不同基质和NAA质量浓度对药用观赏植物扦插生根的影响*

对蛇莓（Duchesnea indica）、翠云草（Selaginella uncinata）、过路黄（Lysimachia christinae）、垂盆草（Sedum sarmentosum）、活血丹（Glechoma longituba）5种药用植物进行扦插繁殖试验,研究了3种基质及NAA 激素3种质量浓度对5种植物扦插生根的影响。结果表明：蛇莓在不使用激素处理的条件下,田园土∶河沙＝1∶1的基质中生根效果最好,使用 NAA 处理后,泥炭土∶珍珠岩＝5∶1的效果最好;在100 mg／L NAA 的处理下,翠云草、过路黄在泥炭土∶珍珠岩＝5∶1的基质中,扦插生根效果最好;垂盆草在50 mg／L NAA 的处理下和田园土∶河沙＝1∶1的基质中进行扦插,其生根效果最好;活血丹在泥炭土∶珍珠岩＝5∶1和50 mg／L NAA 的条件下,生根效果最好。     

不同处理对梅叶冬青插穗生根的影响

为提高梅叶冬青扦插育苗的成活率以及扦插苗质量,研究了插穗粗度、基质类型、ABT-1生根粉浓度、植物生长调节剂类型(NAA、IBA)及其浓度、细胞活性成分(二甲亚砜DMSO)和抗氧化剂(抗坏血酸VC、聚乙烯吡咯烷酮PVP)的添加对梅叶冬青扦插育苗的影响。结果表明:插穗粗度、基质种类和生长调节剂浓度对梅叶冬青扦插生根影响显著。插穗粗度以直径0.9~1.6 cm的生根效果最好。黄土、河沙、园土3种基质中,黄土基质生根效果最好。就生长调节剂浓度而言,以低浓度(50 mg/L NAA、50 mg/L IBA、100 mg/L IBA或200 mg/L ABT-1)处理最佳。ABT-1、IBA、NAA的使用均显著提高了梅叶冬青的生根率,但2种生长调节剂IBA和NAA对生根率的影响差异不显著。以黄土为基质,在50 mg/L NAA的基础上添加抗氧化剂VC(抗坏血酸)显著抑制了梅叶冬青的扦插生根,添加抗氧化剂PVP和细胞活性组分DMSO显著促进了梅叶冬青生根。在所有的处理中,50 mg/L NAA+600 mg/L PVP+0.5%DMSO的处理生根率最高,达到48.89%。     

微型观赏红叶石楠短穗扦插试验初报

微型观赏红叶石楠嫩枝短穗扦插试验结果表明,在全光照自动间歇喷雾条件下,插条生根率及根系生长因植物生长调节剂的种类、质量浓度和处理时间、扦插基质的组分及插穗粗度的不同有明显差异。在6～8月,选择粗度0.3～0.5 cm插条,采用NAA 400 mg/L与IBA 400 mg/L的混合液浸泡处理40 s后,扦插于沙∶泥炭土∶珍珠岩=1∶1∶1(体积比)混合基质中,生根率可达98.3%。     

3种植物生长调节剂对紫叶稠李扦插生根的影响

试验研究不同质量浓度（50、100、200 mg/L）的植物生长调节剂吲哚乙酸（IAA）和吲哚丁酸（IBA）、萘乙酸（NAA）和不同处理时间（30 min、60 min）对紫叶稠李扦插生根的影响。结果表明：30 min、60 min不同质量浓度IAA和NAA均未显著促进紫叶稠李扦插生根,而与CK相比,30 min、60 min IBA处理50、200 mg/L显著促进了紫叶稠李的生根率、根长及根数,且60 min IBA处理50 mg/L效果显著。表明植物生长调节剂IBA对紫叶稠李扦插生根的效果优于IAA和NAA,且60 min IBA处理50 mg/L是最佳组合。     

激素和基质对八角金盘扦插生根的影响

以河沙、黄土、河沙＋黄土为扦插基质,采用ABT1、IBA、NAA3种激素对扦条进行处理,研究激素和基质对八角金盘扦插生根的影响。结果表明：高浓度（200—500mg／L）的激素处理有利于扦插生根,低浓度（50-100mg／L）的激素处理效果不明显。河沙、河沙＋黄土、黄土3种基质中,以透气保湿性好的河沙最优。     

不同基质及生长素对国槐扦插生根的影响

研究了不同扦插基质及生长素对国槐(Sophora japonica)扦插生根的影响。结果表明,国槐扦插基质以河沙+蛭石+草炭(体积比1∶1∶1)生根效果最好,生根率和生根指数分别为85.07%和25.07,生根效果优于河沙+蛭石(体积比1∶1)和河沙单一基质。生长素处理下可以显著促进国槐的扦插生根,以NAA的效果优于IBA和ABT1的处理,以NAA为500mg/L浓度下插穗的生根率和生根指数最高,分别为78.14%和24.71,显著优于对照组。因此实际生产中可选择河沙、蛭石、草炭三者混合作为基质,并在扦插前用500mg/L NAA浸泡插穗,以提高国槐扦插生根。     

棣棠嫩枝扦插育苗试验研究

棣棠嫩枝扦插育苗的成活率受很多因素的影响。试验研究表明,在蛭石为扦插基质,IBA、NAA、ABT2、GGR8（绿色植物生长调节剂）、GGR10五种植物生长调节剂处理插穗时,以ABT280mg/L和IBA40mg/L的浓度促进生根好,扦插后,加强扦插苗的水分、光照、温度、病害和施肥管理,可以进一步促进插穗的生根和生长。     

香石竹扦插繁殖技术

以嫩枝插穗为基本试材,研究不同扦插基质、不同激素的不同浓度对香石竹扦插生根的影响。结果表明:香石竹在河沙、珍珠岩、草炭和蛭石中扦插均能生根,最佳扦插基质是蛭石(生根率97%)。用不同浓度的IBA、NAA生根剂进行香石竹扦插时,使用150mg/L的IBA及100mg/L的NAA处理的香石竹生根率最好。     

绣球品种‘蓝尼康’扦插技术研究

为了提高绣球花的扦插繁殖效率,以国外引进的优良品种绣球花‘蓝尼康’为试材,研究了不同基质、不同种类与浓度的生长调节剂及萘乙酸(NAA)的不同浓度处理对绣球花扦插成活率和生根的影响情况。结果表明:适用于绣球花扦插的基质为珍珠岩∶沙子=1∶1的混合基质,以此基质扦插的成活率为88.6%;在浓度均为500 mg/L的3种植物生长调节剂处理下,最适于绣球花扦插的植物生长调节剂为NAA,以NAA处理的扦插成活率为91%,平均生根长度为2.1 cm;最适于绣球花扦插的NAA浓度为600 mg/L,以此浓度的NAA处理的成活率为94%,生根长度为2.3 cm。     

不同基质与NAA浓度对小蔓长春花扦插生根的影响

以小蔓长春花当年生枝条为试材,采用蛭石、河沙、园土等扦插基质,不同浓度的NAA对小蔓长春花插条进行了扦插生根试验,结果表明：以200mg/L NAA蘸根,以河沙为基质最适宜小蔓长春花扦插生根,生根率达89%;平均生根数4．67条;平均根长3．45cm。NAA各处理在生根长度、生根条数上均较空白对照显著增加。     

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.