松墨天牛室内人工饲养及其生物学特性观察

在室内人工气候箱中对松墨天牛(Monochamus alternatus)进行人工饲养及生物学特性观察.结果表明:人工饲养条件下其羽化期为6～10d,交配2～4 d后产卵,雌虫平均产卵量60.5个;卵期为5～7d,卵的孵化率为85.95%;幼虫共5龄,1龄幼虫死亡率为25.89%,其它龄期幼虫很少死亡,幼虫化蛹率89.74%,蛹期为8～14d,蛹的羽化率为89.58%.成功建立了稳定的实验种群,实现了室内常年人工饲养,保证了实验虫源的供应,人工饲养和自然界松墨天牛的龄级一致,但人工饲养的天牛幼虫期、蛹期、羽化期、成虫帮命都大大缩短,成虫体形也较小,雌虫产卵数大大减少.     

应用携带病毒的赤眼蜂防治马尾松毛虫试验

林间挂放喷涂有松毛虫病毒的赤眼蜂卵卡,试验结果表明,林间赤眼蜂对马尾松毛虫卵的寄生率平均39.4%,室内赤眼蜂对马尾松毛虫卵的寄生率80.0%。林间观察到刚羽化的第二代赤眼蜂在松毛虫卵上活动。携带松毛虫病毒的赤眼蜂通过其寄生行为可把病毒传递到松毛虫幼虫期,松毛虫幼虫病毒感染率3.0%,松毛虫蛹期没有观察到松毛虫病毒传递现象。     

温度对马尾松毛虫发育进度及繁殖能力的影响

将马尾松毛虫Dendrolimus punctata punctata幼虫置于不同温度条件下饲养。结果表明:在20~30℃范围内各龄幼虫的发育历期随温度的上升而缩短,最快19.5 d即可完成幼虫发育,但在20℃条件下部分幼虫会出现滞育;化蛹率随温度上升呈明显的上升趋势,27.5℃时的化蛹率最高,达98.79%,但25,27.5,30℃时的差异不明显;茧蛹重量和成虫怀卵量的变化趋势完全一致,即在27.5℃时最大,温度下降或继续升高都会出现明显下降;而成虫羽化率在不同温度条件下的差异不明显。因此,27.5℃最有利于马尾松毛虫的发育和繁殖。     

松毛虫杂交试验研究初报

在湖南省株洲地区,用马尾松针叶饲养马尾松毛虫、文山松毛虫、赤松毛虫、油松毛虫和云南松毛虫,并进行41组213个配对的种间杂交试验,结果表明:马尾松毛虫文山松毛虫杂交,以及杂交种第一、二代自交和回交,一般都属正常,所产虫卵一与般能受精发育,幼虫一般能正常生长、结茧、化蛹和羽化。文山松毛虫与马尾松毛虫杂交所产的后代有一定的杂种优势,用其与马尾松毛虫回交所产的第二代表现出明显的杂种优势。     

雷公藤总甙对马尾松毛虫生物活性的影响

以无水乙醇为溶剂,用连续回流渗漉法从雷公藤生药中提取出粗提物。经乙酸乙酯纯化后得红褐色的浸膏,经检测为总萜内酯（T1）。就其杀虫活性和作用方式进行了较系统的生物测定。结果表明：T1对马尾松毛虫具有强的拒食、麻醉和毒杀作用,毒杀中浓度LC50为1548．50mg／L,拒食中量AFD50为12．25μg／条,麻醉中量ND50为103．98μg／g,无触杀作用;T1不仅抑制马尾松毛虫幼虫的生长发育．还影响其蛹的羽化和卵的孵化及初孵幼虫存活;抑制中浓度EC50为952．65mg／L;在T1浓度10～10000mg／L之间,马尾松毛虫蛹不完全羽化率为43．3％～63．3％。其卵的不能孵化率为12．0％～84．0％,孵化的幼虫存活率为0．0％～95．6％。     

星天牛幼虫人工饲料的饲养效果及温度对其生长的影响（英文）

【目的】研究星天牛人工饲料、饲养方法及温度对其生长发育的影响,为防治技术研究提供大量、生理标准统一的试虫。【方法】通过连续3年在4种不同配比的人工饲料上连续传代饲养星天牛,研究不同人工饲料配方的饲养效果;比较室内自然温度和恒温模式下星天牛在人工饲料上的化蛹和羽化情况;同时定期测定星天牛幼虫在不同饲料、不同温度模式下的体质量变化。【结果】星天牛幼虫在4种不同配方的人工饲料上均可完成生活史并传代饲养,但其化蛹率、羽化率在不同饲料上差异显著,其中以同时含有木麻黄锯屑和麦麸的Diet A和Diet D上饲养效果较好。在Diet A上,3代(持续3年)星天牛幼虫化蛹率依次为100%,90%和95%,羽化率依次为100%,83%和90%;在Diet D上,3代星天牛化蛹率依次为87%,78%和87%,羽化率依次为87%,67%和80%。在室内自然温度模式下,星天牛幼虫的化蛹率和羽化率较恒温模式(25℃和28℃)下高,且化蛹和羽化时间整齐一致(均在4—5月,与林间观察一致);而在恒温模式下化蛹和羽化时间明显延迟,且无规律性。人工饲料饲养条件下,星天牛幼虫体质量先增加,达到最大值后逐渐减小,直至化蛹或死亡。星天牛幼虫在Diet D上的体质量增长速度较其在Diet A上快,体质量最大值及到达时间因饲料种类、温度模式的不同而存在差异;在室内自然温度模式下,星天牛幼虫在饲养16周(11月下旬)后达到最大值,且在Diet D上的幼虫平均体质量(2.077 g)显著高于在Diet A上的体质量(1.685 g)。而在恒温模式(28℃)下,星天牛幼虫平均体质量在Diet D上饲养16周后达到最大值(2.106 g),而在Diet A上饲养20周后达到最大值(1.785 g)。【结论】星天牛幼虫可在筛选出的人工饲料Diet A和Diet D上连续传代饲养并完成生活史,饲养效果稳定,化蛹率和羽化率高;温度条件是决定星天牛化蛹时间的重要因素,星天牛幼虫在发育过程中不一定需要低温滞育,但是其存在可以提高星天牛幼虫的化蛹率和促进化蛹、羽化的一致性。研究结果为星天牛提供了人工饲料及方法,可为科学研究提供大量试虫,同时通过人工饲养有助于更深入了解其生物学特性;研究结果也可为其他天牛类蛀干害虫幼虫的饲养提供参考。     

饲养容器及密度对杨扇舟蛾生长发育和存活的影响

为实现杨扇舟蛾颗粒体病毒的大量生产,进行了筛选室内大量饲养杨扇舟蛾的适宜容器和密度试验。结果表明,饲养容器和密度对杨扇舟蛾均有显著影响。其中用杯底直径4.5 cm,杯口直径7 cm,高8.5 cm的透明塑料杯做容器饲养的杨扇舟蛾幼虫死亡率、逃逸率最低,化蛹率、蛹羽化率、单雌产卵量和卵孵化率最高,幼虫平均发育历期最短。8头/杯时的饲养密度,幼虫存活率最高,幼虫和蛹的体重增长最多,而且蛹羽化率、总产卵量、单雌产卵量以及产生子代个数也最高。     

杨小舟蛾人工饲养技术探讨

对杨小舟蛾卯、幼虫、蛹和成虫4个虫态进行室内人工饲养,探讨了成虫交配和幼虫饲养2个关键因子对饲养成活率的影响,系统总结了杨小舟蛾人工饲养技术。结果表明,将蛹进行单体饲养,成虫羽化后7～10h配对,交配率可提高到70％,与羽化不久即行配对的交配率存在极显著差异;采用三角烧瓶倒置饲养法饲养幼虫,其化蛹率可提高到85％,与常规饲养法的化蛹率也存在极显著差异。     

马尾松毛虫两种色型幼虫生物学特性研究

根据体色,可将马尾松毛虫幼虫分为黑色型和黄色型两种.用松针饲养同一卵块孵化出的幼虫,研究两种色型马尾松毛虫幼虫生长与发育.结果表明:虫口密度越大,色型比(黑/黄)愈大,黑色型马尾松毛虫的取食量、排粪量、蛹重、化蛹率和生殖力均大于黄色型,但发育历期和死亡率小于黄色型幼虫.     

马尾松毛虫越冬饲养初探

将室内自然温度饲养的第2代马尾松毛虫成虫所产的卵孵化后收集幼虫,分别以自然温度和加温饲养越冬。结果表明,通过加温的方法马尾松毛虫在室内可以继代饲养,室内自然温度越冬饲养1代过程中可以加温饲养3代,加温饲养的马尾松毛虫成虫的产卵量和孵化率与越冬代相比没有明显的差异。     

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.