青钱柳子叶不定根的发生机制

本文以青钱柳子叶为材料,WPM为基本培养基,研究不同质量浓度的外源ABA和IBA对子叶不定根发生的影响,并对不定根发生与内源激素的变化关系进行探讨.结果表明:添加0.5～5 mg·L~(-1) IBA,对子叶不定根发生均有不同程度的促进作用,以1.5 mg·L~(-1)效果最佳,诱导生根率、平均生根条数和根长均达最大,生根率可达到100%;而添加0.01～0.5 mg·L~(-1) ABA和不加激素的对照没有不定根的发生.内源激素的动态测定表明IAA对不定根的发生起关键性作用,根原基的启动需要较高的内源IAA,而不定根的形成与根的伸长需要相对较低的内源IAA水平.较高的IAA/ABA,IAA/GA_3比值有利于不定根的发生,能较好反映出生根过程中内源激素间的平衡需求,GA_3可能不是影响不定根发生的关键因素.研究结果为青钱柳生根诱导及其机制的研究提供依据.     

油茶离体培养诱导再生植株的研究

采用普通油茶Camelliaoleifera优良无性系湘林4号为实验材料,研究了离体条件下带芽的茎段、幼胚、子叶的愈伤组织的形成和植株再生技术。茎段离体培养以MS为基本培养基,附加6-BA3.0mg·L-1+NAA1.0mg·L-1对芽进行诱导,诱导率达到83.33%;继续在此培养基上继代得到丛生芽,增殖比例为1∶20。对于幼胚和子叶,附加2,4-D2.0mg·L-1+KT1.0mg·L-1诱导愈伤组织得到很好的效果,将愈伤组织转到附加6-BA3.0mg·L-1+NAA0.05mg·L-1和6-BA2.5mg·L-1+IAA1.5mg·L-1的培养基上诱导出不定芽,诱导率达到90%以上。芽苗增殖以MS+6-BA2.5mg·L-1+IAA1.5mg·L-1的培养基为好。将无菌苗在MS培养基(附加NAA7mg·L-1)上诱导生根,生根率达93%。     

水曲柳未成熟胚的离体培养研究

以沈阳农业大学植物园内 30a生水曲柳 (Fraxinusmandshurica)为试材。分别于 2 0 0 0年 7月和 8月取水曲柳幼果 ,用 0 1%的HgCl2 进行表面消毒 ,在无菌条件下取出未成熟胚进行诱导培养。在胚成苗后进行继代培养和生根培养。培养结果表明 :在水曲柳胚的发育初期 ,进行胚培养不易成功 ;但当幼胚分化成子叶和胚根时 ,进行胚培养 ,胚的成活率和成苗率均较高。不加任何激素的WPM、MS、DKW和SH培养基都可以作为水曲柳未成熟胚培养的培养基。水曲柳组培苗继代培养的外植体分化率低 ,最高只能达到 2 12 5苗·月 - 1 (培养基为WPM +BA 1mg·L- 1 +NAA 0 1mg·L- 1 )。水曲柳组培苗的生根较容易。用不含任何激素的WPM和QL基本培养基作为其生根培养基效果较好 ,生根率分别为 6 0 %和 6 6 %。     

核桃品种试管嫩茎生根的研究

以 6个早实核桃 (JuglansregiaL .)新品种为试材 ,对长期继代培养的试管嫩茎的生根进行了研究 ,结果表明 :诱导方法、外源IBA的水平、嫩茎发育状态以及光照条件等对生根具有明显的影响。选取生长旺盛、节间较长、叶较小呈嫩黄绿色的幼态嫩茎 ,采用 2步诱导生根法 ,即黑暗条件下 ,在IBA为 5 0～ 10 0mg·L- 1 的 1 4DKW培养基中诱导 10～ 15d ,而后转移至不含IBA的DKW培养基中 ,利用这一方法顺利地诱导了嫩茎生根 ,在对 6个品种的应用中获得了 6 0 5 %～ 89 7%的生根率 ,平均根数 2 0～ 3 6。生根的嫩茎已成功地进行了下地移栽。同时就根原基诱导过程中嫩茎内源IAA和ABA水平变化进行了研究 ,对核桃生根的激素调控进行了讨论     

麻楝扦插生根进程中内源激素和营养物质含量的变化

【目的】研究麻楝扦插生根进程中形态、内源激素和营养物质含量的变化,揭示麻楝插穗内源激素和营养物质含量对其扦插生根的影响。【方法】以麻楝6个月生半木质化枝条为材料进行扦插,在扦插后每隔10 d取一次样,记录插穗生根情况,及测定基部内源激素和营养物质含量。【结果】观测证实麻楝嫩枝插穗生根类型主要为皮部生根型,少量为愈伤组织生根型和中间生根型;其生根进程大致分为3个时期:皮孔萌动根原基诱导期(0～20 d)、不定根表达发生期(20～40 d)和不定根伸长发育期(40 d以后)。外源激素处理组麻楝插穗生根进程研究发现,内源激素IAA含量、IAA/ABA值、IAA/ZR值呈"上升-下降-上升"的变化趋势,ABA含量呈"上升-下降"趋势,GA和ZR含量的变化相似,均为"上升-下降-上升-下降"。营养物质含量变化研究中,处理组可溶性糖与淀粉含量均呈"下降-上升-下降"的变化趋势,可溶性蛋白含量变化表现为先下降而后缓慢上升。【结论】麻楝插穗生根过程中,外源激素IBA的施用可在一定程度上提高插穗内源激素IAA、GA、ZR的含量及IAA/ABA、IAA/ZR的比值,降低ABA的含量。较高浓度的IAA和较为稳定的低浓度ZR有利于插穗不定根的发生;低浓度的ABA有利于不定根的形成与伸长;同时较低水平的IAA和GA对插穗根系伸长生长有益。较高比值的IAA/ZR和IAA/ABA有利于麻楝嫩枝插穗生根。外源激素处理加快了麻楝插穗内各营养物质的代谢进程,对插穗生根有利;各处理可溶性糖和淀粉含量显著高于可溶性蛋白含量,变化幅度也较可溶性蛋白含量大,与麻楝插穗生根的联系更为紧密。     

蓝莓离体快繁及生根特点研究

为了探索蓝莓离体繁育技术方案及其生根的特点,以蓝莓‘夏普蓝’春梢茎段为外植体,就其初代诱导、增殖及生根培养方案进行了筛选实验,对其生根时新梢基部愈伤组织进行了切片观察,并就生根期第0、2、4、6天幼芽中的内源激素IAA及ZR浓度进行了测定。实验结果表明:最适诱导培养基为CQWL+3 mg·L-1 ZT,以此培养基诱导的萌发率达45.2%;最佳增殖培养基为CQWL+1.5 mg·L-1 ZT,增殖系数达4.2倍以上,且增殖的不定芽长势健壮;最佳生根培养基为1/2 CQWL+0.05 mg·L-1 IBA,以此培养基培养的单株长有4~5条根,生根率达73%。切片观察结果表明:生根幼苗基部愈伤组织细胞小,胞质含量多。测定结果表明:添加了0.05 mg·L-1 IBA处理的新梢在生根期间内源激素IAA的浓度升高但变化不明显;内源激素ZR的浓度先下降再升高;IAA/ZR比值稳定。文中认为,培养基CQWL可适用于蓝莓的组织培养;细胞分裂素ZT能促进蓝莓的诱导与增殖;生长素IBA能促进蓝莓的离体生根。     

‘绿岭’核桃种胚无叶腋芽萌发快繁途径的初步研究

以早实薄皮核桃‘绿岭’成熟种胚诱导出的无叶腋芽为外植体,MS为基本培养基,通过调节激素种类和浓度配比,初步研究了‘绿岭’核桃种胚无叶腋芽快繁体系。比较试验结果表明:最佳种胚萌发诱导培养基为MS+IBA 1.0mg/L+6-BA 1.0mg/L+蔗糖30g/L+琼脂6g/L;种胚无叶腋芽伸长培养基为MS+6-BA 2.0mg/L+IAA 1.0mg/L+GA31.5mg/L+蔗糖30g/L+琼脂6g/L。生根采用两步生根法:离叶柄基部2 mm切的茎段先在DKW+IBA 8.0mg/L+蔗糖30g/L+琼脂6.0g/L暗培养20d,然后转入DKW+蔗糖30g/L+琼脂6g/L培养基中进行光照培养,生根率为50%。诱导生根的组培苗移栽到大田后成活率为33.3%。     

大果榉未成熟胚愈伤组织的诱导和植株再生

将大果榉的未成熟胚培养在不同植物激素种类和浓度的术本植物培养基(WPM)上产生愈伤组织,然后将愈伤组织接种在芽的诱导培养基上形成不定芽,不定芽在生根培养基上生根形成完整植株．结果表明:大果榉愈伤组织诱导的适合培养基为WPM附加BA 1．0 mg·L-1+NAA 1．0 mg·L-1,诱导事为59．1％;不定芽的分化培养基为在WPM+NAA 0．5 mg·L-1+6．BA 2．0 mg·L-1,不定芽的诱导率为71．1％,在WPM+BA2．5 mg·L-1+NAA1．0 mg·L-1的培养基种芽分化的平均数未为5．21±1．02;生根培养基以WPM+0．1 mg·L-1 IBA的效果量好,生根率可达63．33％,平均最多生根条数为．再生植株在温室适应培养的存活率为92％．     

南京椴嫩枝扦插生根过程中植物激素的变化

以南京椴嫩枝插穗为研究对象,采用1 000 mg·kg-1 IBA粉剂处理插穗基部,对扦插生根过程中插穗皮部生长素IAA、玉米素核苷ZR、赤霉素GA3、脱落酸ABA含量以及IAA/ABA和IAA/ZR比值进行动态测定,探究嫩枝扦插生根过程中植物激素变化特点及其对生根的影响。结果表明:1)IBA处理可以显著促进南京椴嫩枝插穗生根,生根率接近67%;其生根过程可划分为愈伤组织形成期、根原基诱导期、不定根形成期和不定根生长期,各自对应时间约为10 d。2)IBA处理可以提高嫩枝插穗中IAA含量,IAA对于根原基的诱导和不定根的发生具有较为直接的影响作用,其含量升高有利于生根;GA3含量增加有利于根原基形成,而低水平GA3则更有利于不定根的生长;ABA和ZR含量升高不利于插穗生根,对于根原基的诱导和不定根的发生具有抑制作用;IAA、ABA在插穗根原基诱导和不定根形成过程中具有相互协调作用,IAA/ABA可作为衡量南京椴嫩枝扦插生根能力的指标。3)外源IBA处理可以促进插穗内IAA含量升高,调节ABA、ZR、GA3含量降低,促使IAA/ABA在诱导生根期快速增大,通过相关激素的调控,使插穗向有利于促进生根的生理状态转变。     

外源生长物质对紫叶李扦插生根的影响

为了探究不同外源生长物质对紫叶李扦插生根的影响,以2 a生紫叶李当年生枝条为材料,研究了吲哚乙酸(IAA)、吲哚丁酸(IBA)和α-萘乙酸(NAA)对其扦插生根及其生根过程中营养物质、酶活性及内源激素含量的影响。结果表明:处理(T_3)对紫叶李生根的促进作用最为明显。可溶性糖含量在愈伤组织形成期(15 d)降低,在不定根形成期(20 d)不断积累,在不定根大量生成后(25 d)再次降低;淀粉、可溶性蛋白的变化趋势与可溶性糖基本一致,说明不定根形成需消耗大量的可溶性糖、淀粉和蛋白质为其提供能量。愈伤组织形成期(15 d),POD与PPO活性最高;紫叶李插穗中GA_3含量在根原基诱导与不定根发生初期较低,在不定根伸长期较高;IAA的含量在不定根的形成与伸长期快速上升,说明较高的GA_3与IAA有利于插穗不定根的发生与伸长。综合各因素可知300 mg/L IBA处理最有利于促进紫叶李插穗成活。     

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.