普拉索芦荟组织培养技术研究

取普拉索芦菩嫩茎作外植体，培养于附加不同种类和激素浓度的ＭＳ或改良的ＭＳ培养基上，在附加 ６－ＢＡ１．５ ｍｇ／Ｌ时，丛生芽诱导效果最佳，萌发数量最多；在附加 ６－ＢＡ１．０ｍｇ／Ｌ＋ＮＡＡ０．３ｍｇ／Ｌ时，丛生芽生长最好，芽长且健壮，；在附加Ｉ ＡＡ０．２ ｍｇ／Ｌ时，生根效果最佳；当苗高 ３ ｃｍ以上，根长达２ ｃｍ以上时，开盖 ３ ｄ移入温室（１０～１６℃），炼苗 ３ ｄ后，移栽于蛙石；河沙；腐质土为０．５：１：１．５的混合基质的土壤中，成活率达９１．３％。     

PP333,BA和IAA对“美人指”葡萄试管芽苗增殖和高生长的调控

试验表明，ＢＡ对试管内“美人指”区区２芽苗增殖和高生长的影响均显著；ＩＡＡ对芽增殖的苗影响不显著，而对高生长影响显著。在改良Ｂ５基本培养基附加０．５ｍｇ／ＬＢＡ和０．０５ＩＡＡ的试验条件下，ＰＰ３３３对芽苗的增殖和高生长均有影响。且高生长影响大于增殖的影响。最佳增殖培养基为改良Ｂ３＋ＢＡＱ１．０＋ＩＡＡ０．０５＋ＰＰ３３３１．０；高生长最佳培养基为改良Ｂ５＋ＢＡ０．５＋ＩＡＡ０．１＋ＰＰ３３３０．     

龟背竹组织离体培养的技术研究

龟背竹组织离体培养中芽的诱导与增殖、壮苗以及快繁高生长等指标的最佳培养试验结果表明：基本培养基ＭＳ〉１／２ＭＳ〉Ｂ５〉Ｎ６；植物生长调节剂的应用ＢＡ〉ＫＴ，ＮＡＡ〉ＩＡＡ〉ＩＢＡ〉２．４－Ｄ；浓度范围以ＢＡ５￣７ｍｇ／Ｌ（单位下同），ＮＡＡ０．０５￣１．０为好。为了促进其高生长，添加ＧＡ３ ０．５￣０．９能明显提高龟背竹试管苗的生长速度。     

马尖相思离体培养再生植株的研究

用马尖相思（Ａｃａｃｉａ ｍ ａｎｇｉｕｍ ）１０ 年龄树芽器官为外植体,通过组织培养直接诱导不定芽产生,并获得根茎叶齐全的试管苗。剪取当年枝条的自顶芽往下依次带节的茎段培养,以第二、第三节茎段诱导芽萌动率高而快;芽诱导培养基为改良ＭＳ＋ ６－ＢＡ ２ ｍ ｇ／Ｌ＋ ＮＡＡ ０．５ ｍ ｇ／Ｌ,芽诱导率９０％ ;芽增殖培养基为改良ＭＳ＋ ６－ＢＡ ０．５ ｍ ｇ／Ｌ＋ ＮＡＡ ０．２５ ｍ ｇ／Ｌ＋ ＶＢ２ ５ ｍ ｇ／Ｌ＋ Ｖｃ ４ ｍ ｇ／Ｌ,芽增殖倍数４．８ 倍;生根培养基为１／２ ＭＳ＋ ＡＢＴ ２ ｍ ｇ／Ｌ＋ ＩＢＡ ０．２ ｍ ｇ／Ｌ＋Ａｃ ０．１％ ,生根率９７．０％ ;黄心土为试管苗最佳移栽基质,成活率达到８５％ 。     

黑荆树茎尖培养技术的研究

以黑荆树无菌种子苗的茎类为材料，研究了用不同的细胞分裂素，生长的浓度及其配比，培养基成分的浓度，对茎尖诱导分化芽，芽的伸长及生根的影响，研究结果；培养基为ＭＳ＋６－ＢＡ６．０ｍｇ／Ｌ＋ＬＢＡ０．０１ｍｇ／Ｌ＋ＧＡ３０．１ｍｇ／Ｌ有利于促进茎尖丛生茎的形成和伸长，１／２ＭＳ＋ＮＡＡ０．６ｍｇ／Ｌ有利于诱导芽生根，试管苗移栽成活率达９０％，并在温室里生长正常。     

蓝桉组织培养的研究

用蓝桉（Ｅｕｃａｌｙｐｔｕｓｇｌｏｂｕｌｕｓ）离体芽器官诱导培养，分化形成丛生芽，年繁殖系数３￣（１２）。０．１～０．５ｍｇ／Ｌ的６－ＢＡ或０．５～０．８ｍｇ／Ｌ的ＫＴ诱导外植体（带节茎段）腋芽萌动的效果最佳，诱导率分别达８０．３％和８１．５％。１．５～２０ｍｇ／Ｌ的６～ＢＡ或２０～２．５ｍｇ／Ｌ的ＫＴ分别与０．５～１．０ｍｇ／Ｌ的ＮＡＡ组合，对于促进腋芽分化形成丛生芽及继代培养中芽的增殖具有最佳效果。培养基中的无机盐浓度、蔗糖含量对蓝桉试管苗的生根具有显著影响；ＩＢＡ促进蓝桉试管苗的生根。至目前为止，在１／２ＭＳ无机盐培养基＋ＩＢＡ１．２～１．４ｍｇ／Ｌ＋Ｓ５ｇ／Ｌ中诱导生根，生根率最高可达２６．４％。     

建兰快速繁殖技术研究

通过对兰花茎尖诱导，原球茎增殖和根、芽分化的培养基筛选及对不同发根时间、不同基质移栽效果试验，结果表明：在ＭＳ培养基上附加ＢＡ３－４ｍｇ／Ｌ和ＮＡＡ１－２ｍｇ／Ｌ诱导茎尖，效果较好，诱导率为６９％；原球茎增殖在改良ＭＳ培养基上附加ＢＡ２－３ｍｇ／Ｌ和ＮＡＡ１－２ｍｇ／Ｌ增殖倍数可达４０倍；筛选出可同时进行原球茎增殖及根、芽分化培养的培养基，用该培养基培养外殖体，每瓶可繁殖完整试管苗２０株，原球茎６０余个；试管苗移栽以发根时间７０天以上为宜，移栽基质以苔藓、红壤土、腐殖土混合物（１：１：１）为佳。     

苹果枣组培快繁技术研究

以ＭＳ为基本培养基，取苹果枣萌蘖苗茎段作外植体进行离体快繁研究，筛选出最佳分化培养基的激素配比是６－ＢＡ６．０ｍｇ／Ｌ＋ＮＡＡ０．１ｍｇ／Ｌ，生根培养基ＩＢＡ用量以０．６ｍｇ／Ｌ较好。试管苗繁殖系数达６．２，生根率达９１．６％，移栽成活度达９８％。     

相思杂种——莞屏1号离体快速繁殖的研究

对相思杂种——莞屏１号离体快速繁殖各个培养程序的培养基进行筛选，从而确定适合快速繁殖的最优培养基组分。试验结果表明，最适合诱导不定芽分化与增殖、不定芽伸长以及诱导生根的培养基分别为：ＭＳ＋６ＢＡ１．０ｍｇ／Ｌ＋ＫＴ１．５ｍｇ／Ｌ＋蔗糖３％、ＭＳ＋蔗糖３％、ＭＳ＋ＩＢＡ１．０ｍｇ／Ｌ＋ＮＡＡ０．５ｍｇ／Ｌ＋蔗糖２％。文中还对外植体的分段消毒法和试管苗移栽技术问题进行了探讨     

合果芋试管微繁殖技术的研究

对合果芋试管微繁殖技术研究结果表明：合果芋试管微繁殖需较高质量浓度的矿质营养。对试管芽苗增殖和生长最有效的植物生长调节剂为ＢＡ和ＮＡＡ〈增殖最佳配方为ＭＳ＋ＢＡ１．５ｍｇ／Ｌ＋ＮＡＡ０．２ｍｇ／Ｌ，ＢＡ；ＮＡＡ为７．５：１；高生长最佳配方为ＭＳ＋ＢＡ０．５ｍｇ／Ｌ＋ＮＡＡ）．１ｍｇ／Ｌ，ＢＡ：ＮＡＡ为５．１；培养最知温度为２８℃左右，光照度１５００ｌｘ，每日光照１５ｈ；在１／２ＭＳ＋ＩＢＡ０．５ｍ     

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.     

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.     

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。     

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.