北美红杉组培苗工厂化育苗技术

阐述北美红杉组培苗的工厂化育苗技术。以萌生条茎段为材料，采用多菌灵、新洁而敏、升汞等药剂处理外植体，以降低污染率；采用以芽繁芽的方式进行试管增殖，从而减少变异；通过壮芽及生根培养，获取大量适宜生根的试管苗；试管苗移植2～3年后，以便进一步培育北美红杉扦插苗，并为生产部门提供大量优质的穗条。     

杂交柳优良无性系组培快繁技术研究

试验以我省从江苏省林科所引种栽培的杂交柳优良无性系903,799,795为试材，对不同外植体材料进行初代培养，培养基筛选。继代增殖与生根培养，以及试管苗移栽试验，经系统观测与分析，其试验结果：（1）以当年春根际萌条为外植体进行初代培养，其污染率最低，有利于快速，高效建立无菌培养系；（2）不同优良无性系对培养基的选择存在较大差异。其中903号无性系能适应较大范围的激素浓度变幅，而799，795号无性系对培养基内激素水平要求较严格。（3）不同优良无性系，不同外植体来源与不同类型外植体材料，其芽的诱导率和增殖倍数有着明显差异性。     

北美红杉组培苗工厂化育苗技术

阐述北美红杉组培苗的工厂化育苗技术。以萌生条茎段为材料,采用多菌灵、新洁而敏、升汞等药剂处理外植体,以降低污染率;采用以芽繁芽的方式进行试管增殖,从而减少变异;通过壮芽及生根培养,获取大量适宜生根的试管苗;试管苗移植2～3年后,以便进一步培育北美红杉扦插苗,并为生产部门提供大量优质的穗条。     

欧洲大樱桃试管快繁技术研究

取欧洲大樱桃茎段作外植体，探讨了其快速繁殖技术，筛选出最佳增殖、生根培养基，找出了影响试管苗移栽成活率的因素。试管苗增殖系数达到10左右，生根率达92.5%，生根率达92.5%，移栽成活率达95％以上。     

黑核桃试管苗快繁技术研究

取北加州黑核桃茎段作外植体，探讨了其离体快速繁殖技术，筛选出最佳增值、生根培养基，找出了影响试管苗移栽成活率的因素。试管苗增殖系数达到9左右，生根率75．5％，移栽成活率95％以上。     

741杨和苹果试管苗玻璃化现象及其转化研究

以７４１杨和苹果矮化砧Ｍ２６和Ｍ７为材料，研究了影响７４１杨试管苗玻璃化现象的因素。除培养基中ＢＡ和ＩＢＡ的浓度、琼脂浓度外，光强和温度组合是影响试管苗玻璃化现象的重要因素。７４１杨试管苗玻璃化与其内源ＡＢＡ水平有关。７４１杨无根试管苗的玻璃化率和器官分化能力存在季节变化，春季和夏季较强，冬季较弱；７４１杨无根试管苗的内源ＡＢＡ含量则是春季和夏季低，冬季高。无根正常试管苗ＡＢＡ含量为无根玻璃苗的５．５９倍。苹果无根玻璃化试管苗如在其培养基中加入低浓度（Ｏ．１～０．５ｍｇ／Ｌ）ＡＢＡ，或在较强的光照条件下培养，可以转化为无根正常试管苗，并能正常进行继代和生根。     

乌克兰大樱桃试管快繁技术的研究

用乌克兰优质大楼桃茎段作外植体，探讨其离体快速繁殖技术，筛选出最佳增殖生根培养基，找出了影响试管苗移植成活率的因素。试管苗增殖系数达到11左右，生根率91.2%，移植成活率可达95%以上。     

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%。     

金线莲与菊芋在组织培养中细菌污染的防治

被细菌污染的金钱莲AnoectochilusfrmosanusHay.试管苗选用自配消毒剂D进行灭菌有较好的效果，且在校长时间范围内对材料伤害较小，对菊芋Helianthustuberosus外植体进行消毒也比用吐温效果好。未试验同时还揭示了培养体培养时间与细菌入侵程度的关系，探讨了两种材料在组织培养中细菌污染的防治方法。     

丰水梨试管快速繁殖技术研究

取丰水梨茎段作外植体 ,探讨了其快速繁殖技术 ,筛选出最佳增殖、生根培养基 ,找出了影响试管苗移栽成活率的因素。试管苗增殖系数达到 8.8,生根率 91.3% ,移栽成活率 93%以上。     

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.     

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.     

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.     

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.     

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。