苏桐3号组织培养苗脱毒快速繁殖研究

将苏桐3号组织培养苗高温处理，结合茎尖培养脱除丛枝病病原体MLO后，进行快速繁殖研究。结果表明，在35℃高温下，茎段腋芽生长30d后取其0．3～0．5mm的茎尖，在改良MS附加0．1～0．5mg/L的IBA和1．5～8．0mg／LBA的培养基上进行脱毒培养，试管苗在25—28℃条件下，生长正常。经荧光显微镜和电镜检测，均显示病原MLO已被脱除，脱除MLO的试管苗30d增殖8．0倍，且芽苗粗壮，形态、生长正常。用1／2MS IBA0．5mg,／L NAA0．3mg/L S20％诱导生根培养基，生根率达95％以上，移栽后炼苗，成活率达90％以上。     

边沁桉试管苗生长影响因子的研究

以2年生边沁桉耐寒优株的半木质化枝条上的顶芽或腋芽为外植体培养的试管苗为试材,对影响边沁桉试管苗生长的因子进行研究.结果表明:BA的浓度对苗的增殖系数有极显著影响,对苗高生长无显著影响,BA的适宜浓度为0.5～1.5 m/L; IBA的浓度对生根率和生根数均有极显著影响,IBA的适宜浓度为1.5 ～3.0 mg/L,蔗...     

几种植物生长调节剂对翅荚木试管苗的生根效应

翅荚木试管苗在 1 / 2MS、1 / 2MS IBA(吲哚丁酸 ) 0 0 1～ 1 5mg/L(单位下同 )、1 / 2MS ABT(生根粉 1 0号 )0 5～ 2 5培养基中均生根 ,在不加激素的 1 / 2MS培养基中 ,促进了苗的生长 ;但生根率随所添加的IBA的浓度增大而降低 ,并诱导愈伤组织的产生 ;在添加ABT的培养基中 ,可提高根的诱导率 ,却明显抑制苗的生长。IBA、ABT、GA3 配比适量既促进了苗的生长 ,又抑制了愈伤组织的产生 ,使植株形态正常     

不同品种红掌试管苗生根体系优化研究

以红掌的试管苗为试验材料,研究了生根培养基的不同离子浓度(MS,1/2 MS,1/3 MS,1/5 MS)以及生根培养基中活性炭、NAA、IBA对其生根的影响,并对6个品种红掌(大哥大、粉冠军、火鹤、潘多拉、维多和阿瑞博)试管苗的生根效果进行了比较,结果发现:(1)1/2 MS培养基为促进红掌试管苗生根的最适基本培养基,在1/2 MS中加入2.0 g/L活性炭可显著提高植株生根率,降低黄化率;(2)IBA对根诱导效果优于NAA;两者均在质量浓度为0.000 2 g/L时诱导生根效果最好,质量浓度高于0.000 4 g/L时,诱导生根效果减弱;(3)试管苗以1/2 MS+2.0 g/L活性炭+0.000 2 g/L IBA生根培养,大哥大、潘多拉、粉冠军和阿瑞博4品种生根效果较好,在单株生根数和单株根长大于1 cm的根数2个指标上,显著好于火鹤、维多。     

美国红栌组织培养繁殖研究

对彩叶树种美国红栌试管苗的继代培养和生根培养以及试管苗移栽基质进行了研究,结果表明:在NT(1971)+BA 0.6 mg/L+NAA 0.2 mg/L 培养基上,美国红栌试管苗继代培养的丛生苗分化率最高且生长良好;最佳生根培养基为1/2 MS+IBA 0.1 mg/L+NAA 0.1 mg/L+IAA 1.5 mg/L,试管苗生根率可达90%;移栽基质为泥炭:珍珠岩=2:1混合,苗木成活率可达到90%以上.     

白砂糖对大花萱草‘红运’试管苗生根的影响

以白砂糖代替蔗糖,探讨白砂糖对大花萱草‘红运’试管苗生根生长的影响.将试管苗分为丛生芽芽块(不分切)和单芽两种,分别接种于含不同白砂糖浓度的生根培养基1/2MS上.试验结果表明:白砂糖对大花萱草试管苗生根率和平均生根条数有着重要的影响.不加砂糖培养的试管苗叶片变黄、细弱、生长势极差,无论是丛生芽还是单芽生根率均为0;2.5％的砂糖利于单芽生根,生根率达95％,平均根条数3.59条/株;3.5％的砂糖利于丛生芽生根,生根率达90％,平均根条数7.50条/块;丛生芽生根较单芽生根所需砂糖浓度要高;丛生芽生根在14～21 d生根速度最快,单芽生根在7～14 d生根速度最快.     

国槐组织培养生根的研究

通过不同基本培养基、植物生长调节剂IAA、NAA、IBA和活性炭等对国槐试管苗不定根的诱导进行了系统研究。筛选出国槐最佳生根培养基是1/2MS+IAA0.5mg/L+蔗糖2%+琼脂0.65%,生根率达86%以上;并对不同苗龄试管苗不定根的发育过程进行了研究,结果表明,苗龄为20～25天的试管苗生根率最高可达90%,而且生根周期较短。     

照白杜鹃离体快繁体系建立及种质试管保存

以照白杜鹃新生嫩芽为外植体,应用均匀设计法筛选其最适合的嫩芽基部直接再生芽苗、生根及种质试管保存的培养基,结果表明,最适合的基部直接再生芽苗诱导培养基为:DR ZT 3.00 mg.L-1,诱导率达96%以上;生根培养基:MS(改良) IAA0.50 mg.L-1 IBA 0.10 mg.L-1 KT 0.20 mg.L-1,生根率达98%以上;试管保存培养基:N-68 B92.30 mg.L-1 根皮苷1.50 mg.L-1,保存时间可达36个月以上.并对再生植株进行了快繁,35 d为一个周期,增殖倍数平均达60倍以上.常温条件下,采取"矮化延缓生长"的方法可在试管内保存种质资源.     

北美枫香“秋霞红”组织培养快速繁殖技术研究

通过正交试验等方法对北美枫香"秋霞红"组织培养技术进行了研究。结果表明:在江苏扬州最佳取材时间为4月下旬,选取外植体,经过0.1%Hg Cl2消毒12 min灭菌,成活率为78.7%;添加VC35 mg/L能有效预防试管苗褐变的发生,增加培养容器的透气性可减少试管苗玻璃化发生;2/3MS附加TDZ、BA、NAA等植物生长调节剂可促进试管苗增殖和生长,其中TDZ 0.2 mg/L+BA 1.0 mg/L+IBA 0.1 mg/L+VC35 mg/L组合最适宜增殖与生长培养,增殖倍数达4.5,生长高度为3.8 cm;适宜的生根培养基为1/3 MS+IBA 0.5 mg/L+NAA 0.3 mg/L+AC 3 000mg/L+S 2%,生根率可达92%;经生根的试管苗移栽于泥炭、黄心土为7∶3(V∶V)的混合基质,控制温度23~30℃,相对湿度90%,保湿12~18 d,其间适当遮荫,30 d后成活率达90.8%。     

非洲菊试管苗生根培养试验

非洲菊试管苗继代培养基中高质量浓度的细胞分裂素可抑制根的诱导；生根培养基中适量的生长素能促进根原基的分化和生长，蔗糖和无机盐质量浓度也影响生根的效果。以MS BZ1.0mg/L IAA0.1mg/L培养基上增殖的芽在1/2MS IBA0.01mg/L上培养，供试品种生根率在15d内达均到100%，且幼苗生长健壮，移出试管后经过适当的锻炼，成活率达到100%。以市售白糖和自来水代替蔗糖和去离子水，以河沙代替琼脂试验均取得了良好的效果。     

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.