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%。     

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.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.     

Growth of Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Boron in forest trees and forest ecosystems

This review critically examines the role of boron (B) in forests in view of recent findings on B nutrition and the continuing occurrence of B deficiency. Many perceptions about the role of B in plants and its uptake and mobility have been altered since the last review on B in forest trees in 1990. Now there is evidence for a fundamental role of B in the formation of the pectic structure in primary cell walls in plants, and further roles in membrane function are being explored. In plants, channel-mediated B uptake, active B uptake and B uptake by mycorrhizas have been shown, B transporters have been identified, and B retranslocation has been shown. We explore these findings and their consequences on forest trees and on ecosystems that they dominate. Particular emphasis is placed on B retranslocation and B in mycorrhizal symbiosis, given their importance in trees.     

Survival and Growth of Picea abies Regeneration after Shelterwood Removal with Single- and Double-grip Harvester Systems

Three stands in Sweden were followed for 7 yrs to study the survival and growth of Norway spruce [Picea abies (L.) Karst.] regeneration after shelterwood removal with single- and double-grip harvester systems. The height of all seedlings within circular plots was recorded before and after final cutting. The tallest seedling and one randomly selected seedling on each circular plot were permanently marked and their annual height growth was measured each year during the period 1993-1999. No significant differences between single- and double-grip harvester systems were found with respect to their effects on regeneration density, survival or annual height growth. The annual height growth of the individual seedlings after shelterwood removal was significantly correlated with seedling height before shelterwood removal. Significant differences were found in annual height growth between seedlings with high and low vitality. Logging damage did not affect the annual height growth. Several practical conclusions were drawn. First, the choice of harvester system does not affect seedling height growth or survival after shelterwood removal. Secondly, the removal of a 200 m³ shelterwood with 200 stems ha^-1 does not seem to constitute a serious problem for seedling survival and growth. Finally, estimated vitality and seedling height both seem to be fairly good predictors of postrelease survival and growth.     

Development of Pinus sylvestris Main Stems Following Three Different Precommercial Thinning Methods in a Mixed Stand

Reducing competition by point cleaning may be an attractive alternative to conventional precommercial thinning in forestry. In this study, survival and development of main stems of Scots pine (Pinus sylvestris L.) following point cleaning were examined in a mixed stand of mainly Scots pine and birch (Betula pendula Roth and Betula pubescens Ehrh.) in northern Sweden. Treatments studied were: no precommercial thinning, conventional precommercial thinning, point cleaning of all secondary stems, and point cleaning of only the secondary stems that were higher than the main stem, within a radius of 0.8 m from the main stem, respectively. A randomised complete block design with three replicates was used. Measurements taken 13 growing seasons after these treatments showed that conventional precommercial thinning was the best treatment for retaining Scots pines as main stems. However, conventional precommercial thinning resulted in the poorest timber quality of the remaining Scots pines in terms of stem taper, thickest branch diameter and relative live crown height. In conclusion, point cleaning has to be followed by a complementary cleaning operation if the objective is to retain Scots pines as main stems in such mixed stands.     

Tree planting for dryland salinity control in Australia

Dryland salinity is emerging as a major form of land and water degradation in southern Australia, particularly in Western Australia, South Australia and Victoria, and to a lesser extent in New South Wales, Tasmania and Queensland.Tree planting, in combination with other vegetation treatments, is regarded as a leading solution to dryland salinity. Research has now shown that planting trees can significantly lower groundwater tables, and thereby reverse the causal process of salinisation. Substantial progress has been made towards answering the basic questions of which species to grow, how to plant, where to plant, at what density and configuration to plant, and how much area to plant. The economic potential for commercial tree planting has given impetus to partial reforestation in higher rainfall (> 600 mm yr^–1) areas. Even so, serious constraints are apparent, relating primarily to cost, uncertainty and attitude. The future should bring increasing community input and control, technical refinement and gradual adoption, provided all aspects of the issue are well researched, relevant information is well communicated and programmes are well administered. Some specific requirements for future research are identified in this review.     

Effect of Cuttings on the Scenic Beauty of a Tree Stand

The opinions of 207 respondents on the visual effects of seven different cutting types were asked using a nine-point verbal scale ranging from ''worsens very much'' to ''improves very much''. Other estimates were obtained by letting the same respondents evaluate photographs of stands which had been treated with different cuttings. The direct questions gave results quite similar to the evaluations of photographs for all but young respondents, indicating that most respondents were able to imagine the effect of the treatment correctly. The results based on the evaluation of photographs indicated that the effect of regenerative cuttings is negative while the impact of thinnings is positive. After a few years of cutting the stand is already regarded as clearly more pleasant than immediately after the cutting. Natural regeneration with seed trees seems to be a way to avoid the very negative immediate impact of clear-felling, especially in the case of Scots pine. Women, young, urban people and those who do not own forest or have work related to forests tended to experience thinnings less positively and saw regenerative cuttings as more harmful than the other test groups did.     

Pinus contorta growth in northern Sweden as affected by soil scarification

The aim of this study was to quantify the effects of different soil scarification methods on tree growth. Soil scarification influenced stem volume and stem biomass yield of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) in a 17-year-old field trial in boreal Sweden. Soil scarification (disc trenching, mounding and ploughing) resulted in an average stem volume yield of 3.1 and 34.2 m³ ha^–1 on the poor and intermediate sites, respectively, while corresponding values for no soil scarification were 0.9 and 16.7 m³ ha^–1. In comparison to no scarification, ploughing increased volume yields by 500% on the poor site and by 200% on the intermediate sites. The ranking according to stem volume yield was ploughing > disc trenching = mounding no soil scarification. Averaged over the two sites, the mean annual increment of stem biomass was 219% and 145% higher (in d.w., 0.26 kg and 0.34 kg per sample tree) after ploughing compared with no soil scarification, for the average and dominant sample trees, respectively. Although not significant, the increased growth rate after soil scarification decreased the average stem basic wood density of the sample trees with 1.6% and 5.3%, at the poor and intermediate sites, respectively. In conclusion, soil scarification significantly increased the 17-year stem volume yield compared with no scarification. The results also indicate that the difference in stem biomass yield between ploughing and the other methods, especially no soil scarification, will increase even more in the near future.