长白落叶松离体再生体系的建立

以长白落叶松成熟合子胚诱导出的不定芽为外植体,通过筛选不定芽增殖的最适培养基及激素配比、探讨不同浓度赤霉素(GA_3)及活性炭(AC)对不定芽伸长的作用以及比较不同处理对试管内及试管外生根的影响,最终建立离体再生体系。结果表明:BM+1.0 mg/L TDZ时,不定芽增殖最快,增殖系数为5.0;GA_3对不定芽的伸长有毒害,2.0 g/L活性炭(AC)对不定芽伸长促进作用明显,伸长比率达262%;1/2BM+0.5 mg/L IBA+1.0 mg/L NAA为试管内生根的最佳组合,生根率达26%,不定芽在750 mg/L NAA中浸泡25 s,试管外生根率(37%)最高。     

紫花含笑组培快繁体系建立

以紫花含笑无菌幼苗为材料,研究不同激素组合、光照强度以及移栽基质对诱导不定芽增殖、伸长、生根以及移栽存活的影响.结果表明:MS+ 0.5 mol/L 6-BA+ 0.1 mol/L IBA是紫花含笑不定芽的适宜增殖培养基,其不定芽诱导率达100.0％,平均不定芽数5.2个;强光照有利于不定芽伸长生长;合适的生根培养基为1/2MS+ 3.0mg/L NAA,生根率91.5％,平均生根数为4.36条.组培苗适宜移栽时间在9月份前后,基质为黄心土或混合泥炭土,成活率均达80％以上.     

沙松成熟胚不定芽诱导研究

以沙松成熟胚为外植体进行不定芽的诱导研究,结果表明:初代培养中沙松成熟胚不定芽诱导最佳培养基组合为改良DCR+2.0 mg·L-16-BA,诱导率可达到63.16%;继代培养中最佳培养基为无添加激素的1/2SH培养基,培养30 d不定芽平均伸长0.7 cm;添加0.1 mg·L-1的活性炭对沙松不定芽的伸长生长最为适宜。     

湿地松不定芽增殖培养试验

以湿地松无菌苗带子叶顶芽为外植体,研究了基本培养基、生长调节剂、有机添加物、细胞分裂素等对湿地松不定芽增殖的影响。结果表明:DP+6-BA 4.0 mg.L-1+NAA 0.05 mg.L-1为湿地松不定芽增殖的最佳培养基;培养基附加10 g.L-1肌醇或体积分数为30%的椰子汁对不定芽增殖均有一定的增效作用;培养基中隔代添加6-BA对芽苗伸长生长有利,但对不定芽增殖作用效果不显著。     

杉木成熟合子胚器官发生和体胚发生

以杉木成熟合子胚为起始外植体,研究基本培养基、不同种类的细胞分裂素及生长素对杉木器官发生和体胚发生及不定芽生根的影响,并用石蜡切片法观察不定芽和体胚的发生和发育过程.结果表明:DCR 6-BA 1.0mg·L-1 TDZ 0.002 mg·L-1 NAA 0.1 mg·L-1对成熟合子胚诱导不定芽最有效;DCR 6-BA 1.0 mg·L-1 TDZ 0.003mg·L-1 NAA 0.1 mg·L-1是成熟合子胚诱导体胚的最佳培养基;不定芽在DCR基本培养基中可有效伸长;1/4MS IBA 0.2 mg·L-1 NAA 0.1 mg·L-1对不定芽生根最有效.石蜡切片观察表明:不定芽有2种发生方式,一种是表皮及表皮下的3～4层细胞分生组织化发育而成,另一种是外植体内部的小维管束脱分化发育而成.2种发生方式均为直接器官发生途径.     

双色茉莉茎段离体培养再生植株的研究

以双色茉莉茎段为外植体,探讨外植体取材季节和部位、基本培养基种类、植物生长调节剂组合、活性炭等对茎段器官发生和植株再生的影响.结果表明:在4月和10月取材最好,其诱导率分别达到了92.780/和84%,污染率最低;1/2MS 0.01 mg/L NAA 3.0 mg/L BA 2.0 mg/L KT培养基最适合不定芽的诱导分化,不定芽分化率达到了88.34%;在继代增殖培养中,继代次数最好在6代以内,否则增殖率下降,MS 0.5mg/L IBA 3.0mg/LBA 0.2%活性炭培养基最适合不定芽的增殖(5.92)和大于2cm芽的分化(47.16%).不定芽可在1/2MS培养基中有效伸长,适宜的生根培养基为1/2MS 1.0 mg/L IBA 0.2 mg/L BA,生根率达到100%.     

都百凤桃树离体植株再生培养的研究

以从日本引进的桃树品种都百凤为试材,采用正交设计,研究了6-BA,NAA,接种芽数,活性炭对不定芽增殖与壮苗的影响,探讨了激素、培养基盐浓度、活性炭对都百凤组培苗生根的影响。结果表明,都百风桃树离体植株再生继代增殖培养基为MS＋6BA3mg／L～5mg／L＋NAA0．1mg／L～0．2mg／L＋蔗糖30g／L,培养基pH值为5.9,以3芽为1个转接单位,培养温度为25℃,光照强度2000Lx,光照时间16h／d;生根培养基为1／2MS＋IBA0.2mg／L＋蔗糖20g／L＋琼脂7g／L＋活性炭0．4g／L,培养基pH值为6．0,培养温度为22℃,光照强度1600Lx,光照时间16h／d;组培苗转入生根培养基舌暗处理2d,再转到光照下培养有利于生根。     

非洲紫罗兰不定芽诱导与试管内开花技术研究

以非洲紫罗兰叶片和叶柄为外植体,以MS为基本培养基,比较了外植体类型、接种方式和植物生长调节剂配比对不定芽发生的影响,并初步探讨了试管内开花所需环境条件。结果表明:非洲紫罗兰叶片为较好的外植体类型,可以直接诱导产生不定芽,培养基配方为MS+6-BA0.5 mg/L+NAA0.1mg/L时不定芽诱导率较高;且接种方式对不定芽的诱导有重要影响,以叶片背面向下较好;活性炭有利于试管苗的生长;非洲紫罗兰试管内开花的适宜环境条件是光照时间14h/d,光照强度4 000lx,白天温度28℃,夜间温度20℃。     

弗吉尼亚栎不定芽增殖及试管苗再生影响因子研究

[目的]探析弗吉尼亚栎组织培养中不定芽增殖和生根的关键影响因子,建立弗吉尼亚栎试管苗再生体系,为弗吉尼亚栎无性系选育提供技术支撑。[方法]以弗吉尼亚栎带芽茎段为外植体,采用不定芽增殖途径,研究弗吉尼亚栎组织培养过程中外植体选择、褐化控制以及培养基选择、激素配比对不定芽增殖和生根的影响。[结果]表明:向培养基中添加抗坏血酸、硫代硫酸钠和活性炭均显著降低外植体的褐化半径(p<0.05),其中,外植体在含有3.00、5.00 g·L-1活性碳的培养基中褐化半径最小。基本培养基筛选试验表明:以1/4MS或WPM为基本培养基时,平均芽长和芽数明显优于MS培养基。不定芽增殖最佳培养基为1/4MS+1.20 mg·L-1 6-BA,培养周期40 d,增殖倍数可达6.6。最佳生根培养基为1/4MS+0.50 mg·L-1 IBA+0.50 mg·L-1NAA,生根率达53.33%,且根粗壮,木质化程度较高。组培苗移植到灭菌河沙中,平均成活率达57.78%。[结论]培养基成分和激素配比是影响弗吉尼亚栎不定芽增殖和试管苗再生的主要因子,低盐培养基(1/4MS或WPM)不仅可以促进不定芽增殖,且能够减...     

杉木无性系组培苗增殖优化研究

以杉木T-c 07无性系组培苗的无菌不定芽为材料,采用正交设计方法,对增殖培养基进行优化实验。结果表明:植物生长调节剂6-BA、NAA和IBA对杉木T-c07无性系组培苗多代增殖培养的不定芽萌发和生长影响较大,以DCR+0.30mg·L^-16-BA+0.01 mg·L^-1IBA+30 g·L^-1蔗糖+6.80 g·L^-1卡拉胶培养基配方的优化增殖效果最好,能使已经25代增殖培养的不定芽萌芽率达到100%,增殖倍数提高至3.25倍,而且叶色嫩绿、茎干健壮,长势得到明显改善。     

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.