冻害胁迫下小麦叶片内一些抗冻基因转录水平研究

研究了大田条件下,4个小麦品种幼穗发育不同阶段植株的冻害情况,并比较叶片内谷胱甘肽还原酶(GR)、抗坏血酸过氧化酶(APX)、超氧物歧化酶(SOD)和过氧化氢酶(CAT)等基因的转录水平。结果表明,幼穗发育进程慢的小麦植株受冻害较轻,其叶片内的APX和SOD基因的转录水平较高,与植株的抗冻性表现相一致,表明它们可作为评价小麦抗冻性的鉴定指标;冻害胁迫下,CAT和GR基因的转录水平与小麦植株抗冻性表现不相一致,表明这2个基因可能不适宜作为小麦抗冻性的鉴定指标。     

铜对苋菜幼苗光合参数和活性氧代谢的影响

 【目的】明确铜毒影响苋菜（Amaranthus tricolor）幼苗光合作用和活性氧代谢的生理机制。【方法】采用土培试验测定了不同水平铜处理下苋菜幼苗生长、光合作用、矿质元素吸收和活性氧代谢的相关指标。【结果】2.0～4.0 mmol•kg-1铜处理下植株干重降至无铜处理（对照）的91%～73%,净光合速率和气孔导度均明显减小,但胞间CO2浓度并没发生显著变化,最大光化学效率的变化比实际量子效率小得多,这暗示着光合作用暗反应对ATP和NADH需求减少使光化学下调。此外,叶片光合色素、水分和矿质元素Fe、K和Mg含量均明显降低,Cu含量明显升高。2.0～4.0 mmol•kg-1铜处理显著增加叶片超氧化物歧化酶、过氧化物酶活性和脯氨酸含量,降低过氧化氢酶、抗坏血酸过氧化物酶活性及类胡萝卜素、还原型谷胱甘肽和抗坏血酸含量,并伴随丙二醛含量和细胞电解质渗漏率增加。【结论】2.0 mmol•kg-1以上铜处理引起苋菜活性氧代谢失衡,明显降低净光合速率和实际量子效率,加剧过氧化作用,导致植株生长严重受阻。     

Programmed cell death,antioxidant response and oxidative stress in wheat f lag leaves induced by chemical hybridization agent SQ-1

Male sterility induced by a chemical hybridization agent(CHA) is an important tool for utilizing crop heterosis. Leaves, especially the flag leaves, as CHA initial recipients play a decisive role in inducing male sterility. To investigate effects of different treatment times of CHA-SQ-1 used, morphological, biochemical and physiological responses of wheat flag leaves were detected in this study. CHA induced programmed cell death(PCD) as shown in terminal deoxynucleotidyl transferase-mediated d UTP nick end-labelling(TUNEL) and DNA laddering analysis. In the early phase, CHA-SQ-1 triggered organelle changes and PCD in wheat leaves accompanied by excess production of reactive oxygen species( O~-._2and H_2O_2) and down-regulation of the activities of superoxide dismutase(SOD), catalase(CAT) and guaiacol peroxidase(POD). Meanwhile, leaf cell DNAs showed ladder-like patterns on agarose gel, indicating that CHA-SQ-1 led to the activation of the responsible endonuclease. The oxidative stress assays showed that lipid peroxidation was strongly activated and photosynthesis was obviously inhibited in SQ-1-induced leaves. However, CHA contents in wheat leaves gradually reduced along with the time CHA-SQ-1 applied. Young flags returned to an oxidative/antioxidative balance and ultimately developed into mature green leaves. These results provide explanation of the relations between PCD and anther abortion and practical application of CHA for hybrid breeding.     

羟丙基壳聚糖对小麦幼苗生理功能的影响

利用0.3%羟丙基壳聚糖溶液对小麦幼苗进行喷洒处理,在幼苗发育的5个时段对4种酶活性和叶绿素含量进行测定。结果表明,用羟丙基壳聚糖处理后,硝酸还原酶、核酮糖二磷酸(RuBP)羧化酶、超氧化物歧化酶活性比对照高出20%左右,多酚氧化酶活性变化不显著,随着幼苗发育呈现先高后低的变化,叶绿素含量处理明显高于对照30%左右,说明羟丙基壳聚糖可以促进小麦碳氮代谢,对小麦的抗性和光合作用有明显的促进作用。     

水分胁迫下小麦幼苗的抗氧化机制分析

分析了水分胁迫对小麦幼苗叶片中活性氧(ROS)水平和抗氧化酶活性的影响,结果发现,水分胁迫能够显著提高超氧阴离子(O2-.)和丙二醛(MDA)的含量及超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)的活性,而过氧化氢(H2O2)的含量及过氧化氢酶(CAT)和谷胱甘肽还原酶(GR)的活性变化不明显。这些结果表明,SOD和APX在小麦应答水分胁迫的反应中可能起重要作用。     

外源一氧化氮对增强UV-B辐射后小麦幼苗膜脂过氧化系统的影响

[目的]以硝普钠（sodium nitroprusside,SNP）作为外源一氧化氮（nitricoxide,NO）供体,研究了不同浓度一氧化氮对增强UV-B辐射胁迫后小麦幼苗膜脂过氧化系统的影响。[方法]试验设置3个组：对照组（CK）、紫外线UV-B处理组（B）、UV-B和硝酸钠（SNP）复合处理组（B＋SNP）,分别于处理后的第0、1、2、3、4天取样进行丙二醛（MDA）含量及CAT、POD、SOD等生理生化指标的测定,3次重复,并进行统计学分析。[结果]UV-B辐射后,小麦幼苗中丙二醛（MDA）含量上升,过氧化氢酶（CAT）、过氧化物酶（POD）、超氧化物歧化酶（SOD）活性下降,导致小麦幼苗产生氧化损伤;在UV-B辐射之后施加不同浓度的SNP,可以不同程度地缓解UV-B辐射胁迫下小麦幼苗根和叶的氧化损伤,使MDA含量下降,抗氧化酶CAT、POD、SOD活性上升。其中,0.1mmol/LSNP对叶的氧化损伤缓解作用较明显,0.01mmol/LSNP则对根的氧化损伤缓解作用较明显。[结论]外源NO供体SNP对小麦幼苗由于UV-B辐射引起的氧化损伤有明显的缓解作用,可增强植物对逆境胁迫的适应能力。     

外源一氧化氮对增强UV-B辐射后小麦幼苗膜脂过氧化系统的影响（摘要）（英文）

[目的]以硝普钠（sodium nitroprusside,SNP）作为外源一氧化氮（nitric oxide,NO）供体,研究了不同浓度一氧化氮对增强UV-B辐射胁迫后小麦幼苗膜脂过氧化系统的影响。[方法]试验设置3个组：对照组（CK）、紫外线UV-B处理组（B）、UV-B和硝酸钠（SNP）复合处理组（B＋SNP）,分别于处理后的第0、1、2、3、4天取样进行丙二醛（MDA）含量及CAT、POD、SOD等生理生化指标的测定,3次重复,并进行统计学分析。[结果]UV-B辐射后,小麦幼苗中丙二醛（MDA）含量上升,过氧化氢酶（CAT）、过氧化物酶（POD）、超氧化物歧化酶（SOD）活性下降,导致小麦幼苗产生氧化损伤;在UV-B辐射之后施加不同浓度的SNP,可以不同程度地缓解UV-B辐射胁迫下小麦幼苗根和叶的氧化损伤,使MDA含量下降,抗氧化酶CAT、POD、SOD活性上升。其中,0.1 mmol/LSNP对叶的氧化损伤缓解作用较明显,0.01 mmol/L SNP则对根的氧化损伤缓解作用较明显。[结论]外源NO供体SNP对小麦幼苗由于UV-B辐射引起的氧化损伤有明显的缓解作用,可增强植物对逆境胁迫的适应能力。     

水杨酸对高温强光下小麦抗氧化及光合作用的影响

以浓度为0.5 mmol/L的水杨酸(SA)水溶液喷施灌浆期小麦叶片,然后进行高温强光胁迫处理,研究SA对高温强光下小麦叶片氧化损伤及光合机构运转的影响。结果表明,SA能有效防护高温强光所致的氧化损伤,维持较高的SOD和APX活性,减少H2O2的积累,抑制脂质过氧化作用。明显减轻高温强光胁迫对光合机构的破坏,维持较高的PSⅡ原初光化学效率(Fv/Fm)、实际光化学效率(ФPSⅡ)、光化学猝灭系数(qP)和净光合速率(Pn)。     

苋菜活性氧代谢对铅胁迫的响应

[目的]了解铅对植物生长的抑制作用。[方法]以苋菜品种一点红为试材,采用盆栽试验,以醋酸铅配制土壤铅含量分别为0.1、0.2、0.4、0.8和1.6 mmol/kg干土,不加铅为对照,研究铅处理对苋菜生长、铅积累和活性氧代谢的影响。[结果]播种45 d后,铅胁迫(>0.4 mmol/kg)下苋菜的生长受到明显抑制,其中根受到的抑制程度最高。铅胁迫明显增加了苋菜器官中铅的含量,并主要积累在根部。随着铅处理浓度的增加,成熟叶超氧阴离子产生速率加快,过氧化氢含量、SOD和POD活性增加,CAT和APX活性降低,氧阴离子产生速率、过氧化氢含量、MDA含量和细胞电解质渗漏增加。[结论]铅胁迫引起苋菜活性氧代谢失衡,过氧化作用加剧,导致植物生长受阻。     

Grafting Enhances Copper Tolerance of Cucumber Through Regulating Nutrient Uptake and Antioxidative System

An experiment was carried out to determine plant growth, mineral uptake, lipid peroxidation, antioxidative enzymes, and antioxidant of cucumber plants （Cucumis sativus L. cv. Xintaimici） under copper stress, either ungrafted or grafted onto the rootstock （Cucurbitaficifolia）. Excess Cu inhibited growth, photosynthesis, and pigment synthesis of grafted and ungrafted cucumber seedlings and significantly increased accumulation of Cu in roots besides reducing mineral uptake. Cu concentration in roots of grafted cucumber plants was significantly higher than that of ungrafted plants and obviously lower in leaves. The accumulation of reactive oxygen species （ROS） significantly increased in cucumber leaves under Cu stress and resulted in lipid peroxidation, and the levels of ROS and lipid peroxidation were greatly decreased by grafting. Activities of protective enzymes （superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascorbate peroxidase, APX; dehydroascorbate reductase, DHAR; glutathione reductase, GR） and the contents of ascorbate and glutathione in leaves of grafted plants were significantly higher than those of ungrafted plants under Cu stress. Better performance of grafted cucumber plants were attributed to the higher ability of Cu accumulation in their roots, better nutrient status, and the effective scavenging system of ROS.     

外源NO对干旱胁迫下小麦幼苗抗氧化酶活性的影响

研究干旱胁迫下外源一氧化氮(NO)供体硝普钠(SNP)处理对小麦幼苗叶片抗氧化酶活性的影响。结果表明,低浓度NO可显著提高干旱胁迫下小麦幼苗叶片SOD、POD和CAT活性,缓解膜脂过氧化程度,随着浓度的提高,其缓解作用逐渐降低甚至加剧膜透性增加,NO调控作用具有二元性,且NO的适宜浓度存在品种差异,洛旱6号的适宜浓度为0.1 mmol/LSNP,郑麦9023则为0.5 mmol/L SNP,即抗旱性强的适宜浓度低于抗旱性弱的小麦品种。     

10种荒漠植物叶片超氧物歧化酶活性与植物抗旱性关系的研究

研究了 10种荒漠植物叶片超氧物歧化酶 (SOD)活性 ,其活性由高到低的顺序是 :梭梭、霸王、泡泡刺、珍珠、白刺、狭叶锦鸡儿、沙拐枣、籽蒿、锦鸡儿、红沙。研究表明 ,超氧物歧化酶活性高低与植物所生存的环境相适应 ;植物体内超氧物歧化酶的活性越高 ,其抗旱能力越强     

GH-DREB基因转化小麦及转基因植株后代的抗旱生理指标鉴定

用基因枪法将来自于棉花的DREB转录因子基因和诱导型启动子Rd29A构建的植物表达载体pRdGH转入小麦品种鲁麦22号,获得转基因小麦植株。T0、T1、T2、T3代分子生物学鉴定证实：GH-DREB基因可以稳定遗传。孕穗期到开花期T3代叶片可溶性糖、蒸腾速率、净光合速率测定结果表明：正常条件下,转基因后代与受体鲁麦22的各生理指标无明显差异,而水分胁迫下,转基因后代的净光合速率随着干旱处理时间的延长而逐渐下降,蒸腾速率随着干旱处理时间的延长而逐渐上升,但是,下降与上升幅度比对照低,其中,在胁迫第3天、第6天都与对照差异极显著,叶片的可溶性糖含量与对照相比差异不显著。说明GH-DREB基因在干旱条件下可通过减少蒸腾速率、维持光合作用。     

稀土对水分胁迫下小麦幼苗膜脂过氧化作用的影响

稀土元素能缓解水分胁迫下小麦幼苗叶片渗透势的降低,减少离子的渗漏,明显提高抗旱性.经过稀土处理的小麦幼苗,体内超氧物歧化酶和过氧化物酶活性减弱.抗旱品种比不抗旱品种膜脂过氧化程度低,丙二醛在叶片中积累减少,表现出明显的差异.     

Hg2+胁迫对小麦幼苗POD、CAT和SOD同工酶的影响

[Objective] This work was aimed to explore the mechanism of Hg2+ toxicity on plants. [Method]Activities of peroxidase(POD), catalase (CAT) and superoxide dismutase(SOD) were investigated in wheat (Triticum aestivum L. )seedlings under Hg2+ stress at different concentrations. [Re-pared to POD and SOD. [Conclusion] The toxic effect was related to the concentration of Hg2+ (0.10 mmol/L). The higher concentration of Hg2+ could affect the expression of POD, CAT, and SOD isozymes in the leaves, roots of wheat seedlings and germinated seeds, which further affect the normal metab-olism of membrane lipid and inhibit the growth of wheat seedlings at last.     

盐酸左氧氟沙星胁迫对小麦幼苗生长及生理特性的影响

采用自然条件模拟试验,研究了盐酸左氧氟沙星(OFLX)对小麦幼苗叶片叶绿素和可溶性蛋白含量、抗氧化酶系统及根系活力的影响。结果表明,在0～500 mg.L-1 OFLX处理浓度范围内,OFLX明显降低小麦叶片中叶绿素含量。随着OFLX浓度的逐渐升高,叶片中SOD、POD活性表现为先升后降,但均高于对照;CAT活性及可溶性蛋白含量表现为持续上升;小麦根系活力明显降低,小麦幼苗生长受到抑制。     

Hg2+胁迫对小麦幼苗POD、CAT和SOD同工酶的影响

[目的]为研究Hg2+对植物的毒害机理提供理论依据。[方法]以小麦为材料,研究了不同浓度Hg2+胁迫对小麦幼苗中的过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)同工酶活性变化的影响。[结果]在Hg2+浓度低于0.100 mmol/L时,对小麦幼苗生长的影响不明显;在Hg2+浓度高于0.100 mmol/L时,将会显著阻碍小麦的正常生长发育。小麦幼苗的不同组织对Hg2+胁迫的抵抗强度有所不同,表现为其叶片和根的抗胁迫性比萌发的种胚要强。在小麦幼苗受Hg2+胁迫时,POD、CAT和SOD 3种抗氧化酶同工酶中,CAT同工酶最为敏感。[结论]0.100 mmol/LHg2+浓度是小麦幼苗能否正常生长的阈值。     

水杨酸对高温强光胁迫下小麦叶片光合机构的保护作用

以0.1、0.3、0.5 mmol/L的水杨酸(SA)预先处理灌浆期的小麦叶片,然后进行不同温度和照光处理,探讨水杨酸对高温强光胁迫下小麦叶片psbA基因表达和PSⅡ功能的影响。结果表明,叶面喷施水杨酸可有效调节抗氧化酶SOD、APX的活性,降低叶片MDA的含量,维持较高的光合速率(Pn),减轻逆境对光合机构的破坏。RT-PCR分析结果也显示,水杨酸可以促进小麦psbA基因的表达。其中,以0.3 mmol/L的水杨酸效果最好。     

Ameliorative Effects of Brassinosteroid on Excess Manganese-Induced Oxidative Stress in Zea mays L. Leaves

Manganese （Mn） is becoming an important factor limiting crop growth and yields especially on acid soils. The present study was designed to explore the hypothesis that brassinosteroid application can enhance the tolerance of maize （Zea mays L.） to Mn stress and if so, whether or not the mechanism underlying involves regulation of antioxidative metabolism in leaves. The effects of 24-epibrassinosteroid （EBR） on the growth, photosynthesis, water status, lipid peroxidation, accumulation of reactive oxygen species, and activities or contents of antioxidant defense system in maize plants under Mn stress were investigated by a pot experiment. At supplemented Mn concentrations of 150-750 mg kg^-1 soil, the growth of plants was inhibited in a concentration-dependent manner. The semi-lethal concentration was 550 mg Mn kgq soil. Foliage application with 0.1 mg L^-1 EBR significantly reduced the decrease in dry mass, chlorophyll content, photosynthetic rate, leaf water content, and water potential of plants grown in the soil spiked with 550 mg kg^-1 Mn. The oxidative stress caused by excess Mn, as reflected by the increase in malondialdehyde （MDA） content and lipoxygenase （LOX, EC 1.13.11.12） activity, accumulation of superoxide radical and H2O2, was greatly decreased by EBR treatment. Further investigations revealed that EBR application enhanced the activities of superoxide dismutase （SOD, EC 1.15.1.1）, peroxidase （POD, EC 1.11.1.7）, catalase （EC 1.11.1.6）, ascorbate peroxidase （APX, EC 1.11. 1.11）, dehydroascorbate reductase （DHAR, EC 1.8.5.1）, and glutathione reductase （GR, EC 1.6.4.2）, and the contents of reduced ascorbate and glutathione, compared with the plants without EBR treatment. It is concluded that the ameliorative effects of EBR on Mn toxicity are due to the upregulation of antioxidative capacity in maize under Mn stress.     

Effects of Waterlogging on Photosynthesis and Antioxidant Enzyme Activities of Six Barley Genotypes with Different Waterlogging Tolerance

A field experiment was carried out to study genotypic difference in the effect of waterlogging on photosynthesis, chlorophyll content and antioxidative enzyme activities in barley. Waterlogging caused a rapid decline in net photosynthetic rate (Ph) and stomatal conductance (gs), and little change in chlorophyll content during early days of the treatment. A dramatic increase in malondialdehyde (MDA) content, superoxide dismutase (SOD) and peroxidase (POD) in waterlogged plants in the early days of the experiment was found, indicating the occurrence of oxidative stress in barley plants exposed to waterlogging. There was a highly significant difference in the changed extent of all these parameters among genotypes.Franklin and Yongjiahong Liuleng Damai, which were relatively sensitive to waterlogging in terms of growth, photosynthesis and chlorophyll content, accumulated much more MDA than the other two relatively tolerant genotypes (93-3143 and QS).After removal of waterlogging, the genotypic difference became much greater in recovering of these examined parameters.Yongjiahong Liuleng Damai showed higher recovery, while Franklin only recovered to 50% of the control at the 14 day after waterlogging removal. It may be concluded that it is the difference in anti-oxidative stress caused by waterlogging that account for the major difference in photosynthesis among barley genotypes.