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1.
作物耐盐性的分子生物学研究进展   总被引:31,自引:0,他引:31  
本文从作物耐离子胁迫、耐渗透胁迫和细胞编程性死亡调节三个方面概述了作物耐盐的生理生化机制;介绍了目前利用分子生物学技术克隆与植物耐盐相关的基因,并根据作物的耐盐机理,对这些与耐盐相关的基因进行了分类;总结分析了转耐盐基因植物的研究现状及其转基因植物的耐盐生状况,并提出了利用转基因技术,改良植物耐盐性的方法和对策。  相似文献   

2.
植物耐盐相关基因克隆与基因工程的研究进展(综述)   总被引:1,自引:0,他引:1  
盐渍化是影响植物生长和发育的主要环境因素之一,而基因工程为耐盐新品种的选育通过了一条新途径。很多耐盐基因已经被克隆和详细研究。笔者就与耐盐性相关的渗透调节物质合成关键基因、盐胁迫信号传导以及与相关的调控元件和因子的克隆及其基因工程应用的研究进展作了概述,以期为相关人员的研究提供参考。  相似文献   

3.
植物耐盐性研究及发展   总被引:2,自引:0,他引:2  
本回顾了关于盐渍化现状的研究,概述了植物对盐胁迫的适应方式,从盐离子的吸收、在植物体内的分布、细胞内的区域化、在体内合成有机溶质以及形态分化等方面,探讨了植物耐盐的机制,并指出了对盐渍化环境进行改良、开发利用的可能途径。  相似文献   

4.
植物耐盐研究进展   总被引:1,自引:0,他引:1  
从盐胁迫对植物生长发育及生理代谢的影响,植物的耐盐机理以及利用基因工程手段改良作物耐盐性等方面,对近年来植物耐盐研究的一些进展进行了综述,并对植物耐盐研究进行了展望.  相似文献   

5.
植物耐盐性研究及发展   总被引:3,自引:0,他引:3  
本文回顾了关于盐渍化现状的研究 ,概述了植物对盐胁迫的适应方式 ,从盐离子的吸收、在植物体内的分布、细胞内的区域化、在体内合成有机溶质以及形态分化等方面 ,探讨了植物耐盐的机制 ,并指出了对盐渍化环境进行改良、开发利用的可能途径  相似文献   

6.
对近年来植物在盐环境下所受的伤害和植物的耐盐机理的相关研究作一综述,以期为深入揭示植物耐盐机理,筛选耐盐植物新品种提供参考依据.  相似文献   

7.
耐盐基因工程菌降解偶氮染料特性研究   总被引:3,自引:1,他引:2       下载免费PDF全文
研究通过将耐盐基因BADH转入大肠杆菌E.ColiBL21构建耐盐基因工程菌,并考察了盐度、诱导剂对其生长的影响;探索pH值、温度、染料浓度对降解酸性红B的影响。实验结果表明,基因工程菌的耐盐性较E.ColiBL21有很大提高;降解酸性红B的最适条件为pH=6.5,温度为35℃;在10%(质量分数)盐度条件下,基因工程菌对5种偶氮染料的降解效果均好于E.ColiBL21。  相似文献   

8.
植物耐盐的生理生态适应性研究进展   总被引:3,自引:0,他引:3  
 植物耐盐机制的研究对盐渍土改良利用和选育培育耐盐植物新品种具有重要意义。盐分胁迫下,植物表现一系列生理生态适应性变化。根据近年来对植物耐盐的研究,本文重点阐述了植物体内渗透调节、抗氧化酶活性、光合途径的转变、激素信号转导、植物体内相关蛋白的高表达、形态结构的改变等耐盐的生理生态适应性机制。进一步分析表明,植物耐盐的适应性受多方面调节和控制,应该把多方面的因素都联系起来综合考虑。  相似文献   

9.
海水农业:梦想与现实   总被引:6,自引:0,他引:6  
海水农业定义为利用海水灌溉陆地种植作物。尽管它是一个古老的梦想,但其实验研究始于二战后生态学家Borko和园艺学家Boyko。随着世界人口膨胀,淡水资源短缺形势日趋严峻,发展海水农业成为必然趋势,海水农业有两条途径,其一为培育耐盐传统作物如小麦和番茄,另一为驯化野生耐盐植物,即盐生植物,使之作物化,前一途径随着植物耐盐分子生物学与基因工程技术进展已露曙光;后一途径已取得有限成功如海蓬子与碱蓬的商业  相似文献   

10.
耐盐分胁迫的生物学机理及其基因工程研究进展   总被引:13,自引:0,他引:13  
介绍了盐分胁迫对植物的伤害、植物耐盐的生物学机理以及通过基因工程改良作物耐盐性的研究进展  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
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.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

17.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

18.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
The non-orthogonal localized molecular orbital(NOLMO)is the most localized representation of electronic degrees of freedom.As such,NOLMOs are thus potentially the most efficient for linear scaling calculations of electronic structures for large systems.However,direct ab initio calculations with NOLMO have not been fully implemented and widely used,partly because of the slow convergence issue in the optimization of NOLMO.We devel-  相似文献   

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