毛竹种子“以芽繁芽”组培快繁初步研究

以毛竹种子为外植体,通过“以芽繁芽”方式找到了较好的外植体消毒技术、增殖培养基、生根培养基和炼苗移栽技术等,初步建立了毛竹种胚外植体“以芽繁芽”组培快繁体系。其中最佳消毒时间为10％次氯酸钠溶液0．1％升汞各20min,消毒成功率可达37％;最佳增殖培养基为MS＋TDZ0．5mg／L＋KT2．0mg／L,增殖4-5代则衰退;生根培养基以1／2MS＋IBA1．0mg／L＋KT0．5mg／L＋AC0．1g／L效果较好;炼苗移植成活率可达69％,可应用生产。     

雷公藤组织培养外植体消毒和选择

以雷公藤为材料,研究了雷公藤用不同外植体与不同消毒方法对组织培养的影响.试验结果表明:雷公藤组织培养最佳外植体为无病害的绿色嫩叶;最佳消毒方式为70%的酒精浸泡30 s、10%的NaC1O中消毒15min.该方法污染率最低、苗存活率最高,分别为21.08%、65.66%.     

夏蜡梅组织培养试验初报

以夏蜡梅茎段为外植体，进行夏蜡梅组培试验，结果表明：外植体茎段的最佳消毒方式是先用70％酒精消毒10—15s，再用0．1％HgCl溶液浸泡3—5min；继代增殖培养的最佳培养基为MS＋6-BA2．0mg／L＋NAA0．1mg／L＋蔗糖30g/L，增殖系数4．03，茎芽生长粗壮；最佳生根培养基为I／2MS＋IBA0．4mg/L。     

浅析三倍体毛白杨组织培养中外植体的灭菌

对不同季节的三倍体毛白杨外植体进行2种消毒灭菌剂配合使用，采用不同时间灭菌及对外植．体取材不同的处理。试验结果表明，外植体在2、3月份随采随用，带芽茎段在漂白粉饱和上清液浸泡30min、0．1％升汞15min，水培嫩枝将0．1％升汞改为10min的处理中灭菌较好。     

均匀设计法在植物组织培养外植体消毒中的应用

以2年生刺槐插根苗的叶柄为材,采用均匀设计及其分析方法,以84消毒液为消毒剂,进行外植体消毒试验,得出最佳消毒处理组合为:消毒液有效浓度0.3%,时间4.07min。     

胡桃楸最佳初代组织培养选择的研究

通过对不同消毒方式、树龄、基本培养基类型和激素组合对初代培养进行最佳选择的研究结果表明：先70％酒精30s（2次）再O．1％HgCl2 10min的消毒方式，消毒效果较好，污染率和褐化率均较低，分别为6．9％和20．3％；1年生植株适合做接种外植体；Ms培养基为较适宜胡桃楸的培养基，外植体在MS＋IBA0．01mg／L＋6-BA2．5mg／L上生长最好，其腋芽长为2．27cm。     

野生软枣猕猴桃种子萌发及离体快繁技术研究

试验以野生软枣猕猴桃的幼嫩茎段为外植体,对软枣猕猴桃无菌系建立、增殖培养、生根培养技术等快繁关键技术及种子萌发特性进行研究,以期为野生软枣猕猴桃资源的开发利用提供技术支持。结果表明,采用2.5%次氯酸钠浸泡10min再用0.1%升汞浸泡9min为最佳消毒方法,外植体的污染率和死亡率都比较低,分别是27.5%和17.5%;最佳增殖培养基为MS+6-BA 0.8mg/L+NAA 0.3mg/L,增殖系数达4.84;最佳生根培养基为1/2MS+IBA 1.0mg/L+NAA 0.1mg/L,根系健壮,生根率达到100%;种子在45℃恒温水中浸泡30min,然后用0.08%赤霉素处理24h发芽率最高,为70%。     

荻植株再生体系建立

以成熟种子为外植体建立了荻植株再生体系。荻成熟种子经20％“84”消毒液处理20min,接种于MS＋4％蔗糖（pH5．5）培养基中培养5d,萌发率为92％,褐化率为8％,污染率为0。萌发种子继代转入愈伤诱导培养基MS＋lmg／16-BA＋1mg／12,4-D＋0．5mg／lNAA＋4％蔗糖（pH5．5）,光照条件下愈伤组织诱导率为86％,黑暗条件下愈伤组织诱导率64％。荻愈伤组织在Ms＋1IYlg,L6-BA＋0．1mg／L2,4-D＋0．5mg／LNAA＋4％蔗糖（pH5．5）进行不定芽诱导,不定芽发生率为91％。无根丛生芽继代转入不定根诱导培养1／2MS＋0．25mg／LIBA＋0．25mg／LNAA＋4％蔗糖（pH5．5）,5天可见不定根形成,15天后不定根发生率为92％。研究还发现,荻种子萌发后可直接继代转入不定芽分化培养基形成健壮不定芽,不定芽诱导率为95％。     

辣木组织培养与植物激素培养基筛选试验

以辣木种子为外植体组织培养并在各培养阶段添加不同浓度植物激素培养基的试验结果表明:外植体消毒以脱壳种子→84消毒液预处理→Hg Cl2消毒效果最佳,污染率10%;最好的发芽诱导培养基为Mc+6-BA 0.4 mg·L-1,发芽率达82%;继代增殖培养基为Mc+6-BA 0.5 mg·L-1+KT 0.1 mg·L-1,增殖倍数达5.8倍;生根培养基为1/2Mc+IBA 0.5 mg·L-1+NAA 0.2 mg·L-1+AC 1.0 g·L-1,生根率达80%。炼苗20 d移栽于河沙∶珍珠岩∶刨花(1∶1∶1)混合基质的成活率最高。     

月季品种‘博’茎段离体培养的研究

以现代月季主栽品种‘博’的茎段为外植体进行研究，结果表明：茎段消毒以0．1％升汞溶液消毒10min最为适宜；最佳继代培养基为MS＋BA1．0mg／L＋IBA0．1mg／L，此培养基上诱导出的丛生苗长势较强，节间长度适宜，叶片大小正常，颜色鲜绿，平均增殖系数最高，达到4．25；最佳生根培养基为1／2MS＋NAA0．1mg／L，生根率为75．3％，平均根数3．8条；试管苗移栽基质以珍珠岩最适，其长势最好，成活率最高，可达91．0％。     

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.