不同贮藏温度对不同马铃薯品种花粉生活力的影响

以马铃薯(Solanum tuberosum L.)8个品种(系)为试材,采用氯化三苯基四氮唑(TTC)染色法测定马铃薯花粉活力,研究了在20、4、-4和-20℃条件下保存时间与花粉活力之间的关系。结果表明:在20℃条件下,保存7 d所有品种花粉全部失活;在4℃条件下,保存30 d后,大部分品种花粉活力下降到20%以下,保存120 d后,所有品种花粉活力下降至10%以下,贮藏达240 d则大部分品种花粉失活;在-4℃条件下保存的马铃薯花粉在保存30 d后,各品种的活力平均降低了50%,保存在240 d后则基本上失活;在-20℃条件下保存120 d的马铃薯花粉仍有部分品种花粉活力仍在20%以上,且在保存240 d后各品种花粉活力均未失活。-4℃避光干燥的条件适宜马铃薯花粉的短期贮藏,-20℃条件更适宜长时间贮藏花粉。     

银杏种子脱水敏感性的研究

【目的】研究银杏种子脱水敏感性及相关的生理生化变化,为银杏种子贮藏、种质资源的保存及苗木生产提供理论依据。【方法】银杏种子于25 ℃、湿度(25±2)%条件下脱水67 d,种子含水量每下降5%左右时随机取样测定相关生理生化指标。【结果】当种子含水量降至45.1%时,发芽率并未有明显变化,然而,当种子含水量降至40.1%时,发芽率从开始的92%下降至50%;相关性分析表明种子含水量与发芽率之间存在极显著的正相关(r=0.910)。银杏种子脱水过程中,其相对电导率不断上升。此外,SOD活性变化与POD活性的变化基本相似,均呈现出先下降,后升高至最大值,再下降的趋势,只是其POD活性的上升比SOD早,说明POD的反应比SOD更为敏感。种子含水量与硫代巴比妥酸反应产物(TBARS)含量(r=-0.619)、相对电导率(r=-0.745)之间存在极显著的负相关关系。【结论】银杏种子对脱水高度敏感,表现出顽拗型种子特点。严重脱水降低了银杏种子抗氧化酶活性,并加剧了膜脂过氧化作用,导致种子活力下降乃至完全丧失。     

ErCl_3作用下枯草杆菌所产α-淀粉酶的温度、pH性质

研究ErCl3对枯草杆菌所产α-淀粉酶的酶学性质如温度、pH性质的变化.研究结果表明,在枯草芽孢杆菌培养时加入ErCl3,所产α-淀粉酶的酶活、pH和温度性质具有较大改变.实验结果说明了ErCl3作用下枯草杆菌所产α-淀粉酶的活性提高,提高率为370%.在pH值为5~7时,酶活明显增加,酶活提高率为115.61%~126.32%.酶活最适温度由40 ℃上升为50 ℃,在50～70 ℃始终保持较高酶活性,酶的耐热性增加.     

低浓度尿素对橡胶籽β-葡萄糖苷酶活性和稳定性的影响

为了促进橡胶籽资源的充分利用,本研究以橡胶籽β-葡萄糖苷酶为研究对象,通过对其添加不同浓度的尿素后,测定了β-葡萄糖苷酶残余酶的活性变化,探讨了尿素对β-葡萄糖苷酶活性及其热稳定性的影响,同时以内源荧光光谱分析法研究了不同浓度的尿素对酶结构的影响.结果表明,添加低浓度的尿素时,β-葡萄糖苷酶水解p NPG的活力上升,极限温度下其失活半衰期也得以延长,72℃下等电点纯化β-葡萄糖苷酶的热失活半衰期延长47. 62%;当在β-葡萄糖苷酶溶液中添加高浓度尿素时,酶活下降明显,72℃下其失活半衰期缩短30%.荧光光谱显示,添加低浓度尿素时所引起的酶蛋白结构的变化更利于蛋白结构的稳定;低浓度尿素作用下β-葡萄糖苷酶的活性和稳定性提升,这可能是由于蛋白结构的变化有利于酶与底物的相互作用,从而致使酶活提升的缘故;此外,由于该结构较为稳定,因此热处理时其稳定性较高.     

苦瓜过氧化物酶的提取分离及性质测定

从苦瓜(Momordica charantia L.)中分离和纯化过氧化物酶(POD),分别测定其最适pH值、最适温度、热稳定性、底物浓度对酶活性的影响。结果表明:苦瓜过氧化物酶以邻苯二胺为底物时λmax=425nm,Km=4.6×10-3,Vmax=0.137unit/s,最适pH值为4.6,最适温度是50℃。在温度为50℃时过氧化物酶的酶活力最大,酶活性较高。在温度为60℃以上时过氧化物酶的失活率升高,在温度为70℃以上时过氧化物酶基本失活。抗坏血酸和半胱胺酸对过氧化物酶有明显的抑制作用,其失活率分别达到94%和92%;Al3 的抑制作用稍弱,过氧化物酶的失活率为69%;EDTA的抑制效果最不明显,过氧化物酶的失活率仅为13%。     

拟南芥SYTA基因T-DNA插入纯合突变体的鉴定及表型分析

通过PCR和RT-PCR在DNA和RNA水平上筛选鉴定SYTA基因T-DAN插入失活纯合突变体,当对野生型与突变体种子进行45℃/4h与50℃/1h热激后,野生型种子萌发率分别达到100%与86%,而突变体种子萌发率分别只有83%与27%.当对野生型与突变体植株幼苗进行热激处理后,其存活率与叶片萎黄率相差不大,说明SYTA基因能显著提高拟南芥种子的耐热性,但拟南芥幼苗的耐热性不受SYTA基因的影响.     

七叶树种子离体胚的超低温保存

通过对七叶树种子离体胚超低温(-196 ℃)保存后生活力、相对电导率和脱氢酶活性的测定分析,初 步研究其长期保存的可行性。结果表明：含水率是影响七叶树种子离体胚超低温保存的重要因素,超低温 保存时应对种子进行适度脱水。超低温保存后,七叶树离体胚生活力最高为93 %,其处理组合中57.3 %含 水率+缓速冷冻+快速解冻+10 %二甲基亚砜+10 %蔗糖+20 %聚乙二醇为最佳处理方案。     

入侵植物粗毛牛膝菊种子形态及其萌发特性的研究

以入侵植物粗毛牛膝菊为材料,在观察其种子形态特征的基础上,研究其在不同埋种深度、不同温度条件下种子的萌发情况。结果表明:粗毛牛膝菊种子小,长仅为1.3～2.0 mm,具伞形冠毛,利于远距离传播扩散;重量轻,千粒重为0.228 6～0.230 3 g;含水量较低,为5.78%,利于储存。当埋种深度为0～2 cm时,发芽率较高、差异不显著(P0.05);当埋种深度为4～8 cm时,随着埋种深度的增加,发芽率逐渐降低,差异显著(P0.05),且种子的始见发芽时间和发芽持续时间也延长;当埋种深度为10 cm时,发芽率仅为13%,极显著的低于其他处理(P0.01)。10～35℃条件下,粗毛牛膝菊种子虽均可萌发,但在各温度下的发芽率、发芽势、发芽指数之间均存在差异,25℃是其种子萌发的最适温度,发芽率达97.33%,与15℃(90.67%)、20℃(93.33%)及30℃(96.67%)时发芽率差异不显著,而与10℃(12%)和35℃(52.7%)时差异极显著(P0.01),发芽势(90%)、发芽指数(32)与10℃(0; 0.65)、15℃(57.33%; 19.8)、35℃(34%; 10.82)时差异也显著(P0.05),说明低温与高温都会影响粗毛牛膝菊种子的萌发,同时也推迟其萌发时间且出苗不整齐。     

水和氯离子含量对碳钢接地网在酸性土壤中腐蚀行为的影响

以某变电站的土壤作为研究对象,通过电化学测试,研究了含水量和氯离子含量对碳钢接地网在该土壤中的腐蚀行为的影响.研究结果表明,随着含水量的增加,碳钢接地网的腐蚀速率先增大后减小.当含水量在20%~30%时,腐蚀速率达到最大;当土壤中氯离子含量在0.2%~0.5%之间时,碳钢接地网的腐蚀速率达到最大;经过28 d后,在氯离子含量为0.5%的土壤中,其腐蚀电流密度高达167.4μA/cm2.     

甘油提高巴氏芽孢杆菌脲酶的热稳定性

研究了保存时间和保存温度对碳酸盐矿化菌脲酶活性的影响,发现在低温4℃条件下,脲酶活性在29 d内出现不同程度下降;常温短期储存时,酶活性可以保持3 d,3 d后酶活性值下降明显.为提高脲酶的热稳定性,向碳酸盐矿化菌中添加甘油作为保护剂,常温下添加总体积分数20%的甘油,可以提高酶的稳定性,脲酶活性在30℃下3 d内保持不变,但甘油保护作用有限,高温储存超过7 d后酶活性值下降明显;而在保存温度4℃条件下,添加体积分数为10%的甘油,碳酸盐矿化菌可以储存30 d,底物分解量可以达到初始菌液的95%.     

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.     

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.     

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     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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