麻竹RAPD反应条件的优化

以麻竹DNA为模板,对影响麻竹RAPD扩增的重要参数进行了优化试验,以期建立麻竹RAPD反应的最适体系。最终得出的麻竹RAPD反应体系为:20μL反应体系,2μL10倍反应缓冲液,模板含量为50ng,2 5mmol·L-1的Mg2+,1 5U的Taq酶,dNTP为1 75mmol·L-1,引物浓度为0 4μmol·L-1。优化后的RAPD反应程序为:94℃3min→[94℃1min→37 5℃1min→72℃1min20sec]40个循环→72℃8min→4℃保持。     

油茶随机扩增多态DNA条件的研究

以改进的CTAB法提取油茶嫩叶总DNA,进行随机扩增多态DNA(RAPD)分析,分别测试了Mg2+浓度、引物浓度、dNTP浓度、模板DNA浓度和TaqDNA聚合酶用量对反应结果的影响,确定了油茶RAPD分析的最适反应体系:在25μlPCR反应体积中,含20ng模板DNA,2 5mmol·L-1MgCl2,0 2mmol·L-1dNTP,0 3μmol·L-1引物,1UTaqDNA聚合酶。扩增程序为:94℃预变性180s;94℃变性60s,37℃退火90s,72℃延伸120s,反应40个循环;最后在72℃延伸5min。     

香果树RAPD扩增条件的优化及遗传多样性初步分析

对浙江省天台山自然香果树种群的DNA进行了提取和RAPD扩增条件的优化,分别测试了镁离子、dNTP、模板DNA含量、引物浓度、DNA聚合酶量和牛血清白蛋白浓度对反应结果的影响,通过各因子的组合研究,可知香果树RAPD分析较适宜的扩增条件为:15μLPCR反应体积,1×Taq酶配套缓冲液,1 8mmol·L-1MgCl2,2UTaq酶;10ng模板DNA;20pmol引物;dATP、dCTP、dGTP、dTTP各0 1mmol·L-1。以此适宜条件对12个引物进行扩增,共扩增出51个DNA片段,多态位点百分率为45 1%,种群内遗传多样性较低,进一步研究不同种群香果树的遗传多样性具有一定的意义。     

香榧RAPD分析实验条件的优化

试验通过系统的比较研究 ,建立了香榧 RAPD分析的优化反应体系和实验条件 ,即 2 0μl的反应体系中含有 5 0 ng DNAtemplate、1.5μl 10× Buffer、1U Tag NDA聚合酶、2 .4mmol/L Mg Cl2 、2 40μmol/L d NTPs、0 .8μmol/L Primer。适宜的扩增程序为95℃变性 3 min,1个循环 ;94℃变性 3 0 s,3 6℃退火 3 0 s,72℃延伸 60 s,3 5个循环 ;72℃延伸 5 min,反应终止。该反应体系重复性高 ,条带亮度均匀 ,弥散现象少     

核桃RAPD条件的优化

对核桃RAPD分析中Mgh、引物、dNTPs、TaqDNA聚合酶浓度及复性温度等因素进行了比较影响分析。建立了适合核桃DNA多态性分析的RAPD反应体系：25μL反应液中，3．5mM Mg^2＋、0．2mM dNTPs、0．2μM随机引物、1．0UT aq酶、50ng～100ng模板DNA；反应过程为45个循环，94℃变性60s，36℃退火60s，72℃延伸120s。     

落叶松—杨栅锈菌DNA提取及RAPD条件优化

本文对采自全国8个省市的落叶松—杨栅锈茵茵株进行了基因组DNA提取，并以其为模板对影响RAPD扩增1的重要参数进行优化试验，以期建立落叶松—杨栅锈茵RAPD反应的优化体系。结果表明，PCR扩增体系最佳条件是：25μL体积中，2．5mmol／LM^2 ，30ng／μL模板，0．15mmol／LdNTP，1．5μL引物，0．75UTaq聚合酶。     

我省板栗主载品种（无性系）RAPD反应体系的建立

在RAPD反应中，有许多影响结果的稳定性和准确性。本项研究采用浙江省8个板栗主载品种（无性系，）对RAPD各种反应进行了探索，结果表明，板栗理想的反应体系为：20μl反应体积含有100mmol/L Tris-HCl,500mmol/LKCl,20mmol/LMgCL2,0.01%Gelatin,dATP、dTTP、dGTP的量各为100μmol/L，50－200ng引物，0．75－1．0单位Taq酶，2－10ng模板NDA。反应条件为：94℃预变性2min，再94℃30s、40℃30s、72℃1．5min扩增37个循环；最后在72℃延伸7min。应用上述反应体系进行板栗PAPD反应，扩增产物在1．0％琼脂糖凝胶中电泳，经EB染色后在紫外灯下观察照相，可获得满意的DNA指纹图谱。     

我省板栗主栽品种(无性系)RAPD反应体系的建立

在RAPD反应中,有许多影响结果的稳定性和准确性.本项研究采用浙江省8个板栗主栽品种(无性系),对RAPD各种反应条件进行了探索,结果表明,板栗理想的反应体系为20μl反应体积含有100mmol/LTris-Hcl,500mmo1/LKCl,20mmol/LMgCL2,0.01%Gelatin,dATP、dTTP、dCTP、dGTP的量各为100μmol/L,50~200ng引物,0.75～1.0单位Taq酶,2～10ng模板DNA.反应条件为94℃预变性2min,再94℃30s、40℃30s、72℃1.5min扩增38个循环;最后在72℃延伸7min.应用上述反应体系进行板栗RAPD反应,扩增产物在1.0%琼脂糖凝胶中电泳,经EB染色后在紫外灯下观察照相,可获得满意的DNA指纹图谱.     

万寿菊RAPD分子标记优化体系的建立

以雄性不育和可育万寿菊及其子代为材料,在PE-2400型PCR仪上进行扩增,通过3次正交试验设计,优化得到了最佳的RAPD反应体系,确定了各个因素的最佳水平。在20 μL反应体系中,最佳的浓度配比为:10×Buffer中含10．00 mmol·L-1Tris-HCl、50．00 mmol·L-KCl、0．001％gelatin、dNTP0．25 mmol· L-1、TaqDNA聚合酶1．5 U、MgCl2 1．25 mmol·L-1、DNA20-60 ng、引物0．60 pmol·μL-1,预变性时间5 min, 退火温度37℃较好,1 min的延伸时间也满足了2 kb以下的DNA片段合成,循环35次能得到较好的 RAPD图谱。     

濒危药用植物降香黄檀DNA提取及RAPD反应体系优化

采用改良CTAB法提取了降香黄檀(Dalbergia odorifera T. Chen)新鲜叶片和硅胶干燥后放置3个月的叶片基因组DNA,并对影响RAPD反应的各因素进行了优化。结果显示新鲜的降香黄檀叶可以得到质量较高的DNA,硅胶保存后部分叶片所提的DNA有降解。优化后反应体系为:25μL反应体系中包括,模板的DNA 20ng,Taq DNA Polymerase 2.5U,Mg2 5mmol.L-1,dNTP 0.3 mmol.L-1,引物(S37)0.4μmol.L-1。反应条件为94℃预变性4min;94℃30s,36℃1min,72℃2min,40个循环;72℃延伸10min。     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Growth of Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.     

Boron in forest trees and forest ecosystems

This review critically examines the role of boron (B) in forests in view of recent findings on B nutrition and the continuing occurrence of B deficiency. Many perceptions about the role of B in plants and its uptake and mobility have been altered since the last review on B in forest trees in 1990. Now there is evidence for a fundamental role of B in the formation of the pectic structure in primary cell walls in plants, and further roles in membrane function are being explored. In plants, channel-mediated B uptake, active B uptake and B uptake by mycorrhizas have been shown, B transporters have been identified, and B retranslocation has been shown. We explore these findings and their consequences on forest trees and on ecosystems that they dominate. Particular emphasis is placed on B retranslocation and B in mycorrhizal symbiosis, given their importance in trees.     

Development of Pinus sylvestris Main Stems Following Three Different Precommercial Thinning Methods in a Mixed Stand

Reducing competition by point cleaning may be an attractive alternative to conventional precommercial thinning in forestry. In this study, survival and development of main stems of Scots pine (Pinus sylvestris L.) following point cleaning were examined in a mixed stand of mainly Scots pine and birch (Betula pendula Roth and Betula pubescens Ehrh.) in northern Sweden. Treatments studied were: no precommercial thinning, conventional precommercial thinning, point cleaning of all secondary stems, and point cleaning of only the secondary stems that were higher than the main stem, within a radius of 0.8 m from the main stem, respectively. A randomised complete block design with three replicates was used. Measurements taken 13 growing seasons after these treatments showed that conventional precommercial thinning was the best treatment for retaining Scots pines as main stems. However, conventional precommercial thinning resulted in the poorest timber quality of the remaining Scots pines in terms of stem taper, thickest branch diameter and relative live crown height. In conclusion, point cleaning has to be followed by a complementary cleaning operation if the objective is to retain Scots pines as main stems in such mixed stands.     

Survival and Growth of Picea abies Regeneration after Shelterwood Removal with Single- and Double-grip Harvester Systems

Three stands in Sweden were followed for 7 yrs to study the survival and growth of Norway spruce [Picea abies (L.) Karst.] regeneration after shelterwood removal with single- and double-grip harvester systems. The height of all seedlings within circular plots was recorded before and after final cutting. The tallest seedling and one randomly selected seedling on each circular plot were permanently marked and their annual height growth was measured each year during the period 1993-1999. No significant differences between single- and double-grip harvester systems were found with respect to their effects on regeneration density, survival or annual height growth. The annual height growth of the individual seedlings after shelterwood removal was significantly correlated with seedling height before shelterwood removal. Significant differences were found in annual height growth between seedlings with high and low vitality. Logging damage did not affect the annual height growth. Several practical conclusions were drawn. First, the choice of harvester system does not affect seedling height growth or survival after shelterwood removal. Secondly, the removal of a 200 m³ shelterwood with 200 stems ha^-1 does not seem to constitute a serious problem for seedling survival and growth. Finally, estimated vitality and seedling height both seem to be fairly good predictors of postrelease survival and growth.     

Tree planting for dryland salinity control in Australia

Dryland salinity is emerging as a major form of land and water degradation in southern Australia, particularly in Western Australia, South Australia and Victoria, and to a lesser extent in New South Wales, Tasmania and Queensland.Tree planting, in combination with other vegetation treatments, is regarded as a leading solution to dryland salinity. Research has now shown that planting trees can significantly lower groundwater tables, and thereby reverse the causal process of salinisation. Substantial progress has been made towards answering the basic questions of which species to grow, how to plant, where to plant, at what density and configuration to plant, and how much area to plant. The economic potential for commercial tree planting has given impetus to partial reforestation in higher rainfall (> 600 mm yr^–1) areas. Even so, serious constraints are apparent, relating primarily to cost, uncertainty and attitude. The future should bring increasing community input and control, technical refinement and gradual adoption, provided all aspects of the issue are well researched, relevant information is well communicated and programmes are well administered. Some specific requirements for future research are identified in this review.     

Effect of Cuttings on the Scenic Beauty of a Tree Stand

The opinions of 207 respondents on the visual effects of seven different cutting types were asked using a nine-point verbal scale ranging from ''worsens very much'' to ''improves very much''. Other estimates were obtained by letting the same respondents evaluate photographs of stands which had been treated with different cuttings. The direct questions gave results quite similar to the evaluations of photographs for all but young respondents, indicating that most respondents were able to imagine the effect of the treatment correctly. The results based on the evaluation of photographs indicated that the effect of regenerative cuttings is negative while the impact of thinnings is positive. After a few years of cutting the stand is already regarded as clearly more pleasant than immediately after the cutting. Natural regeneration with seed trees seems to be a way to avoid the very negative immediate impact of clear-felling, especially in the case of Scots pine. Women, young, urban people and those who do not own forest or have work related to forests tended to experience thinnings less positively and saw regenerative cuttings as more harmful than the other test groups did.     

Pinus contorta growth in northern Sweden as affected by soil scarification

The aim of this study was to quantify the effects of different soil scarification methods on tree growth. Soil scarification influenced stem volume and stem biomass yield of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) in a 17-year-old field trial in boreal Sweden. Soil scarification (disc trenching, mounding and ploughing) resulted in an average stem volume yield of 3.1 and 34.2 m³ ha^–1 on the poor and intermediate sites, respectively, while corresponding values for no soil scarification were 0.9 and 16.7 m³ ha^–1. In comparison to no scarification, ploughing increased volume yields by 500% on the poor site and by 200% on the intermediate sites. The ranking according to stem volume yield was ploughing > disc trenching = mounding no soil scarification. Averaged over the two sites, the mean annual increment of stem biomass was 219% and 145% higher (in d.w., 0.26 kg and 0.34 kg per sample tree) after ploughing compared with no soil scarification, for the average and dominant sample trees, respectively. Although not significant, the increased growth rate after soil scarification decreased the average stem basic wood density of the sample trees with 1.6% and 5.3%, at the poor and intermediate sites, respectively. In conclusion, soil scarification significantly increased the 17-year stem volume yield compared with no scarification. The results also indicate that the difference in stem biomass yield between ploughing and the other methods, especially no soil scarification, will increase even more in the near future.