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1.
Maize (Zea mays L. cv. 777) plants grown in hydroponic culture were treated with 50 μm CdSO4. Growth and metabolic parameters indicative of oxidative stress and antioxidant responses were studied in leaves of plants treated with Cd. Apart from increasing lipid peroxidation and H2O2 accumulation, supply of Cd suppressed growth, fresh and dry mass of plants and decreased the concentrations of chloroplastic pigments. The activities of catalase (CAT; EC 1.11.1.6), peroxidase (POD; EC 1.11.1.7), ascorbate peroxidase (APX; EC 1.11.1.11) and superoxide dismutase (SOD; EC 1.15.1.1) were increased in plants supplied 50 μm Cd. Localization of activities of isoforms of these enzymes (POD, APX and SOD) on native gels also revealed increase in the intensities of pre‐existing bands. Stimulated activities of CAT, POD, APX and SOD in maize plants supplied excess Cd do not appear to have relieved plants from excessive generation of reactive oxygen species (ROS). It is, therefore, concluded that supply of 50 μm Cd induces oxidative stress by increasing production of ROS despite increased antioxidant protection in maize plants.  相似文献   

2.
This work was undertaken to investigate the effect of zinc (Zn) nutrition on root antioxidative responses to cadmium (Cd) toxicity of three wheat genotypes differing in Zn efficiency. A hydroponic experiment was carried out in which two bread wheat genotypes (Triticum aestivum L. cvs. ‘Rushan’ and ‘Cross’) and one durum wheat genotype (Triticum durum L. cv. Durum) were exposed to three Zn2+ (10?11.11, 10?9.11 and 10?8.81 μm ) and two Cd2+ (10?11.21 and 10?10.2 μm ) activity levels. ‘Durum’ showed the highest root sulfhydryl (‐SH) groups content and activity of catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) and the lowest root membrane permeability among the studied wheat genotypes. In ‘Durum’, Zn nutrition increased root ‐SH groups concentration of seedlings in Cd‐free nutrient solution. In ‘Cross’, as Zn2+ activity increased from 10?11.11 to 10?9.11 μm , root ‐SH groups concentration was increased while decreased with increasing Zn2+ to 10?8.81 μm . Cadmium increased root membrane permeability at both 10?11.11 and 10?9.11 μm Zn2+ levels. Activity of CAT and APX increased in roots of ‘Durum’ plants exposed to Cd at Zn2+ = 10?9.11 μm and thereafter decreased with increasing Zn2+ activity. In contrast, CAT and APX activity in roots of ‘Cross’ and ‘Rushan’ genotypes exposed to Cd decreased by increasing Zn activity to 10?9.11 μm and then increased at Zn2+ = 10?8.81μm . The results showed an increase in activities of antioxidative enzymes in Cd‐treated plants, although this increase was dependent on the crop genotype and Zn levels in the media.  相似文献   

3.
研究分析了水杨酸(SA)对20%聚乙二醇6000(PEG6000)引起节节麦幼苗根中活性氧(ROS)水平和抗氧化酶活性的影响,结果发现,PEG能够显著提高节节麦根中超氧阴离子(O2-)、过氧化氢(H2O2)和丙二醛(MDA)的含量,明显降低超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)和谷胱甘肽还原酶(GR)的活性;SA能明显抑制PEG诱导的MDA和O2-的积累,缓解PEG对SOD、GR和CAT活性的抑制作用,但对APX的活性没有明显影响。这表明SA可能主要通过影响SOD、GR和CAT的活性缓解了水分亏缺对节节麦造成的伤害。  相似文献   

4.
肖强  杨曙  郑海雷 《作物学报》2011,37(1):177-181
一氧化氮(nitric oxide, NO)是植物中一种重要的信号分子, 在诱导种子萌发, 影响植物生长发育, 促进植物细胞衰亡等方面发挥着重要作用。然而对于外源NO是否参与了Se诱导的脂质过氧化调节过程仍不为人知。我们研究了0.2 μmol L-1和20 μmol L-1Na2SeO3及一氧化氮供体硝普钠(sodium nitroprusside, SNP)处理对水稻叶片叶绿素、H2O2和硫代巴比妥酸反应产物(Thiobarbituric Acid Reactive Substances, TBARS)含量, 愈创木酚过氧化物酶(guaiacol peroxidase, GPX)、超氧化物歧化酶(superoxide dismutase, SOD)、过氧化氢酶(catalase, CAT)以及抗坏血酸过氧化物酶(ascorbate peroxidase, APX)活性等生理生化指标的影响。结果表明, 1 μmol L-1SNP处理促进GPX、APX和CAT活性, 缓解膜脂过氧化, 降低TBARS含量;显著提高0.2 μmol L-1Na2SeO3处理下水稻叶片中叶绿素含量。在20 μmol L-1Na2SeO3处理下, 外加1 μmol L-1SNP更加显著促进GPX和CAT活性, 与此同时明显降低20 μmol L-1Na2SeO3处理引起的H2O2含量上升, 并降低TBARS含量。NO对植物中由Se引起的脂质过氧化具有调节作用。  相似文献   

5.
Although the relationship between fungal endophyte and agronomic grass (Lolium perenne and Festuca arundinacea) in drought tolerance are well documented, the mechanisms responsible for wild grass are not well understood. In this study, we determined the biomass production and growth parameters endophyte infected (E+) and endophyte uninfected (E−) Elymus dahuricus plants under high water (HW) and low water (LW) treatment for 8 weeks in a controlled‐environment condition experiment. We also determined the changes in the activities of the anti‐oxidative enzymes superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) and content of H2O2, as well as levels of proline and chlorophyll a + b were examined in the leaves of E+ and E− plants. Under low water treatment, E+ plants produced more biomass and had higher values in plant height and tiller numbers, but no influence by the fungus were observed in high water treatment. Anti‐oxidative enzyme (include SOD, POD, CAT and APX) activities and contents of proline and chlorophyll a + b increased and H2O2 concentration declined in the E+ plants compared with E− plants under low water treatment. Therefore, endophyte infection was a benefit to growth and anti‐oxidative affection E. dahuricus under low water treatment.  相似文献   

6.
7.
Adverse conditions often induce an increase in active oxygen species (AOS) such as hydrogen peroxide (H2O2). H2O2 is converted to water, and thus becomes detoxified by enzymes such as ascorbate peroxidase (APX; EC 1.11.1.11). APX activity is estimated by the disappearance rate of ascorbic acid, which becomes oxidized. However, ascorbate is also a substrate of guaiacol peroxidase (POX; EC 1.11.1.7). POX oxidizes phenols (including flavonoids), whereby ascorbate accepts an electron from phenoxyl or flavonoid radicals. Ascorbate becomes thereby converted to the monodehydroascorbate radical, which subsequently can become converted to dehydroascorbate. POX isozymes therefore convert hydrogen peroxide to water and oxidize ascorbate, just as APX does. POX activity is usually estimated by monitoring the formation of tetraguaiacol from guaiacol. This reaction is not specific, as some APX isozymes show rather high activity when using guaiacol or similar phenols as a substrate. It is concluded that APX activity can easily be confounded with POX activity, and vice versa. Proper methods should be used to separate the two enzyme activities.  相似文献   

8.
Shiitake (Lentinus edodes) mushrooms were exposed to UV-C light (4 kJ/m2) and stored in modified atmosphere packaging (MAP) prior to 15 days at 1 ± 1 °C and 95% relative humidity plus 3 days at 20 °C. Mushroom firmness, total phenolics, total flavonoids, ascorbic acid and H2O2 contents, superoxide anion (O2) production rate and activities of catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) were measured. UV-C treatment resulted in maintenance of a high level of firmness during 15 days at low temperature and reduced the decrease in firmness during shelf-life storage. Furthermore, treated samples showed higher total flavonoids, ascorbic acid, and delayed the increases in both O2 production rate and H2O2 contents. However, no clear treatment effects were seen in total phenolics contents. The treatment also increased the antioxidant enzyme activities of CAT, SOD, APX and GR throughout the storage period. These results indicate that postharvest application of UV-C radiation can delay softening and enhance antioxidant capacity in shiitake mushrooms.  相似文献   

9.
缩节胺浸种提高棉花幼苗根系活力中的活性氧代谢   总被引:7,自引:0,他引:7  
以国欣棉3号为材料,研究200 mg L–1缩节胺(DPC)浸种12 h对棉花子叶苗根系活力的影响,并从活性氧(ROS)代谢的角度揭示相关的生理机制。结果表明,DPC浸种显著增强了棉花幼苗的根系活力,根尖部位氯化三苯基四氮唑(TTC)染色光密度为清水对照的1.3倍,TTC法测定的根系活力和呼吸速率分别较对照增加167%和90%,非损伤微测技术(NMT)测定的K+净内流速率 (距根尖300 μm处)较对照提高36%。吖啶橙染色结果显示,DPC处理根尖伸长区的凋亡细胞数目较对照减少。此外,DPC处理使根系的过氧化氢酶(CAT)、抗坏血酸氧化酶(APX)和谷胱甘肽还原酶(GR)活力显著高于对照,超氧化物歧化酶(SOD)活力则降低;H2O2含量和超氧阴离子(O2)产生速率较对照分别降低56%和65%,H2O2原位染色结果也显示其根尖部分的褐色较对照明显减弱。根系组织的ROS代谢得到改善可能是DPC浸种提高棉花幼苗根系活力的机制之一。  相似文献   

10.
Leaf senescence is an oxidative process, and most of the catabolic processes involved in senescence are propagated irreversibly once initiated. An experiment was conducted to test the hypothesis that nitrophenolates (Atonik, a plant growth regulator) spray can delay the leaf senescence through reduced oxidative damage. Atonik 3.75 g a.i. ha?1 was sprayed during boll filling stage on cotton, and the senescence process was evaluated by quantifying total chlorophyll contents, photosynthetic rate, Fv/Fm ratio, various reactive oxygen species (ROS) content, antioxidant content and antioxidant enzyme activity from 90 days after sowing (DAS) to 130 DAS. The result indicated that nitrophenolate spray reduced the hydrogen peroxide (H2O2), superoxide anion (O2?) accumulation, lipid peroxidation (malondialdehyde), lipoxygenase activity and membrane permeability over unsprayed control. The antioxidant enzyme activity (superoxide dismutase, SOD; ascorbate peroxidase, APX; peroxidase, POX; glutathione peroxidase, GSH‐Px) were significantly increased by the nitrophenolate spray. POX (118.1 %) and GSH‐Px (143.3 %) activities were enhanced to a higher level compared to APX (8.5 %) activity at 130 DAS. Enhanced accumulation of ascorbate (144.9 %), phenol (154.7 %) and proline (50 %) was seen in nitrophenolate‐sprayed plants compared with unsprayed control plants at 130 DAS. Ascorbate content is increased by higher dehydroascorbate reductase enzyme activity. Ascorbate was thus able to replenish reducing equivalents to phenoxyl radicals resulting in an increase in phenolic compounds. The increased phenolic acid content may be involved in scavenging the ROS produced during senescence process. The higher level of reduced ascorbate and low level of endogenous H2O2 in the leaves may be the prerequisite for delayed leaf senescence in the nitrophenolate‐sprayed plants. Based on the present work, it can be concluded that nitrophenolate‐sprayed plants can postpone the leaf senescence by peroxide/phenolic/ascorbate system which is involved in scavenging the ROS produced during leaf senescence.  相似文献   

11.
Because of astringency at harvest, ‘Rojo Brillante’ persimmons are regularly submitted to deastringency treatment based on exposing fruit to a high CO2 concentration. The treatment conditions that ensure total astringency removal throughout the various maturity stages have been determined to be 95% CO2, 20 °C, 24 h. The aim of this study was to investigate changes in the redox state of persimmon fruit associated with this deastringency treatment. The levels of reactive oxygen species (ROS) (O2 and H2O2), and the activities of the main ROS scavenging enzymes (CAT, POD, APX, and SOD), were determined at harvest and after deastringency in fruit at three different maturity stages.Our results showed that during ‘Rojo Brillante’ persimmon maturation, the level of O2 gradually increased, while APX activity was lowered. The deastringency treatment with CO2 induced oxidative stress in the fruit, observed as an over-accumulation of O2 and H2O2. As a response to ROS accumulation, the activities of the CAT, APX and SOD scavenging enzymes were up-regulated after deastringency treatment. The response of POD enzyme was dependent on maturity stage, showing enhanced activity after CO2 treatment only for the fruit at the most mature stage.  相似文献   

12.
Two chilling‐tolerant genotypes, that is, weedy rice WR03‐45 and cultivated rice Lijiangxintuanheigu and two chilling‐sensitive genotypes, that is, weedy rice WR03‐26 and cultivated rice Xiuzinuo were used in this study to investigate the effects of exogenous abscisic acid (ABA) on protection against chilling damage as well as on changes in physiological features. The results showed that under chilling stress the increased levels of superoxide radical (), hydrogen peroxide (H2O2) and malondialdehyde (MDA) in WR03‐45 and Lijiangxintuanheigu were lower than those in WR03‐26 and Xiuzinuo. Activities of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR)) and non‐enzymatic antioxidants (ascorbate acid (AsA) and reduced glutathione (GSH)) were enhanced in WR03‐45 and Lijiangxintuanheigu, whereas they were decreased significantly in WR03‐26 and Xiuzinuo. Application of exogenous ABA reduced the chilling damage in the four genotypes. The pre‐treatment with ABA decreased the levels of , H2O2 and MDA caused by chilling stress in the four genotypes through increasing the activities of SOD, CAT, APX, GR and the contents of AsA and GSH in the four genotypes under chilling stress. Moreover, pre‐treatment with Fluridone, the ABA biosynthesis inhibitor, prohibited the effects of ABA through enhancing the oxidative damages and suppressing the antioxidant defence systems under chilling stress. The results indicate the mechanism for rice with chilling tolerance is to enhance the capacity of antioxidant defence systems under chilling stress. Furthermore, ABA plays important roles in the tolerance of rice against chilling stress for it could induce the capacity of whole antioxidant defence systems including enzymatic and non‐enzymatic constitutions under chilling stress.  相似文献   

13.
Preclimacteric avocado (Persea americana Mill. cv. Booth 7) fruit were treated with aqueous 1-methylcyclopropene (1-MCP) at 0.93 and 9.3 mmol m−3 and then stored at 20 °C to investigate the effect of 1-MCP on antioxidant systems of mesocarp tissue during ripening. Exposure to 1-MCP concentrations significantly delayed softening and peak ethylene production. 1-MCP significantly delayed accumulation of total soluble phenolics, flavonoids, and total antioxidant capacity although levels eventually reached control fruit maxima. The influence of 1-MCP was more pronounced at the higher concentration. Activities of peroxidase [POD (EC 1.11.1.7)], superoxide dismutase [SOD (EC 1.15.1.1)], catalase [CAT (1.11.1.6)] and l-ascorbate peroxidase [APX (EC 1.11.1.11)] increased during early ripening of control fruit followed by slight (CAT) or significant (POD, APX) declines with further ripening. Increases in activities of all enzymes were delayed in proportion to 1-MCP concentration, and maximum activities attained during ripening were largely unaffected by 1-MCP. Postclimacteric declines in POD and APX were not observed at the higher 1-MCP concentration, possibly reflecting incomplete ripening. The results indicate that changes in antioxidant parameters of avocado fruit are not markedly influenced by 1-MCP but are delayed or altered in proportion to the general suppression of ripening as indicated by ethylene production and fruit softening trends. Together with previously published reports, the data also indicate that the effects of ethylene-action suppression on antioxidant parameters during ripening vary considerably among different fruits. Relationships between antioxidant systems, ethylene and ripening are discussed.  相似文献   

14.
15.
The aims of this study were to compare the physiological responses of krishum (Iris lactea Pall. var. chinensis Koidz) to neutral and alkaline salt stress and identify and examine the mechanisms involved in plant response to salt treatments. In this study, biomass, ion accumulation (Na+, K+, Ca2+, Mg2+), organic solute (proline) concentration, rate of membrane electrolyte leakage (REL) and antioxidase activities including those of superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6) and peroxidase (POD, EC 1.11.1.7) were investigated in krishum under different concentrations of NaCl, Na2CO3 and the mixture of the two salts in the same volume. All three treatments caused increases in Na+ concentration, proline content and REL and decreases in root Mg2+ and K+ content. Increased Ca2+ and antioxidase activities were observed at lower external Na+ concentrations. However, at higher external Na+ levels, decreased Ca2+ and antioxidase activities were detected. Alkaline salt resulted in more damage to krishum than neutral salt including lower SOD, POD and CAT activities and decreased proline content, relative to neutral salt. High Na+ and low K+ in krishum intensified ion toxicity under alkaline condition. Alkaline salt caused greater harm to plants than neutral salt, the primary reason of which might be the lower Ca2+ content in the plant under alkaline salt stress.  相似文献   

16.
Jasmonic acid (JA) treatment significantly reduces rot due to several sugarbeet (Beta vulgaris L.) storage pathogens. However, the mechanisms by which JA protects postharvest sugarbeet roots from disease are unknown. In other plant species and organs, alterations in antioxidant defense mechanisms and elevations in common pathogenesis-related defense enzymes have been implicated in jasmonate-induced disease resistance. To investigate whether these mechanisms are involved in JA-induced disease resistance in stored sugarbeet roots, the activities of several reactive oxygen species (ROS)-scavenging and pathogenesis-related defense enzymes and the total concentration of antioxidant compounds were determined in harvested sugarbeet roots in the 60 d following treatment with JA. ROS-scavenging and pathogenesis-related defense enzymes and the concentration of antioxidant compounds were largely unaffected by JA as JA-treated roots exhibited small declines in superoxide dismutase (SOD) and chitinase activities, and were generally unaltered in ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), β-1,3-glucanase (β-Gluc), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities or antioxidant compounds concentration. The lack of increase in enzyme activities or metabolites related to defense against oxidative stress or pathogens suggests that JA-induced disease resistance in postharvest sugarbeet roots does not arise from a direct increase in any of the ROS-scavenging and defense-related enzymes examined, or the concentration of total antioxidant compounds. However, ROS-scavenging enzymes and pathogenesis-related defense enzymes were affected by storage duration with POD, SOD, β-Gluc, chitinase, and PPO activities elevated and APX and CAT activities reduced in roots stored for 10 d or more. Storage-related changes in activities of ROS-scavenging enzymes and defense-related enzymes provide further evidence that these enzymes are uninvolved in sugarbeet root disease resistance during storage since many of these enzymes increased in activity after prolonged storage when disease resistance generally declines.  相似文献   

17.
Root activity plays a dominant role in grain filling in cereal crops. However, the importance of deep roots for regulating post‐anthesis leaf senescence is not clearly understood in wheat (Triticum aestivum L.). In this study, we used 32P tracing to estimate the difference in wheat root activity at soil depths of 30 and 70 cm and the root restriction method to investigate the effects of vertical distribution of deep roots on leaf senescence, with non‐restricted plants as controls. Recovery of radioactive 32P indicated that deep roots had significantly higher activity than upper roots in wheat. Root restriction at a soil depth of 50 cm caused significant decreases in the activities of superoxide dismutase (EC 1.15.1.1), peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6) and ascorbate peroxidase (EC 1.11.1.11) at 16 days after anthesis and thereafter resulting in an increase in malondialdehyde. As a result, chlorophyll levels and net photosynthesis decreased. Ultimately, the root‐restricted wheat produced a significantly lower grain yield than the non‐restricted controls. These data suggest that deep roots are pivotal for regulating plant senescence, duration of grain filling, and yield formation.  相似文献   

18.
Effects of hydrogen peroxide (H2O2), as exogenous reactive oxygen, on browning and active oxygen metabolism in pericarp of harvested ‘Fuyan’ longan fruit were investigated. The results showed that as compared with the control fruit, there was a higher browning index in pericarp of H2O2-treated fruit. The fruit treated with H2O2 resulted in increased rate of superoxide anion (O2) production, reduced activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), decreased amounts of ascorbic acid (AsA), glutathione (GSH) and carotenoid, and increased malondialdehyde (MDA) content. These results indicated that H2O2-induced browning in pericarp of harvested longan fruit might be due to a reducing capacity of active oxygen scavenging and an increase of accumulation of O2, which might stimulate membrane lipid peroxidation, disrupt cellular membrane structure, and cause the loss of cellular compartmentalization, in turn, resulting in the contact of polyphenol oxidase (PPO) and peroxidase (POD) with phenolic substrates and subsequently oxidation phenolics to form brown polymers.  相似文献   

19.
为确定热休克蛋白70 (HSP70)提高作物耐干旱高温复合胁迫的机制,对干旱、高温反应不同的4个玉米品种的生理特性进行了研究。结果显示:(1) 在干旱、高温、干旱高温复合胁迫条件下,叶片丙二醛(MDA)增加量以隆玉602最低,驻玉309最高;在干旱胁迫条件下,郑单958叶片MDA含量低于浚单20,而在高温胁迫条件下,浚单20叶片MDA含量低于郑单958。(2) 在干旱、高温、干旱高温复合胁迫条件下,隆玉602、郑单958、浚单20三个品种叶片抗氧化防护系统如抗坏血酸过氧化物酶(APX)、谷胱苷肽还原酶(GR)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性增加量均高于驻玉309;在干旱条件下,郑单958叶片APX、GR、SOD、CAT活性增加量显著高于浚单20,在高温条件下,两个品种的表现则相反;在干旱高温复合胁迫条件下,隆玉602 叶片APX、GR、SOD活性增加量显著高于郑单958和浚单20。(3) HSP70抑制剂斛皮素(Quercetin, Q)预处理显著抑制了3种胁迫诱导的4个品种叶片抗氧化酶活性的增加。这些研究结果暗示HSP70提高了干旱、高温、干旱高温复合胁迫诱导的抗氧化防护酶活性,且APX、GR、SOD 这3个抗氧化防护酶活性可以作为评价作物耐干旱、高温和干旱高温复合胁迫的生化指标。  相似文献   

20.
Blueberries (Vaccinium spp. ‘LanFeng’) are harvested and consumed at maturation and have a short storage life at room temperature. Changes in blueberry quality and physiological parameters differ under room or low temperature storage conditions. The storage life of blueberries can be extended at low temperature, but pitting can develop associated with refrigeration, especially during subsequent shelf-life. The objective of this research was to understand the antioxidative metabolism accompanying pitting development of stored blueberry fruit, involving reactive oxygen species and antioxidant systems. Physiological and metabolic disorders, including low firmness, increased cell membrane electrolyte leakage and malondialdehyde (MDA) content, and changes in enzyme activity, were observed in pitting blueberries. Blueberries were stored at 20 °C and 0 °C for 10 days and 60 days, respectively. Hydrogen peroxide and superoxide radical production rate increased more rapidly during shelf-life after cold storage than at room temperature. On the other hand, blueberries during shelf-life after cold storage, when pitting occurred, had lower activity of antioxidant-related enzymes, including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), than those stored at room temperature. The severity of pitting was paralleled by higher cell membrane electrolyte leakage and MDA content, and lower SOD, CAT, and APX activities.  相似文献   

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