培育独本菊的技术要点

独本菊又称品种菊，每盆1株，1株1花，最能体现菊花品种的特征。培育独本菊的要点是冬藏、春种、夏定和秋养等四大环节。冬藏秋末冬初精选脚芽扦插，置向阳、低温(3℃左右)的室内养护，不干透不浇水，以防徒长。春种翌年3月将冬藏的脚芽苗分栽在装有普通培养土的盆内，置室外背风向阳处养护，适当浇水，注意松土，培育植株根系。夏定当苗长到40厘米左右时，分期分批摘心，促使萌发新的脚芽。7月中旬以后摘心抹芽，待盆土内萌发出几个脚芽苗时，选留花花草草从盆边生出的一个顶芽饱满、长势旺盛的脚芽苗，其余全部挖除。待留下的苗长到15厘米…     

菊花的品种复壮栽培技术

阐述了菊花的品种复壮技术，即采用二次脚芽培植法，以保持品种的优良特性。     

杨树与栅锈菌互作的组织病理学研究

用整叶组织透明染色法对亲和性、非亲和性杨树品种与落叶松-杨栅锈菌（Melampsora larici-popu-lina Kleb）相互作用的组织病理学进行了系统的观察。夏孢子接种6h后开始萌发，12h后芽管侵入气孔，此的在寄主细胞内形成吸器。芽管常形成树杈状或根状分枝，一个芽管分别侵入两个气孔或几个芽管同时侵入一个气孔。杨树与栅锈菌相互识别 中的抗锈性的表达主要发生在接种24h后，即气孔下囊形成阶段。表现为夏孢子萌发初期受抑，气孔下囊形成较迟、数量较少、初生侵染菌丝的长度受抑，吸器出现迟、数量少以及寄主叶肉细胞坏死等，但不同组合间在发生时间和程度上有较大差异。接种12h后，感病品种的叶肉细胞中出现吸器，36h后抗病性组合中出现吸器。随着菌丝的增多，抗病品种中的吸器数量、菌落面积小于感病品种、多于近免疫品种。低反应型品种中菌落线性生长受抑和吸器形成的减少均发生在叶肉细胞坏死之后，尚未发现高感品种出现叶肉细胞坏死现象。     

桑天牛在不同树种或品种间产卵选择性试验

选用１１个树种、２３个桑树品种、４０个毛白杨无性系、１６个苹果品种和白杨派６个树种或无性系，进行了桑天牛产卵选择性试验。结果表明：桑天牛在不同树种间产卵选择性差异极显著；在苹果品种间、桑树品种间，毛白杨无性系间，白杨派不同树种及无性系之间，产卵选择性差异均不显著，但在个别品种上产卵数量较少，有待进一步研究。     

不同修剪方式对1年生切花月季生长及产花的影响

通过对“萨蔓莎”、“金徽章”、“坦尼克”３个切花月季品种１年生苗徒长枝采用嫩枝摘心、半成熟枝摘心、半成熟枝折枝、成熟枝剪枝４种不同修剪方式,统计侧枝数、脚芽数、花枝长、花枝数等表明,同一修剪方式对３个切花月季品种生长的影响有一定共性,但不同品种之间又表现差异,而不同修剪方式中以半成熟枝摘心最为合适。     

核桃高效采穗圃系统修剪技术研究Ⅱ早实核桃采穗圃修剪技术研究

研究了抹芽、摘心、短截等夏季修剪措施对核桃采穗圃及短截、缩剪、重缩剪、长放几种冬季修剪措施对云新核桃采穗圃品种问、品种内,强、弱母枝的发芽率、成枝率、枝接长度和利用率、方块芽数量的影响;确定了不同品种提高枝接穗条长度和方块芽数量的修剪技术措施。     

盆栽葡萄的冬剪法

庭院或盆栽葡萄的冬季修剪是调节葡萄第二年植株侧蔓生长与结果的关键，同时可改善枝蔓间的通风透光条件，使其年年能优质高产稳产。修剪时间以落叶至致分流期前进行，修剪方法据不同品种树龄、树势、立地条件、种植稀密程度等情况来确定。一般长势强的葡萄品种，应以长梢修剪为主，留芽 8～ 11个，轻剪长放多留，辅以中稍修剪，留芽 5～ 7个。长势较弱的品种，以短梢修剪，留芽 2～ 4个，辅以中梢修剪。所以，根据不同品种、长势、种植密度程度的不同而决定修剪的。 盆栽葡萄的冬剪法@李霞     

不同品种黑莓在南京地区的生长表现

为了给黑莓品种的鉴定和栽培措施的制定提供科学依据,对11个黑莓品种在南京地区的生长情况进行了调查和分析。结果发现,黑莓功能叶片中叶绿素含量平均为(40.87±4.84)spad,同一品种在不同生长期其叶绿素含量比较稳定,而不同品种却存在着较大的差异。复叶大小平均为(1.51±0.25)dm2,品种间差异显著,其中Chester品种的最大,Triple Crown的最小,前者是后者的1.65倍。小叶数量和单株叶面积分别平均为(4 815±3 880)片和(7.65±5.94)m2,品种间差异极显著,其中Kiowa品种的叶片数量最多,其单株叶面积最大,单株叶面积平均为(22.92±6.72)m2,远远高于其它品种。枝蔓数量和年生长量分别平均为(26.32±10.92)支和(2.14±1.52)dm3,品种间差异也达到了极显著水平,枝蔓发生数量最多的品种也是Kiowa,最少的品种是Young,后者数量不到前者的1/4;Kiowa和Triple Crown这2个品种的枝蔓年生长量最大,Young品种的年生长量最小,前者是后者的10余倍。     

5个黑莓杂交F_1品系及其亲本芽的特性

为给新品种的选育提供科学依据,对5个黑莓杂交F_1品系及其亲本品种的芽间距、萌芽与现蕾物候期、萌芽率和成穗率等生长习性进行了调查与统计分析。结果表明:5个黑莓杂交F_1品系及其5个亲本品种的芽间距平均为(6.58±1.30)cm,各品系或品种间差异显著,但5个品系与各自亲本间的差异不显著;萌芽期为2月下旬~3月上旬,平均持续时间为(18.00±2.26)d,在5个品系间差异较小,在5个亲本品种间差异较大;现蕾期为3月底~5月初,平均持续时间(19.40±2.50)d,在5个品系间差异较大,在5个亲本品种间差异较小;萌芽率较高,平均为(92.20±3.15)%,品系及品种间差异不显著;平均成穗率为(77.19±10.23)%,品系及品种间差异显著;杂交F_1品系‘7-7-4’具有高的萌芽率和成穗率,且物候早,在萌芽特性方面表现优良,是值得进一步观察和培育的育种中间材料。     

银杏幼树嫁接良种技术研究

用郯城９号、５号、１３号、１６号、３１３号、３１７号６个银杏品种进行嫁接试验，嫁接成活率均在８３．３％以上，品种间无明显差异，新梢生长量以郯城９号最大为４２．０ｃｍ，郯城９号等５个品种间无显著差异，均与３１３号（２１．２ｃｍ）有显著差异。以郯城９号为试材进行嫁接部位、接穗留芽数、接穗年龄及粗度试验，结果表明：嫁接部位在苗高５０～８０ｃｍ较好，成活率均在８５％以上，幼树生长旺盛；接穗留３芽成活率可达９０％以上，留单芽成活率仅６０％；接穗年龄对嫁接成活率影响不显著，但接后新梢生长以１～３年生较好；接穗粗度以０．４～０．９ｃｍ为好。     

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.     

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.     

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。