大叶栎容器育苗试验

对大叶栎容器育苗不同基质,芽苗移栽不同截根长度、不同发育期,苗生长期遮荫试验表明:芽苗移栽时截根留2～4 cm有利于苗木的生长;茎芽幼叶展开期移栽成活率高,达97.53在%;全光照育苗对苗木生长明显大于遮荫条件下生长苗木;黄心土基质的苗木成活率、苗高、根系数量及生物量均最高.     

桃儿七组织培养苗炼苗移栽技术

从炼苗时间、移栽基质、移栽季节等方面对桃儿七组培苗炼苗移栽技术进行了研究。结果表明,一定范围内,炼苗时间越长组培苗移栽成活率越高,开瓶炼苗5d最适宜出瓶移栽;移栽基质选用草炭土与珍珠岩按2∶1比例混合,成活率最高,25～30d均有新叶和新根长出。在兰州地区,10—11月和3—4月适宜进行桃儿七组培苗的移栽,成活率最高达98.1%。移栽后10个月,植株生长健壮,根系发达。本研究结果为利用组织培养技术进行桃儿七的快速繁殖提供技术支撑。     

三倍体毛白杨组培快繁技术研究

三倍体毛白杨在MS＋BA0.5＋IBA0．25＋NAA0．2的培养基上每3周能增殖5.6-7.8倍,在1／2MS＋IAA1.0的培养基上生根率72．8％～76％。试管苗温室锻炼成活率达到82．1％,大田移栽成活率最高达86．3％。不同品系增殖能力略有差异,以蛭石＋草炭土为锻炼基质和大田覆盖遮荫网均能大幅度提高试管苗的成活率。     

河北杨无菌微型扦插生根苗炼苗移栽技术研究

以河北杨无菌微型扦插生根苗为试验材料,分别从生根瓶苗驯化过渡方法、移栽基质筛选、遮荫保湿措施等几方面开展研究。结果表明:生根瓶苗在智能温室闭瓶2d、开瓶3d的驯化过渡法其炼苗成活率最高,达90.67%;移栽介质国产泥炭+珍珠岩(8:2)中移栽成活率达54.67%,优于西宁地区常用的其他4种介质;在智能温室中不需采用其他遮荫保湿措施,其移栽成活率就能达到78.67%。     

丽格海棠叶片的组织培养研究

取丽格海棠叶片作外植体,通过试验,分析不同激素配比对芽的诱导、增殖及生根的影响,筛选出丽格海棠叶片组织培养的适宜培养基及试管苗最佳移栽基质。结果表明：其最佳诱导培养基为MS＋6-BA1．5mg／L＋NAA0．8mg／L,不定芽诱导率达100％;最佳继代培养基是MS＋6-BA1．0mg／L＋NAA0．5mg／L,增殖倍数达6．5倍;最佳生根培养基是1／2MS＋NAA0．4mg／L,生根率达100％;试管苗最佳移栽基质为用1／2MS大量元素浇透的草炭,移栽成活率为85％。     

野生山丹组培快繁的研究

以山丹的叶片、鳞片、幼嫩茎段、种子为外植体,进行组织培养研究。结果表明:不同外植体诱导分化能力不同,其中种子>鳞片>幼嫩茎段>叶片;不同浓度激素组合配比对山丹外植体鳞片诱导不定芽也有显著差异,其中以MS 6-BA2.0mg/l NAA0.1mg/l诱导的不定芽迅速形成小鳞茎;而且不同部位百合鳞片分化小鳞茎能力不同,分化能力大小为基部>中部>上部;不同继代培养基对山丹鳞茎增殖有显著影响,以MS 6-BA1.0mg/l NAA0.1mg/l继代繁殖效果最佳;不同生根培养基对山丹继代苗生根影响差异显著,以MS IBA0.5mg/l为佳,生根率为80%,平均每棵苗生根8.1条;不同移栽基质对山丹生根苗移栽成活率影响不同,以泥炭土为佳,移栽成活率可达100%。     

光叶楮组织培养快速繁殖技术的研究

对光叶楮组织培养中的外植体灭菌、苗玻璃化预防、增殖培养、根原基诱导及室外移栽进行的试验结果表明:以优良母株的具腋芽茎段为外植体,经过0.1%的HgC l2灭菌后,外植体成活率为53.6%;培养基中添加4.0%的蔗糖及增加培养容器的透气性能能较好地预防玻璃苗的发生;在MS培养基中附加BA,NAA等植物生长调节剂可有效促进试管苗的增殖和生长,其中以1.5 mg/L BA 0.1 5 mg/L NAA的组合最为适宜;适宜的根原基诱导培养基为1/2MS 0.5 mg/L IBA 0.3 mg/L NAA 100 mg/L LH 2%蔗糖;具根原基试管苗移栽于混合基质(蛭石∶珍珠岩∶泥炭=6∶3∶1,体积比)中,温度控制在20~30℃,相对湿度为85%~90%,保湿15~20 d,其间适当遮荫,30 d后试管苗成活率达90%。     

黑琥珀李试管苗移栽技术

取黑琥珀李生根试管苗进行移栽试验 ,保持移栽成活率 95%以上 ,并从试管苗质量、移栽基质、有效叶片数、湿度、温度等方面 ,探讨了影响试管苗移栽成活率的因素。     

安祖花试管苗移栽成活率初探

取安祖花生根试管苗进行移栽试验，保持移栽成活率在90％以上，并从试管苗移栽基质、有效叶片数、湿度、温度等方面，探讨了影响试管苗移栽成活率的因素。     

蕨菜孢子组织培养技术的研究

以蕨菜孢子为外植体试材,进行组织培养试验,采取MS基本培养基,附加不同种类、不同浓度的植物生长调节剂,进行了诱导培养、增殖培养、生根培养、炼苗移栽的研究,探索其组织培养的适宜条件。结果表明,蕨菜孢子的最佳诱导培养基为1/2MS;增殖培养基为1/2MS+6BA 1.5mg/L+NAA0.05mg/L;生根培养基为1/2MS+NAA 0.05mg/L+IBA 0.2mg/L,生根率达98.6%以上,平均生根条数为7.4条/株,根长长达6.1cm;经过炼苗移栽,苗势较为旺盛,移栽成活率达到95%以上。     

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.     

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。     

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 Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.