干旱胁迫条件下植物渗透调节的研究

用P-V曲线技术研究了三种海滨木本植物在干旱胁迫条件下渗透调节的能力。结果表明经干旱处理植物水饱和时的渗透势和初始质壁分离时的渗透势都降低。而抗旱能力较强的桉属植物钝叶桉(Eucalyptus obtusifolia)和产胶桉(Eucazyptus gummifera)的ψ_x~(100)和ψ_x~0处于较低水平。与Epacris obtusifolia相比,它们在叶水势和土壤水势较低时,仍然可维持组织的紧涨和较高的叶导性。     

“新丰宝”植物生长促进剂对干旱条件下小麦幼苗NR活性的PRO？…

本文以２６３１小麦为材料，研究了干旱条件下“新丰宝”植物生长促进浸种的小麦幼苗ＮＲ活性的Ｐｒｏ含量的变化。结果表明，用“新丰宝”浸种后的小麦幼苗ＮＲ活性和Ｐｒｏ含量都有所提高，叶片水分状况较好。     

米槁对水分胁迫的生理响应

为探讨药用植物米槁对干旱胁迫的适应性,以米槁幼苗为研究材料,采用室内人工控水的方法,经预实验设3个水分梯度:CK(土壤相对含水量(80±5)%)、MD(土壤相对含水量(60±5)%)、SD(土壤相对含水量(35±5)%),研究了米槁幼苗对水分胁迫的生理响应机制.结果表明:同一实验期内随着干旱胁迫的加剧,RWC逐渐降低,电导率、MDA含量、渗透物质含量及抗氧化酶活性均增加.而同一水分处理下,随着干旱胁迫时间的延长,叶片相对含水量呈先大幅下降后小幅回升趋势;渗透物质、电导率、MDA含量和抗氧化系统都呈逐渐升高趋势.并且干旱胁迫越剧烈,米槁幼苗叶片RWC越小,电导率、MDA、渗透物质含量及抗氧化酶活性越大,机体抵抗干旱反应越强.但总体而言,米槁幼苗表现出较强抗旱性,对水分条件的适应范围较广.     

水分胁迫下玉米幼苗光合变化和生理特性分析

对不同水分胁迫下玉米幼苗光合变化和生理特性的系统研究表明,在轻度干旱初期,玉米叶片光合速率(Pn)、蒸腾速率(Tr)有所下降,同正常供水(CK)条件相比差异不显著;在中度和重度干旱条件下,Pn,Tr开始就比CK明显降低并不断增大,其间气孔导度(Gs)则同光合速率、蒸腾速率几乎呈平行关系,同时幼苗生长也受到了明显抑制;3种胁迫下,叶片含水量也逐渐减少,丙二醛(MDA)含量、细胞膜透性和渗透调节物质含量随着胁迫程度加深和胁迫时间延长明显增加,保护酶系统(SOD,POD,CAT)活性随着胁迫时间的延长,总体呈现出先升高后降低的趋势.     

干旱胁迫下假单胞菌HN1202对小麦种子萌发及幼苗生长的影响

为研究假单胞菌HN1202在干旱胁迫下对小麦幼苗的抗渗透胁迫能力,应用聚乙二醇6000模拟渗透胁迫,研究小麦种子的萌发状况;通过不同水分管理,研究干旱胁迫下无土栽培的小麦幼苗形态、渗透调节、保护酶活性及膜质过氧化作用的生理变化.研究发现干旱胁迫下接种HN1202的小麦种子发芽势、发芽率分别高于阴性对照组3.9%、8%,小麦幼苗的株高、根长分别比对照组提高了28.3%、21.9%.小麦叶片含水量、叶绿素含量分别比对照组提高了4.1%、13.4%;可溶性蛋白、可溶性糖、游离脯氨酸含量比对照组分别提高了17.0%、12.6%、41.6%;CAT、SOD含量比对照组增加了45.9%、14.0%; MDA比对照组降低12.8%.研究结果表明,干旱胁迫加剧了小麦的氧化胁迫,接种HN1202可提高小麦叶绿素含量,增加渗透势,增强小麦幼苗抗氧化酶的活性,降低膜质过氧化,提高小麦幼苗抗旱能力.     

四翅滨藜抗旱生理特性研究

通过盆栽控水和聚乙二醇(PEG)渗透胁迫(PEG渗透势为0%,5%,10%,15%,20%)试验,测定四翅滨藜幼苗叶的保水力、相对含水量、水分饱和亏、相对电导度、叶绿素含量、MDA含量、光合生理指标等,对四翅滨藜幼苗的抗旱生理特性进行研究。结果表明:盆栽控水6d土壤含水量(质量分数)下降为8.3%时,对其幼苗的光合生理指标没有明显影响;在渗透胁迫下,四翅滨藜幼苗叶相对含水量、叶绿素含量、自由水含量等呈下降趋势;水分饱和亏、相对电导度、MDA含量、束缚水含量等呈上升趋势;在严重胁迫(PEG渗透15%,20%)下,这些生理指标的变幅较大。四翅滨藜幼苗叶保水能力强,束缚水含量较高,抗旱性强。     

“新丰宝”植物生长促进剂对干旱条件下小麦幼苗NR活性和PRO含量的影响

本文以２６３１小麦为材料,研究了干旱条件下“新丰宝”植物生长促进剂浸种的小麦幼苗ＮＲ活性和Ｐｒｏ含量的变化。结果表明,用“新丰宝”浸种后的小麦幼苗ＮＲ活性和Ｐｒｏ含量都有所提高,叶片水分状况较好。     

磁场处理黄瓜种子的生物学效应

用磁感应强度为100、200、300和400 mT的磁场分别处理黄瓜种子1、5和10 min,与对照组比较,观察其幼苗抗旱性的变化.结果表明,重度干旱胁迫时处理组幼苗中脯氨酸含量最多可增加15.3%,表明磁场能通过降低细胞渗透势来增加黄瓜幼苗抗旱性;过氧化物酶(peroxidase,POD)、超氧化物岐化酶(superoxide dismutase,SOD)活性最大增强幅度为17.5%和26.2%,表明磁场可以通过清除植物体内自由基和增强代谢增强黄瓜幼苗对水分胁迫的抗性;丙二醛(malondialdehyde,MDA)含量下降幅度为12.9%～23.4%,表明磁场处理可以降低膜脂过氧化程度,减少干旱对黄瓜幼苗的伤害.     

PV曲线技术比较三种木本植物的水分状况

用ＰＶ曲线技术对三种木本植物木麻黄,湿地松,异叶南洋衫的水分状况进行比较,结果表明：抗旱性较强的浊灶松水饱和时的渗透热ｑ＾１００π和初始原壁分离时的渗透势ｑ＾０π及总体体积弹性模量ε都较低。在植物水分关系研究中,ＲＷＣ,ＲＯＷＣ,ＲＤＷ和Ａｐ,ε和Ｖ０等水分参数具有重要意义。     

抗旱剂对粳稻幼苗生长和一些生理特性的影响

以粳稻合系22-2为材料,研究幼苗期干旱胁迫下喷施乙酰水杨酸和EDTA抗旱剂对幼苗生长和一些生理指标的影响。结果表明,幼苗期干旱胁迫下喷施乙酰水杨酸和EDTA有利于促进粳稻幼苗叶片和根系生长,增加叶片叶绿素和可溶性糖含量,降低脯氨酸含量,提高叶片渗透调节能力和保水能力,显著降低丙二醛含量,减少细胞膜伤害,有利于抗旱保苗。两种抗旱剂中乙酰水杨酸处理对提高粳稻幼苗抗旱能力的效果较EDTA强,浓度均以1g/L较佳。     

Markedness and its Interpretation in Language Use

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the