水分胁迫对小麦根细胞质膜氧化还原系统的影响

水分胁迫使小麦根质膜ＮＡＤＨ和ＮＡＤＰＨ的氧化速率及Ｆｅ（ＣＮ）６＾３－和ＥＤＴＡ－Ｆｅ＾３＋的还原速率明显降低。对照与胁迫处理的质膜氧化还原系统活性均不受鱼藤酮、抗霉素Ａ和ＤＣＮ等呼吸链抑制剂的影响。在不加Ｆｅ（ＣＮ）６＾－３作为电子受体时,水杨基羟肟酸（ＳＨＡＭ）可明显刺激质膜ＮＡＤＨ的氧化和Ｏ２吸收速率。水分胁迫促使ＳＨＡＭ刺激的ＮＡＤＨ氧化明显降低,但却使Ｏ２吸收略有上升。     

低温胁迫下红松幼苗活性氧的产生及保护酶的变化

在不同低温胁迫时间下,对红松（Ｐｉｎｕｓ ｋｏｒａｉｅｎｓｉｓ Ｓｉｅｂ．ｅｔ．Ｚｕｃｃ）幼苗针叶中Ｈ２Ｏ２、Ｏ＾－．２、膜脂过氧化产物丙二醛（ＭＤＡ）、组织自动化氧化速率及保护酶超氧化物歧化酶（ＳＯＤ）、过氧化物酶（ＰＯＤ）、过氧化氢酶（ＣＡＴ）和抗坏血酸过氧化物酶（ＡＳＰ）的动态变化过程进行了测定。结果表明,随着低温胁迫时间的延长,Ｏ＾－．２产生速率和Ｈ２Ｏ２含量先上升后下降;ＭＤＡ的含量呈波     

水分胁迫对小麦根细胞质膜氧化还原系统的影响

水分胁迫使小麦根质膜ＮＡＤＨ和ＮＡＤＰＨ的氧化速率及Ｆｅ（ＣＮ）６３－和ＥＤＴＡ－Ｆｅ３＋的还原速率明显降低。对照与胁迫处理的质膜氧化还原系统活性均不受鱼藤酮抗霉素Ａ和ＫＣＮ等呼吸链抑制剂的影响。在不加Ｆｅ（ＣＮ）６３－作为电子受体时,水杨基羟肘酸（ＳＨＷ）可明显刺激质膜ＮＡＤＨ的氧化和Ｏ２吸收速率。水分胁迫促使ＳＨＡＭ刺激的ＮＡＤＨ氧化明显降低,但却使Ｏ２吸收略有上升。     

2,4—D和乙烯利对玉米幼苗抗旱性效应的研究

水分胁迫下,２０ｍｇ／Ｌ２,４－Ｄ和４００ｍｇ／Ｌ乙烯利（ＣＥＰＡ）分别不同程度地降低和提高玉米幼叶生长部位的相对含水量（ＲＷＣ）、水势（ψｗ）和渗透调节能力（ＯＡ）。胁迫后期,玉米幼叶中脯氨酸含量（Ｐｒｏ）为：ＣＥＰＡ〉对照（ＣＫｓ）〉２,４－Ｄ。随胁迫宾进行,２,４－Ｄ处理幼叶的膜相对透性（ＲＰ）始终处于较高水平且增长幅度较大,叶片延伸生长速率（ＬＥＲ）对ＲＰ的变化较为敏感;而ＣＥＰＡ处理则与     

人Mn—SOD基因结构

人Ｍｎ┐ＳＯＤ基因结构吕星孙志贤裴雪涛吴祖泽（北京放射医学研究所,北京１００８５０）关键词锰超氧化物歧化酶基因结构超氧化物歧化酶（ｓｕｐｅｒｏｘｉｄｅｄｉｓｍｕ－ｔａｓｅ,ＳＯＤ）催化超氧阴离子自由基（Ｏ－·２）转变为Ｈ２Ｏ２和Ｏ２的歧化反应（２Ｏ－...     

c—erbB2对大鼠黄体细胞hCG诱导的孕酮分泌的影响

采用离体细胞体外孵育法,研究反义ｃ－ｅｒｂＢ２寡脱氧核苷酸（ａｎｔｉｓｅｎｓｅ ｃ－ｅｒｂＢ２ ＯＤＮ）对大鼠黄体细胞ｈＣＧ诱导的孕酮分泌的影响,及其与外源性ｃＡＭＰ和Ｃａ＾２＋以及蛋白抑制剂放线菌酮（ＣＹＸ）之间的关系。结果表明,反义ｃ－ｅｒｂＢ２以剂量相关方式抑制黄体细胞ｈＣＧ诱导的孕酮的产生,同时使ｃ－ｅｒｂＢ２蛋白染色阳性的黄体细胞百分数下降,无义ｔａｔ ＯＤＮ没有相应的作用。１０＾－４     

干旱胁迫对黄瓜PSⅡ颗粒铁组分Mossbauer谱的影响

黄瓜（Ｇｃｕｍｉｓ ｓａｔｉｖｕｓ Ｌ）叶片ＰＳⅡ颗粒的Ｍｏｓｓｂａｕｅｒ谱呈现４套双峰,依它们的化学位移相四敬矩劈塑数值,分别属于氧化态Ｃｙｔ－ｂ５５９,还原态Ｃｙｌ－ｂ５５９、Ｆｅ＾３＋－Ｑ画物和Ｆｅ＾２＋－Ｑ复合物。干埋胁迫旱影响ＱＡ／ＱＢ中铁（Ｆｅ）参与电子传递的速率,使ＰＳⅡ颗粒的ｏｓｓｂａｕｅｔ谱中Ｆｅ＾２＋的吸收双峰消失,即还原态Ｇ７ｙｔ－Ｂ５５９转变为氧化态Ｃｙｔ－ｂ５５９Ｆｅ＾２     

杜氏盐藻细胞质膜氧化还原系统

杜氏盐藻细胞质膜具的氧化ＮＡＤ（Ｐ）Ｈ,还原Ｆｅ（ＣＮ）＾３－６和Ｏ２的氧化还原系统。当Ｆｅ（ＣＮ）＾３－６浓度为０．６ｍｍｏｌ／Ｌ,氧化ＮＡＤＨ的Ｋｍ为９６μｍｏｌ／Ｌ,Ｖｍａｘ为１５９ｎｍｏｌ１０＾－８ｃｅｌｌｓｍｉｎ＾－１,最适ｐＨ为８．５。ＴｒｉｔｏｎＸ－１００可促进ＮＡＤＨ和Ｆｅ（ＣＮ）＾３－６的氧化还原活性。ＮＡＤＨ能促进藻细胞的氧吸收,最适ｐＨ为８．５。在无外源电子供体存在时,细胞质     

植物-病原物互作过程中的活性氧

活性氧与水分胁迫、环境污染、衰老及低温等方面的关系已有大量的报道。在植物－病原物互作过程中,病原物作为一种特殊的胁迫因子而起作用。近年来对植物一病原物互作过程中活性氧的研究已成为植物病理生理学研究的一个热点,本文对此作一综述。１植物─-病原物巨作过程的活性氧的产生在正常情况下,植物体内活性氧（ａｃｔｉｖｅｏｘｙｇｅｎｓｐｅｃｉｅｓ,ＡＯＳ,包括超氧阴离子Ｏ－２;过氧化氢Ｈ２Ｏ２;氢氧自由基ＯＨ;单线态氧１Ｏ２）处于低水平状态,在植物过敏性反应（ＨＲ）早期阶段常出现ＡＯＳ迅速释放,这种ＡＯＳ迅速释…     

渗透胁迫下稻苗中铁催化的膜脂过氧化作

在－０．７ＭＰａ渗透胁迫下,水和思苗体内Ｏ２↑－．和Ｈ２Ｏ２大量产生,Ｆｅ＾２＋含量与膜脂过氧化产物ＭＤＡ含量呈极显著的正相关。外源Ｆｅ＾２＋、Ｆｅ＾３＋、Ｈ２Ｏ２、Ｆｅ＾２＋＋Ｈ２Ｏ２、ＤＤＴＣ均能刺激膜脂过氧化作用,而铁离子的螯合剂ＤＴＰＡ则有缓解作用。ＯＨ的清除剂苯甲酸钠和甘露醇能明显地抑制渗透胁迫下Ｆｅ＾２＋催化的膜脂过氧化作用。这都表明渗透胁迫下水稻幼苗体内铁诱导的膜脂过氧化作用主要是由     

渗透胁迫对杧果叶片活性氧伤害的影响

杧果叶片经渗透胁迫处理后,叶水势Ψ_L下降,O₂^·产生速率和MDA含量增加,SOD、POD和CAT的活性水平与O₂^·和MDA的变化相一致。结果表明,杧果叶片的渗透胁迫损伤,是由O₂^·引发的膜脂过氧化,致使MDA含量增加,破坏细胞膜系统所致。渗透胁迫处理过程中,GSH和AsA含量下降。     

Generation of Active Oxygen Free Radicals and Its Injury to Microsome Membranes in Wheat Leaves Under Drought Stress

The microsome membrane of wheat ( Triticum aestivum L. ) leaves under different time of drought stress was purified to determine the active oxygen free radicals generated and their severity of injury to the membrane. During the drought stress the rate of O2- and H2O2 generation increased for a certain time and then decreased. The concentration of MDA increased continuously. The activity of SOD decreased gradually. The concentration of —SH group and MDA increased from the beginning until the 36th hour under drought stress, thereafter MDA content continued to increase while the —SH content decreased. Several physiological indexes related to membrane injury, such as root electroconductivity, leaf water potential and water content were all affected accordingly.     

干旱胁迫下小麦叶片微粒体活性氧自由基的产生及其对膜的伤害

从不同干旱胁迫时间下的小麦(Triticum aestivum L.)叶片中提取微粒体膜,测定活性氧自由基变化和膜伤害程度。结果表明,随着干旱胁迫时间的延长发生以下变化:(1)O_2~-和H_2O_2的产生速率在一定时间内逐渐加快然后下降;(2)膜脂过氧化产物丙二醛(MDA)的含量逐渐增加;(3)微粒体膜上的SOD活性逐渐下降;(4)—SH基的含量在一定时间内逐渐增多以后下降;(5)与膜伤害程度有关的生理指标如根系电导率、叶片水势及其含水量等均有变化。     

Generation of Activated Oxygen and Change of Cell Defense Enzyme Activity in Leaves of Korean Pine Seedling Under Low Temperature

Changes of activated oxygen O2 and H2O2, malondialdehyde (MDA) content and activity of enzymes involving cell defense in leaves of Korean pine (Pinus koraiensis Sieb. et. Zucc) seedling under different time of low temperature stress were studied. With the increase of stress time,the rate of O2 generation and H2O 2 content increased to a certain degree and then decreased. The increase of MDA content fluctuated as well as its decrease after the low-temperature stress was removed. The activity of cell defense enzymes, viz. superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascrobate peroxidase (ASP) were gradually decreased. However, after cold pre-treatment of the seedlings all these indexes showed marked changes and different ways of adaptivity to cold stress; thus enhanced the cold tolerance of the plant.     

Effects of Exogenous Spermidine on Antioxidant System Responses of Typha latifolia L. Under Cd^2＋ Stress

The effects of foliar spraying with spermidine (Spd), ranging in concentration from 0.25 to 0.50 mmol/L, on the antioxidant system under Cd^2 stress (range 0.1- 0.2 mmol/L Cd^2 ) in Typha latifolia L. grown hydroponically were investigated in order to offer a referenced evidence for an understanding of the mechanism by which polyamines (PAs) relieve the damage to plants by heavy metal and improve the phytoremediation efficiency of heavy metal-contaminated water. The results showed that Cd^2 stress induced oxidative injury, as evidenced by an increase in the generation of superoxide anion (O2), as well as the hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents in both leaves and caudices. With the exception of superoxide dismutase (SOD) activity in the leaves, an increase in the activities of catalase (CAT), guaiacol peroxidase (GPX), and glutathione reductase (GR) was observed in both leaves and caudices, SOD activity was increased in caudices, and ascorbate peroxidase (APX) activity was increased in leaves following Cd^2 treatment. The reduced glutathione (GSH) content in both leaves and caudices and the reductive ascorbate content in leaves was obviously increased, which were prompted by the application of exogenous Spd. Spraying with Spd increased the activity of GR and APX in both leaves and caudices, whereas the activity of SOD, CAT, and GPX was increased only in caudices following spraying with Spd. The generation of O2 and the H2O2 and MDA content in both leaves and caudices decreased after spraying with Spd. The decrease in MDA was more obvious following the application of 0.25 than 0.50 mmol/L Spd. It is supposed that exogenous Spd elevated the tolerance of T. latifolia under Cd^2 stress primarily by increasing GR activity and the GSH level.     

外源亚精胺对荇菜抗Hg2+胁迫能力的影响

3 mg/L的Hg2降低了叶内亚精胺(spermidine,Spd)、精胺(spermine,Spm)含量,促进了腐胺(put resci ne,Put)合成,喷施Spd可提高叶内Spd、Spm含量,对Put含量则在低浓度下使其下降、高浓度(将近1mmo1/L)下使之上升.3mg/L的Hg2 可显著降低SOD、CaT、APx活性,提高02-产生速率,导致膜脂过氧化物(MDA)过量积累,造成叶绿素、可溶性蛋白大幅度下降.而喷施Spd可减轻Hg2 处理的这些作用,喷施的最适浓度为0.1～0.5 mmol/L.     

6-苄（基）腺嘌呤和抗坏血酸对渗透胁迫时杨树光合作用光抑制的影响

研究了6-BA和A5A对渗透胁迫时杨树幼苗叶片光合作用光抑制和活性氧代谢的影响．结果表明,渗透胁迫时杨树叶片净光合速率(Pn)和表观量子效率(AQY)降低,光合作用光抑制加剧,超氧化物歧化酶(SOD)活性升高,抗坏血酸过氧化物酶(APX)活性降低,O2产生加快,H2O2和膜脂过氧化产物丙二醛(MDA)含量升高．6-BA和A5A预处理使胁迫时叶片SOD和APx活性升高。O2生成减少。H2O22和MDA含量降低,同时缓解了光合作用的光抑制．相关分析表明,杨树叶片活性氧水平和MDA含量与Pn和AQY呈负相关．胁迫时杨树叶片活性氧的积累与光合作用光抑制有一定关系,6-BA和A5A对光抑制的缓解作用与其对活性氧清除系统的促进作用有关。     

外源亚精胺可缓解荇菜镉毒害

研究了外施浓度为0．01mmol·L^-1的亚精胺（Spd）对不同浓度镉（Cd2＋）胁迫下荇菜（Nymphoides peltatum）叶片的叶绿体结构、叶绿素含量、可溶性蛋白含量、超氧阴离子（O2）产生速率和丙二醛（MDA）含量,以及保护酶——超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性的影响。结果表明,（1）Cd2＋胁迫可使荇菜细胞的叶绿体结构遭到破坏,叶绿素含量减少。外施Spd则可有效地保护叶绿体结构,减少叶绿素的流失。（2）在单一Cd2＋处理条件下,随着Cd2＋浓度的升高,叶绿素含量呈现先升后降的趋势,可溶性蛋白含量则逐渐下降。外源Spd处理显著提高了二者的含量,并延缓了它们的下降速度。（3）在单一Cd^2＋处理条件下,SOD、POD和CAT活性分别在Cd2＋浓度为1、1和2mg·L1时达到最高值,而后随着Cd^2＋浓度的增加其活性逐渐下降。外施Spd使它们的活性分别提高了5．8％、37．5％和3．3％,并降低了O2^-产生速率和MDA的含量。上述结果表明,Spd增强了荇菜对Cd^2＋毒害的抗性,并在一定程度上缓解了Cd^2＋对荇菜的毒害。     

Involvement of Singlet Oxygen in the Breakdown of Photosynthetic Pigments in the Leaves of Rice Seedling Exposed to Osmotic Stress and Light

The combined effects of osmotic stress and light on the generation of singlet oxygen (102) and its relation to the breakdown of photosynthetic pigments in leaves of hybrid rice (Oryza sativa L. subsp, indica cv. Shanyou 63) seedlings were studied under the condition of incubating the leaves with –0.8 MPa polyethylene glycol (PEG) solution. Under osmotic stress and increasing light intensity, the production of ¹O2 monitored as p-nitrosodimethylaniline (NDA) bleaching were increased in chloroplasts, degradation of chloro- phyll (Chl) and carotenoid (Car) were accelerated and Car loss preceded Chl causing a significant increase of Chl/Car ratio. A close correlation was observed between ¹O2 production and the contents of Chl, Car and malondialdehyde (MDA). Pretreatment with scavengers for ¹O2. such as β-carotene (β-Car) and histidine (His) reduced MDA content and retarded the degradation of photosynthetic pigments in rice leaves exposed to osmotic stress of -0.8 MPa and light intensity of 250 μmol · m- 2 · s-1, in contrast to that with photosensitizer riboflavin (RF). These results indicate that ¹O2 which generated in chloroplast from photosensitized reactions involving triplet Chl may play a significant role in the breakdown of photo- synthetic pigments and the preferential destruction of Car in the leaves under combined osmotic stress with light.     

拟南芥AtUNE12基因的耐盐功能初探

bHLH转录因子家族成员在植物生长发育、生理代谢及非生物胁迫响应过程中起重要作用。本研究选取拟南芥抗逆相关bHLH转录因子家族中AtUNE12基因为研究对象,对其进行耐盐功能初探。首先构建AtUNE12基因的植物过表达载体（pROKⅡ-AtUNE12）,通过农杆菌介导的浸花法转化拟南芥,利用qRT-PCR技术检测获得T₃代AtUNE12过表达转基因植株。在盐胁迫下,分析过表达AtUNE12与野生型拟南芥长势、根长及鲜重;比较过表达AtUNE12与野生型植株的电解质渗透率、失水率、MDA含量、POD与SOD活性及H₂O₂含量,鉴定AtUNE12基因是否具有耐盐能力。结果表明：过表达AtUNE12基因降低了拟南芥植株的失水率、电解质渗透率及MDA含量,保护细胞膜结构的完整性;增强了POD与SOD活性,降低了拟南芥植株内的H₂O₂含量,进而增强拟南芥植株的ROS清除能力,从而提高拟南芥的耐盐能力。