果胶酶预处理辅助提取沉香精油研究

为提高沉香精油的提取得率并缩短提取时间,利用单因素法研究不同果胶酶预处理条件对沉香精油提取的影响。结果表明,当果胶酶预处理温度为60℃、质量分数为2%、预处理时间为5 h时,沉香精油的提取得率达21.33%,与未进行预处理的提取工艺相比,提取得率增加了11.05%,果胶酶预处理可提高沉香精油提取得率。利用气质联用色谱检测预处理后沉香精油的主要化学成分,结果表明果胶酶预处理辅助提取沉香精油提高了精油得率,同时保留了精油纯度,具有良好的应用前景。沉香精油提取后残渣的主要化学成分测定结果表明,综纤维素质量分数为73.26%、木质素质量分数为20.98%、灰分质量分数为0.23%。研究结果可为精油提取后残渣利用提供基础数据。     

烤烟烟叶与造纸法再造烟叶热裂解产物的对比分析

为了更好的评价天然烤烟烟叶与造纸法再造烟叶在卷烟中的作用,对比研究了烤烟烟叶和造纸法再造烟叶的化学组成以及它们在不同温度下的热裂解产物.利用改进后的热裂解装置模拟了卷烟的燃烧行为,研究了烤烟烟叶和造纸法再造烟叶在大气环境中于300、600和900℃下的热裂解行为,并采用气相色谱 - 质谱联用仪对热裂解产物进行分析.结果表明,烤烟烟叶和造纸法再造烟叶的热裂解产物种类随着热裂解温度的增加而增多;在相同热裂解温度条件下,造纸法再造烟叶与烤烟烟叶的热裂解产物种类也存在差异.     

不同产地沉香的高效液相色谱指纹特征

【目的】针对不同地区所产沉香品质差别较大以及传统沉香产地鉴别主要依赖经验判断等问题,研究不同产地沉香的高效液相色谱(HPLC)指纹特征,探讨色谱指纹分析技术对沉香产地溯源的可行性,为沉香资源品质评价和原产地保护提供科学依据。【方法】以36批次来自3个不同产地的沉香为研究对象,优化高效液相色谱分离条件,基于"中药色谱指纹图谱相似度评价系统"获得色谱峰保留时间、峰面积信息,筛选不同产地沉香的高效液相色谱指纹图谱,并利用指纹特征峰变量进行主成分分析(PCA)和正交偏最小二乘判别分析(OPLS-DA),建立沉香产地判别方法。【结果】不同产地沉香高效液相色谱指纹图谱的85个特征峰变量分析发现,莞香系沉香的色酮种类最多,相对含量最高;星洲系沉香的沉香四醇色谱峰极高,其余色酮相对含量较低;惠安系沉香的色酮种类较多,相对含量较莞香系稍低,较星洲系稍高,依其产地地理位置分布,在3个产地中体现出一定过渡性;主成分分析显示,样品基本上可依据产地不同聚合成3类;正交偏最小二乘判别分析对训练集和检验集样品产地的判别正确率均为100%。【结论】不同产地沉香2-(2-苯乙基)色酮类成分的组成和含量存在较大差异,显示出一定地域性,利用高效液相色谱指纹图谱结合正交偏最小二乘判别分析可判别沉香产地,为濒危珍贵沉香的产地溯源提供一种新的鉴别方法。     

2种白木香所产沉香的木材组织构造和化学成分比较

【目的】比较新品种“热科沉香‘1号’”和普通白木香经打钉法结香2年后所产沉香的组织构造和化学成分,为筛选出优良的白木香种质或优树提供参考。【方法】采用木材解剖学方法观测木材三切面,从宏观和微观角度观察2种沉香的木材组织构造;利用气相色谱-质谱联用(GC-MS)方法检测2种沉香的化学成分,并进行对比分析。【结果】1)“热科沉香‘1号’”对创伤的修复能力较弱,结香颜色呈黄褐色,结香体积更大且容易结香,沉香物质主要积累在导管和轴向薄壁组织中;普通白木香对创伤的修复能力较强,结香颜色呈棕褐色,结香体积较小且速度较慢,沉香物质主要积累在内涵韧皮部和木射线薄壁组织中。2) GC-MS分析结果表明,2种白木香所产沉香倍半萜和色酮类成分的总相对百分含量分别为75.88%和70.41%,但“热科沉香‘1号’”所产沉香以色酮类成分为主,普通白木香所产沉香倍半萜和色酮类成分含量相当。3)“奇楠”沉香的标志性成分2-(2-苯乙基)色酮与2-[2-(4-甲氧基)苯乙基]色酮之和在“热科沉香‘1号’”所结沉香中的含量为25.19%,而在普通白木香所结沉香中的含量为5.97%,前者约为后者的4.22倍。【结论】“热科沉香‘1号’”所产沉香的质量更优,是一种易产香、产量高、质量优的种质,值得进一步培育和评价。     

4批次沉香品质鉴定

采用二氯甲烷浸泡提取沉香成分,利用气相色谱质谱联用法对化学成分进行分离鉴定。共鉴定出32种化合物,其中9种2-(2-苯乙基)色酮类化合物,色酮含量0.46%～18.21%,并通过中药色谱指纹图谱相似度评价系统进行沉香品质鉴定,2#、3#沉香品质最优,1#最次,这和GC/MS成分分析沉香色酮含量相一致。采用二氯甲烷浸泡法富集沉香香气成分,所需样品量少,前处理方便,为沉香品质鉴定提供一定参考。     

气相色谱-质谱与高效液相色谱分析不同品质沉香化学成分

通过分析不同品级星洲系沉香样本的醇提取物含量、密度、气相色谱-质谱(Gas Chromatography-Mass Spectrometer,GC-MS)和高效液相色谱(High Performance Liquid Chromatography,HPLC)数据,结合主成分分析法、线性判别模型和随机森林等多变量分析方法,筛选与沉香品质密切相关的因素,建立沉香分级模型。结果表明,不同品质星洲系沉香的醇提取物含量、色酮类含量、倍半萜种类及含量的差异较大;以醇提取物含量、倍半萜类总含量、2-(2-苯乙基)色酮含量等5个因素为指标,可为沉香品质分级体系提供依据。     

10批次伪品沉香鉴别方法的相关性

【目的】针对目前沉香市场真假混杂、难以鉴别的现状,采用多种方法对10批次伪品沉香进行鉴别,分析各方法之间的相关性及可替代性,探究沉香真伪鉴别的有效手段,为沉香产业的健康发展提供帮助,为识别伪制沉香、完善沉香的质量标准提供依据。【方法】采用《药典》(2015版)中规定的醇溶性浸出物含量、显色反应、薄层色谱分析以及具有专属性分辨2-(2-苯乙基)色酮类成分的高效液相色谱(HPLC)分析沉香鉴别方法,对10批次伪品沉香进行鉴别,并通过对比8批次正品人工沉香样品和对照样品,探索各方法的准确性以及相关性。【结果】在10批次伪品沉香样品中,其醇溶性浸出物含量均达到要求;显色反应对颜色的判断具有强烈的主观性;薄层色谱分析鉴别具有专属性,但受沉香成分多样性、含量不一等因素影响,部分样品判别荧光斑点不清晰;HPLC方法制样简单,节省原料,可有效避免人为主观因素影响,能够对复杂沉香成分进行分离,通过对照指纹图谱6个特征峰和4个辅助峰,判断结果精确度高。【结论】各方法之间相辅相成,互相佐证,考虑到沉香样品检测过程需降低时间和原料成本,基于各方法的优势及精准程度,建议在沉香真伪鉴别中采用以醇溶性浸出物含量、HPLC指纹图谱结合显微鉴别为主,显色反应和薄层色谱分析为辅的方法。     

气相色谱-质谱与高效液相色谱分析不同品质 沉香化学成分

通过分析不同品级星洲系沉香样本的醇提取物含量、密度、气相色谱-质谱（Gas Chromatography-Mass Spectrometer, GC-MS） 和高效液相色谱（High Performance Liquid Chromatography, HPLC）数据,结合主成分分析法、线性判别模型和随机森林等多变量分析方法,筛选与沉香品质密切相关的因素,建立沉香分级模型。结果表明,不同品质星洲系沉香的醇提取物含量、色酮类含量、倍半萜种类及含量的差异较大;以醇提取物含量、倍半萜类总含量、2-(2-苯乙基)色酮含量等5个因素为指标,可为沉香品质分级体系提供依据。     

不同郁闭度橡胶林对套种土沉香幼树生长特性的影响

为探究并筛选出较适宜土沉香套种的橡胶林分,在3种不同郁闭度(0～0.1,0.2～0.3,0.7～0.8)橡胶林进行土沉香幼树套种种植。测定土沉香幼树在试验地林下形态指标、总生物量干质量、生理生化指标,采用主成分分析土沉香幼树各指标对不同郁闭度橡胶林的响应信息,通过比较筛选出适宜土沉香幼树生长的橡胶林。结果显示：1)郁闭度为0.2～0.3的橡胶林,土沉香幼树形态指标增长量最高,总生物量干质量最大,叶绿素总量、可溶性蛋白含量、过氧化氢酶活性显著高于其他2种郁闭度的橡胶林;丙二醛含量较低,可溶性糖含量、超氧化物歧化酶活性与另2种郁闭度的橡胶林无显著差异。2)郁闭度为0.7～0.8的橡胶林,土沉香幼树生长最差,总生物量干质量最低。3)郁闭度为0～0.1的橡胶林,土沉香幼树生长适中。4)主成分分析表明,套种于橡胶林郁闭度为0.2～0.3的土沉香幼树各指标综合得分最高,其3 a生橡胶林较适宜土沉香幼树混交套种种植。     

活性炭对卷烟烟气中汞和铅的吸附

为探究活性炭孔隙结构及表面化学性质对卷烟主流烟气中重金属元素汞和铅吸附作用的影响,分别以H_3PO_4及H_3PO_4复合KH_2PO_4活化法制备的两种杏壳活性炭作为卷烟滤嘴的吸附剂材料,研究了活性炭不同的孔隙结构及表面含氧官能团含量在吸附中的作用。结果表明:活性炭的孔隙结构是影响重金属元素吸附性能的重要因素之一,活性炭中孔径范围在0.852~1.096 nm的孔隙有利于卷烟主流烟气中重金属元素汞的吸附,孔径范围在1.245~1.534 nm的孔隙有利于卷烟主流烟气中重金属元素铅的吸附;比表面积与汞、铅元素的吸附无明显相关性;提高活性炭表面含氧酸性官能团含量有利于卷烟烟气中汞和铅的吸附;汞和铅在活性炭表面的吸附位一致,存在竞争吸附现象。     

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.     

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.