芍药盆花促成栽培技术研究

选择13个芍药品种进行促花栽培；并以大富贵芍药为试材，进行了不同栽培基质试验，不同容器试验，不同浓度生根粉浸根试验及不同浓度抑制剂施用试验。结果表明：芍药适宜盆花促成栽培的品种有：大富贵，莲台，白玉冰，铁杆紫，金带围。适宜的栽培基质是草炭土＋珍珠岩，容器是窗纱网袋＋周转箱。合理的生根粉浸根浓度为0．005％。以前期每株根施2g多效唑，后期喷施0.015%的多效唑或缩节胺控制株型效果最好。     

芍药促成栽培品种对比试验

选择13个芍药品种进行促花栽培;并以大富贵芍药为试材,进行了不同栽培基质试验,不同容器试验,不同浓度生根粉浸根试验及不同浓度抑制剂施用试验。结果表明:芍药适宜盆花促成栽培的品种有:大富贵、莲台、白玉冰、铁杆紫、金带围。适宜的栽培基质是草炭土+珍珠岩,容器是窗纱网袋+周转箱。合理的生根粉浸根浓度为0.005%。以前期每株根施2g多效唑,后期喷施0.015%的多效唑或缩节胺控制株型效果最好。     

不同基质栽培非洲菊的切花产量和品质

试验对栽培于温室中珍珠岩、沸石、砂质和岩棉基质上非洲菊Ｆａｍｅ、Ｐａｒｔｙ、Ｒｅｇｉｎａ、Ｘｉｍｅｎａ进行评价,17个月的时间里测定其切花产量和品质(花柄长度和宽度)。结果表明,珍珠岩基质栽培的非洲洲菊产量最高,达75～80枝,沸石基质的产量最低,砂质与岩棉基质产量中等。相比其它品种,Ｐａｒｔｙ品种略显高产。切花品质受基质、品种和种植时间影响,第一阶段(7～8月)珍珠岩基质栽培的切花品质更好,但第二阶段各基质无差异不同基质栽培非洲菊的切花产量和品质     

台湾金线莲组培苗移栽技术研究

影响台湾金线莲组培苗移栽生长的因素有栽培基质、种植密度（株行距）、种植深度、肥料等。研究结果表明：栽培基质、种植密度、种植深度对移栽成活率、株高的影响极显著，种植密度和肥料对叶数的影响极显著。栽培基质以70％泥炭土＋25％树皮＋5％其他原料效果最好，种植密度5cm×5cm，种植深度1cm最佳。种植后的肥水管理采用2号配方肥料更能促进台湾金线莲健康生长。     

武汉地区不同栽培基质对一品红生长和品质的影响

笔者以更早生天鹅绒品种为试验材料,对武汉地区5种不同栽培基质中盆栽一品红的生长发育情况和盆花品质进行了比较研究。试验结果表明：泥炭：珍珠岩=1：1是武汉地区较适宜一品红生长发育的栽培基质,同时可以显著提高一品红的盆花品质,可以在武汉地区规模化生产中推广使用。     

几种室内盆花无土栽培繁育技术

实践表明：仙客来、美叶光萼荷、袖珍椰子、巴西木等室内盆花无土栽培时，播种、育苗基质用蛭石、沙；扦插用蛭石、珍珠岩；出苗和生根后移栽基质用泥炭1＋蛭石1或泥炭1＋珍珠岩1＋沙1为宜，生长周期筛选的花卉通用型营养液浇灌生长良好。     

仙客来栽培基质配方的研究

仙客来为多年生球根花卉，为世界著名盆花品种之一。经多年的栽培基质研究结果表明：仙客来对栽培基质理化性质的要求是pH值高于6，总孔隙度大于85％，通气孔隙介于28％～33％之间，EC值小于1；基质合理配方为进口泥炭3：椰糠4：蛭石2：珍珠岩1；国产泥炭3：进口泥炭3：蛭石3：珍珠岩1。该基质对仙客来总生物量，包括叶片数、新芽数、根数和球茎大小都有显著的促进作用。     

多效唑对盆栽‘奥斯特’北美冬青生长和坐果的影响

以1年生‘奥斯特’北美冬青扦插容器苗为试验材料,采用叶面喷施和土壤浇施2种方法,研究了多效唑对其盆栽苗生长和坐果的影响。结果表明:多效唑可以有效矮化盆栽北美冬青的株型,提高封顶枝比例,使株型紧凑饱满,以土壤浇施150 mg/L(原药1 000倍稀释液),或叶面喷施300 mg/L(原药500倍稀释液)多效唑为宜。在适宜的处理质量浓度下,喷施当年效果优于浇施,浇施第2 a效果优于喷施;从试验结果看,多效唑对北美冬青盆栽苗的坐果数量有一定的负作用。     

一品红千禧品种株型控制研究

研究了摘叶、前期不同时期喷施多效唑和后期低浓度多效唑灌根三种途径控制一品红千禧品种的株型，结果表明：摘2～3叶能明显抑制其顶端优势，降低顶芽株高2．5-2．8cm，在打顶前和打顶后7d进行40mg／L的多效唑喷施，植株矮化效果最好，降低高度13．8cm，后期3张苞叶转色时用1mg／L的多效唑灌根，能降低株高2．9cm，而对苞叶的大小基本无影响，提高了植株的观赏性。     

水培盆栽花卉技术

目前，花卉无土栽培的盆花只采用有基质的盆栽，如沙培、陶粒培、泥炭培、珍珠岩培、锯沫培、砾岩培、蛭石培、水苔培等，这些无土盆栽花卉，轻便，比较清洁卫生和省时，用营养液每星期淋１次～２次便可，病虫害减少，生长较好，质量较高，并且由于是用较透气的基质种植，将土培花卉改为无土培容易成活，容易栽培，但当栽培时间较长，植物长大根素发达时，盆内基质被根系包裹则不易冲洗，盆内同样会沉积污物和藏虫害，用户外出时间稍长，供水问题仍不能解决。 无基质栽培的水培盆栽花卉目前在国内外实属少见。传统的说法和做法，水培法必须…     

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.     

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。     

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.     

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.