CTAB法抽提香榧种子胚乳DNA的改进

香榧种子胚乳DNA抽提是RAPD和AFLP分子标记构建遗传图谱的基础性工作。经多次实验，我们对CTAB法抽提香榧种子胚乳DNA进行了改进，即先将胚乳冷冻，抽提时加入β－巯基乙醇，抽提过程中用高盐TE重悬DNA－CTAB沉淀，最后用异丙醇沉淀DNA。OD260／OD280比值检测结果为平均1．824，而且DNA得率也较高，证明用此法抽提的DNA能完全满足RAPD和AFLP的分析的要求。     

快速微量提取竹子叶片DNA的方法

介绍了一种快速微量提取角竹叶片DNA的方法。该方法简便易行，操作简单，所需材料少，提取的DNA纯度较高，OD260/OD280。一般在1．9左右，可满足一般的RAPD、SSR、转基因植株的PCR检测为基础的实验需要。     

一种从榛子叶芽提取DNA的方法

以榛子叶芽为试材,用略有改进的CTAB法提取基因组RDNA。提取的DNA纯度和完整性都较好,电泳条带清晰,DNA无降解,OD260／OD280。值介于1．8-1．9,分子量接近23Kb,与叶片提取的DNA相比,RAPD扩增条带一致。该方法可以直接用于榛子RAPD分析中的DNA提取。     

马尾松针叶DNA提取方法研究

采用3种不同的方法（CTAB法、SDS法和试剂盒法）提取马尾松幼嫩针叶基因组DNA,并分别从取样材料类型、样品的保存、提取液中PVP含量、取样质量、抽提过程中提取程序的改进等方面进行提取马尾松基因组DNA效果的凝胶电泳比较．结果表明：CTAB法适合于在马尾松群体分子生物学研究中基因组DNA的提取：采用低温冷藏法保存的春季抽梢针叶0．2g,在CTAB的提取液中加入2％的PVP,常规CTAB法提取程序中添加等体积的混合液（V酚：V氯仿：V异戊醇=25：24：1）并在此前加入1／10体积的10×CTAB,可以有效地提高马尾松基因组DNA的提取质量,获得显带平直、纯度较高的马尾松基因组DNA,OD260／OD280值在1．8左右．这为马尾松群体分子生物学的研究提供了一个经济、简便而有效的DNA提取方法．     

两种方法提取凯特杏DNA的研究

采用CTAB法和SDS法，分别从杏的幼叶、嫩芽中提取DNA，通过计算产率，测定OD260和OD280的比值认为，CTAB比SDS法提取的DNA数量和纯度都高，而且两种方法都表明幼嫩材料中提取的DNA数量比成熟叶片高出2倍之多，纯度也较高。     

红檵木DNA提取及其检测

用改良的异丙醇沉淀法对红木 (Loropetalumchinensevar .rubrum)叶片总DNA进行了提取。结果表明 ,OD2 60 /OD2 80 值接近 1 80 ,符合RAPD分析的要求 ,且方法简便 ,成本低 ,速度快。     

乌桕基因组DNA提取方法研究

以改良CTAB法和SDS法提取乌桕基因组DNA,对提取条件进行了正交试验,优化出乌桕基因组DNA提取的适宜条件,采用紫外分光光度检测、琼脂糖凝胶电泳分析及限制性内切酶进行了检测。结果表明:改良CTAB法的A1B2C2D2组合提取的基因组DNA纯度高,无拖尾现象,OD260/280值在1.8～2.0,OD260/230在2.0。     

从白刺老干中提取高纯度DNA的方法

采用CTAB法、SDS法和匀浆CTAB法对白刺越冬老干进行基因组DNA提取,通过琼脂糖凝胶电泳及分光光度计对DNA纯度进行检测,结果表明,用常规的CTAB法和SDS法提取DNA纯度低,匀浆CTAB法得到高纯度的DNA,其OD260/OD280值为1.873～1.923。     

芒果总DNA提取方法比较分析

为了研究不同提取方法对芒果总DNA提取质量的影响,以‘紫花芒’等11个芒果品种的叶片为材料,采用SDS法、CTAB法、改良CTAB法提取芒果叶片总DNA,并对提取的总DNA浓度、OD260/280、OD260/230、琼脂糖电泳结果、ISSR扩增产物进行了比较分析。结果表明,改良CTAB法能较好地去除芒果叶片中的多酚、多糖、单宁和色素等杂质。提取的总DNA浓度高达387 ng/μL,OD260/280在1.81~1.87之间,OD260/230在2.01~2.09之间。SDS法、CTAB法提取总DNA的ISSR扩增产物条带少,改良CTAB法提取的总DNA的扩增效果图谱清晰,多态性高。3种提取方法的结果比较而言,以改良CTAB法提取总DNA的效果最好,可用于后续实验的研究。     

山竹子基因组DNA提取及SRAP反应体系优化

采用改良CTAB法提取山竹子基因组DNA,并以me1和em3正反向引物组合对山竹子进行了SRAP体系的优化。结果表明：使用CTAB free缓冲液进行前处理可去除大部分的杂质,获得的DNA纯度较高,OD260/OD280均在1.7~1.9之间,RNA消化彻底,DNA无明显降解,进行SRAP分析条带清晰,多态性好。在25μL反应体系中,5种主要成分的适宜浓度或用量分别是：Taq DNA聚合酶0.5 U,Mg2＋2.0 mmol.L-1,dNTPs 0.15~0.2 mmol.L-1,模板DNA 10~50 ng,引物0.6~0.8μmol.L-1。该体系适用于山竹子SRAP分析,进行遗传图谱构建、基因定位与克隆、比较基因组学、遗传多样性、cDNA指纹图谱等方面的研究。     

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.