香椿组培快繁效率的影响因子

香椿组织培养对基本培养基、激素种类以及浓度有较广泛的适应性,但不同的培养基及培养条件下,其快繁效率不同.通过对香椿用材品种茎段的离体培养,探讨了香椿组培快繁效率的影响因子.结果表明:香椿组培快繁效率高的诱导培养基为MS 6-BA0.5 mg·L-1 NAA0.1～0.5 mg·L-1,适宜分化丛生芽的理想培养基为4/5 MS 6-BA0.5～1.0mg·L-1 NAA0.1 mg·L-1 GA30.5 mg·L-1,芽年增殖系数达5.612以上,有效芽苗率达100%,适合生根培养基为1/2 MS NAA0.5 mg·L-1 GA30.1 mg·L-1或1/2 MS IBA0.5 mg·L-1 GA30.1 mg·L-1,生根率达90%以上.移栽土壤基质以黄心土表面覆盖0.5～1.0 cm厚细沙,移栽成活率可达90%以上.     

库拉索芦荟组织培养技术研究

以美国库拉索芦荟初接种试管苗为材料,MS为基本培养基,研究了不同配方培养基对库拉索芦荟试管苗生长的影响,筛选出了适宜于库拉索芦荟试管苗生长的培养基,结果表明：继代培养基中,BA浓度以2．0～3．0mg·L^-1、蔗糖浓度以3％为宜,继代培养基以MS＋BA3．0mg·L^-1＋NAA0．5mg·L^-1为最佳,茅增殖系数为5．2;生根培养中,NAA激素对试管苗生根率和生根数都有极显著的影响,生根培养基以MS＋NAA0．5mg·L^-1为最佳,生根率达100％,平均生根数6．3条;试管苗炼苗3—7d后移栽到营养土：沙土=3：1的基质上,移栽成活率可达70％以上。     

高精油互叶白千层组培快繁技术

以高精油含量的互叶白千层优良单株(H21、H35、H38)为试验材料,通过茎段离体培养,开展不同单株的组培快繁技术研究。结果表明,3个单株在诱导培养基MS+1.0mg·L-16-BA+0.05mg·L-1NAA上均取得较高的诱导率,但单株间诱导率存在极显著差异;H21、H35、H38在最佳增殖培养基(B1+1.5mg·L-16-BA+0.01mg·L-1NAA)上增殖培养40d,其增殖倍率分别为4.1、5.3、5.6,有效芽苗率高达90%以上;H21、H35、H38在培养基1/2B1+0.5mg·L-1ABT+0.5mg·L-1NAA诱导生根,生根率分别为65%、96%、93%,最佳生根培养基为1/2MS+0.5mg·L-1ABT+0.5mg·L-1NAA;以纯黄心土为移栽基质,炼苗30d,3个无性系平均移栽成活率高达84.8%。     

东京樱花组培快繁技术研究

以春季萌发的东京樱花嫩枝为外植体,研究植物激素、GA3等因素对东京樱花的组织培养的影响。实验结果表明:在MS+BA1.0mg·L-1+NAA0.1mg·L-1的培养基上,不定芽诱导率达95.83%;不定芽的最佳增殖培养基为MS+BA1.0mg·L-1+NAA0.1mg·L-1+GA30.5mg·L-1;当芽伸长至2cm时,将其切下置于生根培养基1/2MS+NAA0.1mg·L-1+IBA0.5mg·L-1中,生根率达95%以上,移栽成活率达90%。     

福贡龙竹种子无菌诱导植株再生及快速繁殖

以福贡龙竹种子为外植体,开展组培快繁技术研究。结果表明,用75%酒精消毒60s,再用0.1%的Hg Cl2溶液消毒30min的效果最好;适宜诱导形成丛生芽的培养基为MS+6-BA 2mg/L+IBA 0.5mg/L+KT 0.2mg/L;最佳继代增殖培养基为MS+6-BA 3mg/L+NAA 0.2mg/L;以MS+IBA 1mg/L+NAA 0.5mg/L为最佳生根培养基;将生根组培苗炼苗移栽,90d后成活率达81%以上。     

黄金宝树组培育苗技术研究

以黄金宝树基部半木质化萌芽条为外植体,MS为基本培养基,探讨6-BA、KT、NAA对黄金宝树组培育苗的影响,试验结果表明,黄金宝树组培育苗最佳培养基配方分别为:初代培养基MS+6-BA 0.3 mg.L-1+KT 0.5 mg.L-1+NAA 0.3mg.L-1+蔗糖30 g.L-1+卡拉胶8 g.L-1、增殖培养基MS+6-BA 0.5 mg.L-1+KT 0.3 mg.L-1+NAA 0.3mg.L-1+蔗糖30 g.L-1+卡拉胶8 g.L-1、生根培养基1/2 MS+NAA 0.5 mg.L-1+蔗糖20 g.L-1+卡拉胶8 g.L-1。初代培养诱导率达80%以上,有效芽条增殖率达3倍以上,生根率达95%以上,移栽成活率达90%以上。     

托里桉组培快繁技术初步研究

以2 a托里桉超级苗不同株系的茎段为外植体进行组培快繁研究,结果表明：适合诱导的培养基为MS改良+6-BA 0.5mg·L-1+NAA 0.1 mg·L-1;适合6号株系增殖培养基为MS改良+6-BA 0.2 mg·L-1+NAA 0.1 mg·L-1,适合7号、10号株系的增殖培养基为MS改良+6-BA 0.3 mg·L-1+NAA 0.2 mg·L-1;适当缩短继代周期是解决桉苗顶稍枯萎、上部叶片脱落等症状简单、有效的方法;适合的生根培养基为1/2MS改良+ IBA 0.2 mg·L-1+ ABT 0.6 mg·L-1,生根苗移栽成活率可达90%。     

红心软枣猕猴桃组织培养与快繁技术研究

以红心软枣猕猴桃幼嫩茎段为外植体,1/2MS为基本培养基,附加不同种类、浓度的生长调节物质,对软枣猕猴桃的幼嫩茎段快速繁殖进行研究。结果表明:最佳诱导培养基为1/2MS+6-BA0.8 mg·L-1+NAA 0.05 mg·L~(-1);最佳继代增殖培养基为1/2MS+6-BA 0.6 mg·L-1+ZT 0.2 mg·L~(-1),繁殖系数7以上;最佳生根培养基为1/2MS+IBA 0.1 mg·L~(-1),生根率98%以上,每株有5～10条根,根粗苗壮。当苗根长到1.0～1.5 cm时,移栽到纯沙中,成活率达95%以上。     

笃斯越桔组培繁殖育苗技术研究初报

以笃斯越桔去叶带芽嫩茎为试验材料,对长白山笃斯越桔组培繁殖育苗技术进行了研究。结果表明,笃斯越桔的外植体诱导丛生芽的最佳培养基配方为WPM 2ip3.0 mg.L-1,分化率可达73%;最佳继代培养基配方为WPM 2ip15.0 mg.L-1 NAA0.2 mg.L-1,增殖系数达7.2倍;最佳生根培养基配方为1/4MS IBA0.10 mg.L-1,生根率达97%以上。生根小植株在阔叶腐殖土上,经温室炼苗45 d,圃地移栽成活率可达85.7%以上。     

千屈菜组培技术研究

以千屈菜茎段为外植体进行离体培养试验,结果表明:MS+6-BA0.8 mg.L-1+IBA0.1 mg.L-1为芽诱导最佳培养基;MS+6-BA0.4 mg.L-1+NAA0.1 mg.L-1为芽增殖最佳培养基;1/2MS为生根最佳培养基;温室大棚内搭设"小拱棚"覆盖薄膜炼苗14 d,选择黑土为炼苗基质,炼苗成活率可达90%。     

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.