桉树组培苗嫩梢扦插育苗专用生根粉的研究

采用两种植物生长调节剂对桉树组培苗嫩梢扦插育苗的试验表明，吲哚丁酸配制的生根粉对桉树嫩梢扦插的插条具有促进生根作用，且其Ｉ４号生根粉对各种桉树的嫩梢插条的促根作用更中明显，在试验的４种桉树无性系组培苗中，插条生根率都达到８０％以上。     

桉树组培苗嫩梢扦插育苗技术

1990年进行了巨尾桉、尾叶桉、雷林1号桉组培苗嫩梢的扦插育苗试验。结果表明,嫩梢扦插繁殖苗木具有遗传性稳定、生根率高、繁殖系数大,操作简单等优点。并具体介绍了嫩梢扦插育苗的技术措施。     

巨尾桉组培苗嫩梢 扦插育苗推广和应用

巨尾桉组培苗嫩梢扦插育苗推广和应用黄良胜，兰祥元关键词组培苗，嫩梢扦插，育苗，巨尾桉巨尾桉（Ｅｕｃａｌｙｐｔｕｓｇｒａｎｄｉｓ×Ｅ。ｕｒｏｐｙｌｌａ）是通过人工控制授粉杂交培育而成的杂种桉，原产巴西。它生长快，是优良的短轮伐期造纸材树种。桉树杂种自然...     

迷迭香工厂化育苗技术

用迷迭香小苗枝条为外植体进行组织培养，用组培苗嫩梢作为插穗进行扦插育苗试验。结果表明：芽增殖以MS＋6BA0.5mg/L NAA0.01mg/L 蔗糖30g/L培养基的增殖率达1.4倍；不定根诱导以1／3MS＋IBA0.5mg/L 蔗糖20g/L的培养基效果好，生根率达100％；以组培苗嫩梢扦插，生根率达98％以上。利用芽增殖培养→生根炼苗培养→移栽上盆→扦插→出圃这一流程生产苗木，成本低、苗木质量优、繁殖速度快，可在生产上推广应用。     

福建桉树组培苗嫩梢扦插育苗技术探讨

对福建桉树组培苗嫩梢扦插育苗采穗圃的建立与管理、穗条采集、扦插技术、扦插后的苗木管护,以及主要环境因子对扦插效果的影响等技术进行了探讨。     

互叶白千层工厂化育苗技术

以互叶白千层萌芽条茎段为外植体材料，运用组织培养快速繁殖和组培苗嫩梢扦插技术方法，进行工厂化育苗，结果表明，该技术降低了苗木生产成本，并能在短期内获得大量组培苗，年产苗木可达112万株。     

桉树萌条嫩梢扦插育苗技术研究

将尾叶桉（Ｅｕｃａｌｙｐｔｕｓｕｒｏｐｈｙｌｌａ）的播种苗萌条嫩梢分别用不同药物１，２，３，４，５号处理，并以清水作对照，进行扦插育苗试验．结果表明，用药物处理可提高扦插生根率．同时，可降低扦插苗的死亡率．用２，３，４，５号药物处理的插穗生根率比对照高１０％左右，药物对降低扦插苗死亡率的效果以２号，５号药物最佳．根据对桉树组培苗嫩梢扦插试验，１１月和３月是扦插育苗的最佳季节，５月～８月不宜扦插；桉树的不同种和不同无性系，其扦插生根率是不同的，以雷林１号８５０１和刚果１２号Ｗ５生根率高，而巨尾桉Ｃｕ１较难生根．     

木荷无性繁育技术试验初报

对木荷进行扦插和嫁接育苗试验,扦插试验结果表明:采用体积比为1∶1的黄心土+河沙作为插床基质有利于插条生根;扦插前用ABT-6或IBA处理插条均有显著的促根效果,其中用浓度为50 mg/L的ABT-6溶液浸泡插条基部10 h,扦插生根率达72%;带顶芽的插条抽梢率显著高于不带顶芽的插条。嫁接试验的结果表明:顶芽接穗嫁接的成活率达76%,且其抽梢率显著大于侧芽嫁接。     

巨尾桉幼态扦插培育容器苗技术试验

以巨尾桉组培苗为母株，通过截顶促萌、生产的幼态萌芽作插条，扦插培育容器苗，质量可达到组培苗标准。在插条管理方面要掌握好激素处理、保温、保湿、防治病菌及选择适宜季节扦插等关键技术措施，才能保证扦插苗的成活率。     

互叶白千层组培苗嫩梢扦插育苗技术研究

文章以经筛选的互叶白千层组培苗8~13 cm的嫩梢作为插穗,研究了基质、季节、木质化程度、材料来源和生根促进剂浓度等对穗条生根率的影响。结果表明:采用组培苗半木质化嫩梢作插穗,用含1 000 mg/kg IBA的生根粉处理插穗基部,于春季(4月初)扦插于珍珠岩∶黄心土∶泥炭土(1∶1∶1)的基质上,插穗生根快,平均生根率达92.3%,操作简单,繁殖速度快。     

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.