金眶行鸟在鄱阳湖繁殖的习性研究

为金眶行鸟在长江中、下游繁殖的首次报道。目前为止有关文献与报道仅将金眶行鸟（普通亚种）记录为长江中、下游的旅鸟。它的繁殖地分布在内蒙古中部、山东、山西、陕西、青海等黄河以北地区。通过作者观察发现，每年4～6月间在大量金眶行鸟在鄱阳湖保护区范围内的梅西湖、朱市湖和大湖池等地繁殖，本文从繁殖生境、配对、营巢、产卵、孵化出雏等方面对金眶行鸟的繁殖生态进行报道。     

绒毛梣及红梣的形态特征及其变异调查

绒毛ＦｒａｘｉｎｕｓｖｅｌｕｔｉｎａＴｏｒｒ.及美国红Ｆ .ｐｅｎｎｓｙｌｖａｎｉ ｃａＭａｒｓｈ .都是木犀科属树种 ,原产北美 ,二十世纪初引入我国 ,现为自鸭绿江口至甬江口滨海盐碱地区的主要造林树种之一。由于最早引进的两树种的采种母树距离较近 ,往往对其混采混育的结果 ,致使各地营造的绒毛林内常混生大量的红植株。林业生产中绒毛和红多为有性繁殖 ,林木个体间在形态、习性等方面出现较多变异。我们在进行多年观察的基础上 ,对两树种的形态特征及变异情况进行了调查 ,结果介绍如下。1　调查地区2 0 0 0年秋冬季…     

朱鹮的过去现在和未来——写在“保护朱鹮的二十年”之际

朱的过去朱最早记载，见于我国西汉司马迁所著《史记》，距今两千多年历史，春秋时代《禽经》载名朱鹭。明代《食物本草》书中“又有红鹤，相类色红，《禽经》所谓朱鹭是也”。它在动物分类上，属鹳形目，亚科，被誉为“东方宝石”。朱系亚洲东部特有种。历史上曾广泛分布于中国、日本、朝鲜半岛和俄罗斯的远东地区。但是在本世纪下半叶以来，由于受人类活动的严重影响，朱栖息地环境不断恶化，分布区迅速缩小，种群数量急剧减少，至70年代后期，俄罗斯和朝鲜半岛的朱相继绝迹。日本为挽救濒于灭绝的朱，于1981年把野外仅存的…     

池杉快速无性繁殖法(Ⅰ) 插床改进和营养期连续多次扦插育苗

<正> 池杉(Taxodium ascendens Brongn)原产北美,于本世纪二十年代引种我国,推广发展很快,成为我国淮河流域以南数省,特别是长江中、下游平原湖区的速生用材和园林绿化树种。在池杉无性系选育及应用优良无性系造林工作中,快速无性繁殖是个技术关键。通过两年来的试验趼究,我们应用电子叶扦插繁殖圃等     

根河地区鸟类生态分布及区系特点

根河地区在大兴安岭北段,见有132种鸟类,隶属14目29科。130种为繁殖鸟,以黑嘴松鸡、金??鴴、黄雀、白头??巫鸟和栗??巫鸟为地理代表种。金鸻等16种和亚种鸟类为该区繁殖新发现。     

长江经济带污水处理工艺空间分布研究

以2013年长江经济带1839座城镇污水厂为研究对象,分析了长江经济带上、中、下游城市污水处理工艺的空间分布特征.结果表明:长江经济带污水厂数量表现为下游>上游>中游,江苏省污水厂数量最多,为512座.长江经济带污水厂主要处理工艺为A2/O和氧化沟处理工艺,A/O次之.其中,上游城市主要以CASS和氧化沟工艺为主,中游...     

金弹子的嫁接繁殖及驯化栽培

以金弹子(Diospyros cathayensis)的植物学特征和生态学特性为切入点,通过多年驯化栽培中的观察和研究,基本掌握了野生金弹子的嫁接繁殖、驯化栽培等方法,总结出一套适合武陵山区野生金弹子驯化栽培和苗木繁殖的实用技术,为武陵山区人工栽培金弹子奠定基础。     

药用植物金铁锁栽培研究现状

该文对我国西南地区特有的药用植物金铁锁的形态特征、生长习性、资源分布、药用价值等方面进行了阐述,并对其种子繁殖与栽培、组织培养等方面的研究现状进行了概述,并且分析了目前金铁锁开发利用中存在的问题,在此基础上提出了一些建议,为其进一步开发和合理应用提供参考。     

金苞花茎段的离体培养

金苞花(Pachystachys lutea Nees),又称黄虾花,是爵床科(Acanthaceae)中具有较高观赏价值的花灌木。花形奇特,金黄色,花期长,在适宜条件下,可全年开花。为了快速繁殖此种花卉,曾有用金苞花茎尖,腋芽组织培养成功的报道,但往往在继代培养中出现落叶、退化现象,影响了快繁速度。为此,我们改进培养方法,对继代繁殖过程中出现的落叶,退化现象加以抑制。本文以金苞花茎段为材料,探讨了IAA、BA对其茎段离体培养的增殖和生长效应。     

菊花“丽金”的快速繁殖研究初报

前言利用组织培养技术繁殖菊花,国内外已有不少报道,但菊花品种丽金是近年引进的名贵切花品种,作盆花栽培,观赏效果亦很好。丽金花色鲜红艳丽,在节日期间颇能增添喜庆色彩。因此,不管在广东内地或港澳地区,都深受群众欢迎,近年来,丽金已成为港澳花卉市场上菊之上品。丽金也是广州市民喜爱的菊花品种之一。1980年、81年、82年连续三年在广州市迎春花会上获得一、     

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.     

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.     

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。