地被石竹组织培养再生体系的研究

为建立地被石竹组织培养再生技术体系,以地被石竹的叶片和茎段为外植体,MS为基本培养基,对影响再生的生长调节物质进行了研究。结果表明,茎段比叶片易诱导不定芽;叶片在6-BA 2.0 mg/L上不定芽的再生频率较高;茎段在MS 6-BA 5.0mg/L、MS 6-BA 5.0mg/L IBA 0.1mg/L和MS 6-BA 5.0mg/L IAA0.1mg/L上再生频率较高,分别达75.6%6、5.0%和68.5%。     

水栀子的组织培养和快速繁殖

以水栀子茎切段为外植体,进行植株再生和快速繁殖研究。结果表明在以MS BA3mg/L NAA0.4mg/L的培养基上,不定芽诱导效果较好,分化率达100%;增殖培养时,在MS BA1mg/L IAA0.2mg/L GA30.3mg/L的培养基上效果较好;再生苗在1/2MS IAA(0.1～0.5)mg/L的培养基上生根效果较好。     

玫瑰海棠的组织培养

以玫瑰海棠的幼嫩组织作外植体,在含不同植物激素的培养基上进行丛生芽的诱导、芽的继代增殖、芽生根与移栽研究,以快速获得再生植株.结果表明,丛生芽诱导培养基以MS＋6-BA 1.5 mg/L＋NAA 0.1 mg/L较好,诱导系数达12;增殖培养基以MS＋6-BA1.5 mg/L＋IAA 0.1 mg/L较好,增殖系数达11.3,且增殖芽生长好;生根培养基以1/2MS＋NAA 0.5 mg/L为最佳,生根率达100%,幼苗生长势旺.     

廊坊杨4号组培苗再生体系建立研究

以廊坊杨4号无菌苗为研究对象,确定了影响组培苗生长的关键因子及组培苗生长的最佳条件,并建立了稳定高效的再生体系。试验结果表明廊坊杨4号无菌苗的最适基本培养基是MS培养基,继代培养基为MS+6-BA 0.5 mg/L+IAA0.15 mg/L;不定芽分化培养基为MS+6-BA 0.5 mg/L+2,4-D0.05 mg/L;1/2MS+IBA 0.15 mg/L是其最适生根培养基组合。     

牡丹组培快繁技术研究

以牡丹的当年生茎尖为外植体进行簇生芽诱导,对牡丹的快繁技术进行改良研究。结果表明,诱导簇生芽时,在MS 6-BA2.0mg/L NAA0.2mg/L 200mg水解乳蛋白培养基上的诱导效果较好,分化率达100%;继代培养时,以MS 6-BA1.0mg/L KT0.5mg/L NAA0.1mg/L 200mg水解乳蛋白培养基的增殖倍数最高,达11.8倍;再生苗在1/2MS NAA0.1mg/L 200mg水解乳蛋白培养基上生长良好;在炼苗中,移栽基质以蛭石 草炭土较好,其有助于小苗的后期生长。     

桔梗丛生芽的诱导及植株再生

用桔梗茎段为外植体,以MS为基本培养基,对添加不同浓度和比例的外源激素对桔梗丛生芽的诱导、增殖及植株再生的影响进行探讨。结果表明:丛生芽诱导培养基以MS+6-BA0.3mg/L+NAA0.05mg/L效果最佳;增殖培养基以MS+6-BA2.0mg/L+NAA0.5mg/L效果最佳;生根培养基以1/2MS+NAA0.2mg/L效果最佳。     

三角梅愈伤组织诱导和植株再生

以三角梅(Bougainvillea glabra choisy.)当年生枝条为材料,比较研究不同激素配比条件下外植体愈伤组织的诱导及植株再生。结果表明:三角梅茎段在MS+6-BA 0.3mg/L+NAA 0.05mg/L培养基上,可诱导出愈伤组织,愈伤组织分化的最佳培养基为MS+6-BA 1.0mg/L+NAA 0.1mg/L,经再分化可获得无性系芽,继而产生丛生芽;将高度大于3cm的增殖芽接种于添加1/2MS+IAA 1.0mg/L培养基上可诱导产生不定根,生根率高达50%。生根后移栽成活,获得完整再生植株。     

紫叶黄栌观赏特性及快繁技术研究

以紫叶黄栌的当年生嫩枝茎段为外植体进行簇生芽诱导,研究结果表明,诱导簇生芽时,在MS 6-BA2．0 mg／L NAA0．2 mg／L培养基上的诱导效果较好,分化率达100％;继代培养时,以MS 6-BA1．0 mg／L KT 0．5 mg／L NAA0．1 mg／L培养基增殖倍数较高,达到11．8倍;再生苗在1/2MS NAA0．1 mg／L的培养基上生长良好;在炼苗中,移栽基质以蛭石 森林土较好,可促进小苗后期生长。     

环保型植物--驱蚊香草组培快繁技术的研究

以市场出售的驱蚊香草为试材,进行组培快繁技术的研究。通过对不同部位的外植体的试验结果表明:MS作为基本培养基,NAA、2,4-D对生长分化作用不明显,而6-BA、IBA对生长分化作用明显,且MS 6-BA0.20mg/L IBA0.04mg/L有利于愈伤组织的形成和分化,1/2MS IAA0.3mg/L培养基生根效果较好。     

野生柱穗醉鱼草嫩芽的组培技术研究

以野生柱穗醉鱼草的嫩芽为外植体,分诱导培养,茎芽增殖,继代培养,生根培养4个阶段进行其组培技术研究,结果表明:外植体消毒用0.1%升汞液浸泡7 min效果较好;最佳的诱导培养基是MS 6-BA 0.5 mg/L NAA0.02 mg/L;茎芽增殖培养基是MS 6-BA 0.5 mg/L NAA0.02 mg/L;继代培养基是MS 6-BA 0.5 mg/L;生根培养基是MS 6-BA 0.5 mg/L NAA 0.02 mg/L AC 0.3%。     

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.     

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。