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.     

微波消解-ICP-OES法测定麻竹中12种矿质元素含量的实验

利用微波消解对麻竹叶进行前期处理,采用电感耦合等离子体发射光谱(ICP-OES)法测定竹叶中的12种元素含量。结果表明,该测定方法快速、准确、分析精度高;麻竹叶中所含的12种元素从高到低的排序为K、Ca、Mg、P、Mn、Al、Si、Na、Fe、Zn、Cr和Cu,其中,富含人体必需的Fe、Ca、Si等常量元素和Mn、Cu等微量元素,且K、Ca、Mg、P等元素的含量较高。本项实验建立了微波消解-ICP-OES法测定麻竹竹叶中的矿质元素的检测方法,麻竹叶中微量元素含量丰富。     

簕竹属竹叶中黄酮类成分分析及其抗氧化活性

为探索簕竹属主要竹种竹叶提取物中黄酮类成分的开发利用,以簕竹属10个竹种的竹叶为原料,提取、分离和纯化后得到竹叶提取物,建立了测定竹叶提取物中5种黄酮类成分的HPLC方法,采用DPPH法和ABTS法对竹叶提取物的抗氧化活性进行评价。竹叶中5种黄酮类成分异荭草苷、荭草苷、牡荆苷、异牡荆苷和木犀草苷的HPLC方法为：采用YMC-Pack ODS-A色谱柱(250 mm×4.6 mm, 5μm),以0.5%乙酸/水溶液(A)和乙腈(B)为流动相,14%B等梯度洗脱40 min,进样量10μL,流速1 mL/min,柱温30℃,检测波长340 nm。此条件下,5种黄酮类成分在40 min内实现完全分离,分离度均大于1.2,其质量浓度与峰面积具有良好的线性相关性,相关系数R²>0.999,加标回收率在94.36%～105.37%之间,相对标准偏差(RSD)在0.98%～3.48%之间,表明该方法稳定可靠。测得的10种簕竹属竹叶提取物中5种黄酮类成分的总量为62.30～223.24 mg/g,其中凤尾竹竹叶提取物中的质量分数最高,为223.24 mg/g。10种簕竹属竹...     

梁山慈竹茎秆的化学成分

【目的】探明梁山慈竹茎秆的化学成分,为丛生竹资源综合利用提供依据。【方法】采用国标方法,分析茎秆中一般性化学组成;采用微波消解-ICP/MS技术,同时测定茎秆中18种无机元素;经95%乙醇提取后所得茎秆浸膏,依次用蒸馏水、30%乙醇、60%乙醇和80%乙醇和丙酮等不同馏分梯度洗脱,采用硅胶柱色谱、Sephadex LH-20柱色谱、高压制备色谱等手段分离得到单体化合物,结合理化性质、波谱学以及文献数据对比,对化合物进行结构鉴定。【结果】梁山慈竹茎秆中灰分含量为1.24%,苯醇抽出物含量为3.27%,冷、热水抽提物含量分别为9.16%和11.58%;1%Na OH抽出物含量为30.71%,多戊糖含量为19.44%,木质素含量为22.18%,综纤维素含量为72.70%。各无机元素含量依次为Ca(587.13 mg·kg~(-1))、Mg(448.75 mg·kg~(-1))、Al(76.51 mg·kg~(-1))、Fe(66.38 mg·kg~(-1))、Na(51.40 mg·kg~(-1))、Zn(16.47 mg·kg~(-1))、Mn(15.52 mg·kg~(-1))、Cr(5.26 mg·kg~(-1))、Ni(3.54mg·kg~(-1))、Mo(3.03 mg·kg~(-1))、Cu(2.48 mg·kg~(-1))、Pb(2.46 mg·kg~(-1))、Cd(0.39 mg·kg~(-1))、Se(0.35 mg·kg~(-1))、Ag(0.26 mg·kg~(-1))、As(0.23 mg·kg~(-1))、Co(0.09 mg·kg~(-1))、Hg(0.07 mg·kg~(-1))。分离鉴定出10种化合物,分别为异荭草苷、对羟基苯甲醛、苜蓿素、苜蓿素-7-O-葡萄糖苷、阿魏酸、对香豆酸、对羟基苯甲酸、异牡荆苷、2,6-二甲氧基-1,4-对苯醌、β-谷甾醇。经检索,上述化合物均为首次从该植物中分离得到,阿魏酸和2,6-二甲氧基-1,4-对苯醌为首次从牡竹属植物中发现。【结论】梁山慈竹茎秆的纤维原料特征多介于针叶木和阔叶木之间,是较理想的造纸原料。茎秆中Ca,Mg,Al,Fe,Na,Zn,Mn,Cr元素的含量丰富,其他元素含量在0.07~3.54 mg·kg~(-1)之间,大部分元素含量水平远低于竹叶中各元素含量。茎秆中次生代谢成分种类和数量都较竹叶中少,包含了黄酮类和酚酸类等具有化感作用成分,可针对性地开展相关研究。     

牡竹属10种竹叶矿质元素含量分析

为了明确牡竹属竹叶中矿质元素的组成,采用ICP-MS法测定了牡竹属10种竹叶中主要矿质元素的含量。结果表明,10种竹叶中含有丰富的矿质元素,其中K、Ca、Mg含量较高,其次是Mn、Fe、Al、Na、Zn元素,Cr、Ni、Cu元素在竹叶中的含量较少,Co、As、Se、Mo、Hg和Pb含量很低。研究结果为牡竹属竹叶的开发利用提供了科学依据。     

苦竹各器官主要营养元素分布及采伐的养分输出

本文根据四川长宁苦竹(Pleioblastus amarus)各器官生物量以及其主要营养元素含量和储量,研究了苦竹采伐的养分输出问题。结果表明:苦竹各器官中N、P、K、Si、Ca、Mg等6种营养元素以代谢旺盛的竹叶和竹鞭中含量最高;6种养分元素在各器官贮存量(单位:kg.hm-2)从大至小的排序为:叶(510.8)>竹根(230.62)>杆(182.14)>枝(163.77>竹鞭(59.19)>竹蔸(41.16)。苦竹采伐的养分年输出量(单位:kg.hm-2)从大至小的排序为:Si(50.23)>K(38.77)>N(35.58)>Mg(4.55)>P(3.86)>Ca(3.31)。对比该地区的降雨输入,苦竹林地养分以Si失衡最为严重;其次为K、N。若采伐时将竹叶带出竹林,6种元素的养分输出总量将增加1.48倍。可见,竹叶归还林地对维持地力具有极其重要的作用。     

不同品种油橄榄叶茶微量元素检测与分析

采用火焰/石墨炉原子吸收光谱仪测定27个油橄榄叶茶试样中锌、铁、铜、钼、钙、镁、钾等矿物质元素。结果检测到油橄榄叶茶产品中的Zn元素含量范围为14.54-27.04mg/kg,平均值为20.61mg/kg,变异系数(CV)为16.84%,含量差异不大;油橄榄叶茶产品中的Fe元素含量范围为5.69-76.29mg/kg,平均值为36.34mg/kg,变异系数(CV)为59.71%,含量差异极显著;油橄榄叶茶产品中的Cu含量范围为2.85-10.27mg/kg,平均值为7.82mg/kg,变异系数(CV)为24.21%,含量差异显著;油橄榄叶茶产品中的Mn含量范围为7.49-78.88mg/kg,平均值为31.35mg/kg,变异系数(CV)为48.62%,含量差异极显著;油橄榄叶茶产品中的Ca含量范围为1.09%-3.43%,平均值为1.98%,变异系数(CV)为30.0%,含量差异显著;油橄榄叶茶产品中的Mg含量范围为0.02%-0.275%,平均值为7.82%,变异系数(CV)为61.56%,含量差异极显著;油橄榄叶茶产品中的K含量范围为0.74%-1.64%,平均值为0.96%,变异系数(CV)为25.98%,含量差异显著。本研究的开展可为云南油橄榄高值化产品的开发提供一定的理论基础。     

低共熔溶剂-球磨法提取竹叶黄酮碳苷工艺优化

以低共熔溶剂为提取溶剂，用球磨法从毛竹叶中提取黄酮碳苷类化合物，采用高效液相色谱-飞行时间质谱(LC-Q-TOF-MS)测定竹叶中4种黄酮碳苷(异荭草苷、荭草苷、异牡荆苷和牡荆苷)的含量，通过单因素试验和正交试验，对低共熔溶剂的含水量、提取时间、液料比等因素进行考察。结果表明，从竹叶中提取黄酮碳苷的最佳工艺为：低共熔溶剂(氯化胆碱和乙二醇构成)含水量50%、提取时间150 s、液料比6∶1(mL∶g)。在该条件下，从竹叶中提取4种黄酮碳苷的总提取得率为1.55 mg/g,其中，异荭草苷0.99 mg/g、荭草苷0.23 mg/g、牡荆苷0.04 mg/g、异牡荆苷0.29 mg/g。该方法提取得率比浸渍提取法提高了7.6%,且节约了时间和有机溶剂。利用该优化工艺，结合LC-Q-TOF-MS检测，成功应用于以毛竹叶为原料制成竹茶样品的黄酮碳苷提取与测定。     

不同品种竹叶多糖的化学特征及其含量研究

通过对17个品种竹叶多糖酸水解、衍生化和气相色谱分析,研究其单糖的物化特征;以硫酸 - 蒽酮法,研究不同品种竹叶多糖的含量差异.结果表明:不同品种竹叶多糖主要由阿拉伯糖、木糖、葡萄糖、半乳糖组成,其中木糖占43.9% ～ 65.5%,阿拉伯糖占11.7% ~ 19.6%,葡萄糖占7.2% ～ 20.8%,半乳糖占7.7% ～ 14.1%;不同单糖间的比例存在明显差异,部分品种竹叶含5.0% ～ 6.9%未知单糖.不同品种竹叶多糖质量分数在1.9% ～ 5.7%之间,其中鹅毛竹含糖量最高(5.7%),长叶苦竹含糖量最低(1.9%).本研究从17个品种竹叶中筛选出多糖含量在4%以上的有鹅毛竹、矮箬竹、巴山木竹下部、铺地竹、毛竹、百夹竹、唐竹和金丝慈竹下部,淡竹来源广泛,可成为提取竹叶多糖的最佳原料.     

GC-O与GC-MS联用法鉴定香竹竹叶中关键气味活性物质

实验运用SDE方法对香竹竹叶中挥发性物质进行提取,利用GC-O与GC-MS联用的法方对其中气味活性物质进行定性分析,共鉴定出29种气味活性物质.研究发现,对香竹竹叶的特征性气味起关键性作用的化合物种类主要有醇(9种)、醛(9种)、萜类化合物(5种)、酮(3种)、酯类(2种)和含硫化合物(2种).香竹竹叶中重要的气味活性化合物为2-甲基丁醛(黑巧克力味),嘧啶(刺激味,辛辣味),2-甲基噻吩(刺鼻汽油味),己醛(青草味),糠醛(烤香、肉香),3-己烯醛(青草味),1-庚烯-3-醇(青草味、刺激味),乙二硫醚(刺激味、咸菜味),3-甲硫基丙醛(煮土豆味、煮肉味),2-甲基-3-呋喃硫醇(甜香),辛醛(花香,绿草,橘皮味),橙花醇/香叶醇(橘子味、花香).     

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.     

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。     

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.