Physiological Indices and Selection of Methods on Rapid Identification for Sweet Potato Drought Resistance

The relationships between the changes of relative water content （RWC）, malondialdehyde （MDA） contents, superoxide dismutase （SOD） activity and free proline contents in sweet potato leaves, and drought resistant ability under different concentration of polyethylene glycol （PEG） treatment applied at rhizosphere of sweet potato seedlings were studied. A highly positive correlation between RWC and drought resistance （r =0.783, P〈0.01）, a highly negative correlation between MDA contents and drought resistance （r = -0.848, P〈0.01）, a highly positive correlation between SOD activity and drought resistance （r = 0.777, P〈0.01） was observed. Free proline contents in leaves was not related obviously to the sweet potato drought resistance under 25% PEG treatment. The stronger the drought resistance of variety, the less decrease of RWC and increase of MDA contents, the more increase of SOD activity. By determining these physiological indices in sweet potato leaves under 25% PEG treatment, rapid identification of drought resistant ability of different varieties can be obtained in the lab.     

37 ℃持续热应激肉鸡血气改变的动态分析

80只25日龄雄性AA肉鸡,随机分为对照组(21～24 ℃,相对湿度50%±5%)和试验组(37 ℃±0.5 ℃,相对湿度70%±5%),自由采食和饮水.在12 d的试验期间,动态检测血气指标、呼吸频率、直肠温度和生产性能的变化.结果显示热暴露初期呈现代偿性呼吸性碱中毒,其特点为动脉血二氧化碳分压(3.82±0.36)降低,pH(7.48±0.04)升高;中期呈现失代偿性代谢性酸中毒,其特点为血浆HCO-3浓度(19.00±2.55)降低,pH(7.37±0.06)显著下降(P＜0.05);后期酸碱平衡趋于正常.热应激后,肉鸡日增重和日采食量极显著下降(P＜0.01)、料肉比极显著升高(P＜0.01);呼吸频率极显著升高(P＜0.01);热暴露第1、5、7、9和12天体温极显著升高(P＜0.01).动脉血氧分压与呼吸频率呈极显著负相关(P＜0.01),与体温呈显著负相关(P＜0.05);血氧饱和度与体温极显著负相关(P＜0.01).表明37 ℃持续热应激的肉鸡呈现由代偿性呼吸性碱中毒转变为失代偿性代谢性酸中毒,最后趋于正常的动态变化过程.     

用铬变素2R法对家蚕微孢子虫孢子染色的研究

采用铬变素 2R法 (Chromotrope 2R)染色家蚕微孢子虫 (Nosemabombycis,N .b)孢子和绿僵 (Nomuraearile yi)孢子、曲霉 (Aspergillusflavus)孢子、花粉粒 (Pollengranule)等与N .b孢子形状相似物 ,结果表明 :Chromotrope 2R法特异性地将N .b孢子染成粉红色 ,绿僵孢子、曲霉孢子、花粉粒未被染成红色 ,初步认为Chromotrope 2R法可应用于母蛾镜检的N .b鉴定 ,能明显提高N .b的检出率与准确性 ;染色N .b孢子的最佳时间与温度为 4 0min ,30℃。鉴于本染色法的条件、技术操作简便 ,染色特异性强 ,因而具有良好的应用前景     

空气污染对果树生长结果的影响

通过调查 ,空气污染中SO2 和粉尘对果树生长发育有不良影响 ,严重的叶片焦枯脱落 ,果锈连片 ,影响产量和品质。污染程度与污染源距离、污染物种类与浓度、风向等有关     

犬腺病毒SY-45株不同大小蚀斑特性研究

应用蚀斑方法将SY－45毒株经过3次蚀斑纯化直到蚀斑大小相对稳定。从不同大小的蚀斑中挑选出三种蚀斑，大斑直径约3mm(简称LP）、中斑约2mm(简称MP）、小斑约1mm(简称SP）。分别在MDCK细胞上增殖并进行了三种不同大小斑毒对犬的毒力、免疫原性和在MDCK细胞上产毒量比较，以筛选最佳的疫苗株，试验结果表明用不同大小蚀斑病毒大剂量人工感染易感犬后，所有的试验犬临床症状和病理解剖学和病理组织学表现均正常；对挑选的4窝CAV HI抗体效价小于等于1：2的健康幼犬进行免疫试验，测定血清的中和抗体效价和血凝抑制抗体效价，结果表明：大斑毒的免疫原性要稍高于中斑毒，而明显高于小斑毒；不同大小蚀斑毒在MDKC细胞上产毒量差异很大，大斑毒可达10^7TCID50／mL、小斑毒达10^6TCID50／ml、小斑毒达10^4.5TCID^50/mL。综合所有试验结果表明：大斑毒株具有产毒量高、安全性好、免疫原性强的优点，是较为理想的疫苗株。     

罐顶对罐壁应力的影响

在大型油罐设计中采用线性理论的方法,分析论述了罐顶对罐壁是否产生影响这一问题。通过对拱顶油罐、浮顶油罐的罐壁边界条件、罐顶边界条件的分析计算,求出各层壁板挠度方程中的待定系数,便可得出其应力。从线性方程中,可看出影响罐壁应力的主要因素是挠度方程中的待定系数。待定系数除受储罐尺寸、液位高度的影响外,还受罐顶重量、罐顶剪力和弯矩的影响。以10万m~3浮顶油罐和拱顶油罐为例,进一步证明,液位是罐壁应力的控制因素,而罐顶重量、罐顶剪力和弯矩对罐壁应力的影响可以忽略不计。     

植物在水分胁迫下脯氨酸积累的研究─—Ⅳ关于植物体内脯氨酸积累的直接触发因子

依据干旱胁迫下数种植物幼苗体内游离脯氨酸、叶气孔、叶水量的变化，剖析了植物与环境因子、气孔因子、氧气因子、酶因子及能量因子之间的相互依存关系，提出了ＰＲＯ积累系统（ＰＡＳ）。认为水分胁迫下植物体内ＰＲＯ的大量积累是氧化受抑和合成受激共同调控的结果。氧气最有可能为直接触发因子。     

PEG诱导水分胁迫对柑桔幼苗细胞质膜透性及脯氨酸含量的影响

柑桔叶片相对含水量(RWC)随聚乙二醇(PEG)处理渗透势的降低而依次降低;叶片细胞质膜透性随PEG处理浓度的增加而依次增大;幼苗叶片累积脯氨酸的数量随水分胁迫时间和强度递增。     

Stoffbildung, CO2-Gaswechsel, Kohlenhydrat- und Stickstoffgehalt von Winterweizen bei erhöhter CO2-Konzentration und Trocken-streß

Dry Matter Production, CO₂ Exchange, Carbohydrate and Nitrogen Content of Winter Wheat at Elevated CO₂ Concentration and Drought Stress
Methods of mathematical modelling and simulation are being used to an increasing degree in estimating the effects of rising atmospheric CO₂ concentration and changing climatic conditions on agricultural ecosystems. In this context, detailed knowledge is required about the possible effects on crop growth and physiological processes. To this aim, the influence of an elevated CO₂ concentration and of drought stress on dry matter production, CO₂ exchange, and on carbohydrate and nitrogen content was studied in two winter wheat varieties from shooting to milk ripeness. Elevated CO₂ concentration leads to a compensation of drought stress and at optimal water supply to an increase of vegetative dry matter and of yield to the fourfold value. This effects were caused by enhanced growth of secondary tillers which were reduced in plants cultivated at atmospheric CO₂ concentration. Analogous effects in the development of ear organs were influenced additionally by competitive interactions between the developing organs. The content and the mass of ethanol soluble carbohydrates in leaves and stems were increased after the CO₂ treatment and exhausted more completely during the grain filling period after drought stress. Plants cultivated from shooting to milk ripeness at elevated CO₂ concentration showed a reduced response of net photosynthesis rate to increasing CO₂ concentration by comparison with untreated plants. The rate of dark respiration was increased in this plants.     

分子标记用于赤眼蜂分子监测的研究

通过对松毛虫赤眼蜂（Trichogramma dedrolimi Matsumura）以及玉米螟赤眼蜂（Trichogramma ostriniae Pang et Chen）rDNA-ITS2基因的克隆测序，并联机检索GenBank核酸序列库中其它赤眼蜂的相关序列，利用核酸分析软件找到松毛虫赤眼蜂和玉米螟赤眼蜂ITS2序列中一段有鉴别意义的标志，并据此设计出蜂种的特异PCR引物，实现了松毛虫赤眼蜂和玉米螟赤眼蜂rDNA特异区带的PCR扩增。研究表明该特异区带具有种的特异性。我们认为该分子标记技术可用于目前我国生防中常用的松毛虫赤眼蜂和玉米螟蒌眼蜂的分子监测，如田间种群动态监控和寄生效果评估。