铅胁迫对芦竹抗氧化酶活性的影响

研究了在不同浓度Pb2+胁迫下,芦竹(Arund donax Linn.)体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)3种抗氧化酶活性随时间的变化情况。结果显示,芦竹遭受Pb2+胁迫初期,3种酶活性较对照值有明显增高;随着污染浓度加大和时间延长,3种酶活性又出现下降,降低程度与受污染浓度和时间有关。Pb2+胁迫初期,芦竹幼苗体内的抗氧化能力增强,表现出对抗氧化酶的激活效应,但随着植物生长,Pb2+在植物体内迁移,其叶片内抗氧化能力降低,表现出对抗氧化酶的抑制效应。抗氧化酶活性产生的效应强弱及维持期长短与Pb2+胁迫浓度有关,胁迫初期一般是Pb2+浓度高,抗氧化酶活性升高明显;胁迫后期Pb2+浓度低,活性维持期长。Pb2+胁迫对过氧化氢酶和过氧化物酶的影响没有超氧化物歧化酶的影响显著,但3种酶活性的变化趋势基本一致。     

氯苯对小麦抗氧化酶活性的影响

研究了不同浓度的 1 ,2 ,4 三氯苯对扬麦 1 0号和皖麦 3 8叶片和根系中超氧化物歧化酶 (SOD)和过氧化物酶 (POD)的影响。结果表明 :(1 )随 1 ,2 ,4 三氯苯浓度的升高 ,两小麦品种叶片中SOD和POD活性都逐步升高 ;(2 )随 1 ,2 ,4 三氯苯浓度的升高 ,两小麦品种根系SOD的活性亦逐步升高 ,而POD活性呈现先升高后降低的趋势 ;(3 ) 1 ,2 ,4 三氯苯诱导小麦叶中正常表达的POD和SOD同功酶活性较对照提高 ,并能诱导新的POD同功酶的表达。     

卫星搭载处理对辣椒萌发过程中抗氧化酶活性的影响

测定经卫星搭载后的辣椒种子萌发过程中抗氧化酶的活性。结果表明:辣椒种子经卫星搭载处理后,其发芽势和发芽率分别比对照提高了3.5%和5.3%;在萌发过程中,可溶性蛋白质MDA含量低于地面对照,但SOD活性高于对照;卫星搭载的种子在萌发13d的幼苗体内SOD、G-POD、APX和CAT活性分别较对照提高了14.29%、25.23%、1.84%和21.52%。表明卫星搭载处理提高了辣椒种子和幼苗体内抗氧化酶活性,对萌发初期保护膜系统的修复具有重要的意义。     

γ射线辐照对春兰根状茎生长及抗氧化酶活性的影响

将春兰(Cymbidium goeringii)的离体根状茎切成长各约1cm的顶段、中段和末段,用60Coγ射线进行辐照,剂量分别为0、5、10、20、30和50Gy。测定了不同辐照剂量下新生根状茎的生长,研究了辐照原初根状茎愈创木酚过氧化物酶(G-POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)等抗氧化酶活性以及过氧化物酶同工酶谱的影响。结果表明:辐照剂量为30和50 Gy处理的根状茎虽能存活,但未有新生根状茎的发生,生长停滞。辐照原初根状茎上CAT和SOD的活性随着辐照剂量的增加均有先升高后降低的趋势,而G-POD的活性则表现为先略降低后升高。综合新生根状茎的生长、抗氧化酶活性及过氧化物同工酶谱的结果,春兰诱变育种的适宜剂量应在20~30Gy间,且最合适的诱变部位是根状茎的顶段。     

镉对龙葵种子萌发及子叶抗氧化酶活性的影响

龙葵（Solanum nigrumL.）是Cd超累积植物,可用于植物冶金和Cd污染土壤的植物修复。超累积植物的生理基础研究有助于提高其对Cd的富集效率。龙葵种子在含有不同浓度CdCl（20、30、50、100、150、200μmol·L-1和300μmol·L-1）的琼脂培养基上萌发7d。结果表明,龙葵在200μmol·L-1和300μmol·L-1Cd时发芽率显著降低,而低浓度Cd（30～150μmol·L-1）胁迫下无显著差异;在Cd≥30μmol·L-1时,活力指数、发芽势均显著降低,幼苗的生长受到显著抑制。幼苗生长分析表明：在30～150μmol·L-1Cd处理下根长下降约17%～35%,显著低于200～300μmol·L-1Cd处理（下降79%～90%）;株高随Cd浓度的升高逐渐下降。子叶抗氧化酶活性分析表明：100～150μmol·L-1Cd胁迫下,CAT和APX活性显著上升;在Cd胁迫下,SOD活性降低但维持在较高的活性水平。表明龙葵幼苗能忍耐小于150μmol·L-1Cd,抗氧化酶活性在抵抗Cd毒害方面发挥重要作用。     

镉硫交互对东南景天抗氧化酶活性的影响

通过营养液培养试验研究不同硫镉水平对超积累东南景天抗氧化酶活性的影响。结果表明,在增施镉水平下东南景天叶片的MDA含量随着硫水平增加显著降低,Cd0水平下S2处理显著降低MDA含量达12.4%。相反,东南景天叶片的MDA含量随着镉水平的提高显著增加18.4%～137.7%。镉硫交互对超积累东南景天叶片抗氧化酶活性有显著影响。超积累东南景天叶片SOD活性随着硫、镉水平的增加而增加,以S3〉S2〉S1,Cd100〉Cd10〉Cd0。增施硫显著提高Cd10和Cd100水平下东南景天叶片POD活性。在S1,S2水平下,增加Cd水平东南景天叶片POD活性显著增加,POD活性以Cd10〉Cd100〉Cd0。超积累东南景天叶片CAT活性随着硫水平增加而增加8.9%～21.3%,CAT活性随着Cd水平的增加而显著增加,增幅以S1和S2水平下较大。随着S,Cd水平的增加东南景天叶片的APX活性显著增加。镉硫交互对4种抗氧化酶的效应以APX〉CAT〉POD〉SOD。     

水分胁迫对苹果属植物抗氧化酶活性的影响研究

试验研究水分胁迫对 3种苹果属植物湖北海棠、西府海棠和新疆海棠根系和叶片抗氧化酶活性的影响结果表明 ,随水分胁迫的加重 ,3种海棠抗氧化酶活性逐渐增强 ,当土壤绝对含水量降至 6 .5 %时 ,过氧化氢酶 (CAT)活性首先达高峰 ,而超氧化物歧化酶 (SOD)活性高峰则出现于土壤绝对含水量为 2 .8%时 ,之后 2种酶活性逐渐降低 ,复水后又均有所升高 ;过氧化物酶 (POD)活性高峰出现于土壤绝对含水量为 3.2 %时 ,之后逐渐下降 ,至复水后仍呈下降趋势 ;丙二醛 (MDA)含量随水分胁迫的加重而逐渐增加 ,当土壤绝对含水量降至 1 .8%时其含量最高 ,复水后则呈下降趋势。种间抗氧化能力耐旱型新疆海棠 >西府海棠 >干旱敏感型湖北海棠     

镉胁迫对玉米幼苗抗氧化系统及光合作用的影响

采用水培方法,在玉米幼苗进入三叶期后向培养液中加入不同浓度氯化镉（0、10^-6、10^-5、10^-4 mol·L^-1）,胁迫不同时间（5、10、15 d）后对幼苗进行各项指标检测。结果表明,低浓度（10^-6 mol·L^-1）及中浓度（10^-5 mol·L^-1）镉胁迫对幼苗生长均有较强刺激作用,而中浓度胁迫对地上部分作用更明显;低浓度镉胁迫对根部及叶片抗氧化酶（SOD、POD、CAT及ASA－POD）活性影响较小,只是根部POD、ASA－POD活性明显升高,而中浓度胁迫对除SOD外其他抗氧化酶活性均有显著促进作用;MDA含量均未有显著升高,可见根部及叶片未受到氧化损伤;两种浓度胁迫下,Fv′/Fm′虽下降,净光合速率有所升高。高浓度镉（10-4 mol·L^-1）胁迫下幼苗生长几乎停止;根部SOD及CAT活性升高,而POD和ASA－POD被明显抑制,叶片中CAT、POD及ASA－POD活性显著升高;根部受到显著氧化损伤;各项光合参数（Fv/Fm、Fv′/Fm′和净光合速率）均显著降低。     

盐胁迫对白榆无性系抗氧化酶活性及丙二醛的影响

为了促进滨海盐渍荒漠化地区的植被恢复、引种栽培与盐碱土的改良利用,以3个白榆无性系Y65225、Y46和Y51为试验材料,采用盆栽模拟方法,分析白榆无性系在不同浓度(0.0％、0.3％、0.5％、0.7％和0.9％)NaCl处理下抗氧化酶(SOD、POD和CAT)活性、丙二醛(MDA)含量变化及各指标的相关性,并运用隶属函数法,综合评价3个白榆无性系的耐盐性.结果表明:在各盐浓度胁迫下,Y51能够维持较高的抗氧化酶活性,抗氧化能力最强;Y46的抗氧化酶活性下降最大,抗氧化能力最差,Y46的MDA含量增加幅度最大,受到的盐害最大;Y51的MDA含量增加幅度最小,受到的盐害最小.3个白榆无性系的SOD活性与POD活性,呈极显著正相关,CAT活性与SOD活性、POD活性相关性不显著,CAT、POD活性与MDA含量相关性不强,SOD活性与MDA含量呈显著负相关关系,即SOD活性的增加,可显著减少MDA的积累,增强其抗盐性.综合各项指标,Y51抗盐能力最强,Y65225次之,Y46最差.建议在滨海盐碱地区造林时,优先采用Y51无性系.研究结果将为今后白榆无性系在盐碱地的栽培,提供一定的参考.     

水杨酸对废电池胁迫下绿豆幼苗抗氧化酶活性及生理特性的影响

采用室内有培养土的纸杯培养方法,研究了不同浓度水杨酸（SA）处理对废电池胁迫下,绿豆幼苗抗氧化酶及生理特性的影响。结果表明,废电池胁迫下,超氧化物歧化酶（SOD）活性升高,过氧化物酶（POD）活性降低,光合色素、可溶性蛋白含量下降,脯氨酸和丙二醛（MDA）含量升高,电导率增大,膜稳定性降低,显示出一定的毒害效应;低浓度（≤100mg·L-1）的外源SA处理能够明显增强废电池胁迫下绿豆叶片SOD、POD活性,改善多项指标,但随着SA浓度升高,SOD和POD酶活性逐渐降低。说明低浓度SA能通过刺激抗氧化酶活性,减轻氧化胁迫,缓解废电池对绿豆幼苗的毒害作用,但高浓度SA（≥100mg·L-1）缓解作用降低。     

镉对超富集植物圆锥南芥氮素代谢的影响研究

采用土培方法,研究了不同Cd添加(01、02、04、08、01、60和240 mg kg-1)对超富集植物圆锥南芥叶片中氮素含量以及氮代谢关键酶活性的影响。结果表明,随着Cd添加浓度的增加,圆锥南芥的生物量、叶片数、直径长以及Cd含量均呈增加趋势。Cd添加浓度为240 mg kg-1时,生物量增加了137%,叶片数增加了1.02倍,直径较对照增加了130%,叶片中Cd含量达到451 mg kg-1。NO3--N和NH4+-N呈先降低后升高的变化趋势,在Cd浓度为240 mg kg-1时,达最大值。在Cd处理浓度为102、04、08、0 mg kg-1时,NO3--N和NH4+-N含量间无显著性差异(p>0.05)。在Cd添加浓度为240 mg kg-1时,硝酸还原酶(NR)活性只相当于对照的67%,与对照间的差异显著。在Cd处理浓度为10~160 mg kg-1时,NR活性与对照间无显著性差异(p>0.05)。谷氨酰胺合成酶(GS)、谷氨酸合酶(GOGAT)活性以及可溶性蛋白质含量在Cd处理浓度为10~240 mg kg-1时,与对照间无显著性差异(p>0.05)。谷氨酸脱氢酶(GDH)活性呈先升高后降低的变化趋势。游离脯氨酸含量在Cd浓度为102、0、408、01、602、40 mg kg-1时,分别为对照的0.67倍1、.29倍1、.54倍、2.38倍、2.54倍、1.14倍。     

EXOGENOUS CALCIUM ALTERS ACTIVITIES OF ANTIOXIDANT ENZYMES IN TRIFOLIUM REPENS L. LEAVES UNDER PEG-INDUCED WATER DEFICIT

This study was designed to examine whether external calcium (Ca²⁺) would improve the tolerance of Trifolium repens L to polyethylene glycol (PEG)-induced water deficit, and to determine the physiological mechanisms of Ca²⁺ effect on plant tolerance to water deficit. T. repens seedlings were subjected to PEG-induced water deficit alone or combined with 5 mM calcium chloride (CaCl₂) for 72 h. During PEG-induced water deficit period, leaf relative water content (RWC) decreased gradually, and chlorophyll content increased after 24 and 48 h of water deficit but decreased below the control level after 72 h. The Ca²⁺-treated plants had higher RWC and chlorophyll content than untreated plants. Smaller amounts of thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H₂O₂) accumulated in Ca²⁺-treated plants than in untreated plants during the period of water deficit. The activity of superoxide dismutase (SOD) increased gradually during the experimental period, and external Ca²⁺ treatment further promoted SOD activity under water deficit. The activity of the catalase (CAT) was not influenced after 24 and 48 h of water deficit and insignificantly increased after 72 h, whereas the activity of ascorbate peroxidase (APOX) increased linearly and glutathione reductase (GR) activity slightly increased over the course of treatment. Seedlings treated with Ca²⁺ had higher CAT, GR, and APOX activities than untreated plants under water deficit. These results suggested that exogenous Ca²⁺ application enhanced T. repens tolerance to PEG-induced water deficit, and this enhancement was related to alleviation of lipid peroxidation and maintenance of antioxidant activities.     

EFFECTS OF PHYTOHORMONES ON PROLINE CONTENT AND ANTIOXIDANT ENZYMES OF VARIOUS WHEAT CULTIVARS UNDER SALINITY STRESS

Salinity stress is one of the important agricultural problems in the world. A factorial experiment based on completely randomized design with four replications was conducted to evaluate the effects of phytohormones (gibberellic acid and abscisic acid) on the activity of antioxidant enzymes (peroxidase, superoxide dismutase and catalase), rubisco activity and content, and proline in three wheat cultivars (Gascogen, Zagros, and Kuhdasht) under control and salinity stress (3.5 and 7 dS m^?1). The results showed that salinity stress (3.5 and 7 dS m^?1) decreased the activity of catalase, rubisco, carboxylase, but increased peroxidase, superoxide dismutase activity and proline content. Gibberellic acid caused 58.03% increased in rubisco carboxylase activity in Zagros at 7 dS m^?1 in comparison with abscisic acid under salinity stress compared with the control plants in Kuhdasht. Activity of superoxide dismutase in Kuhdasht cultivar at 7 dS m^?1 salinity level showed 76.43% increased in Gascogen under salinity stress compared with the control plants with gibberellic acid application. The highest proline content as an osmolyte was found in Zagros at 7 dS m^?1 salinity level with abscisic acid (194 μmol g^?1 DM) application. Peroxidase activity increased 83.31% and catalase activity decreased 61.27% compared with the control plants in Zagros. Gibberellic acid application significantly prevented reduction in rubisco content under salinity stress. In conclusion, increased in peroxidase and superoxide dismutase activity and proline content decreased the adverse effects of salinity stress on studied cultivars. Also, the foliage spray of gibberellic acid enhanced and improved the growth condition. In this experiment, Zagros cultivar showed more tolerance to salinity stress than the other two cultivars.     

EFFECTS OF METHYL JASMONATE TREATMENT ON ALLEVIATION OF CADMIUM DAMAGES IN SOYBEAN

In the present study, the interactive effects of methyl jasmonate (0, 0.01, and 0.1 mM) and cadmium chloride (0 and 500 μM) on growth, biochemical, and physiological parameters of soybean plants were investigated. The plants were first treated with methyl jasmonate and then exposed to cadmium stress. Cadmium reduced shoot dry weight and total chlorophyll contents and increased lipid peroxidation in leaves. Methyl jasmonate, especially at a lower level (0.01 mM), significantly alleviated the cadmium damage to shoot dry weight and total chlorophyll contents and also, reduced lipid peroxidation. The increase in catalase and polyphenol oxidase activities were also observed under cadmium stress. The activity of ascorbate peroxidase was enhanced by methyl jasmonate under no stress and cadmium stress. However, peroxidase activity increased under no stress conditions. Based on our results it could be concluded that the application of methyl jasmonate caused significant alleviation of cadmium damages to soybean plants.     

Cd2+胁迫对西瓜幼苗光合生理及活性氧代谢的影响

通过盆栽试验,研究了土壤中Cd2+对西瓜(Citrullus vulgaris)幼苗光合特性及活性氧代谢的影响。结果表明:Cd2+降低了小型西瓜叶绿素总含量,改变了叶绿素a/b的值,其叶绿素总含量与土壤中Cd2+浓度极显著(P0.01)负相关;减弱了西瓜幼苗的净光合速率(Pn),降低了胞间CO2浓度(Ci)、气孔导度(Gs)和蒸腾速率(Tr)。西瓜叶片中超氧阴离子自由基(·O2-)产生速率、过氧化氢(H2O2)和丙二醛(MDA)含量随着土壤中Cd2+浓度的升高而增加,且H2O2和MDA含量与Cd2+浓度极显著(P0.01)正相关。在Cd2+胁迫下,过氧化氢酶(CAT)活性变化显著,其活性与H2O2含量、MDA含量极显著(P0.01)负相关。Cd2+胁迫引起叶绿素等光合相关生理因子降低,是导致西瓜幼苗净光合速率降低的直接原因;活性氧代谢失调,脂膜过氧化加重是导致其净光合速率降低的另一重要原因。     

INDUCTION OF OXIDATIVE STRESS AND ANTIOXIDANT ENZYMES BY EXCESS COBALT IN MUSTARD

This study focuses on induction of oxidative stress and antioxidative defense mechanism on exposure to excess cobalt (Co) in mustard (Brassica campestris L.; cv. ‘T-59’) plants grown in refined sand. Plants were grown for 40 days at normal (0.1 μM) Co. Additional cobalt was supplied from d 41 at 6 levels, i.e., 0.1 (control), 100, 200, 300, 400 and 500 μM as cobalt sulfate. The primary site of Co toxicity was shoots where middle leaves developed interveinal chlorosis after three days of excess cobalt supply (>100 μM). At severity these chlorotic spots became necrotic and affected areas appeared dry and papery, at this stage, growth of the plants were completely checked, the upper part of the stem became dry and hanged down. The toxicity of cobalt at d 46, i.e., six days after metal supply, (DAMS) reduced the dry weight, concentrations of chlorophyll a, b and carotenoids in leaves and tissue Fe with decreased activity of catalase and lipid peroxidation. Enhancement in proline concentration and elevated activities of antioxidant enzymes peroxidase, superoxide dismutase and ascorbate peroxidase were observed in leaves and roots in response to excess Co supply in mustard. Cobalt concentration of mustard in leaves and roots, ranged from 200 to 397 μg g^?1 at excess Co as compared to 1.1 to 2.5 μg Co g^?1 dry matter in control (0.1 μM Co).     

腌制加工对不同品种叶用芥菜抗氧化物质含量和抗氧化活性的影响

本试验以4个不同品种叶用芥菜为材料,研究了腌制加工对叶用芥菜抗氧化物质含量(维生素C、总酚、总黄酮)和抗氧化活性(TEAC值和FRAP值)的影响。结果表明:与腌制前相比芥菜中抗氧化物质含量与抗氧化活性都有不同程度的下降。维生素C含量下降最为显著(P<0.01),幅度为40.70%~57.46%,总黄酮含量下降不显著,幅度为2.30%~10.62%,总酚介于二者之间;抗氧化活性的变化在品种间存在较大差异,雪里蕻和金丝芥腌制后抗氧化活性下降幅度未达到显著水平(TEAC 8.49%~10.83%,FRAP 9.03%~14.06%),而笋壳青菜和瘤子芥菜下降幅度达到显著水平(TEAC 14.45%~19.14%,FRAP 28.05%~35.77%,P<0.05)。总酚和总黄酮与抗氧化活性呈现极显著的正相关,总酚与TEAC和FRAP的R2分别为0.9482和0.9395,总黄酮与TEAC和FRAP的R2分别为0.8287和0.9129。维生素C与抗氧化活性的相关性较弱(TEAC,R2=0.2968,FRAP,R2=0.0979),酚类物质在腌制叶用芥菜抗氧化活性中起重要作用。