乌饭树树叶中黄酮类物质的分离、纯化及结构鉴定

研究了乌饭树树叶中黄酮类化合物,利用色谱分离技术从中分离出4个黄酮类单体,利用高效液相色谱-质谱以及核磁共振技术进行分析鉴定,得出4个化合物,分别为白杨黄素( Ⅰ )、芹黄素( Ⅱ )、山奈酚(Ⅲ)和木犀草素(Ⅳ),这4种化合物均为首次从乌饭树树叶中提取分离得到.     

新疆圆柏黄酮类成分的研究

采用硅胶、Sephadex LH-20柱等色谱手段,对新疆圆柏叶的黄酮类成分进行了研究,从中分离鉴定了9个黄酮类化合物:柏木双黄酮(Ⅰ)、柏木双黄酮4',4'-二甲醚(Ⅱ)、穗花杉双黄酮(Ⅲ)、罗汉松双黄酮A(Ⅳ)、儿茶素(Ⅴ)、槲皮素(Ⅵ)、异高黄芩素7-O-β-D-木糖苷(Ⅶ)、杨梅素3-O-β-D-葡萄糖苷(Ⅷ)和芦丁(Ⅸ).其中化合物Ⅰ、Ⅱ、Ⅴ、Ⅶ、Ⅷ和Ⅸ为首次从该植物中分离得到,化合物Ⅷ和Ⅸ为首次从该属植物中分离得到.二苯代苦味肼基自由基(DPPH·)清除活性测试结果表明,化合物Ⅴ和Ⅵ的抗氧化活性较高,与阳性对照品抗坏血酸的接近;黄酮苷类化合物Ⅷ、Ⅷ和Ⅸ次之,而双黄酮类化合物Ⅰ、Ⅱ、Ⅲ和Ⅳ活性较差.     

楸树叶中抗氧化活性成分的分离和鉴定

前期研究发现,楸树叶粗提物的乙酸乙酯萃取相具有较强的抗氧化活性。为了进一步明确其抗氧化活性成分,以硅胶柱色谱结合清除 DPPH自由基法,寻找抗氧化能力较强的组分,并利用半制备液相色谱对该组分进行分离、纯化,以清除 DPPH自由基、还原力和清除 ABTS自由基能力作为考察指标,根据理化性质及光谱数据鉴定化合物。结果从楸树叶粗提物的乙酸乙酯萃取相中分离得到了2个化合物,分别为木犀草素(1)和芹菜素(2)。化合物1的抗氧化活性强于BHT和化合物2;化合物1清除DPPH自由基、还原力及清除ABTS自由基的IC50值分别为23.89,29.77和43.47μg mL -1;化合物1的抗氧化活性强于化合物2,主要因其在黄酮类化合物母核的 B环上具有邻二酚羟基结构。木犀草素和芹菜素2个化合物首次从楸树叶中分离得到。     

红花忍冬的黄酮类成分研究

对红花忍冬(Lonicera syringanthaM axim.)干燥地上部分进行化学成分研究。分离鉴定了5个黄酮类化合物:木犀草素(Ⅰ)、木犀草素-7-O-β-D-葡萄糖苷(Ⅱ)、香叶木素(Ⅲ)、香叶木素-7-O-β-D-葡萄糖苷(Ⅳ)和柏黄酮(Ⅴ)。经文献检索,这5个化合物均为首次从该种植物中分离得到,其中化合物Ⅲ、Ⅳ、Ⅴ系首次从该属植物中分得。     

青梅黄酮类化合物的微乳薄层色谱分离鉴定

研究了青梅黄酮类化合物的新微乳薄层色谱分离鉴定方法。以调酸后的十二烷基硫酸钠-正丁醇-正庚烷-水微乳液为展开剂,利用聚酰胺薄膜层析色谱法能使青梅黄酮类化合物完全分离。从青梅果皮中分离得到6个黄酮类化合物斑点,果肉中得到3个黄酮类化合物斑点,但二者的斑点显著不同。与用正丁醇-乙酸-水(4∶1∶5)为展开剂的常规层析方法相比,微乳薄膜层析法检测灵敏度更高,分离效果更好。     

金花忍冬地上部分化学成分研究(Ⅱ)

采用硅胶柱层析、凝胶柱层析等手段,对金花忍冬地上部分化学成分进行了分离纯化,并通过波谱解析和理化鉴定确定了它们的结构.共分离鉴定了7个化合物:其中3个黄酮类化合物:大波斯菊苷(Ⅰ)、五浅裂益母草素(Ⅱ)、槲皮素(Ⅲ);2个双黄酮类化合物:穗花杉双黄酮(Ⅳ)和喜柏双黄酮(Ⅴ);另外还分得绿原酸(Ⅵ)和胡萝卜苷(Ⅶ).7个化合物均为首次从该种植物中分离得到,其中化合物Ⅰ和Ⅱ系首次从该属植物中分得,并首次报道了化合物Ⅱ的1H NMR和13C NMR数据.     

高速逆流色谱分离制备杭白菊中黄酮类成分(英文)

建立高速逆流色谱分离纯化杭白菊总黄酮结晶中芹菜素-7-O-芸香糖、木犀草素-7-O-葡萄糖、芹菜素-7-O-葡萄糖以及金合欢素-7-O-葡萄糖4种黄酮类化合物。高速逆流分离过程分为两步,分别采用乙酸乙酯-乙醇-水-乙酸(体积比4∶1∶5∶0.2)和氯仿-甲醇-水(体积比4∶3∶2)两个体系。在第一步中,100 mg的总黄酮结晶分离得到了11.2 mg的芹菜素-7-O-芸香糖、15.3 mg的木犀草素-7-O-葡萄糖、28.2 mg的芹菜素-7-O-葡萄糖。然后收集到尾吹液,旋蒸至干得到35 mg的浸膏。在第二步中,当采用氯仿-甲醇-水(体积比4∶3∶2)体系时,从35 mg的浸膏中分离纯化得到14.5 mg的金合欢素-7-O-葡萄糖。4个化合物的纯度分别为99.4%、93.6%、99.1%和99.5%,电喷雾电离质谱和氢、碳核磁共振波谱鉴定化合物的结构。     

4种润楠属植物精油成分分析

采用水蒸气蒸馏法提取润楠属(Machilus)的短序润楠(M.breviflora)、浙江润楠(M.chekiangensis)、红楠(M.thunbergii)、凤凰润楠(M.phoenicis)4种植物的鲜叶精油;采用色谱-质谱联用技术(GC-MS)对精油样品进行分离和鉴定,共鉴定出108种挥发性化合物;用气相色谱面积归一法测定各组分的相对质量分数。结果表明,4种植物精油中均出现的成分是香橙烯、δ-杜松烯、蓝桉醇、α-古芸烯、a-葎草烯、芳樟醇、匙叶桉油烯醇、反式石竹烯,其中芳樟醇、匙叶桉油烯醇具有较高的药用价值。     

江西五梅山自然保护区虎皮楠群落研究

为了解江西五梅山自然保护区药用树种虎皮楠(Daphniphyllum oldhamii)群落的分布和生长情况,采用样方调查法,在虎皮楠自然集中分布的区域设置样方并开展全面调查,研究结果表明:(1)虎皮楠群落中共有维管束植物62种,隶属31科53属。植物区系组成以北温带分布和热带亚洲分布占比最高;(2)群落的垂直结构可分为乔木层、灌木层和草本层,乔木层较草本层和灌木层发达。群落根据Raunkiaer生活型谱划分,居于第一的是高位芽植物,占79. 03%;(3)群落中虎皮楠的重要值为17. 58,为该群落的优势种;多样性指数(H)灌木层最高,均匀度指数乔木层最高;物种丰富度灌木层最高;(4)年龄结构显示,江西五梅山自然保护区虎皮楠正处于年轻茂盛的阶段,种群比较稳定。     

沉香叶抗肿瘤活性化学成分研究

在抗肿瘤活性部位筛选的基础上,利用多种柱色谱方法对沉香属白木香叶中的化学成分进行了分离,通过理化常数和波谱分析鉴定其中所分得化合物的结构.从该植物中共分得10个化合物,结构分别鉴定为:洋芹素-7,4'-二甲醚(1)、木犀草素-7,3',4'-三甲醚(2)、木犀草素-7,4'-二甲醚(3)、芫花素(4)、木犀草素(5)、羟基芫花素(6)、2-O-α-L-鼠李糖-4,6,4'-三羟基二苯甲酮(7)、对羟基苯甲酸(8)、β-胡萝卜苷(9)、7α-羟基-β-谷甾醇(10).化合物7为新化合物,化合物1～6及8、10为首次从该植物中分到.     

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.     

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.     

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.     

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。