百合鳞片离体培养的研究

以‘布鲁拉诺’、‘提伯’和‘索蚌’3个百合品种的鳞片为外植体，比较了不同的消毒方法、不同品种、取材不同部位及接种方法对百合鳞片离体培养的影响。结果表明，最佳的消毒方法是0．1％升汞消毒8min，污染率较低，成活率最高，可达90．9％，且采用小鳞茎整体消毒可以有效降低污染率。不同百合品种分化小鳞茎的能力有较大差异，分化能力依次为‘布鲁拉诺，〉“索蚌’〉‘提伯’。百合鳞片不同部位分化小鳞茎的能力从大到小依次为下部、中部、上部。近轴面向上接种的鳞片分化能力强于远轴面向上，小鳞茎再生率最高，可达100％。     

不同基质对百合埋片繁殖的影响

该文采用百合埋片新技术研究了３种野生百合和３个栽培品种鳞片繁殖与栽培基质的关系。结果表明，蛭石十锯末的比例约为１：１时，鳞片产生小鳞茎最多，达到２２２个／１５０个鳞片。素沙的效果最差，１５０个鳞片仅产生了８６个小鳞茎，从种或品种比较，王百合产生小鳞茎的最少，１２０个鳞片仅产生２０个仔球；川百合、宜昌百合。ｐｉｒａｔｅ、ｍｅｄａｉｌｌｏｎ和ｃｏｎｎｅｃｔｉｃｕｔｌｅｍｏｎ在适宜的栽培条件下比较容易诱导出鳞茎。     

GA3、IBA以及不同基质对精粹百合鳞片扦插繁殖的影响

以亚洲系精粹百合为试材,研究了外源GA3和IBA以及锯木屑、草炭2种基质不同培养方式下对鳞片繁殖的影响。结果表明:锯木屑埋片处理最有利于提高繁殖系数和生根数量,而锯木屑扦插处理形成的小鳞茎个体较大,萌发率高。植物生长调节剂处理各因素的影响效力为激素种类>处理时间>质量浓度。IBA显著促进了小鳞茎形成和发根,且根与小鳞茎同时发生;GA3处理有利于获得个体较大、形状匀称的健壮鳞茎,但繁殖系数较低,根的数量较少,小鳞茎形成1周后基部开始生根,18℃下GA3显著促进了小鳞茎的萌发。培养过程中母鳞片贮藏物质的消耗进程不同:IBA处理的鳞片20℃培养60d后应及时移栽防止小鳞茎腐烂,GA3处理可延长至80d;对照与GA3处理效果相近,但需要较长培养时间和最佳培养温度。     

百合组织培养及快繁技术的研究与探讨

百合鳞茎不同部位鳞片都可以经诱导形成小鳞茎及芽,但中层鳞片明显高于内层和外层;同一鳞片的基部段诱导能力最强;百合鳞茎中层下部及中部鳞片是优良组培苗外植体。百合鳞片组织培养适宜配方为MS NAA0.1 BA0.5;移栽基质采取透气保水保肥的腐殖质及沙、土基质有较高的成活率。     

朱顶红鳞茎和花剑生长发育研究

采用解剖鳞茎法,盆栽法和大田栽培法对朱顶红鳞茎结构、鳞片发育、花剑发育、花剑数量和叶片数量等进行了观察研究,结果显示,鳞茎一般分为三部分,分别为外部、中部和内部鳞片,内部鳞片中心不断分化发育形成幼鳞片和花剑,幼鳞片不断的生长成叶片,一般新鳞片从生长开始到衰老需要三年时间,鳞茎每年分化生长2个花剑并有败育现象;每个花剑上一般分化生长2-4个小花并有败育现象;鳞茎每年生长叶子8片左右,每生长4片叶子产生一个花剑。     

武汉地区百合鳞片扦插技术研究

为提高武汉地区百合鳞片扦插繁殖系数,试验设计了不同鳞片部位、扦插时间、扦插深度3个处理,从扦插产生的籽鳞茎大小和数量来看,春季用百合种球的靠外层鳞片扦插效果最好。     

西洋百合“卢浮宫”的组培技术研究

以鳞片为外植体、MS为基本培养基,以不同激素成分及不同质量浓度水平下诱导西洋百合"卢浮宫"的小鳞茎状突起,进行组培试验。结果表明:"卢浮宫"百合的诱导以取其完整的鳞片为外植体、并以鳞片背部突起处紧贴于MS 6 BA2 0mg·L-1 NAA0 2mg·L-1的培养基上诱导效果为最好。"卢浮宫"百合的诱导是由外植体(鳞片)产生小鳞茎状突起而分化成苗的,并不经愈伤组织分化产生。筛选出的最佳继代增殖培养基为MS 6 BA0 7mg·L-1 IBA0 3mg·L-1,生根培养基为1 2MS 6 BA0 3mg·L-1 IBA0 7mg·L-1。移植基质选择河泥和珍珠岩(体积比7∶3)混合,成活率达98%。     

激素和变温处理对百合鳞片扦插繁殖的影响

以亚洲百合品种‘精粹’为试材,探讨GA3和IBA以及不同培养温度对鳞片扦插繁殖的影响。结果表明:低浓度IBA处理(IBA-80mg·L-1-1h)的繁殖系数较大、小鳞茎形成的整齐度较高,IBA处理可在较短时间内促使小鳞茎膨大;若培养时间充分,GA3处理更有利于形成个体较大的鳞茎。5℃低温预处理加速IBA处理母鳞片淀粉的降解和总可溶性糖的利用,进一步提高IBA处理的繁殖系数、平均级数和小鳞茎直径;但5℃低温预处理与GA3处理结合,抑制母鳞片中淀粉的降解以及小鳞茎对可溶性糖的吸收利用,致使小鳞茎生长缓慢。本试验条件下IBA-100mg·L-11h结合5℃低温预处理为提高繁殖系数和整齐度的最佳处理;GA3-100mg·L-1-2h结合25℃恒温培养最有利于小鳞茎的发育膨大,为获得优良个体的最佳处理。     

宜兴百合组培快繁体系的建立

以宜兴百合鳞片为外植体进行试管培养,经试验筛选出各培养阶段适宜的培养基为:(1)小鳞茎诱导,MS 6-BA 0.5mg/L NAA 1mg/L KT 0.2mg/L;(2)分化及继代,MS 6-BA 0.2mg/L NAA 0.5mg/L;(3)生根,MS PP3331 mg/L NAA 0.1 mg/L。     

东方百合鳞茎冷藏期间含水量变化规律的研究

以"索蚌"和"西伯利亚"鳞茎为试材,通过测定2个百合品种的鳞茎、外层鳞片、内层鳞片、芽、基盘和根冷藏前后鲜重和干重的变化,研究在3～5℃低温冷藏条件下,不同冷藏时间对各部位含水量变化的影响.结果表明:两品种冷藏前后鲜重变化明显,干重变化不大.冷藏期间两个品种不同部位的含水量变化情况基本一致,变化最大的都是外层鳞片和根,鳞茎和内层鳞片次之,芽和基盘变化最小.冷藏期间两品种同一部位含水量变化有所不同,索蚌只有芽的含水量变化幅度比西伯利亚小,其余各部位含水量变化幅度均比西伯利亚大.     

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.