银染过程的时间考量

本文介绍了水稻几种细胞质雄性不育品种线粒体DNA的AFLP(Amplified Fragment Length Ploymorphism)预扩、选扩和变性的PCR程序.两种PAGE银染的方法中,强碱法简便节约,而弱碱法的成像效果好,但操作过程中时间的把握至关重要.     

杉木叶片原生质体分离及RNA提取体系的建立

【目的】以杉木组培苗幼嫩叶片为材料,分析不同因素对杉木原生质体分离的影响,建立杉木叶片原生质体分离体系,以期为杉木基因功能验证提供有效的技术平台;比较不同RNA提取方法,筛选获得杉木原生质体总RNA提取的有效方法,为今后利用杉木原生质体开展分子生物学研究提供技术支持,也可为其他林木原生质体的总RNA提取研究提供参考。【方法】选取杉木组培苗最上端未分轮的幼嫩叶片为材料,通过分析5种不同酶组合、真空处理时间(0、5、10、15、20 min)、渗透压(0.3、0.4、0.5、0.6 mol·L-1甘露醇)、BSA浓度(0.1%、0.2%、0.3%、0.4%)及酶解时间(1、2、3、4、5 h)5个条件,进行杉木叶片原生质体的分离。采用改良Trizol法、改良Trizol+10μg糖原法、CTAB-Li Cl法、CTAB-Li Cl+10μg糖原法、改良CTAB-异丙醇法、改良CTAB-异丙醇+10μg糖原法、天根RNA提取试剂盒法共7种方法提取杉木原生质体RNA,通过杉木内参基因和2个特异基因进行RNA质量验证,比较不同方法的提取效果。【结果】在1.5%纤维素酶R-10、1%离析酶R-10、0.2%果胶酶Y-23、0.5 mol·L-1甘露醇以及0.3%BSA的混合酶液中,真空处理10 min,酶解2 h,可分离出高活力的纯净杉木原生质体,其产量可达到7.27×106个·g-1,活力可达到94%。7种方法皆能提取出杉木叶片原生质体的总RNA,但不同方法间存在明显差异,其中改良Trizol法、改良Trizol+10μg糖原法、改良CTAB-Li Cl法、改良CTAB-Li Cl+10μg糖原法提取的RNA有不同程度的降解现象,其余方法所提取的RNA完整性较好,且OD260/280和OD260/230值均在1.8~2.0范围内;在RNA得率方面,改良CTAB-异丙醇+10μg糖原法可高效提取杉木原生质体RNA,106个细胞RNA产量平均可达到6.89μg,分别是改良CTAB-异丙醇法和天根RNA提取试剂盒法的1.73倍和1.58倍;综合考虑,改良CTAB-异丙醇+10μg糖原法提取杉木原生质体RNA的效果最好。【结论】以杉木组培苗幼嫩叶片为材料,分离条件为纤维素酶R-10浓度1.5%、离析酶R-10浓度1%、果胶酶Y-23浓度0.2%、甘露醇浓度0.5 mol·L-1、BSA浓度0.3%,真空处理10 min,酶解2 h,可大量获得高质量的杉木原生质体;利用改良CTAB-异丙醇+10μg糖原法,可高效提取杉木原生质体RNA,106个细胞RNA产量平均可达到6.89μg。研究结果为杉木重要性状关键基因的功能研究及其在育种中的应用提供了重要基础。     

花生油还原法绿色制备银纳米颗粒

介绍了一种以乙醇作为溶剂,花生油作为还原剂和稳定剂,环境友好的制备银纳米颗粒的策略。利用X射线衍射(XRD)、透射电镜(TEM)和选区电子衍射(SAED)技术对溶液相法和溶剂热法两种方法合成的银纳米颗粒进行了表征。结果表明:溶液相法制备的银纳米颗粒粒径尺寸均匀,但晶体结构较差;而溶剂热法制备的颗粒粒径尺寸相差较大,存在少量特殊结构,但晶体结构较好;此外,两种方法都能获得面心立方体结构的单晶银纳米颗粒。     

八角基因组DNA的提取方法

采用4种植物基因组DNA提取方法(CTAB法、SDS法、高盐法、试剂盒法)对八角基因组DNA进行提取试验.结果表明,对传统CTAB法稍加改良可以得到较为理想的提取效果,改良的内容包括①在加入CTAB提取缓冲液之前,先用CTAB-free缓冲液抽提1～2次;②将CTAB提取缓冲液中CTAB的用量从2％提高到3％;③提取缓冲液的用量由样品干重的10倍增加到60倍.用改良CTAB法提取的DNA经RAPD-PCR扩增,条带清晰,其质量能够满足分子标记的要求.     

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。     

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.     

mRNA差异显示法研究杉木木材形成相关cDNA

利用差异显示法(DDRT-PCR)研究杉木的2个自然变异类型(句容0号及独干杉)木材形成过程中基因表达差异.通过银染后切割回收54个差异条带,经2次扩增和纯化、克隆转化及反向Northern杂交验证后共获得29个阳性克隆.测序后进行比对分析,结果表明:1)Blastn比对(分值＞60)有9个cDNA克隆在GeneBank中找到了相似的功能,分别与核糖体蛋白基因、信号传导功能、泛素蛋白基因、抗性功能、组氨酸磷酸转移蛋白、细胞发生功能及能量代谢相关;2)Blastx比对有12个序列可进行功能推测;3)还有8个cDNA在数据库中未发现匹配信息.这些信息可为杉木木材形成相关基因的分离和克隆提供研究基础.     

桉树植物杀灭钉螺的初步研究

目的研究桉树植物杀灭钉螺的效果.方法对桉树属中的异心叶桉和赤桉树叶的水提剂、乙醇提取物和桉油等提取物,采用室内浸杀法,观察其在恒温(25±1℃)下的杀螺效果及对钉螺卵毒性作用.结果:异心叶桉和赤桉树叶的水提剂浸泡钉螺72h后的LC50为分别为0.24%和0.18%;乙醇提取物浸泡钉螺72h后的LC50分别为12.1mg/l和16.5mg/l;两种桉油浸泡钉螺72h后的LC50分别为42.0mg/l和9.7mg/l.异心叶桉乙醇提取物在50.0mg/l时浸泡钉螺卵5d以上、25.0mg/l浸泡钉螺卵7d以上,可完全抑制钉螺卵的孵出.结论异心叶桉和赤桉两种桉树叶的水提剂、乙醇提取物和桉油对钉螺都具有较强的杀螺作用.提示这两种桉树可能是研究植物杀螺剂较有价值的候选植物.     

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。     

蒸馏-超滤法处理杨木自催化乙醇法蒸煮废液的研究

针对杨木自催化乙醇法蒸煮废液成分复杂,副产物价值高等特点,采用蒸馏-超滤法分离回收废液中的乙醇和木质素副产物,降低废液污染程度.实验分析了多种因素对分离回收过程的作用规律,确定了最佳的工艺条件.结果表明,在浓缩体积比值0.5、截留相对分子质量(Mr)10000、压力0.20MPa、搅拌速度600r/min、温度30℃的最优条件下,该法能有效回收废液中有用组分,并能显著降低废液污染程度.     

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.     

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.     

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.     

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。     

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.