野葛愈伤组织诱导与不定芽分化

采用MS为基本培养基，附加NAA、6-BA和IAA3种激素．诱导野葛不同外植体愈伤组织形成；再将愈伤组织接种在不同浓度6-BA的MS培养基上．分别在光照和黑暗条件下进行不定芽的诱导。结果表明．野葛幼叶、茎段和顶芽在适宜激素的诱导下均能形成愈伤组织，但不同激素组合其愈伤组织诱导率不同。幼叶愈伤组织诱导的最适培养基为MS NAA1．0mg／L 6-BA1．0mg/L．其诱导率为75％．茎段愈伤组织诱导的最适培养基为MS NAA1．0mg／L 6-BA3．0mg／L IAA0．2mg/L，其诱导率为70％。不同外植体形成的愈伤组织其不定芽的分化诱导率不同．茎段愈伤组织在不同浓度6-BA下均能诱导出不定芽；光照有利于芽的分化．在光培养条件下，茎段愈伤组织不定芽平均诱导率为66．7％。     

云南松成熟胚的离体培养

采用云南松(yunnanensis)成熟胚为外植体,培养室温度为25±4℃,培养基的蔗糖浓度为8％。以 1／2MS为基本培养基,在BA0．5-2．0mg／L+NAA0．5-1．5mg／L的激素配比范围内,可诱导离体胚产生愈伤组织及不定芽。外植体愈伤组织的诱导率达80％,由愈伤组织诱导不定芽,其分化率达17．8％。研究结果表明,激素的种类和浓度对外植体愈伤组织及不定芽的诱导起主要作用。     

花叶木槿组织培养技术的研究

以花叶木槿叶片、茎段、芽为外植体进行的离体再生研究结果表明,叶片愈伤组织诱导最佳的培养基是MS＋6-BA2mg／L＋NAA0．2mg／L＋2,4-D0．2mg／L;茎段在MS＋6～BA3mg／L＋NAA0．4mg／L上诱导的愈伤组织有不定芽分化,分化率45％;芽在MS＋6-BA3mg／L＋NAA0．4mg／L培养基上效果较好,在MS＋6-BA1mg／L＋NAA0．2mg／L上生根效果最好,可达100％。     

松塔景天组织培养与快速繁殖的研究

以松塔景天幼嫩叶片作为外植体,利用含有不同浓度配比植物生长调节剂的培养基分别进行愈伤组织的诱导、不定芽的诱导、生根培养及驯化移栽,建立了松塔景天组织培养和快速繁殖体系。试验结果表明：诱导愈伤组织的最适培养基为MS＋6-BA 0．5 mg/L ＋NAA 0．05mg/L ,愈伤组织诱导率达87．78％;诱导不定芽的最适培养基为MS＋6-BA 1．0mg/L＋ NAA0．1 mg/L ,不定芽诱导率达88．89％;组培苗最佳生根培养基为1/2 M S＋IB A 0．3 m g/L ,生根率达91．33％;组培苗的移栽成活率达84％。     

灯盏细辛离体叶片再生植株的研究

以灯盏细辛（Erigeron breiscapus）叶片为外植体,研究不同培养基配方对灯盏细辛离体培养过程中愈伤组织、不定芽形成,壮苗培养和离体植株生根等方面的影响。研究结果表明,低浓度的细胞分裂素与生长素配比可诱导灯盏细辛愈伤组织产生,其中MS＋BA1．00mg／L＋NAA0．50mg／L培养基配方,愈伤组织诱导率达到99．22％;不定芽诱导需要较高浓度的细胞分裂素,适宜培养基MS＋KT4．00mg／L＋IBA0．50mg／L的不定芽诱导率为38．51％,诱导系数为0．49;MS＋BA0．50mg／L＋NAA0．50mg／L＋水解酪蛋白1000．00mg／L＋PVP1000．00mg／L＋GA0．50mg／L培养基可促进不定芽分化生长,形成离体植株;离体植株生根需要高浓度生长素,适宜培养基为1／2MS＋BA0．50mg／L＋NAA3．00mg／L＋IBA3．00mg／L＋活性炭0．30％。     

短葶山麦冬茎尖愈伤组织的诱导与植株再生

以短葶山麦冬茎尖为外植体,进行了优化愈伤组织诱导与植物再生的最适激素配比试验。结果表明：诱导愈伤组织的最佳培养基为MS+2.0 mg/L 2,4-D+1.5 mg/L 6-BA+1.0 mg/LNAA,愈伤组织紧密块状,生长状况良好,诱导率达94.55%;愈伤组织继代培养最佳培养基为MS+1.0 mg/L 2,4-D+1.50 mg/L 6-BA+0.5 mg/LNAA,愈伤组织净增鲜重为1.08g,增殖系数达到5.1;愈伤组织分化不定芽最佳培养基在MS+4 mg/L6-BA+0.5 mg/LNAA,不定芽增殖系数达到5.54,最有利于不定芽形成。     

短柄五加愈伤组织诱导及再生体系的建立

以短柄五加(Acanthopanax brachypus Harms)当年生嫩枝为材料,选择叶片、叶柄为外植体,使用6-BA、NAA、IBA、2,4-D等激素,配制成不同质量浓度的培养基,进行短柄五加愈伤组织诱导,同时分析愈伤组织诱导丛生芽和丛生芽增殖培养基的最佳配方,建立短柄五加植株的再生体系。结果表明,短柄五加叶片是较适宜诱导愈伤组织的外植体,愈伤组织诱导的培养基是MS+0.3mg/L 6-BA+0.5mg/L NAA,诱导率为75.0%;愈伤组织诱导不定芽形成的适宜培养基为MS+6-BA 1.0mg/L+NAA 0.1mg/L,不定芽诱导率为100%;适宜不定芽增殖的培养基为MS+6-BA3.0mg/L+NAA 0.2mg/L,增殖系数为5.80;同时活性炭能够有效防止愈伤组织诱导过程中的褐化问题。     

红掌组织培养快繁技术研究

分别采用红掌叶片和茎尖作为外植体,建立了组织培养快繁技术体系,结果表明：以0．1％ HgCl2作为消毒剂最佳的消毒时间均为8min ,叶片愈伤组织诱导、不定芽分化和增殖最佳培养基分别为 M S＋IAA2．0mg／L＋6－BA 0．2mg／L、MS＋NAA0．5mg／L ＋6－BA2．0mg／L ,茎尖不定芽诱导与增殖最佳培养基为MS＋IAA0．2mg／L ＋KT2．0mg／L ,最佳的生根培养基为1／2MS＋IAA0．5mg／L＋6－BA 0．2mg／L。     

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％。     

葡萄柚品种哈路比叶片离体再生体系的优化

为给葡萄柚的大规模育苗提供方法,以葡萄柚品种哈路比的叶片为外植体,在MS培养基中添加不同浓度配比的激素,探索其离体再生的优化体系。试验结果如下:培养基为MS+0.6 mg/L 6-BA+1.0 mg/L 2,4-D愈伤组织诱导率最高为78.57%,愈伤组织呈黄绿色,结构疏松,长势良好;MS+3.0 mg/L 6-BA+1.5 mg/L NAA是诱导愈伤组织分化不定芽的最佳培养基激素浓度配比,分化率最高为48%,不定芽分化快,长势良好;培养基MS+2.0 mg/L IBA有利于诱导生根,生根率达60.74%。初步建立了葡萄柚哈路比的离体再生体系。     

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.