糖和激素对香花槐微体快繁的的影响

以香花槐的幼茎为材料建立无性系，研究了蔗糖、BA、NAA和IBA等物质对香花槐嫩梢增殖倍数、嫩梢长度以及根诱导的影响。试验结果表明，增殖培养适宜蔗糖浓度为30g／L，BA浓度为0．5mg／L，N从浓度为0．05mg/L。根诱导可用NAA或IBA，但以NAA为最好，适宜的浓度为O．5～1．0mg／L。     

大马士革蔷薇的组织培养与快速繁殖

以大马士革蔷薇的当年生枝条为外植体,研究了不同浓度6-BA和NAA外源激素配比组合对其离体培养的影响,结果表明：适宜的诱导腋芽培养基为MS＋BA0．4mg／L＋NAA0．2mg／L;继代增殖培养基为MS＋BA0．5mg／L＋NAA0．2mg／L;生根培养基为1／2MS＋NAA0．3mg／L。     

尾叶桉丛生芽和生根的诱导

为了建立优良尾叶桉无性系组织培养与再生体系．培育速生耐寒转基因桉树新品种，研究了以广西林业科学研究院提供的尾叶桉（Eucalyptus urophylla）无菌苗为材料，选取带腋芽茎段作为外植体．诱导丛生芽的发生以及植株再生的过程。通过多种生长调节剂不同浓度组合的对比试验，筛选出尾叶桉茎芽分化的最佳培养基为MS＋ZT0．5mg／L＋NAA0．4mg／L；芽继代增殖最佳培养基为MS＋ZT0．5mg／L＋NAA0．2mg／L；适合生根的培养基为1／2MS＋NAA2．0mg／L＋IBA0．3mg／L。     

KT与BA对彩色马蹄莲组培苗增殖和生根的影响

在MS＋NAA0．5mg／L＋蔗糖40g／L＋琼脂4．5g／L的培养基上接种彩色马蹄莲（BlackMagic）继代培养产生的丛芽块添加外源激素KT和BA的浓度及其不同组合,研究外源激素KT和BA对丛芽块增大、不定芽个数、生根数和生根长度的影响。初步研究结果表明：KT的浓度为10mg／L时,丛芽块的增长最大为1．14cm2,BA浓度为0．5mg／L时丛芽块增长最快为1．24cm2。外源激素KT和BA相互作用时,KT10mg／L＋BA0．5mg／L激素组合有利于丛芽块的增大。同时在无BA条件下,MS＋NAA0．5mg／L＋KT10mg／L＋蔗糖40g／L＋琼脂4．5g／L有利于彩色马蹄莲不定芽的增殖,但KT、BA均抑制根的生长,且浓度越大抑制作用越明显。     

激素对沙漠玫瑰愈伤组织培养的影响

用沙漠玫瑰无菌苗充分伸展的叶片诱导出愈伤组织,进行愈伤组织的继代培养,以获得适于悬浮培养的愈伤组织,比较了不同植物生长调节剂及其配比在沙漠玫瑰离体培养中的效应．认为叶片接种到BA1～2mg／L NAA0.2～0.4mg／L的MS培养基中,愈伤组织的诱导效果最好;愈伤组织继代培养时．含2．4-D1～3mg／L或2．4-D1～2mg／L BA0.5～1.0mg／L的MS培养基的愈伤组织继代培养效果较好。     

神仙草组织培养快繁技术的研究

以神仙草的茎段和叶片为外植体,研究神仙草在添加了不同的激素成分及不同浓度的培养基中对不定芽诱导、继代增殖和生根培养的影响,结果表明:初代培养的适宜培养基是MS+BA 1.0 mg/L+NAA 0.1 mg/L;继代增殖适宜培养基是:MS+BA 2.0 mg/L+NAA 0.1 mg/L;生根适宜培养基是:1/2MS+NAA 1.0mg/L。     

一品红组织培养技术研究

一品红组织培养以花轴序、叶片或顶芽、腋芽为外殖体，在MS BA2．0mg／L NAA0．50nm／L 蔗糖30g/L 琼脂5g/L CH70mg／L pH5．8的培养基上进行初代培养后转接到MS BA0．5 NAA0．20 蔗糖30g／L 琼脂5g／L。 pH5．8的培养基上扩繁，增殖率为13．1，丛生芽分化快；生长速度快，将2cm左右嫩梢剪下接种在1．／2MS NAA0．1 蔗糖15g/L 琼脂5mg／L pH5．8的培养基上诱导生根，10d左右即可生根。一品红组培苗生根与继代次数关系密切，继代次数10次以下，生根率达100％，之后逐渐下降，需要重新建立培养系。试验总结出一品红12个品种组织培养的一整套技术，为一品红工厂化生产提供了技术依据。     

麝香百合的组织培养与快速繁殖

利用麝香百合茎段，采用水培法形成的珠芽作为外植体进行组织培养。试验结果表明，最佳诱导分化培养基为MS BAl．0mg／L NAA0．4mg／L，继代增殖培养基为MS BA2．0mg／L NAA0．1mg／L，生根培养基为1／2MS mA0．3～0．4mg／L，生根率达98％～99％，最佳移栽基质为蛭石：细砂：油渣(140：59：1)，成活率达96％。     

银木组织培养繁殖研究

以40年生银木顶芽和腋芽为外植体进行主体培养，筛选出各培养阶段适宜的培养基分别为：（1）启动，1／2MS＋BA0．5mg/L NAA0.01mg/L;(2)丛生芽分化及继代增殖，MS＋BA0．5mg/L NAA0.01mg/L。     

长白山濒危树种刺楸组培快繁技术研究

以长白山刺楸人工林选择的刺楸优良个体休眠枝条为试验材料，进行刺楸组培快繁各个阶段最适培养基的筛选。结果表明，刺楸组织培养的最适外置体为叶柄；愈伤组织诱导的最适培养基为WPM＋2，4－D0．50 mg／L＋NAA0．1 mg／L，诱导率96％；愈伤组织诱导再分化最适培养基为WPM＋KT2．0 mg／L＋6－BA0．50 mg／L＋NAA 0．1 mg／L，分化率达82％；不定芽继代培养最适培养基为WPM＋KT1．0 mg／L＋6－BA0．50 mg／L＋NAA 0．1 mg／L，增殖系数为3．69；不定芽生根培养最适培养基为WPM＋NAA 0．5 mg／L，生根率达到85％。     

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

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.