落叶松—杨栅锈菌DNA提取及RAPD条件优化

本文对采自全国8个省市的落叶松—杨栅锈茵茵株进行了基因组DNA提取，并以其为模板对影响RAPD扩增1的重要参数进行优化试验，以期建立落叶松—杨栅锈茵RAPD反应的优化体系。结果表明，PCR扩增体系最佳条件是：25μL体积中，2．5mmol／LM^2 ，30ng／μL模板，0．15mmol／LdNTP，1．5μL引物，0．75UTaq聚合酶。     

闽楠、红楠AFLP反应体系建立

以闽楠、红楠总基因组DNA为模板,对AFLP分析各环节的条件进行了优化和筛选,建立了适合于闽楠、红楠AFLP分析的最佳反应体系.其中:酶切反应条件为在20μL反应体系中,加入模板DNA 150 ng,Buffer22μL,BSA 0.2μL,EcoRI 3U,Msel 2U,37℃酶切4 h,65℃变性10 min,4℃保存;连接反应条件为将酶切产物中加入5μL连接体系(包括T4 Buffer 2.5μL,EcoRI接头5 pmol,MseI接头50 pmol,T4连接酶1U),16℃连接过夜.预扩增反应条件为在20μL体系中,加入稀释25倍的连接产物5μL,Mg2+(25 mM/L)1.6μL,dNTP(2 mM/L)2 μL,预扩增引物E00、M00各30 ng,Taq酶1U.选择性扩增反应条件为:在20μL体系中,加入稀释100倍的预扩增产物5μL,Mg2+ 1.2μL,dNTP 2μL,选择性扩增引物(E+3/M+3)60 ng,Taq酶1U.本实验结果为闽楠、红楠AFLP分析打下了良好的实验基础.     

桢楠DNA提取和RAPD条件的优化

以桢楠（Phoebe zhennan）新鲜叶片、硅胶干燥叶片为材料,研究了DNA的提取方法,并对影响RAPD反应的各因素进行了优化。得到了桢楠RAPD的优化反应体系及程序,适合桢楠RAPD反应的体系总体积为25μL,DNA模板2μL,Taq DNA聚合酶用量0.3μL,引物用量1μL,Mg2＋用量5μL,dNTPs用量0.5μL,ddH2O16.2μL;适合桢楠RAPD扩增的程序是94℃预变性3 min,94℃变性1min,36℃复性1 min,72℃延伸2 min,42个循环,最后72℃延伸10 min,产物于4℃保存,同时结果表明硅胶保存的样品完全可以与传统的新鲜叶片得到同样的PCR扩增结果,完全可以满足研究需要。     

麻竹RAPD反应条件的优化

以麻竹DNA为模板,对影响麻竹RAPD扩增的重要参数进行了优化试验,以期建立麻竹RAPD反应的最适体系。最终得出的麻竹RAPD反应体系为:20μL反应体系,2μL10倍反应缓冲液,模板含量为50ng,2 5mmol·L-1的Mg2+,1 5U的Taq酶,dNTP为1 75mmol·L-1,引物浓度为0 4μmol·L-1。优化后的RAPD反应程序为:94℃3min→[94℃1min→37 5℃1min→72℃1min20sec]40个循环→72℃8min→4℃保持。     

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。     

云南箭竹基因组DNA的提取及RAPD反应条件的优化

用改良的SDS法从云南箭竹硅胶干燥的叶片中提取基因组DNA进行RAPD扩增。通过正交法对RAPD反应条件优化,6个试验因子的最适条件为:模板DNA1.5ng/μL,随机引物0.8～1.0μmol/L,dNTPs浓度0.1～0.15mmol/L,Mg2+浓度2.0～2.5mmol/L,Taq酶用量0.5～1.0U。最佳热循环参数为:94℃预变性2min,之后进行40次循环(94℃变性30s,36℃退火60s,72℃延伸90s),最后72℃总延伸7min后在4℃终止反应。     

核桃RAPD条件的优化

对核桃RAPD分析中Mgh、引物、dNTPs、TaqDNA聚合酶浓度及复性温度等因素进行了比较影响分析。建立了适合核桃DNA多态性分析的RAPD反应体系：25μL反应液中,3．5mM Mg^2＋、0．2mM dNTPs、0．2μM随机引物、1．0UT aq酶、50ng～100ng模板DNA;反应过程为45个循环,94℃变性60s,36℃退火60s,72℃延伸120s。     

我省板栗主载品种（无性系）RAPD反应体系的建立

在RAPD反应中，有许多影响结果的稳定性和准确性。本项研究采用浙江省8个板栗主载品种（无性系，）对RAPD各种反应进行了探索，结果表明，板栗理想的反应体系为：20μl反应体积含有100mmol/L Tris-HCl,500mmol/LKCl,20mmol/LMgCL2,0.01%Gelatin,dATP、dTTP、dGTP的量各为100μmol/L，50－200ng引物，0．75－1．0单位Taq酶，2－10ng模板NDA。反应条件为：94℃预变性2min，再94℃30s、40℃30s、72℃1．5min扩增37个循环；最后在72℃延伸7min。应用上述反应体系进行板栗PAPD反应，扩增产物在1．0％琼脂糖凝胶中电泳，经EB染色后在紫外灯下观察照相，可获得满意的DNA指纹图谱。     

我省板栗主栽品种(无性系)RAPD反应体系的建立

在RAPD反应中,有许多影响结果的稳定性和准确性.本项研究采用浙江省8个板栗主栽品种(无性系),对RAPD各种反应条件进行了探索,结果表明,板栗理想的反应体系为20μl反应体积含有100mmol/LTris-Hcl,500mmo1/LKCl,20mmol/LMgCL2,0.01%Gelatin,dATP、dTTP、dCTP、dGTP的量各为100μmol/L,50~200ng引物,0.75～1.0单位Taq酶,2～10ng模板DNA.反应条件为94℃预变性2min,再94℃30s、40℃30s、72℃1.5min扩增38个循环;最后在72℃延伸7min.应用上述反应体系进行板栗RAPD反应,扩增产物在1.0%琼脂糖凝胶中电泳,经EB染色后在紫外灯下观察照相,可获得满意的DNA指纹图谱.     

濒危药用植物延龄草RAPD反应体系的建立

以濒危药用植物延龄草(Trillium tschonoskiiM.)的叶片为材料,采用改良的CTAB法提取基因组DNA进行RAPD扩增,优化了RAPD扩增反应的程序及模板、引物、dNTP、Taq酶浓度等参数。结果表明:适合延龄草的RAPD扩增程序为:94℃预变性5 min,然后执行40个循环,每个循环中94℃变性1 min,36℃退火1 min,72℃延伸2 min,最后72℃延伸10min;适宜的反应体系为:25μL总体积中含DNA模板50 ng,Mg2+2.5 mM,引物0.6μM,dNTP 0.2 mM,Taq DNA聚合酶3 U。     

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.     

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.     

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.     

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.     

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。