镉对鲫鱼肝胰脏CAT和SOD活性的影响

为了探索不同质量浓度Cd2+胁迫对过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性的影响,以鲫鱼为材料,采用急性毒性试验,研究了质量浓度为0.5,2.0,6.0mg/L的Cd2+溶液染毒24,48,72,96h后,鲫鱼肝胰脏CAT和SOD活性变化.结果表明:在试验剂量范围内,0.5,2.0mg/L的Cd2+对鲫鱼肝胰脏CAT活性有诱导作用,6.0mg/L的Cd2+对CAT活性有抑制作用;0.5mg/L的Cd2+对鲫鱼肝胰脏SOD活性有诱导作用,2.0,6.0mg/L的Cd2+对SOD活性有抑制作用;Cd2+胁迫对鲫鱼CAT和SOD活性的影响呈剂量效应,二者关系曲线为抛物线,抛物线顶点是鲫鱼对Cd2+污染从适应到中毒反应的阈值,可间接作为检测环境污染情况的指标.但SOD对Cd2+污染的反应比CAT更灵敏,用SOD监测Cd2+污染具有更好的效果.     

不同强度紫外线对蚜虫生态学特征及有关酶活性的影响

用不同强度紫外线照射桃蚜,处理两代后对第3代桃蚜进行生殖生命表研究。结果表明,发育历期、净增值率、生长周期、内禀增长率等在紫外线照射下发生了很大变化,且不同强度紫外线照射桃蚜的生物学指标有显著差异,紫外线强度越大,桃蚜发育历期和平均世代周期越长,净增值率和内禀增长率越大;紫外线对桃蚜生态学特征的诱变是不可恢复型的。桃蚜体内存在超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)等保护酶系统,用紫外线处理桃蚜4h后,SOD、CAT及POD的活力水平均高于正常虫休,表明保护酶与桃蚜抗逆境性有关。     

锌、铜对水稻幼苗生长及超氧物歧化酶的影响

通过使用缺Ｃｕ或Ｚｎ与缺Ｃｕ、Ｚｎ的木村Ｂ营养液培养耐性品种ＩＲ８１９２—３２—２和敏感品种ＩＲ２６幼苗至七叶期，缺Ｃｕ的稻苗只是新生叶叶尖枯黄，扭曲。而缺Ｚｎ与缺Ｃｕ、Ｚｎ的稻苗叶脉间全部褪绿，根系衰退。缺Ｚｎ与缺Ｃｕ、Ｚｎ的稻苗叶绿素含量、根长、株高和可溶性蛋白含量显著低于对照，且不耐性品种降低的幅度大。凡是缺素培养的稻苗，根和叶的ＳＯＤ活性均显著减弱。     

水分胁迫对若干芸苔属蔬菜某些生理生化指标的影响

采用６个耐旱性不同的十字花科芸苔属蔬菜［结球甘蓝（耐旱）、球茎甘蓝、黄花芥蓝、花椰菜、大叶芥菜、大白菜（不耐旱）］为试验材料，经水分胁迫处理后，叶细胞质膜透性、脂质过氧化产物丙二醛（ＭＤＡ）以及多胺（Ｐｕｔ、Ｓｐｄ、Ｓｐｍ）含量均有不同程度的增加．与此同时，叶片中超氧物歧化酶（ＳＯＤ）、过氧化物酶（ＰＯＤ）活性和吲哚乙酸（ＩＡＡ）含量均有所下降．经相关统计分析发现，叶片质膜透性与ＭＤＡ含量成极显著正相关，与ＰＯＤ、ＳＯＤ活性和ＩＡＡ含量成极显著负相关；ＭＤＡ与ＰＯＤ、ＳＯＤ活性和ＩＡＡ含量成极显著负相关；而ＰＯＤ与ＳＯＤ活性、ＩＡＡ含量以及ＳＯＤ活性与ＩＡＡ含量则均成显著正相关．文中对蔬菜抗旱性机理进行了初步讨论     

多元醇对油菜衰老的生理调控及增产作用探讨

 研究了不同时期喷施多元醇对甘蓝型油菜的生理效应及增产效果。结果表明：初花期喷施多元醇能显著提高油菜叶片叶绿素含量和光合速率，减少脂质过氧化产物丙二醛积累和乙烯释放量，使叶片超氧物歧化酶与过氧化氢酶活性下降变慢；多元醇能增强油菜根系活力，使植株稳健生长；多元醇还能改善油菜的经济性状，增加有效分枝数和每株角果数，初花期和盛花期喷施多元醇分别增产10.4%和7.2%，对油菜籽的品质无不良影响，对油菜生育期影响不大。     

茶多酚和L-EGCG的抗烟致脂质过氧化作用

从茶叶中提取的天然多酚类化合物茶多酚和L-表没食子儿茶素没食子酸酯(L-EGCG)对由香烟气相物质诱发的大鼠肺细胞的脂质过氧化有很强的抑制作用,且复合体茶多酚及其主要单体L-EGCG抑制效果接近,同时两者对超氧阴离子自由基和羟自由基都有十分明显的清除作用,表明茶多酚与L-EGCG的抗脂质过氧化机理之一是有效地清除了脂质过氧化的启动子氧自由基.     

编码棉花胞质铜锌超氧物歧化酶基因的克隆与表达分析

 【目的】克隆编码棉花胞质铜锌超氧化物岐化酶基因并分析其表达特性。【方法】采用 RACE 技术克隆基因，Northern blotting 检测基因的表达谱；采用氮蓝四唑（NBT）光下还原法测定不同生育期的酶活性。【结果】获得了棉花胞质铜锌超氧化物岐化酶基因cDNA 全长序列（GenBank 注册号：DQ445093）；该基因cDNA全长共682 bp，开放阅读框456 bp，编码152个氨基酸。分子结构预测结果：酶蛋白理论分子量约为15.03 kD，理论等电点为6.09，与其它植物的蛋白质氨基酸序列同源性在82%～87%之间。Southern blotting显示不同棉种该基因的拷贝数基本一致，均属于低拷贝基因。Northern blotting显示该基因在不同的组织、不同的生育期表达量不同；酶活性测定显示盛花期最高。【结论】棉花胞质铜锌超氧化物岐化酶基因在陆地棉中属于低拷贝数基因；在整个生育期中mRNA的含量呈规律性动态变化，前期较低，后期较高，在盛花期达到顶峰；变化曲线与不同时期的酶活性变化一致；不同器官的基因表达检测结果显示：基因在根中表达量最高，叶片次之，花中的表达最低。     

Differential response of zucchini varieties to low storage temperature

Several parameters related to cold damage in zucchini have been measured in fruits from different varieties cultivated in the province of Almería (south-eastern Spain). The purpose of this work is to correlate physiological parameters with commercial quality and chilling damage, in order to establish reliable criteria for selecting varieties having better genetic adaptation to low-temperature storage. The results show that, for varieties harvested during February, the variety Natura was the best adapted to storage at 4 °C, as its fruits suffered less from chilling injuries, had a lower weight loss, and the levels of metabolites malonyldialdehyde and H₂O₂ were not as high as in the other varieties. Genetic variation was detected for some of the parameters analysed. The positive correlation among the levels of MDA, H₂O_2, and chilling injury, as well as the negative correlation among catalase and chilling injury, makes these parameters good indicators of chilling damage in our system.     

Stimulation of ROS-scavenging systems in squash (Cucurbita pepo L.) plants by compost supplementation under normal and low temperature conditions

The beneficial effect of compost, the final product of aerobic biodegradation of organic matter, on growth, lipid peroxidation [as malondialdehyde (MDA], hydrogen peroxide (H₂O₂) and superoxide anion (O₂^•−), activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), as well as reduced ascorbate (ASC) and glutathione (GSH) and their oxidized forms was investigated in squash (Cucurbita pepo L. cv. Eskandarany) plants exposed to normal and low temperature (LT) conditions. LT stress of 8 °C significantly reduced the plant growth of untreated plants, but compost alleviated the adverse effect of stress and significantly increased the fresh and dry weights under normal and stress conditions. LT also induced accumulation of H₂O₂ and O₂^•− and resulted in increased lipid peroxidation, pointing out to cellular oxidative stress. Under compost application, such reactive oxygen species (ROS) and peroxidized lipids were markedly reduced, but SOD, CAT, APX and GR activities, key enzymes of ROS-scavenging systems, were significantly increased. Data also indicated that there were general reductions in total ascorbate and glutathione pool in LT control plants, but compost-treated ones considerably have maintained higher levels of such redox metabolites. Significantly higher ratios of ASC/DHA (dehydroascorbate) and GSH/GSSG (glutathione disulfide) were generally found in compost-treated plants than in untreated-ones. It is evident that compost induced enhancement of LT tolerance was related to up-regulation of enzymatic and non-enzymatic antioxidant systems. Such enhancement would eventually protect plant cells from LT-induced oxidative stress reactions via scavenging ROS.