三倍体毛白杨愈伤组织诱导及腋芽增殖技术研究

以三 本毛白杨试管苗叶片作为外植体进行愈伤组织的诱导，最适的愈伤组织诱导培养基为MS＋NAA1.0mg/L 6-BA0.1mg/L；分化培养基为：1／2MS＋BA0.5mg/L。利用腋芽增殖试管苗，单芽增殖有效苗可达12株以上；生根培养基为MS＋IBA0.8-1.2mg/L，试管苗的生根率可达85.93%；炼苗成活率达到93.8%，田间移栽成活率为87.5%。     

西伯利亚花楸试管苗保存技术

以西伯利亚花楸幼嫩茎段为外植体,0.1%(m/v)升汞消毒6 m in,在MS+6BA 0.8 mg/L+NAA 0.08 mg/L+KT 0.4 mg/L+IBA 0.04 mg/L的增殖培养基上,成功地建立了西伯利亚花楸试管苗增殖体系。研究了不同保存条件和培养基对试管苗保存效果的影响,结果表明:试管苗在(2±2)℃的冰箱冷藏室,可有效保存240天以上,在MS+琼脂7 g/L+蔗糖50 g/L的培养基上,试管苗的生长得到明显的抑制。保存后的试管苗增殖、生根、驯化效果良好,生长正常。     

蓝花楹组培技术研究

以蓝花楹实生苗茎尖作为外植体的组培技术研究结果表明,其组培中的启动培养基宜为MS 6-BA1.0 mg/L NAA0.2 mg/L;增殖培养基宜为MS 6-BA2.0 mg/L NAA0.4 mg/L或MS 6-BA2.0 mg/L NAA0.5 mg/L;生根培养基宜为1/2 MS NAA0.5 mg/L.其试管苗适宜的移栽基质为营养土 蛭石(比例1:1),移栽成活率为55.10 %.有利于其试管苗增殖的光照条件为3 000 lx.继代次数对其试管苗的增殖和生根均有影响,而适宜转向生根培养的继代数最少为9代.     

东风菜叶柄无性系建立研究

为保护野生资源,满足人工栽培的需要,以东风菜叶柄为材料,进行了愈伤组织诱导、分化培养,不定芽生根培养,试管苗生根继代增殖培养、移栽、定植的研究,建立起变异植株的无性系。结果表明:MS+2,4-D2.5mg/L是叶柄愈伤组织培养的理想培养基;MS+GA30.5mg/L+AgNO31.5mg/L+NAA 0.1mg/L是愈伤组织分化培养的理想培养基;用NAA20mg/L的无菌溶液对不定芽切口进行处理后,接种到White+IAA0.1mg/L培养基上培养,是不定芽生根培养和试管苗生根继代培养的理想方法;定植的试管苗保持了野生东风菜的所有植物学性状。     

欧李组培快速繁殖体系的建立

以欧李4个品种的茎尖为外植体,1/2MS和MS为基本培养基,初步建立了欧李试管苗的组培快速繁殖体系,其最佳的初代培养基是MS 0.1 mg/LNAA 1.0mg/L6-BA和MS 0.4mg/LNAA 1.0mg/L6-BA,最佳的增殖培养基是MS 0.2mg/L NAA 0.8mg/L6-BA和MS 0.2mg/L NAA 0.6mg/L 6-BA 0.05 mg/LPP333,并分别确定了最好的生根培养基.     

凌霄组织培养及快速繁殖的研究

该文以凌霄的生长点为材料,对生长点的生长、不定芽的分化、试管苗的生根及继代、试管苗的移栽与扦插等进行了研究,完成了凌霄的组织培养,建立起凌霄的无性系。结果证明:1/2MS+IAA0.3mg/L+NAA0.1mg/L是凌霄生长点生长培养的理想培养基;MS+BA1.2mg/L+IAA0.2mg/L+NAA0.1mg/L是凌霄不定芽分化培养的理想培养基;1/3MS+IAA1mg/L是凌霄试管苗生根培养的理想培养基;炉灰渣是凌霄试管苗移栽和扦插的理想基质。     

冀北山区野生红柴胡组织培养与快速繁殖研究

以冀北山区野生药用植物红柴胡的腋芽为外植体,以MS+6-BA 1.5mg/L+IBA 0.5mg/L为诱导培养基,以MS+6-BA 1mg/L+IBA 0.5mg/L为增殖培养基,以1/2MS+IBA 0.5mg/L为生根培养基,采用渐进法炼苗,注重适时移栽,成活率达到90%以上,且苗齐苗壮。     

柽柳的组织培养研究

以野生耐盐变异柽柳植株的萌动芽为材料,进行了不同植物生长调节剂及浓度对萌动芽生长、生长芽分化、不定芽生根的影响及试管苗的移栽、扦插、移植试验,成功建立了耐盐野生变异柽柳植株的无性系。结果表明:MS+BA 0.1 mg.L-1+GA 0.5 mg.L-1+IAA 0.2 mg.L-1是暗培养条件下培养芽生长的理想培养基;MS+AgNO31.0 mg.L-1+BA 1.0mg.L-1+NAA 0.1 mg.L-1是不定芽分化培养的理想培养基;1/2MS+IAA 0.4 mg.L-1是试管苗生根培养的理想培养基;移植到海边沙滩上的试管苗保持了耐盐变异性状,并且生长旺盛,根系发达。     

蕨叶薰衣草“西班牙之眼”的组培快繁技术

以蕨叶薰衣草"西班牙之眼"(Lavandula pinnata L.)无菌苗的带芽茎段作为外植体,在附加不同浓度6-BA、NAA、IBA的MS培养基上,研究了不同激素浓度组合对其芽苗增殖和生根的影响。结果表明:蕨叶薰衣草"西班牙之眼"种子萌发的最适培养基为1/2MS+3%蔗糖,萌发率为92%;诱导芽苗增殖的最适培养基为MS+6-BA1.5 mg/L+NAA0.1 mg/L,增殖系数为5.4;最适生根培养基为1/2MS+IBA0.5 mg/L,生根率为94.5%。     

橙花长寿花叶柄组织培养技术研究

以橙花长寿花叶柄作为外植体,对其进行不定芽诱导及增殖培养研究,结果表明:最适宜叶柄分化的培养基为MS+6-BA0.5mg/L+NAA2.0mg/L,最适合芽增殖的培养基为MS+6-BA0.5mg/L+NAA0.4mg/L,生根培养基为1/2MS+IBA0.2mg/L,试管苗移栽基质中成活率达98%。     

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.     

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.     

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.     

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。     

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.