萱草属植物ISSR-PCR反应体系的优化

以萱草属的3种植物为材料,对影响ISSR-PCR扩增效果的因素Taq酶用量、Mg2 浓度、dNTP用量、引物用量、模板DNA浓度以及退火温度等指标进行单因子筛选和优化,建立了适合萱草属植物ISSR-PCR分析的最佳PCR反应体系:20μL反应体系中Taq酶0.6U、Mg2 1.8 mmol/L、1×Buffer 2 μL、dNTP0.2 mmol/L、引物0.6mmol/L、DNA模板10 ng/μL.扩增程序为94℃预变性5 min,94℃变性40 s,52℃退火45 s,72℃延伸1.50 min,共39个循环;72℃完全延伸5 min,4℃保持.该反应体系及扩增程序扩增谱带清晰,产物量多,为利用ISSR-PCR分子标记研究萱草属植物的遗传多样性提供标准反应条件.     

香榧RAPD分析实验条件的优化

试验通过系统的比较研究 ,建立了香榧 RAPD分析的优化反应体系和实验条件 ,即 2 0μl的反应体系中含有 5 0 ng DNAtemplate、1.5μl 10× Buffer、1U Tag NDA聚合酶、2 .4mmol/L Mg Cl2 、2 40μmol/L d NTPs、0 .8μmol/L Primer。适宜的扩增程序为95℃变性 3 min,1个循环 ;94℃变性 3 0 s,3 6℃退火 3 0 s,72℃延伸 60 s,3 5个循环 ;72℃延伸 5 min,反应终止。该反应体系重复性高 ,条带亮度均匀 ,弥散现象少     

岷江百合ISSR-PCR反应体系的优化

以岷江百合为材料,对影响ISSR-PCR反应的主要参数进行优化,建立了适用于岷江百合的ISSR-PCR反应体系.20μL反应体系中,内含1×PCR buffer、1.25 mmol/L Mg2 、0.4 mmol/L dNTPs、0.6 μmol/L引物、0.5 U Taq DNA聚合酶、20ng模板DNA.扩增程序为:94℃预变性5min;94℃变性40 s,52.8℃退火45 s,72℃延伸1min 30s,共45个循环;最后72℃延伸8 min.该优化系统的建立为今后利用ISSR标记技术开展岷江百合遗传多样性研究奠定了基础.     

松口蘑SRAP反应体系的优化

以松口蘑为材料,建立了松口蘑SRAP反应的优化体系。即在20μL反应体积中,模板DNA 10ng,引物浓度0．3μmol／L,dNTP 250mmol／L,MgCl 22．5mmol／L,Taq DNA聚合酶0．5U,1×Buffer;反应程序为：94℃预变性5min,94℃变性1min,35℃退火1min,72℃延伸1min,共5个循环;94℃变性1min,50℃退火1min,72℃延伸1min,共35个循环：72℃延伸5min。     

狗牙根ISSR—PCR反应体系的建立与优化

以改良的CTAB法提取的狗牙根叶片DNA为模板,采用单因素多水平方法对狗牙根ISSR反应体系进行构建和优化,系统分析Taq酶、Mg2+、模板DNA、dNTPs、引物和buffer这6种1SSR反应成分的浓度对扩增结果的影响,结果表明:20.0μL PCR反应体积中,20.0 ng模板DNA,0.4 μmol/L引物,0.5mmol/L Mg2+,0.05mmol/L dNTPs,0.2U TaqDNA聚合酶,2.0 μL 10×buffer.反应程序为;94℃预变性5 min;94℃变性45 s,55 C退火45 s,72℃延伸1.5 min,35个循环;再72℃延伸7 min,4℃保温.     

七叶树RAPD反应体系的优化

以七叶树新鲜叶片为材料,研究了七叶树RAPD分析过程中的影响因素包括Taq酶、Mg2+、dNTP、引物、模板DNA浓度、变性时间、循环次数等,建立了适合七叶树RAPD反应的PCR体系。即20μl反应体系中含有dNTP 0.25 mmol/L,Mg2+2.5 mmol/L,Taq酶1.0U,引物0.8μmol/L,DNA模板50ng。扩增程序为:94℃预变性5min,然后40个循环(94℃变性30 s,33℃退火40 s,72℃延伸60 s),最后72℃延伸10min,4℃保存。     

利用正交设计优化茶树ISSR反应体系

为优化茶树ISSR分子标记反应体系,对影响茶树ISSR反应较大的Mg2+浓度、dNTP浓度、模板DNA浓度、TaqDNA聚合酶浓度、引物浓度5个因素在4水平上进行优化试验,建立了适合于茶树ISSR-PCR(Inter Simple Sequence Repeats-Polymerase Chain Reaction)的最佳体系:20μL反应体系中,TaqDNA聚合酶0.75U/μL,10×buffer(含Mg2+)2.0mmol·L-1,模板DNA20ng,dNTP0.1mmol·L-1,引物0.3μmol·L-1。反应程序为:94℃预变性5min,94℃变性1min,50～60℃退火40s,72℃延伸90s,34次循环,72℃延伸7min,4℃保存。     

鹅掌楸ISSR-PCR反应体系的建立及优化

为建立鹅掌楸简单序列重复区间扩增ISSR的PCR优化反应体系,以鹅掌楸叶片基因组DNA为材料,系统地测试了模板DNA、引物、dNTPs、Mg2+浓度、TaqDNA聚合酶用量及退火温度对ISSR-PCR反应体系的影响。结果表明:优化的PCR反应体系为:20μL总体系中,含30 ng模板DNA,0.3μmol.L-1随机引物,0.2 mmol.L-1dNTPs,1.4 mmol.L-1Mg2+,0.8 UTaqDNA聚合酶;最佳退火温度为60℃;PCR反应程序为:94℃预变性5 min;94℃变性1 min,60℃退火45 s,72℃延伸2 min;45个循环;72℃再延伸7 min。     

福建柏无性系ISSR-PCR反应体系的建立

福建柏无性系ISSR-PCR反应体系的模板,引物,taq酶,甲酰胺及程序中的退火温度,循环数等优化实验结果表明：福建柏ISSR-PCR反应最适体系为2.0μL 5 μM引物,1.0μL 35ng/μL DNA模板,12.5μL 2×Reaction Mix,0.75U 2.5U/μL Golden DNA Polymerase,2.0％甲酰胺总反应体系为25μL.ISSR-PCR反应最适程序为：94℃预变性3min;94℃变性30s;48.5℃退火30s;72℃延伸1min,35个循环;72℃再次延伸5min.     

SRAP标记体系优化及在茶树种质资源研究中的应用

以Me3和Em5正反向引物组合对凤凰水仙茶树品种进行了SRAP分析体系的优化。结果表明：茶树SRAP-PCR最佳反应体系为：Mg2＋浓度3.0 mmol.L-1;Taq酶2.0 U;dNTPs浓度0.2 mmol.L-1;引物浓度2.0μmol.L-1;10×Buffer 2.0μL;模板DNA 20 ng;反应总体积为25μL。经过重复试验,确定茶树SRAP-PCR扩增程序为：94℃预变性5 min;94℃变性1 min,35℃复性1 min,72℃延伸100 s,5个循环;94℃变性1 min,50℃复性1 min,72℃延伸100 s,35个循环;最后72℃延伸5 min。采用已优化的体系对30份茶树品种进行SRAP分析,经2%的琼脂糖凝胶电泳得到了清晰且重复性好的扩增谱带,说明该反应体系稳定可靠,适用于茶树种质资源的分子标记分析。     

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.     

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.     

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。