菠萝叶片总RNA提取方法的比较

为了探究不同提取方法对菠萝叶片组织总RNA提取质量的影响,以‘台农16号’菠萝品种的叶片为材料,采用改良Tirs-硼酸法、改良SDS法、试剂盒法提取菠萝叶片组织总RNA,并对提取的总RNA浓度、OD260/OD230、OD260/OD280、琼脂糖电泳结果进行了比较分析。结果表明:改良Tris-硼酸法和试剂盒法能较好地去除菠萝叶片组织的多糖、皂苷元、蛋白质以及纤维等次生代谢物质,OD260/OD230大于2.000,OD260/OD280在1.900~2.100之间。改良SDS法提取总RNA产率最高,达到290.9μg/m L。试剂盒法提取总RNA产率为30.1μg/m L,远小于其它2种提取方法所得总RNA产率。改良Tris-硼酸法所得电泳图谱条带完整度最好。比较分析3种提取总RNA方法的结果,以改良Tris-硼酸法提取总RNA的效果较理想,可满足后续研究工作的需要。     

适用于转录组测序的灰毡毛忍冬体胚总RNA提取方法筛选

为了找到适用于转录组测序要求的灰毡毛忍冬体胚总RNA的提取方法,以体胚发育过程中的球形胚、心形胚、鱼雷胚和子叶胚为实验材料,比较分析了EASYspin Plus植物RNA快速提取试剂盒法、RNA Cleanup Kit试剂盒法及改良CTAB法3种方法的RNA提取效果。结果表明:改良CTAB法提取的RNA浓度较低,提取过程中发生降解;RNA Cleanup Kit试剂盒法提取的RNA完整性较差,RIN值没能达到转录组测序的要求。EASYspin Plus植物RNA快速提取试剂盒法提取的RNA质量最高,且完整性好,能够满足转录组测序的要求。     

不同化学类型樟树叶片总RNA提取方法比较

采用SDS/酸酚法、Trizol试剂法、常规CTAB法及改良的CTAB法,分别提取5种化学类型樟树叶片总RNA,并对提取效果进行了比较分析。结果表明:Trizol法难以提取樟树叶片总RNA,得率很低;SDS/酸酚法和常规CTAB法得到的RNA存在DNA污染,富含蛋白、多糖、多酚等杂质;这3种方法均不适于富含多糖多酚类物质的樟树叶片总RNA的提取。改良的CTAB法能够提取得到樟树5种化学类型叶片总RNA,且在操作过程中,异樟比油樟和脑樟更易提取。此法能有效去除多糖和蛋白,提取得到的RNA 28S和18S rRNA条带清晰,OD260/OD280值为2.0左右,平均产率分别为115.8μg/g FW。经RT-PCR检测,所得总RNA质量高、完整性好、成功率高,可以满足下一步实验的要求,可作为樟树叶片总RNA提取的首选方法。     

芒果总DNA提取方法比较分析

为了研究不同提取方法对芒果总DNA提取质量的影响,以‘紫花芒’等11个芒果品种的叶片为材料,采用SDS法、CTAB法、改良CTAB法提取芒果叶片总DNA,并对提取的总DNA浓度、OD260/280、OD260/230、琼脂糖电泳结果、ISSR扩增产物进行了比较分析。结果表明,改良CTAB法能较好地去除芒果叶片中的多酚、多糖、单宁和色素等杂质。提取的总DNA浓度高达387 ng/μL,OD260/280在1.81~1.87之间,OD260/230在2.01~2.09之间。SDS法、CTAB法提取总DNA的ISSR扩增产物条带少,改良CTAB法提取的总DNA的扩增效果图谱清晰,多态性高。3种提取方法的结果比较而言,以改良CTAB法提取总DNA的效果最好,可用于后续实验的研究。     

金柑叶片和果实总DNA提取方法比较

为了研究不同提取方法对金柑总DNA提取质量的影响,以融安金柑等3个金柑品种的叶片和果实为材料,采用SDS提取法、CTAB提取法、试剂盒法提取金柑总DNA,并对所提取DNA的总浓度、A_(260/280)、A_(260/230)、凝胶电泳结果、SCo T扩增产物进行比较分析。结果表明:CTAB提取法和试剂盒提取法能较好地去除金柑叶片和果实中的蛋白质、RNA、多酚、多糖、单宁、色素等大分子物质以及盐类等小分子杂质。提取的总DNA浓度最高达178 ng/μL,A_(260/280)在1.82~1.94之间,A_(260/230)在1.89~2.04之间。SDS提取法、CTAB提取法和试剂盒提取法所提取的金柑叶片和果实总DNA的扩增效果图谱清晰,多态性高。3种提取方法中,CTAB提取法所提取总DNA浓度较高,纯度最好,可用于后续相关研究。     

金柑果肉组织总RNA提取方法比较

为给高通量测序等对RNA质量要求较高的后续试验提供基础,以‘桂金柑一号’等5个金柑品种的果实为材料,采用异硫酸胍提取法、CTAB提取法、SDS提取法、试剂盒提取法提取金柑果实总RNA,并对所提取的总RNA浓度、A260/A280、A260/A230、凝胶电泳结果、RT-PCR扩增产物等指标进行比较分析。结果表明:CTAB提取法、SDS提取法和试剂盒提取法能较好地去除金柑果实中的蛋白质、金柑甙、柠檬萜、DNA、多酚、多糖、单宁、色素等大分子物质以及盐类等小分子杂质。采用异硫酸胍提取法所提取的总RNA浓度最高,达到95.9μg/g,其A260/A280在1.69～1.73之间,A260/A230 2.14;其它RNA提取方法所提取的总RNA浓度最高达到76.9μg/g,其A260/A280分布在1.88～1.97之间,A260/A230分布在2.00～2.09之间,符合高质量RNA的要求范围。除了异硫酸胍提取法所提取的RNA琼脂糖电泳结果未见清晰的5S条带,其余方法所提取的RNA经琼脂糖电泳均可以观察到清晰的28S、18S、5S条带。但采用异硫酸胍提取法、CTAB提取法、SDS提取法和试剂盒提取法所提取的金柑果实总RNA进行反转录均可以得到清晰的扩增产物。在4种提取方法中,采用CTAB提取法所提取金柑果实总RNA浓度较高,纯度也较理想,琼脂糖电泳和RT-PCR效果好,是进行后续相关研究的较佳选择。     

木本植物根系总RNA提取方法的比较和分析

以杂种马褂木不定根和杨树、柳树、柽柳根系组织为材料,比较异硫氰酸胍法、Tiangen试剂盒、CTAB改良法、Trizol法和改良Trizol法提取总RNA的效果。结果表明,改良Trizol法通过在离心后的匀浆上清液中加入低浓度的无水乙醇以及结合后续的高盐溶液,能有效去除多糖,提取的RNA中28S rRNA亮度约为18S rRNA的两倍,OD260/OD280值介于1.7～2.1之间,各林木树种根系组织RNA得率均大于150μg/g,而且整个提取时间只要2～3 h。表明改良Trizol法方便、快捷、高效,完全适用于林木树种根系组织RNA的提取。     

山核桃花芽总RNA提取方法研究

以山核桃的花芽为材料,利用改良CTAB法、异硫氰酸胍法和改良热酚法提取其总RNA,并对RNA产率、纯度、电泳图谱和RT-PCR进行分析,结果表明:改良CTAB法明显优于其它两种提取方法,用它提取的28S rRNA、18S rRNA条带清晰、稳定,无降解,OD260/OD280值保持在1.9～2.0,产率相对较高;经RT-PCR检测发现,改良CTAB提取的RNA能被成花基因特异引物扩增出清晰的条带,说明该法完全适合于山核桃花芽总RNA的提取,并可用于Northern杂交、cDNA文库构建等分子生物学操作.     

3种方法提取菠萝蜜叶片和种子总RNA的比较

为了筛选最适的菠萝蜜总RNA提取方法,采用Trizol提取法、Tris-硼酸提取法和试剂盒提取法提取菠萝蜜叶片和种子总RNA,通过紫外分光光度计检测、琼脂糖凝胶电泳、RT-PCR检测以及Agilent2100检测,对提取结果进行比较分析。结果表明:采用这3种方法均能从菠萝蜜叶片和种子中提取到总RNA,Tris-硼酸提取法较其他2种方法所提取的总RNA产率高,但杂质较多;采用Tris-硼酸提取法能提取完整性较好的总RNA,28S、18S和5S清晰可见,但提取质量较试剂盒提取法差;试剂盒提取法省时省力,有明显的28S和18S条带,A260/A280分布在1.92~1.98,A260/A230分布在2.04~2.09,叶片总RNA产率42.3ng/μL,种子总RNA产率15.6ng/μL。RT-PCR检测结果表明在约200bp处存在清晰整洁的电泳条带,Agilent2100检测结果显示杂峰极少,28S峰积分面积约是18S峰积分面积的2倍。经综合评定认为,试剂盒提取法是适合菠萝蜜叶片和种子总RNA提取的方法。     

枣花蕾总RNA提取方法的比较

为了探究枣花蕾总RNA提取的最优方法,以沾化冬枣的花蕾为材料,利用改良CTAB法、Trizol法和2种RNA提取试剂盒(PureLinkTMRNA小提试剂盒和北京奥莱博生物技术有限公司提供的植物RNA提取试剂盒)分别提取花蕾的总RNA,并对RNA浓度和电泳图谱进行比较分析,利用奥莱博生物技术有限公司提供的植物RNA提取试剂盒法可提取到纯度较高,完整性好的总RNA,并可用于Northern杂交、cDNA文库构建和半定量RT-PCR等分子生物学试验。     

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.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

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.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

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。     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.