风信子组培快繁技术的研究

采用不同诱导、继代和生根培养基进行风信子组培快繁技术研究，结果表明：鳞片不定芽诱导的最佳培养基为MS 6-BA1．0—1．5mg／L NAA0．2—0．4mg／L；不定芽继代培养的最佳培养基为MS 6-BA1．0mg／L NAA0．2mg／L；最佳生根培养基为1／2MS NAA0．3mg／L；蛭石1份 珍珠岩1份 园土1份是风信子试管苗最佳的驯化移栽基质，在该基质中生根苗移栽成活率达90％。     

丽格海棠叶片的组织培养研究

取丽格海棠叶片作外植体,通过试验,分析不同激素配比对芽的诱导、增殖及生根的影响,筛选出丽格海棠叶片组织培养的适宜培养基及试管苗最佳移栽基质。结果表明：其最佳诱导培养基为MS＋6-BA1．5mg／L＋NAA0．8mg／L,不定芽诱导率达100％;最佳继代培养基是MS＋6-BA1．0mg／L＋NAA0．5mg／L,增殖倍数达6．5倍;最佳生根培养基是1／2MS＋NAA0．4mg／L,生根率达100％;试管苗最佳移栽基质为用1／2MS大量元素浇透的草炭,移栽成活率为85％。     

花叶菖蒲组织培养与快繁技术试验

取花叶菖蒲的茎尖作外植体，培养于附加不同激索配比的MS培养基匕进行不定芽诱导、增殖及试管苗生根等试验，结果表明，6种配比培养基中，最适合花叶菖蒲不定芽诱导的培养基为MS＋6-BA5mg／L；增殖培养基为MS＋6-BA5Mg／L＋NAA0．5mg／L；试管苗生根诱导前在空白Ms培养基先壮苗培养一代，生根培养基为MS＋NAA0．5mg／L。试管苗不经炼苗可直接出瓶，移栽于蛭石：珍珠岩为1：1的混合基质中，成活率可达98％以上。     

火鹤组织培养与快繁技术研究

以火鹤茎尖作为外植体进行组织培养，得出了愈伤组织的诱导发生、不定芽的分化诱导、生根的最佳培养基分别为：MS＋NAA0．05mg／L＋6-BA1．0mg／L，MS＋NAA0．20mg／L＋6-BA0．5mg／L，1／2MS＋NAA0．10mg／L；蛭石是火鹤组培苗移栽炼苗的最佳基质，成活率可达到100％。     

海南龙血树组织培养快速繁殖技术研究

以海南龙血树优株顶芽和茎段为外植体,通过不同细胞分裂素、生长素以及培养基不同浓度的组合对诱导芽的分化、增殖、伸长及生根的对比实验及试管苗移栽管理,筛选出MS 蔗糖30 g/L 6-BA 3．0 mg/L NAA 0．01 mg/L培养基诱导芽的形成,MS 蔗糖30 g/L 6-BA 2．0 mg/L NAA 0．01 mg/L培养基用于芽的增殖,MS 蔗糖30 g/L 6-BA 0．5 mg/L培养基用于壮芽伸长;1/2MS 蔗糖15 g/L NAA 0．2 mg/L用于诱导芽生根;选用泥炭土、椰糠和珍珠岩混合基质,于晚春和秋季移栽试管苗,成活率达90％左右,达到工厂化苗木生产的要求。     

猪笼草组培快繁技术

猪笼草具节茎段经消毒处理后接种到MS＋6-BA3．0mg／L＋NAA0．1mg／L＋Vc50mg／L的培养基中,诱导出侧芽;切取侧芽带1～2个节的茎段接入1／8MS＋6-BA0．8mg／L＋NAA0．1mg／L培养基中,诱导愈伤组织和芽并继代培养,扩繁2．5～3．0倍。继代3～5次后取高度大于3cm具2个节的芽,切顶芽在1／8MS＋6-BA0．05mg／L＋IAA0．1mg／L芽增殖培养基中培养。具节茎段则先在1／8MS＋6-BA0．5mg／L＋NAA0．1mg／L培养基中培养,待其抽出侧芽后再转入芽增殖培养基中培养,繁殖倍数可扩增1．5倍。将继代培养芽丛中具2个节的芽接到1／4MS＋NAA0．2mg／L＋IAA0．5mg／L＋活性炭500mg／L培养基中,30d生根率可达75％;炼苗20d左右移栽,成活率85％以上。     

垂花蝎尾蕉的组织培养

报道了垂花蝎尾蕉顶芽诱导植株再生的研究结果,试验表明:诱导芽分化的适宜培养基为MS 6-BA5mg/L;6-BA5~6mg/L NAA0.5mg/L的激素配比对芽的增殖效果好;无根苗在NAA0~2mg/L的MS培养基上都能生根;试管苗移栽在表土混沙(2∶1)的基质中,成活率可达90%。     

大哥大红掌实用化生产的组织培养研究

以叶片、叶柄或叶茎为外植体,在培养基MS+6-BA 1～2mg/L+NAA 0.1mg/L+2,4-D 0.1～0.2mg/L上均可诱导愈伤组织的产生,其中以MS+6-BA1.0 mg/L+NAA0.1mg/L+2,4-D 0.1mg/L效果最好,诱导率可达87%以上;其最佳的分化培养基MS+6-BA 1.5mg/L+NAA 0.2mg/L上,分化率可以达到90%以上,大哥大红掌最佳的增殖培养MS+6-BA 2mg/L+NAA0.2mg/L,培养30d芽的增殖系数达到3.45,降低6-BA浓度或提高NAA浓度有利于培养壮苗;1/2MS+NAA 0.1mg/L+1g/L活性炭的培养基诱导植株生根效果最好,生根率86%,平均每株苗生根3条;生根试管苗移栽于泥炭土:珍珠岩=5∶1的基质,成活率约86%。     

何首乌茎段快速繁殖技术的研究

对何首乌茎段快繁技术进行了研究。结果表明：何首乌最佳诱导培养基为MS＋6-BA1．0mg／L＋NAA0．05mg／L或Ms＋6-BA1．0mg／L＋NAA0．02mg／L，对于芽增殖，以MS＋6-BA1．0mg／L＋NAA0．05mg／L培养基较好，培养30d后芽增殖率可达到4．02。诱导生根培养基以1／2MS＋6-BA1．0mg／L＋NAA0．1mg／L或MS＋6-BA0．5mg／L＋NAA0．05mg／L较好，培养20d后生根率分别可达91．7％和96．3％。     

美花红千层的组织培养研究

以美花红千层茎段为外植体,进行腋芽诱导以及增殖、生根、炼苗移栽试验,以建立高效的美花红千层离体快繁体系。结果表明:以美花红千层单芽茎段在MS+6-BA0.5mg/L培养基上萌芽效果最好,芽诱导率为87%;试管苗在改良MS(NH4NO3减半)+6-BA0.3mg/L+NAA0.1mg/L培养基上继代效果最好;试管苗在1/2MS+IBA0.3mg/L+NAA0.1mg/L培养基上生根效果最好,生根率为99.3%;试管苗经炼苗,移栽至珍珠岩和腐质土3∶1混合基质中成活率最高,为95%。     

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.     

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。     

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.