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%。     

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%。     

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％。     

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.     

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。     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.