酒石酸对Cd胁迫下油菜种子萌发和生长的影响

研究了酒石酸对Cd胁迫下油菜种子萌发和生长的影响.结果表明,单独Cd胁迫下,随着Cd浓度的增大(0-50 mg·L-1),油菜种子根长和根鲜重逐渐降低(P<0.05),芽长和芽鲜重在Cd浓度较高(1-50 mg·L-1)时才逐渐降低(P<0.05);而仅高Cd浓度(50 mg·L-1)胁迫才使种子发芽势、发芽率显著降低(P<0.05).单独酒石酸胁迫时,随着酒石酸浓度的增大(0-10 mmol·L-1),油菜种子生长指标(根长、芽长和根鲜重等)均逐渐降低(P<0.05);而仅高浓度酒石酸(5-10 mmol·L-1)胁迫才使种子萌发指标(发芽势、发芽率和发芽指数等)显著降低(P<0.05).当酒石酸和Cd共同作用时,低浓度酒石酸(1-2.5 mmol·L-1)对各浓度Cd胁迫下的油菜种子萌发指标(发芽势、发芽率、发芽指数、活力指数)和芽鲜重均无显著影响(P>0.05);但高浓度酒石酸(5-10 mmol·L-1)对各Cd胁迫下的各指标呈抑制作用(P<0.05),即高浓度酒石酸加重了Cd对种子萌发的毒害.同时表明酒石酸和Cd的胁迫对油菜种子生长的影响大于种子萌发,且对油菜种子幼根的抑制效应大于幼芽.     

3种裸燕麦种子萌发期耐盐性的研究

以青引3号、白燕2号和青莜2号三种裸燕麦为研究对象,用NaCl制作胁迫溶液,设置0（对照）、50、100、150、200 mmol/L 5个盐浓度梯糜,通过测定不同盐浓度胁迫下,不同品种裸燕麦种子的发芽率、发芽指数和活力指数,评价盐胁迫对裸燕麦种子萌发的影响.结果表明：随着盐胁迫浓度的增加,三种燕麦的发芽率、发芽指数与活力指数均呈降低趋势,不同品种裸燕麦种子的耐盐性存在差异,青引3号抗盐胁迫作用略强于白燕2号与青莜2号.     

离子钛对苦荞铅胁迫缓解作用初探

采用不同浓度离子钛处理对铅胁迫后苦荞幼苗的影响,研究其对苦荞种子发芽率、发芽势、发芽指数、根系形态、可溶性糖、可溶性蛋白、丙二醛、愈创木酚过氧化物酶、过氧化氢酶及超氧化物歧化酶含量等生理生化指标的影响.研究发现,铅胁迫后,与正常浇水组相比苦荞种子发芽率、发芽势及发芽指数等降低,抑制苦荞根系伸长;离子钛处理后,与T0+Pb组相比,显著提高苦荞种子的发芽率、发芽势及发芽指数,加强根系生长,促进可溶性糖、可溶性蛋白、超氧化物歧化酶和愈创木酚过氧化物酶含量增加.经初步研究发现,离子钛对缓解铅胁迫具有明显效应.     

干旱和复水对大豆叶片光合生理特性及产量的影响

实验运用盆栽技术,选用豫豆29作为材料,对逐步干旱和旱后复水过程中大豆各项生理指标的变化及最后作物产量进行了研究.研究发现,在土壤相对含水量高于22%时,处理组大豆凌晨叶片水势和对照组相比基本没有下降,但当含水量低于22%时,处理组叶片水势急剧下降,表现为一定的阈值反应(约为-0.89 MPa),存在明显的凌晨叶片水势临界值.低于此临界值,叶片水势急剧下降,净光合速率也明显降低.复水后大豆叶片水分状况得到改善,大豆叶片的净光合速率和蒸腾速率都表现为接近于直线的上升,气孔导度的恢复也很快, 并在实验的最后接近对照组的水平,这表明豫豆29的叶片光合在水分胁迫解除后有迅速恢复的能力.成熟期,处理组与对照组的种子产量相差不大,所以适当的干旱胁迫并不影响最终的大豆产量.     

盐胁迫对决明种子萌发和幼苗生理特性的影响

为探讨在盐胁迫下决明种子和幼苗各项生理生化指标的影响,采用NaCl模拟不同程度的盐胁迫,对盐胁迫下决明种子的发芽率、发芽指数、活力指数、胚根长、下胚轴长度及鲜质量、幼苗叶片MDA和O2-.质量分数及抗氧化酶活性指标的生理特性进行了测定,结果表明:当盐浓度为50mmol/L及其以上时,随着胁迫浓度和胁迫时间的增加决明种子的发芽率、发芽指数、活力指数均显著降低;决明幼苗胚根长、下胚轴长和鲜质量也表现出缩短和下降现象;幼苗叶片中丙二群(MDA)和超氧阴离子(O2-.)质量分数呈上升趋势;超氧化物歧化酶(SOD)活性呈先上升后下降的趋势,而过氧化氢酶(CAT)和过氧化物酶(POD)活性则在胁迫初期随着胁迫浓度的增加呈上升的趋势,在胁迫的中后期随着胁迫浓度和时间的增加呈先升后降的趋势.盐胁迫对决明种子萌发和幼苗生长具有显著的抑制作用,但决明种子及幼苗通过自身的调节也主动适应盐胁迫环境条件.     

硒对盐胁迫下加工番茄种子萌发及抗氧化酶系统的影响

以"双丰87-5"和"佳禾2号"2个番茄品种为实验材料,探讨了在100mmol/LNaCl盐胁迫下不同浓度硒(Se)对番茄种子萌发的影响。结果表明:在低浓度范围内,随着外源Se浓度的升高,番茄种子的发芽率、发芽指数、活力指数和抗氧化酶系统的活性逐渐升高,丙二醛含量逐渐降低;而高浓度的外源Se浸种处理,则抑制种子的萌发。可见适宜浓度的Se对盐胁迫下番茄种子发芽均有不同的促进作用,以Se浓度为0.004mmol/L时作用效果最佳。     

土壤极端干旱期树种的水分关系研究

对极端干旱条件下的造林树种柠条、河北杨、小叶杨、北京杨、刺槐及乡土经济树种海红的水分生态关系进行了研究.结果表明水势的日变化均为抛物线型,日均水势分别为柠条-2.028MPa、河北杨-1.289MPa、小叶杨-0.964MPa、北京杨-0.943MPa、刺槐-2.383MPa和海红-1.556MPa.环境因子日变化对水势的日变化影响为温度＞湿度＞光照.水势日变化与环境因子关系类型以对数、幂函数、直线和抛物线型为主.蒸腾速率的日变化柠条为抛物线型;河北杨、小叶杨、北京杨均呈旗型.柠条、北京杨、小叶杨和河北杨的蒸腾速率日均值分别为0.7117g·g     

水分胁迫对黄土高原弃耕地不同演替阶段5个优势种种子萌发的影响

以典型黄土高原半干旱区弃耕地不同次生演替阶段出现的物种黄蒿、冷蒿、车前、赖草、短花针茅为材料,0(对照),-0.2,-0.4,-0.8,-1.2 MPa5个渗透势处理聚乙二醇(PEG-6000)模拟水分胁迫,测定各物种的种子吸水率、萌发率、萌发指数、萌发速率等指标.结果表明:对照溶液中,5个物种的最大吸水率均显著高于-1.2 MPa溶液;各物种吸水速率快慢为:冷蒿、黄蒿、车前、短花针茅、赖草,其中冷蒿的吸水率最大,达到自身的279%,赖草的吸水率最小,为自身的113%.随着PEG浓度的提高,5个物种种子的萌发均受到不同程度的抑制,发芽率、发芽指数和发芽势随PEG浓度的升高而下降;与对照相比,在-1.2 MPa渗透势下,黄蒿、冷蒿、车前、赖草、短花针茅的发芽率分别下降了46.5%,47.3%,62.7%,56.7%,100%,短花针茅完全受到抑制,不萌发.随着溶液渗透势的提高,半数萌发时间延长,萌发速率减慢;对比各PEG渗透势,冷蒿萌发速率最快,短花针茅的最低,黄蒿、车前和赖草居中.     

盐胁迫对两种源苦楝种子萌发特性的影响

为研究盐胁迫下苦楝种子萌发特性并比较种源间差异,用不同浓度(0、50、100、150、200 mmol/L)NaCl溶液处理两种源地(江苏滨海及安徽滁州)苦楝种子,比较种子发芽率、发芽指数、活力指数及幼苗生长的变化。结果表明:随盐处理浓度升高,两种源地苦楝种子发芽率、发芽指数和活力指数总体均呈各自不同的下降模式,且种子活力的下降先于发芽率的下降。胚根和胚轴生长在盐胁迫环境中受到不同程度的抑制,盐浓度对幼根的影响较小。总体来说,滨海苦楝种子在萌发时的耐盐性优于滁州种子。     

盐胁迫对两种源苦楝种子萌发特性的影响

为研究盐胁迫下苦楝种子萌发特性并比较种源间差异,用不同浓度(0、50、100、150、200 mmol/L)NaCl溶液处理两种源地(江苏滨海及安徽滁州)苦楝种子,比较种子发芽率、发芽指数、活力指数及幼苗生长的变化。结果表明:随盐处理浓度升高,两种源地苦楝种子发芽率、发芽指数和活力指数总体均呈各自不同的下降模式,且种子活力的下降先于发芽率的下降。胚根和胚轴生长在盐胁迫环境中受到不同程度的抑制,盐浓度对幼根的影响较小。总体来说,滨海苦楝种子在萌发时的耐盐性优于滁州种子。     

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.     

Features of Women's language

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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