛和香叶醛的总含量在7月达到峰值,其次是5月。通过对叶得油率和精油主成分含量变化规律进行分析,得出柠檬醛型樟树叶的最佳采收时间为7月,其次为5月。     

黄樟油素新资源—香楠的精油成分研究

香楠(Cinnamomum rigidissimum)是我国特有植物,其伐根材富含精油,出油率高达1.44％,含黄樟素61.72％,丁香酚甲醚28.62％。香楠资源在广东海南岛尖峰岭地区比较集中,为当地主要用材树种之一。据调查,利用现有伐根蒸油,可产50—60吨根油。为配合综合利用,本研究对叶精油也进行了成分分析,其中松油醇—4含量较多。     

高含量邻伞花烃樟树精油成分分析

以广西樟科樟属樟树为研究对象,采用水蒸气蒸馏法从樟树枝、叶中提取精油,测定其含油率,并利用气相色谱仪和气-质联用仪对精油进行分析。结果表明,樟树枝、叶的平均得油率分别为0.28%,0.67%;从枝、叶精油中共鉴定出相对质量分数≥0.27%组分39种;枝、叶精油共有组分19种,含量较高的组分有α-蒎烯、月桂烯、α-水芹烯、邻伞花烃、芳樟醇、龙脑、4-松油醇、α-松油醇、橙花叔醇、石竹烯氧化物、葎草烯氧化物等;枝和叶精油中相对质量分数高于2%的成分分别有11种和9种,占精油总量的78.35%和83.45%,其中枝、叶精油相对质量分数最高的前3种分别为1,8-桉叶油素、邻伞花烃、α-松油醇和邻伞花烃、β-花柏烯、香芹酚,相对质量分数分别为24.69%,19.94%,7.68%和41.97%,11.40%,7.23%;枝精油的主导成分为1,8-桉叶油素,相对质量分数为24.69%,叶精油的主导成分为邻伞花烃,相对质量分数高达41.97%。研究表明,该品种樟树叶精油中有含量较高的邻伞花烃,对精油成分进行分析,可为樟树的开发利用和培育提供参考。     

无性繁殖方式对芳樟叶精油及主成分的影响

在福建省南平市郊林场,分别以组培苗、扦插苗造林的6年生的优良芳樟无性系(187、PC1、PC2和变异2)为研究对象,测定不同优良无性系叶精油及其芳香醇和樟脑含量,分析不同繁殖方式的芳樟叶精油含量、主成分及无性系在栽培过程中的差异性及遗传稳定性。结果表明:不同的繁殖方式对子代芳樟无性系的叶精油含油量及主成分有不同的影响,其中扦插子代樟脑含量变化不明显,组培子代芳樟无性系的樟脑含量比母本的樟脑含量降低了-12.50%~24.52%,但子代芳樟无性系在栽植过程叶精油含油量及主成分都能够较好保持稳定性,无性系187扦插苗造林更有利提高芳樟叶精油的品质。     

不同化学类型樟树叶挥发油成分的GC-MS分析

为明确不同化学类型樟树叶挥发油化学成分组成特点,采用同时蒸馏萃取法提取5种不同化学类型樟树叶挥发油,运用GC-MS法对其化学成分进行分析,并比较了不同化学类型樟树叶挥发油含量和组成的差异。结果表明:芳樟叶挥发油共鉴定出54种成分,占挥发油总量的96.41%,其主要化学成分为芳樟醇、樟脑、石竹烯、桉叶油醇等;异樟叶挥发油共鉴定出53种成分,占挥发油总量的94.99%,主要为异橙花叔醇、芳樟醇、桉叶油醇、樟脑等;油樟叶挥发油共鉴定出53种成分,占挥发油总量的96.67%,主要为桉叶油醇、芳樟醇、松油醇、樟脑等;脑樟叶挥发油共鉴定出57种成分,占挥发油总量的95.73%,主要为樟脑、芳樟醇、石竹烯、桉叶油醇等;龙脑樟叶挥发油共鉴定出48种成分,占挥发油总量的95.61%,主要为龙脑、芳樟醇、左旋乙酸冰片酯、樟脑等。5种化学类型樟树叶挥发油化学成分在组成和含量上有所差异,鉴定出的共有成分有25种,主要为芳樟醇、桉叶油醇、松油醇、樟脑等,但是含量水平存在差异。     

樟树精油主要化学成分概述

芳樟醇、樟脑、1,8-桉叶油素、异橙花叔醇和龙脑是樟树精油的五大主要化学成分,具有良好的开发和利用价值。概述了上述组分的结构和理化性质、获取途径(提取纯化、化学合成)的研究现状,以及在香精香料、医药化工等不同领域的加工利用研究进展,目的在于为芳樟精油不同成分的点对点精准开发研究和利用提供前期资源储备。     

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.