热激处理对甘蓝幼苗叶片保护酶活性和膜透性的影响

试验对耐热性不同的2个甘蓝品种的种子进行了热激处理,在苗期测定了热激处理对甘蓝叶片中保护酶活性和膜透性的影响。结果表明,热激处理后,耐热品种叶片中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性的增幅大于不耐热品种,而不耐热品种叶片中丙二醛(MDA)的含量和膜透性的增幅大于耐热品种。     

结球甘蓝小孢子培养技术体系的优化研究

以20份类型丰富的F1及亲本甘蓝为试材,探讨了不同甘蓝类型、F1及其亲本材料、供体植株的生长温度、供体植株的花期、高温热激时间、NLN培养基pH值等因素对甘蓝小孢子胚胎产量及质量的影响,为建立高效、完善的结球甘蓝小孢子培养技术体系提供依据。结果表明:不同叶球类型与小孢子的产胚率无明显相关性,但不同栽培季节及熟性的甘蓝品种间却存在显著差异,其中春秋类型的早、中熟甘蓝要明显好于晚熟的越冬甘蓝;用产胚能力强与产胚能力弱的材料分别做亲本杂交,所得杂交种的出胚率介于两亲本之间,表明小孢子产胚能力是一种受基因调控的遗传性状;供体植株的生长温度对于结球甘蓝胚状体的产生并无显著影响;从胚胎发生频率及胚胎质量来说,初花后10 d内(开花初期至盛花中期)是取样的最佳花期阶段;对于大多数基因型而言,32.5℃热激预培养48 h较24 h更有利于胚胎发生,热激32.5℃48 h并结合NLN-pH6.2为最佳处理组合,比目前在甘蓝类蔬菜中常用的32.5℃24 h+NLN-pH5.8的培养体系在基因型反应范围及胚胎发生频率方面都有显著提高。     

棉花早期热激处理与高温期蕾铃脱落关系的初步研究

研究了棉花早期热激处理与高温期蕾铃脱落的关系，结果表明：早期热激处理有助于高温期棉株体内产生更丰富的热激蛋白，从而提高棉株的耐热程度，降低脱落率达１．７～３．０个百分点。但不同的品种，早期热激处理的最适生长阶段不同品种有差异     

热激处理对柰李果实贮藏品质的影响

热激处理可用于控制采后果实的病害、腐烂及后熟.对不同温度与时间组合的热激处理与柰李低温贮藏品质之间的关系进行研究.结果表明,40℃、4 h的热激处理对提高柰李抗冷性和保持柰李贮藏品质的效果较好.     

高温锻炼对小麦细胞膜热稳定性的影响

通过电解质渗漏量的变化研究了冬小麦细胞膜的耐热性.耐热性的程度用50℃下热致死时间表示.研究结果表明,小麦幼苗在34℃下锻炼3天可获得最大耐热性.在20℃/15℃(日/夜)生长条件下.耐热品种与热敏感品种之间耐热性无明显差异,它们在50℃下热致死时间为8～26Min.在34℃下锻炼3天后,耐热品种的耐热性明显地高于热敏感品种,耐热品种的50℃热致死时间为87～110min,而热敏感品种为35～55min.     

抽穗和灌浆早期高温对耐热性不同籼稻品种产量的影响及其生理原因

选用4个耐热性不同的籼稻品种,分别于抽穗(始穗后0~10 d)和灌浆早期(始穗后11~20 d)进行高温(白天温度>33℃)处理,以同期自然温度(白天温度<30℃)为对照,研究高温对产量的影响及其生理机制。结果表明,与对照相比,高温处理显著降低热敏感品种的花粉可育率、受精率,而耐热品种与对照无显著差异。高温胁迫明显降低热敏感品种的结实率,导致产量显著下降,且抽穗期高温处理影响大于灌浆早期处理。高温胁迫显著增加耐热品种黄华占叶片的抗氧化酶活性,对热敏感品种影响不大。高温胁迫显著降低热敏感品种籽粒ATP酶活性,耐热品种结果则相反。高温处理增加两类品种叶片温度和丙二醛(MDA)含量,降低根系活力和叶片光合速率,耐热品种增降的幅度显著小于热敏感品种。在高温胁迫下较低的叶片温度,较强的根系活力和抗氧化保护系统能力及较高的籽粒ATP酶活性是耐热性品种保持较高产量的重要生理原因,也是耐热品种的重要生理特征。     

减数分裂期高温胁迫对耐热性不同水稻品种产量的影响及其生理原因

以两个耐热性不同的籼稻品种为材料,在减数分裂期进行高温(白天温度>35℃)处理,以同期自然温度(白天温度<33℃)为对照,研究减数分裂期高温对产量的影响及其生理机制。结果表明,高温处理与对照相比,显著降低了热敏感品种双桂1号的花药开裂率及花粉育性,对耐热品种黄华占影响较小;明显降低了每穗颖花数、结实率和粒重,从而使产量显著下降,其中耐热品种下降幅度小于热敏感品种;热敏感品种粒宽显著缩短,长宽比显著增大,而对耐热型品种影响不大;明显降低了水稻的根系活力和幼穗的核糖核酸(RNA)含量,显著增加了叶片丙二醛(MDA)含量和幼穗的乙烯释放速率,热敏感品种变化幅度大于耐热品种;显著增加了耐热品种叶片的抗氧化酶活性,对热敏感品种无显著影响。总之,根系活力和抗氧化保护系统能力强、RNA含量高、MDA含量低及乙烯合成少是耐热性品种在高温胁迫下保持较高产量的重要生理原因。     

热激处理对棉花耐逆性的影响

 从不同生育期热激处理对棉花抗氧化酶活性和细胞膜伤害的影响及萌动期热激处理对棉花自然高温期的抗氧化酶活性和细胞膜伤害的影响这两个方面研究热激处理与棉花耐逆性的关系。结果表明：热激处理后棉花体内的SOD、POD、CAT的酶活性都增高,在自然高温期MDA的含量下降,蕾铃脱落率下降,热激处理能在一定程度上诱导棉花耐逆性的获得。     

热胁迫过程中白菜型油菜种子DNA的甲基化

过高的环境温度对植物造成热胁迫和热损伤,从而影响植物的生长、发育,以及种子的寿命。以白菜型油菜耐热品种庆元本地油菜和不耐热品种绍兴矮大秆油菜新收获种子为材料,研究了不同温度处理对油菜种子活力以及基因组DNA甲基化水平和状态的影响。结果表明,种子经37℃和4℃处理2 h,发芽率和活力指数与对照差异不显著;经70℃处理2 h后,耐热和不耐热品种种子发芽率和活力指数均明显降低,37℃热诱导后再进行70℃热胁迫处理,发芽率和活力指数均高于直接70℃处理的种子,表明热诱导可以显著提高种子的耐热性。甲基化MSAP分析结果表明,种子热胁迫过程中基因组DNA甲基化水平降低,同时有甲基化和去甲基化现象发生,并以去甲基化现象为主。相关性分析结果显示种子发芽势、发芽率、下胚轴长和活力指数与双链DNA内部发生甲基化的条带数呈负相关,而与双链DNA外部发生甲基化的条带数呈正相关。更为重要的是耐热与不耐热性材料在热胁迫中表现完全相反的甲基化变异模式,耐热品种去甲基化的条带数多于不耐热品种,但甲基化的条带数目则相反,显示DNA甲基化与种子耐热性有重要关系,在热胁迫过程中,种子可能通过DNA甲基化变化调控相关基因的表达来应对高温胁迫。     

二次回归旋转正交组合设计对红枣多酚提取工艺的优化

为了提高残次红枣的综合利用,在单因素试验的基础上采用二次回归正交旋转组合设计方法研究超声处理时间、液料比、提取温度3个因素对红枣多酚提取率的影响。结果表明,最佳工艺条件为超声处理时间20 min,液料比16∶1,提取温度66℃,在此最佳提取条件下多酚提取率为0.76%。     

Heat Transfer Model and Application of Buried Tube Heat Exchanger for Ground Source Heat Pump

This paper introduces the theoretical basis and application method for heat transfer model of buried tube (pipe in pipe and U- type) heat exchanger for ground source heat pump, and a practical example is calculated. Then, the calculation results are analyzed and discussed. In particular, the correlation coefficient and calculation method of tube group exchanger is discussed; the method for determining known parameter and some basic data for main procedure GSHP.HTM is analyzed. The calculation formula and data sampling for JSW.HTM subroutine is introduced. At last, the problems in application of calculation procedure, to which should pay attention, are discussed.     

Experimental Study of Ground-source Heat Pump Systems with Horizontal Heat Exchanger

This paper describes the double layer horizontal ground source heat pump systems constructed in 1998 with the buried depth of 0.9 m and 1.8 m. The program of study includes experimental equipments, heat exchanger size, testing meter and methods for data analysis. In addition, the heating and cooling performance at typical days are also illustrated. Among the influencing factors on the performance of the ground source heat pump systems, the parameter of heat exchanger and operation patterns of heat pump systems are analyzed.A heat transfer model has been set up for horizontal heat exchanger.     

Experiment and Simulation on Heat Transfer Efficiency of Double pipe Heat Exchanger for River Water source Heat Pump

The river water source heat pump system is an important technique to utilize renewable energy in Chongqing and heat exchanger can influence overall energy efficiency of system obviously. A test was carried out to study the heat transfer efficiency of double pipe heat exchanger with semicircular reentrant tube. It was found that the heat transfer efficiency would increase while curvature of semicircular reentrant tube rose. And when the ratio of R to r was five, heat transfer efficiency for semicircular reentrant tube would be increased 2.5% than that of straight double pipe heat exchanger. Flow, temperature field and heat transfer process of semicircular reentrant tube were simulated with computational fluid dynamics(CFD) tool to study the heat transfer mechanism. The modified RNG κ ε Turbulence Model was adopted to ensure the accuracy of simulation analysis under the situation of rotary flow and great curvature. Thus, it was indicated that there was obvious secondary flow vertex in reentrant tube. And disturbance of vertex on boundary layer was the main reason for which heat transfer efficiency of double pipe heat exchanger would increase as curvature of semi toroidal reentrant tube rose. Based on the experiment and simulation, the recommended curvature for reentrant tube was proposed with the consideration of sediment in river water and heat transfer efficiency of heat exchanger.     

小麦耐热性获得和耐热性表现关系的研究

以Seui82×Siete Cerros重组近交系为供试材料,采用电解质渗漏测定细胞膜热稳定性的方法,对耐热性获得与大田生产条件下的耐热性表现的关系进行了研究,发现供试材料幼苗相当热损伤率的变幅为39.0%～75.8%,基因型间在该性状上表现出显著的差异.在幼苗相对热损伤率和大田环境条件下耐热性表现的相关分析中,发现相对热损伤率与大棚升温及第2播期的千粒重、穗粒重热感指数呈显著的正相关,并和第2播期产量性状表现显著的负相关,和升温处理的产量性状也表现出较高的负相关.研究认为细胞膜热稳定性是一个耐热性评价的理想生理指标.     

小麦耐热性鉴定和热处理对品质的影响

为鉴定育成小麦品种的耐热性,同时也为小麦耐热育种提供种质资源,用千粒重热感指数和产量热感指数法鉴定河北、山西和山东省13个推广品种的耐热性。结果表明,晋麦47、石优20、泰山5366和金禾9123耐热性好;石麦22和石4185的产量在正常和热处理环境中差异不大,耐热性较好;衡136的产量和千粒重在正常环境下较高,但在热处理下产量和千粒重较低,耐热性较差。尧麦16的湿面筋、蛋白质、吸水率和延展性的差异极显著。石麦19、邢麦6、沧麦028、石麦22和金禾9123的湿面筋和蛋白质差异显著。     

Coupled Conduction-convective Heat Transfer in the Louvered Fin Heat Exchanger

The heat transfer process in the louvered fin heat exchanger is analyzed,and the corresponding physical and mathematical models on the coupled conduction-convective heat transfer for the louver fin geometry are proposed.The control volume-based finite element method(CVFEM) is employed to solve numerically the problem.The computed(results) reveal the flow structure and heat transfer in the geometry in detail.Compared with the empirical correlation of heat transfer and friction coefficients previously proposed,the computed results show better consistency with the experimental results.     

Experimental Study of Flow and Heat Transfer in Heat Exchanger with Small Channels

The experimental study of the flow resistance and heat transfer characteristics are conducted for water and ethylene glycol solution (66% Wt) flowing in the heat exchanger with small rectangular microchannels . The heat exchanger having the channels of 0.4 mm in width, 2.0 mm in height, and 20 mm in length is heated by a hearing rod at the bottom surface, the upper and two side surfaces are adiabatic. During experiments, the Reynolds number are ranged from 2 to 2 500. The experimental results show that the flow friction factor decreases and Nusselt number increases with increasing Reynolds number for water and ethylene glycol solution. At a fixed Reynolds number, the Nusselt number for ethylene glycol solution with larger Prandtl number is greater than that for water. Meanwhile, the correlations of flow resistance and heat transfer in the heat exchanger with small channels are obtained for engineering application.     

Heat Conduction due to Moving Heat Sources in Semi infinite Body

Combined image method with heat source function method,heat conduction due to moving heat sources is analysed in semi infinite body and cylinder with heat exchanging on its surface.The distribution of temperature is obtained when the wall temperature is constant and the wall heat flux is zero.The result is useful for engineering calculation.