提高农杆菌介导小麦遗传转化效率的几个因素

利用gua基因的瞬时表达研究了农杆菌介导的小麦遗传转化，探讨了影响转化效率的几个因素．结果发现，当转化时茵液浓度的OD600为1．0、侵染时间为1h、超声波处理30s、共培养期间使用抗氧化剂以及用胚性愈伤组织作为外植体等，均可使转化效率得到明显提高、综合使用这些优化的转化条件，可使小麦的瞬时转化效率提高3倍多．     

豫麦18再生系统的建立及愈伤对抗生素G418抗性的研究

以小麦品种豫麦18为受体进行外源基因转移,以豫麦18的成熟胚为外植体进行愈伤诱导,通过分化培养基的分化获得小麦幼苗,建立了豫麦18再生系统.同时,通过实验认为,培养基中25 mg/L的G418可以作为筛选转基因抗性愈伤的浓度.     

小麦遗传转化方法的研究进展

综述了近年来小麦遗传转化方法的研究进展，分析了几种转化方法的优缺点，指出基因枪法是目前小麦转化上应用最成功的方法，同时提出了提高小麦转化频率的几种措施。     

废旧电池浸出液对小麦种子发芽率及幼苗生长的影响

以小麦为实验材料,探讨不同浓度的废旧电池浸出液对小麦种子萌发和幼苗生长的影响.实验结果表明：小麦种子对废旧电池浸出液十分敏感,当废旧电池浸出液的浓度较小时,对小麦种子萌发和幼苗生长影响较小;当浓度较大时,会抑制小麦种子的萌发、幼苗及根的生长,且浓度越大影响越大.     

外源DNA导入麦类作物结实率的研究

以普通小麦和硬粒小麦为受体、以亲缘关系不同的7个材料作供体，研究了花粉管通道法转化植株的当代结实率。结果表明：（1）受体为普通小麦时，在授粉后4-8h转化植株的结实率较高；受体为硬粒小麦时，时间上较为分散。（2）不同供体的转化植株的结实率差异较大；不同浓度的外源DNA导入后的当代结实率也存在较大的差异。（3）在不同的缓冲系统中，PBS系统的转化植株的结实率高于SSC和TE系统。由此可知，在不同条件下，利用花粉管通道法转化植株，其结实率受到一定的影响。     

Cu,Cd对小麦幼苗生长代谢及2种酶活性的影响

通过水培试验研究Cu,Cd对小麦幼苗生长代谢及植物过氧化氢酶和淀粉酶活性的影响.结果表明,培养10 d的小麦幼苗对Cu,Cd的富集量是随着重金属胁迫浓度的增大而增大,重金属胁迫浓度较低时,对小麦幼苗的株高和生物量影响不大,随着浓度增加,小麦幼苗生长明显受抑制;同时小麦幼苗中的过氧化氢酶活性随重金属胁迫浓度增加而上升,淀粉酶活性则先上升后降低.     

转基因小麦的环境风险

随着转基因植物种植面积的不断增加,转基因植物对环境的影响受到越来越多的关注.小麦面包品质改良是目前转基因小麦研究的重点之一.文章对小麦遗传转化、转基因植物生态风险和转基因小麦的环境适应等相关问题进行了一系列的综述.     

基因工程改良小麦品质的研究进展和展望

小麦优质育种工作包括改良营养吕质和改良加工品质两方面的内容,十几年来,通过基因工程实现小麦遗传转化弥补了经典小麦育种的不足,突破了可利用基因库的限制,取得了可喜的进展,一些实验室已经成功获得了转基因小麦,报道了外源基因在小麦后代整合和遗传的证据,与小麦品质紧密相关的分子也逐步搞清楚,主要基因已经被克隆,许多实验室正在加紧进行这方面的工作,应用转基因的方法改良小麦品质是植物基因工程研究最有希望的突破口。     

三叶鬼针草对小麦根尖细胞的致畸作用

为了确定入侵植物三叶鬼针草对小麦根尖的细胞遗传毒性,选择不同浓度的三叶鬼针草根、茎、叶浸提液处理小麦根尖,采用常规染色体压片技术,观察小麦根尖细胞有丝分裂的变化。结果表明,不同浓度的三叶鬼针草根、茎、叶浸提液处理小麦,可以显著降低根尖细胞的有丝分裂指数,显著提高微核率和染色体畸变率,且影响程度均随浓度的升高逐渐增大。而相同浓度三叶鬼针草根、茎、叶浸提液处理小麦根尖,影响程度由大到小的顺序为叶,茎,根。综合三叶鬼针草浸提液对小麦根尖细胞有丝分裂3个指标的影响,三叶鬼针草对小麦根尖细胞有明显的遗传毒性。     

Cu对小麦种子萌发及幼苗生长的影响

研究重金属元素Cu对小麦种子萌发、幼苗生长和细胞分裂的影响.结果表明:低质量浓度(≤80mg/L)的Cu对小麦生长有促进作用;高质量浓度(>80mg/L)的Cu抑制小麦幼苗生长及细胞分裂,影响酶活性,提高小麦幼苗pro的含量.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme     

WIMAX与WI-FI技术分析及联合组网

介绍了WiMAX与Wi-Fi两种无线宽带接入技术,并对两者之间的关系及相互之间的影响做了对比及分析,并对WiMAX的关键技术进行了详细说明,最后对两者的联合组网方式做了简单的探讨。