长白落叶松胚性愈伤组织诱导及体细胞胚胎发生

【目的】以长白落叶松的未成熟合子胚为外植体,进行胚性愈伤组织的诱导、增殖培养及体细胞胚胎发生的相关研究,揭示影响长白落叶松胚性愈伤组织诱导的关键因素,并探讨继代培养过程中添加不同种类、浓度的生长调节剂对胚性愈伤组织增殖及体胚发生的影响。【方法】采集长白落叶松3个家系优良单株的种子,诱导胚性愈伤组织,比较外植体采集时间、家系、2,4-D浓度及基本培养基对胚性愈伤组织诱导的影响。诱导出的胚性愈伤组织继代于含不同种类、浓度生长调节剂的增殖培养基,通过体胚发生途径获得体细胞胚。选取发育正常的体胚进行萌发,待体胚生根后移栽。【结果】不同时间采集的未成熟合子胚,其胚性愈伤组织诱导率存在较大差别,授粉后63天的合子胚诱导率为5.61%,授粉后70天诱导率为22.35%,而授粉后80天未诱导出胚性愈伤组织;‘长77-22’、‘长77-37’和‘长73-50’3个家系胚性愈伤组织的平均诱导率分别为6.69%,11.17%和3.11%;2,4-D浓度对长白落叶松胚性愈伤组织诱导具有一定影响,在一定范围内胚性愈伤组织的诱导率会随2,4-D浓度升高而升高,当其浓度为1.5 mg·L~(-1)时胚性愈伤组织的诱导率最高,达到11.11%,而当2,4-D浓度超过1.5 mg·L~(-1)时,胚性愈伤组织的诱导率则开始下降;BM,MS,S培养基均能诱导出胚性愈伤组织,其中,BM培养基的诱导率最高,S培养基的诱导率次之,MS培养基的诱导率最低。胚性愈伤组织在含2,4-D 0.3 mg·L~(-1)、6-BA0.1 mg·L~(-1)及KT 0.1 mg·L~(-1)的BM培养基上增殖15天可获得相对较多的胚性愈伤组织,增殖率为345.93%;在含2,4-D 1.5 mg·L~(-1)、6-BA 0.5 mg·L~(-1)及KT 0.5 mg·L~(-1)的BM培养基上培养14天,再经诱导可获得较多的体细胞胚胎,每克愈伤组织平均诱导179.87个体胚,并且这些体胚的萌发率及植株再生率相对较高,分别为75.00%,66.67%;再生植株移栽成活率为27.08%。【结论】不同长白落叶松家系的胚性愈伤组织诱导率不同,散粉后70天的合子胚适合诱导胚性愈伤组织,基本培养基为BM,添加2,4-D 1.5 mg·L~(-1)。胚性愈伤组织长期继代在含高浓度生长调节剂的培养基上易丧失胚性,且增殖速度慢,但体胚的发生量及萌发率相对较高;适当降低生长调节剂浓度利于愈伤组织保持胚性及增殖,但体胚的发生量及体胚的萌发率有所下降;当培养基中生长调节剂浓度较低时,不利于愈伤组织的增殖,但仍能使其胚性长期保持;采用浓度为0.5 mg·L~(-1)的NAA代替0.15 mg·L~(-1)的2,4-D有助于胚性愈伤组织的增殖,并能在一定程度上提高体胚的萌发率。因此,可根据不同阶段的培养目的,选择添加不同种类和浓度生长调节剂的增殖培养基进行继代。     

挪威云杉及杂种落叶松稳定胚性细胞系及体胚再生系统的建立

本文报道了挪威云杉(Picea abies)和杂种落叶松(Larix deciduas× L. kaempferi)人工授粉种子诱导胚性细胞系及植株的再生.挪威云杉在德国Saxon Ore 山区被选为对空气污染有抗性的树种并种植在位于Waldsieversdorf的林木遗传育种研究所的种植园中.对挪威云杉测试了几个不同亲本组合的种子形成胚性细胞系的能力.这些云杉种子于1992-01采收,含有干燥的成熟合子胚.作为对照,相同的亲本组合云杉种子于1993-08和1998-08采收,合子胚处于成熟中.杂种落叶松则只有一个人工授粉组合,大田试验证实幼苗生长良好.分别于1995和1996年采收含有未成熟合子胚的未成熟种子.诱导愈伤形成用附加细胞分裂素(激动素和/或BAP)和生长素(NAA, 2,4-D)及有机氮源(水解酪蛋白和谷氨酰胺)的标准培养基(SPE和MSG),于黑暗下培养.尽管在建立培养体系后5～12周产生了大量胚性愈伤组织,诱导率超过25%,但1 a后只有超过1%的胚性愈伤组织稳定生长.挪威云杉稳定胚性细胞系的数量与成熟合子胚的采收季节及建立细胞系的时间(8月或1月)无关,但在8月收获的合子胚在挪威云杉5～12周后胚性愈伤组织诱导率要高些,然而能在悬浮培养中生长及随后成熟体胚能顺利再生植株的稳定胚性细胞系的数量有限.挪威云杉体胚未充分发育的根影响其移栽到土壤中的成活率.在建立的12个细胞系中只有一个在干燥保存后能从体胚再生正常植株.同时考察了影响挪威云杉形成成熟体胚的因素,如用PEG4 000(7.5%)及ABA[8mg·L-1(30.26μmol)-1]处理及ABA灭菌方式(高温高压灭菌或过滤灭菌)对成熟体胚形成的影响.总体来说,过滤灭菌的ABA增加了成熟体胚的数量.营养培养基中用淀粉部分取代蔗糖只导致2个细胞系中的一个增加了成熟体胚的数量.1995和1996年对人工授粉杂种落叶松合子胚发育与自然授粉(不套授粉袋)的相比较,发现人工授粉袋的使用延迟了合子胚的发育.我们的实验中成熟合子胚没有形成胚性细胞系,只有未成熟合子胚形成了胚性细胞系.1995年用落叶松未成熟合子胚建立的胚性细胞系没有形成体胚,而1996年建立的4个胚性细胞系得到了可以移栽到温室中的再生植株.1.5 a的连续继代培养以后,大多数的杂种落叶松和挪威云杉的胚性细胞系的再生能力都下降.导致这种现象可能有多种原因包括培养物的老化以及出现难以检测到的内生细菌.尽管一组实验从最初培养即用了抗生素,但没有收效.因此目前只得到少量的稳定胚性细胞系(<5%),长期继代后丧失再生能力及无法成功移栽到土壤都是植株再生的重要的限制因素,有待进一步研究克服这些困难.     

刺槐未成熟合子胚的体细胞胚胎发生和植株再生

以刺槐不同胚龄的未成熟合子胚为外植体,采用混合正交试验设计,研究幼胚胚龄和不同外源激素种类及质量浓度对刺槐胚性愈伤组织的诱导和体细胞胚分化、萌发的影响.结果表明:开花后8周(55天左右)是胚性愈伤组织和体胚诱导的最佳外植体取材时期;MS+2,4-D 5.0 mg·L-1 +BA0.5 mg·L-1是诱导胚性愈伤组织的最佳培养基,出愈率最高为95.42％±0.02％;MS +NAA0.5 mg·L-1 +BA0.5 mg·L-1+谷氨酰胺250 mg·L-1+水解酪蛋白500 mg·L-1是体细胞胚诱导和分化的最佳培养基,直接体细胞胚发生率最高为92.40％±0.12％,通过愈伤组织诱导体细胞胚发生的频率最高为90.73％ ±0.49％.一旦形成球形胚,将培养物转接到不含任何生长调节剂的MS培养基上,体细胞胚经成熟萌发可进一步形成完整小植株.     

黑松未成熟胚的体细胞胚胎发生和植株再生

以未成熟合子胚为外植体,建立黑松体细胞胚胎发生和植株再生体系。研究基本培养基、2,4-D和6-BA对胚性愈伤组织诱导的影响,探讨ABA和PEG对体细胞胚成熟及植株再生的影响。结果表明:在添加4mg·L-12,4-D+2mg·L-16-BA的DCR培养基上胚性愈伤组织诱导率为3.33%;在添加30mg·L-1ABA+25g·L-1PEG的培养基DCR上,每克愈伤组织体细胞胚数量达72个,体细胞胚的萌发率为63.8%、植株转化率为43.5%,高质量的黑松体胚能提高体胚萌发率和植株转化率,再生植株1个月移栽成活率为50%。该研究可为抗病黑松的快速大规模繁殖提供一条新途径。     

长白落叶松愈伤组织及不定芽的诱导

以长白落叶松成熟合子胚为研究对象,从外植体消毒方式及愈伤组织与不定芽诱导的适宜培养基、激素组合和配比的选取等方面着手,进行长白落叶松愈伤组织及不定芽诱导的研究。结果表明:先用4%NaClO消毒去皮种子15 min后,再用0.5%NaClO消毒胚2 min为长白落叶松成熟合子胚的最佳消毒方法;BM为愈伤组织诱导的最适培养基;当BM+2.0 mg·L^-1 TDZ时,愈伤组织诱导率最高,为89%;BM+1.5 mg·L^-1 TDZ时,不定芽诱导率最高,为80.0%。     

麦芽糖、NAA及ABA对华北落叶松体细胞胚成熟及生根的影响

研究了麦芽糖、NAA、ABA对华北落叶松体细胞胚发生及体细胞胚根发生和再生完整植株的影响。结果表明 :在胚性愈伤组织继代、增殖过程中 ,以 0 5mg·L- 1 的NAA代替 2 ,4 -D后 ,有利于体细胞胚的成熟和根发生。在ABA 16mg·L- 1 时 ,产生的华北落叶松体细胞胚 ,能够再生良好植株 ,ABA大于 2 0mg·L- 1 时对体细胞胚根的发育不利。在含 3%麦芽糖、4 %PEG4 0 0 0活性炭 1g·L- 1 的成熟培养基上 ,华北落叶松每克愈伤组织子叶胚达 10 6 7个 ,生根率达 5 7 89% ;显著地提高了成熟体细胞胚及其根的质量。     

地被菊间接体细胞胚发生途径的转基因受体体系的研究

采用三步培养法建立了地被菊花品种‘玉人面'间接体细胞胚发生途径的转基因受体体系.试验以地被菊花品种‘玉人面'茎段(节间)为外植体,研究了生长调节剂、光照强度等因子对其间接体细胞胚诱导和分化的影响,同时进行了抗生素敏感性试验.结果表明:胚性愈伤组织诱导培养基为MS KT 2.0 mg·L-1 2,4-D 2.0 mg·L-1 NAA 0.5 mg·L-1,诱导15 d后,将获得的黄绿色致密颗粒状胚性愈伤组织转入胚性愈伤组织分化培养基MS KT 2.0 mg·L-1 2,4-D 1.0 mg·L-1 NAA 0.5 mg·L-1中,诱导15 d后再转入MS KT 2.0 mg·L-1 NAA 0.5 mg·L-1的分化培养基中培养20 d,光照强度为1 000～2 000 lx,胚性愈伤组织诱导率、分化率分别为95.3%、92.7%,平均每个外植体分化的芽数为17.8个,获得的再生芽的稳定性为99.5%.抗生素敏感性试验表明:地被菊花品种‘玉人面'间接体细胞胚发生途径的转基因受体体系中,卡那霉素选择压为20 mg·L-1;头孢霉素在胚性愈伤组织诱导时的选择压为300 mg·L-1,在胚性愈伤组织分化培养时选择压为100 mg·L-1.     

华北落叶松胚性愈伤组织诱导影响因子的研究

以成熟合子胚为外植体,用完全随机、正交设计等试验方法加之组培技术来研究影响华北落叶松(Larix princi-pis-rupprechtii)胚性愈伤组织诱导的几种主要因子。结果表明:诱导胚性愈伤组织过程中的最佳灭菌方式为2%Na-ClO灭菌30 min,剥皮、去胚乳处理。其中污染率和NaClO的灭菌时间呈负相关:NaClO灭菌时间越长,污染率越低。诱导胚性愈伤组织的最佳琼脂浓度为4 g·L-1,且过高和过低的琼脂浓度不仅降低了其诱导率,提高了愈伤组织的褐化水平,也影响了外植体的发育形态。外源激素的正交试验结果表明:2,4-D是主要影响因子,对诱导率的影响显著,其次是KT,最后是6-BA。最佳的植物外源激素配比是2,4-D 1.8 mg·L-1+6-BA 0.3 mg·L-1+KT 0.3 mg·L-1。     

桃幼胚及幼胚子叶再生的研究

以玉露桃和湖景蜜露桃幼胚及幼胚子叶为试材,研究基本培养基类型、激素、损伤方式等因素对再生的影响。结果表明:培养基是影响幼胚诱导愈伤组织的最重要因素,MS适合供试材料诱导愈伤组织;激素诱导愈伤组织因品种而异,NAA1.0mg·L-1对45d、0.5mg·L-1对55d玉露,BA0.5mg·L-1对55d湖景蜜露效果较好,在试验浓度范围内2,4-D对供试幼胚均无明显效果;幼胚的发育状态是影响诱导愈伤组织的另一因素,玉露桃45d愈伤组织诱导率最高,达96.6%,而55d诱导率为81.6%。愈伤组织可在MS 0.05mg·L-1NAA 1.0mg·L-1BA培养基上分化成芽,再生芽在1/2MS 1.0mg·L-1IBA培养基上生根。幼胚子叶不定芽再生培养基的激素配比为NAA0.50mg·L-1 BA10.0mg·L-1、NAA0.05mg·L-1 TDZ3.0mg·L-1;带胚芽子叶纵向刻伤再生率高;不定梢(芽)在1/2MS 2%蔗糖 7.5g·L-1琼脂 IBA1.0mg·L-1 Ad20mg·L-1的培养基上能生根。     

杂种落叶松胚性愈伤组织诱导的研究

以杂种落叶松兴7×日77-2、日12×兴9、日3×兴9、日3×兴2、日5×兴9未成熟合子胚为外植体,初步建立杂种落叶松胚性愈伤组织诱导体系。结果表明:不同杂种落叶松在不同培养基和蔗糖浓度下的诱导情况不尽相同,基本培养基中MSG与MS培养基的诱导效果比较好,激素浓度的差异对杂种落叶松也有影响,2,4-D浓度为2.0 mg/L时,诱导率高,蔗糖浓度为30 g/L能诱导出胚性愈伤组织,高浓度的蔗糖反而抑制了胚性愈伤的形成。ABA分别为0、5、10、20、30 mg/L的5个处理中,除对照及ABA30 mg/L时没有诱导出体细胞胚,其他试验组均有一定数量的体细胞胚,但诱导率较低。几种杂种落叶松胚性愈伤组织诱导最适合的采样时间是7月中旬。     

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。     

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.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.