共查询到20条相似文献,搜索用时 31 毫秒
1.
Harminder Pal Singh Daizy R. Batish Ravinder Kumar Kohli Komal Arora 《Plant Growth Regulation》2007,53(1):65-73
Arsenic (As) toxicity and its biochemical effects have been mostly evaluated in ferns and a few higher plants. In this study,
we investigated the effect of As (10.0 and 50.0 μM) on seedling growth, root anatomy, lipid peroxidation (malondialdehyde
and conjugated dienes), electrolyte leakage, H2O2 content, root oxidizability and the activities of antioxidant enzymes in mung bean (Phaseolus aureus Roxb.). Arsenic significantly enhanced lipid peroxidation (by 52% at 50.0 μM As), electrolyte leakage and oxidizability in
roots. However, there was no significant change in H2O2 content. Arsenic toxicity was associated with an increase in the activities of superoxide dismutase (SOD), guaiacol peroxidase
(GPX) and glutathione reductase (GR). In response to 50.0 μM As, the activities of SOD and GR increased by over 60% and 90%,
respectively. At 10.0 μM As, the activity of ascorbate peroxidase (APX) increased by 83%, whereas at 50.0 μM it declined significantly.
The catalase (CAT) activity, on the other hand, decreased in response to As exposure, and it corresponded to the observed
decrease in H2O2 content. We conclude that As causes a reduction in root elongation by inducing an oxidative stress that is related to enhanced
lipid peroxidation, but not to H2O2 accumulation. 相似文献
2.
In plants, salicylic acid (SA) is a signaling molecule that regulates disease resistance responses, such as systemic acquired resistance (SAR) and hypertensive response (HR). SA has been implicated as participating in various biotic and abiotic stresses. This study was conducted to investigate the role of SA in adventitious root formation (ARF) in mung bean (Phaseolus radiatus L) hypocotyl cuttings. We observed that hypocotyl treatment with SA could significantly promote the adventitious root formation, and its effects were dose and time dependent. Explants treated with SA displayed a 130% increase in adventitious root number compared with control seedlings. The role of SA in mung bean hypocotyl ARF as well as its interaction with hydrogen peroxide (H2O2) were also elucidated. Pretreatment of mung bean explants with N, N’-dimethylthiourea (DMTU), a scavenger for H2O2, resulted in a significant reduction of SA-induced ARF. Diphenyleneiodonium (DPI), a specific inhibitor of membrane-linked NADPH oxidase, also inhibited the effect of adventitious rooting triggered by SA treatment. The determination of the endogenous H2O2 level indicated that the seedlings treated with SA could induce H2O2 accumulation compared with the control treatment. Our results revealed a distinctive role of SA in the promotion of adventitious rooting via the process of H2O2 accumulation. This conclusion was further supported by antioxidant enzyme activity assays. Based on these results, we conclude that the accumulation of free H2O2 might be a downstream event in response to SA-triggered adventitious root formation in mung bean seedlings. 相似文献
3.
Dibyendu Talukdar 《Physiology and Molecular Biology of Plants》2013,19(1):69-79
The adverse effects of arsenic (As) toxicity on seedling growth, root and shoot anatomy, chlorophyll and carotenoid contents, root oxidizability (RO), antioxidant enzyme activities, H2O2 content, lipid peroxidation and electrolyte leakage (EL%) in common bean (Phaseolus vulgaris L.) were investigated. The role of exogenous nitric oxide (NO) in amelioration of As-induced inhibitory effect was also evaluated using sodium nitroprusside (100 μM SNP) as NO donor and 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (200 μM PTIO) as NO scavenger in different combinations with 50 μM As. As-induced growth inhibition was associated with marked anomalies in anatomical features, reduction in pigment composition, increased RO and severe perturbations in antioxidant enzyme activities. While activity of superoxide dismutase and catalase increased, levels of ascorbate peroxidase, dehydroascorbate reductase and glutathione reductase decreased significantly and guaiacol peroxidase remained normal. The over-accumulation of H2O2 content along with high level of lipid peroxidation and electrolyte leakage indicates As-induced oxidative damage in P. vulgaris seedlings with more pronounced effect on the roots than the shoots. Exogenous addition of NO significantly reversed the As-induced oxidative stress, maintaining H2O2 in a certain level through balanced alterations of antioxidant enzyme activities. The role of NO in the process of amelioration has ultimately been manifested by significant reduction of membrane damage and improvement of growth performance in plants grown on As + SNP media. Onset of oxidative stress was more severe after addition of PTIO, which confirms the protective role of NO against As-induced oxidative damage in P. vulgaris seedlings. 相似文献
4.
Ariana A. Huerta‐Heredia Ricardo Marín‐López Teresa Ponce‐Noyola Carlos M. Cerda‐García‐Rojas Gabriela Trejo‐Tapia Ana C. Ramos‐Valdivia 《Engineering in Life Science》2009,9(3):211-218
The effect of oxidative stress on indole alkaloids accumulation by cell suspensions and root cultures of Uncaria tomentosa in bioreactors was investigated. Hydrogen peroxide (H2O2, 200 μM) added to U. tomentosa cell suspension cultures in shaken flasks induced the production of monoterpenoid oxindole alkaloids (MOA) up to 40.0 μg/L. In a stirred tank bioreactor, MOA were enhanced by exogenous H2O2 (200 μM) from no detection up to 59.3 μg/L. Root cultures grew linearly in shaken flasks with a μ=0.045 days?1 and maximum biomass of 12.08±1.24 g DW/L (at day 30). Roots accumulated 3α‐dihydrocadambine (DHC) 2354.3±244.8 μg/g DW (at day 40) and MOA 348.2±32.1 μg/g DW (at day 18). Exogenous addition of H2O2 had a differential effect on DHC and MOA production in shaken flasks. At 200 μM H2O2, MOA were enhanced by 56% and DHC by 30%; while addition of 800 and 1000 μM H2O2, reduced by 30–40% DHC accumulation without change in MOA. Root cultures in the airlift reactor produced extracellular H2O2 with a characteristic biphasic profile after changing aeration. Maximum MOA was 9.06 mg/L at day 60 while at this time roots reached ca. 1 mg/L of DHC. Intracellular H2O2 in root cultures growing in the bioreactor was 0.87 μmol/g DW compared to 0.26 μmol/g DW of shaken flasks cultures. These results were in agreement with a higher activity of the antioxidant enzymes superoxide dismutase and peroxidase by 6‐ and 2‐times, respectively. U. tomentosa roots growing in the airlift bioreactor were exposed to an oxidative stress and their antioxidant system was active allowing them to produce oxindole alkaloids. 相似文献
5.
D.R. Batish H.P. Singh N. Setia S. Kaur R.K. Kohli 《Plant Physiology and Biochemistry》2006,44(11-12):819-827
2-Benzoxazolinone (BOA), a well-known allelochemical with strong phytotoxicity, is a potential herbicidal candidate. The aim of the present study was to determine whether phytotoxicity of BOA is due to induction of oxidative stress caused by generation of reactive oxygen species (ROS) and the changes in levels of antioxidant enzymes induced in response to BOA. Effect of BOA was studied on electrolyte leakage, lipid peroxidation (LP), hydrogen peroxide (H(2)O(2)) generation, proline (PRO) accumulation, and activities of antioxidant enzymes-superoxide dismutase (SOD, 1.15.1.1), ascorbate peroxidase (APX, 1.11.1.11), guaiacol peroxidase (GPX, 1.11.1.7), catalase (CAT, 1.11.1.6) and glutathione reductase (GR, 1.6.4.2) in Phaseolus aureus (mung bean). BOA significantly enhanced malondialdehyde (MDA) content, a product of LP, in both leaves and roots of mung bean. The amount of H(2)O(2), a product of oxidative stress, and endogenous PRO increased many-fold in response to BOA. Accumulation of PRO, MDA and H(2)O(2) indicates the cellular damage in the target tissue caused by ROS generated by BOA. In response to BOA, there was a significant increase in the activities of scavenging enzymes SOD, APX, GPX, CAT, and GR in root and leaf tissue of mung bean. At 5 mM BOA, GR activity in roots showed a nearly 22-fold increase over that in control. The present study concludes that BOA induces oxidative stress in mung bean through generation of ROS and upregulation of activities of various scavenging enzymes. 相似文献
6.
Glucose-6-phosphate dehydrogenase (G6PDH) has been implicated in supplying reduced nicotine amide cofactors for biochemical
reactions and in modulating the redox state of cells. In this study, the role of G6PDH in thermotolerance of the calli from
Przewalskia tangutica and tobacco (Nicotiana tabacum L.) was investigated. Results showed that Przewalskia tangutica callus was more sensitive to heat stress than tobacco callus. The activity of G6PDH and antioxidant enzymes (ascorbate peroxidase,
catalase, peroxidase and superoxide dismutase) in calli from Przewalskia tangutica and tobacco increased after 40 °C treatment, although two calli exhibited a difference in the degree and timing of response
to heat stress. When G6PDH was partially inhibited by glucosamine pretreatment, the antioxidant enzyme activities and thermotolerance
in both calli significantly decreased. Simultaneously, the heat-induced H2O2 content and the plasma membrane NADPH oxidase activity were also reduced. Application of H2O2 increased the activity of G6PDH and antioxidant enzymes in both calli. Diphenylene iodonium, a NADPH oxidase inhibitor, counteracted
heatinduced H2O2 accumulation and reduced the heat-induced activity of G6PDH and antioxidant enzymes. Moreover, exogenous H2O2 was effective in restoring the activity of G6PDH and antioxidant enzymes after glucosamine pretreatment. Western blot analysis
showed that G6PDH gene expression in both calli was also stimulated by heat and H2O2, and blocked by DPI and glucosamine under heat stress. Taken together, under heat stress G6PDH promoted H2O2 accumulation via NADPH oxidase and the elevated H2O2 was involved in regulating the activity of antioxidant enzymes, which in turn facilitate to maintain the steady-state H2O2 level and protect plants from the oxidative damage. 相似文献
7.
Recent studies from our laboratory have showed that resveratrol, a polyphenol found predominantly in grapes rendered strong cardioprotection in animal models of heart disease. The cardioprotection which was observed was primarily associated with the ability of resveratrol to reduce oxidative stress in these models. The aim of the current study was to corroborate the role of resveratrol as an inhibitor of oxidative stress and explore the underlying mechanisms of its action in heart disease. For this purpose, we used a cell model of oxidative stress, the hydrogen peroxide (H2O2) exposed adult rat cardiomyocytes, which was treated with and without resveratrol (30 μM); cardiomyocytes which were not exposed to resveratrol served as controls. Cell injury, cell death and oxidative stress measurements as well as the activities of the major endogenous antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were carried out in control and H2O2 exposed cardiomyocytes, treated with and without resveratrol. Pharmacological blockade using specific blockers of the antioxidant enzymes were used to confirm their role in mediating resveratrol action in H2O2 exposed cardiomyocytes. The status of H2O2 and antioxidant enzymes in serum samples from spontaneously hypertensive rats (SHR) treated with and without resveratrol (2.5 mg/kg body weight) was also examined.Our results showed significant cell injury and death in H2O2 exposed cardiomyocytes which was prevented upon resveratrol treatment. SOD and CAT activities were decreased in H2O2 exposed adult rat cardiomyocytes; treatment with resveratrol significantly prevented this reduction. However, GPx activity was not altered in the H2O2 exposed cardiomyocytes in comparison to controls. Pharmacological blockade of SOD and/or CAT prevented the beneficial effect of resveratrol. In SHR, H2O2 levels were increased, but CAT activity was decreased, while SOD remained unchanged, when compared to WKY rats; resveratrol treatment significantly prevented the increase in H2O2 levels and the decrease in CAT activities in SHR.Based on our results, we conclude that treatment with resveratrol prevents oxidative stress induced cardiomyocyte injury mainly by preserving the activities of critical antioxidant enzymes. This may be a crucial mechanism by which resveratrol confers cardioprotection. 相似文献
8.
Cadmium causes oxidative stress in mung bean by affecting the antioxidant enzyme system and ascorbate-glutathione cycle metabolism 总被引:2,自引:0,他引:2
Ascorbate (AsA)-glutathione (GSH) cycle metabolism is an essential mechanism for the resistance of plants under stress conditions.
In a greenhouse pot experiment, the influence of cadmium (Cd) (25, 50, and 100 mg/kg soil) on plant dry weight and leaf area,
photosynthetic parameters (net photosynthetic rate (PN) and chlorophyll (Chl) content) and oxidative stress, and the possible protective role of AsA-GSH cycle metabolism was studied
in two mung bean (Vigna radiata (L.) Wilczek.) cvs. Pusa 9531 (Cd-tolerant) and PS 16 (Cd-susceptible) at 30 days after sowing. The contents of thiobarbituric
acid-reactive substances (TBARS), H2O2, and the leakage of ions were the highest at 100 mg Cd/kg soil, and the effect was more pronounced in cv. PS 16 than in cv.
Pusa 9531. This was concomitant with the strongest decreases in PN, plant dry weight, and leaf area. The changes in the AsA-GSH redox state and an increase in AsA-GSH-regenerating enzymes,
such as glutathione reductase, monodehydroascorbate reductase, dehydroascorbate reductase, and other antioxidant enzymes,
such as superoxide dismutase and ascorbate peroxidase, strongly supported over-utilization of AsA-GSH in Cd-treated plants.
However, the oxidative stress caused by Cd toxicity was partially overcome by AsA-GSH-based detoxification mechanism in the
two genotypes studied because an increases in lipid peroxidation (TBARS, ion leakage) and H2O2 content were accompanied by a corresponding decrease in reduced AsA and GSH pools. Thus, changes in AsA-GSH pools and the
coordination between AsA-GSH-regenerating enzymes and other enzymatic antioxidants of the leaves suggest their relevance to
the defense against Cd stress. 相似文献
9.
Harminder P. Singh Shalinder Kaur Daizy R. Batish Ved P. Sharma Nidhi Sharma Ravinder K. Kohli 《Nitric oxide》2009,20(4):289-297
Nitric oxide (NO) is a bioactive gaseous, multifunctional molecule playing a central role and mediating a variety of physiological processes and responses to biotic and abiotic stresses including heavy metals. The present study investigated whether NO applied exogenously as sodium nitroprusside (SNP) has any protective role against arsenic (As) toxicity in Oryza sativa (rice). Treatment with 50 μM SNP (a NO donor) significantly ameliorated the As-induced (25 or 50 μM) decrease in root and coleoptile length of rice. Further, As-induced oxidative stress measured in terms of malondialdehyde (MDA), superoxide ion (), root oxidizability and H2O2 content was lesser upon supplementation of NO. It indicated a reactive oxygen species (ROS) scavenging activity of NO. NO addition reversed (only partially) the As-induced increase in activities of antioxidant enzymes – superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, and catalase. The study concludes that exogenous NO provides resistance to rice against As-toxicity and has an ameliorating effect against As-induced stress. 相似文献
10.
Raj K. Sairam Kumutha Dharmar S. Lekshmy Viswanathan Chinnusamy 《Acta Physiologiae Plantarum》2011,33(3):735-744
This study was conducted to examine the extent of oxidative stress and the role of antioxidant enzymes on hypoxia tolerance
in highly tolerant wild species Vigna luteola, and mung bean (Vigna radiata) cvs. T 44 (tolerant) and Pusa Baisakhi (susceptible). Two days of water-logging caused about 40–50% decline in superoxide
radical (O2
·−) and hydrogen peroxide (H2O2) contents in all the genotypes, however, further water-logging to 8 days caused significant increase in O2
·− and H2O2 contents, and the values were 80–90% of the control values. In control and revived plants O2
·− and H2O2 contents were higher in Pusa Baisakhi, while under water-logging stress T 44 and V. luteola showed greater increases in the O2
·− and H2O2 contents. Hypoxia induced increase in superoxide dismutase, ascorbate peroxidase, and glutathione reductase activities were
higher in T 44 and V. luteola compared with Pusa Baisakhi; and the increases in T 44 and V. luteola continued up to 8th day of water-logging, while in case of Pusa Baisakhi, the maximum increase was observed only on the 2nd
day of water-logging. Gene expression studies showed enhanced expression of cytosolic-Cu/Zn-superoxide dismutase (SOD) and cytosolic-ascorbate peroxidase (APX) in the roots of waterlogged V. luteola and T 44, while little expression was observed in control or treated plants of Pusa Baisakhi. PCR band products were cloned and
sequenced, and partial cDNAs of Cu/Zn-SOD and APX, respectively, were obtained. Results suggest that increase in the activity of antioxidant enzymes is to scavenge reactive
oxygen species produced both during and after relief from water-logging stress. 相似文献
11.
《Journal of Plant Interactions》2013,8(2):131-136
Abstract In a hydroponic system, experiments were conducted to study the effect of different levels of mercury treatments (0, 5, 10, 25 and 50 µM Hg) on Indian mustard (Brassica juncea L. Czern & Coss.) cv. Pusa Jai Kisan. Concentration-dependent inhibitory effects were observed on growth characteristics (plant dry mass, leaf area, shoot and root length). These were accompanied by an increase in shoot Hg content and in oxidative stress characteristics such as the MDA and H2O2 levels. The plant growth decreased maximally at 50 µM of Hg. Despite a reduction in growth, activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) were enhanced with increase in Hg-treatments. The Hg-induced alterations in growth are linked with increase in lipid peroxidation (MDA and H2O2), whereas the enhancement in activities of antioxidant enzymes protects plants from Hg-induced oxidative stress. 相似文献
12.
Zinc (Zn) is a necessary element for plants, but excess Zn can be detrimental. The effect of Zn and high irradiance (HI) stress on the growth, lipid peroxidation (MDA), membrane permeability (EC), hydrogen peroxide (H2O2) accumulation, non-enzymatic antioxidants like proline accumulation and ascorbic acid (AsA) and the activities of major antioxidant enzymes (superoxide dismutase, SOD; peroxidase, POX; polyphenol oxidase, PPO) of bean leaves were investigated under controlled growth conditions. The root length was not reduced at excess Zn level. Application of Zn significantly increased Zn concentration in the leaves of bean plants. Under Zn and HI stress, the Zn-deficient and Zn-excess conditions significantly increased the EC, MDA and H2O2 content of excised leaves of bean. The SOD activity was found to be increased significantly in both Zn-deficiency and Zn-excess leaves under Zn and HI stress. Under both Zn and HI stress conditions, the antioxidant enzyme activities; POX, PPO and the non-enzymatic antioxidants, AsA and proline accumulation were found to be significantly increased in the Zn-excess leaves which showed that the bean plant had the ability to tolerate the excess level of Zn and HI stress. A significant increase in MDA, H2O2, and EC with a simultaneous decrease in the antioxidant enzyme activities under Zn-deficiency compared to Zn-sufficient condition shows the inefficiency of the bean plant in response to Zn deficiency. To the best of our knowledge, this is the first report on the effect of Zn stress combined with HI stress in bean plant. 相似文献
13.
Cadmium-induced oxidative stress symptoms such as lipid peroxidation and H2O2 production were examined in the marine alga Nannochloropsis oculata. Changes in antioxidant enzyme levels and isozyme patterns were also examined. Increasing concentrations of Cd produced growth inhibition. Among the responses to added Cd, the H2O2 content and malonyldialdehyde accumulation increased significantly, indicating a state of oxidative stress. In the case of ascorbate peroxidase activity the increase was about 2.5 times and a marked induction of the isozyme APX2 contributed to this increase. Guaiacol peroxidase activity increased about 4-fold, this being due mainly to the isozyme GPX3. Catalase activity increased slightly, whereas superoxide dismutase and glutathione reductase activity decreased markedly. Alterations of antioxidant enzyme levels and isozyme pattern changes in Cd-treated alga suggest that they might be involved in the heavy metal tolerance in this alga. 相似文献
14.
Marshall Keyster Ashwil Klein Ifeanyi Egbichi Alex Jacobs Ndiko Ludidi 《Plant signaling & behavior》2011,6(7):956-961
Ascorbate peroxidase is one of the major enzymes regulating the levels of H2O2 in plants and plays a crucial role in maintaining root nodule redox status. We used fully developed and mature nitrogen fixing root nodules from soybean plants to analyze the effect of exogenously applied nitric oxide, generated from the nitric oxide donor 2,2′-(hydroxynitrosohydrazono)bis-ethanimine, on the enzymatic activity of soybean root nodule ascorbate peroxidase. Nitric oxide caused an increase in the total enzymatic activity of ascorbate peroxidase. The nitric oxide-induced changes in ascorbate peroxidase enzymatic activity were coupled to altered nodule H2O2 content. Further analysis of ascorbate peroxidase enzymatic activity identified three ascorbate peroxidase isoforms for which augmented enzymatic activity occurred in response to nitric oxide. Our results demonstrate that nitric oxide regulates soybean root nodule ascorbate peroxidase activity. We propose a role of nitric oxide in regulating ascorbate-dependent redox status in soybean root nodule tissue.Key words: antioxidant enzymes, ascorbate peroxidase, nitric oxide, oxidative stress, reactive oxygen species, redox homeostasis, soybean root nodules 相似文献
15.
Low temperatures and high light cause imbalances in primary and secondary reactions of photosynthesis, and thus can result in oxidative stress. Plants employ a range of low‐molecular weight antioxidants and antioxidant enzymes to prevent oxidative damage, and antioxidant defence is considered an important component of stress tolerance. To figure out whether oxidative stress and antioxidant defence are key factors defining the different cold acclimation capacities of natural accessions of the model plant Arabidopsis thaliana, we investigated hydrogen peroxide (H2O2) production, antioxidant enzyme activity and lipid peroxidation during a time course of cold treatment and exposure to high light in four differentially cold‐tolerant natural accessions of Arabidopsis (C24, Nd, Rsch, Te) that span the European distribution range of the species. All accessions except Rsch (from Russia) had elevated H2O2 in the cold, indicating that production of reactive oxygen species is part of the cold response in Arabidopsis. Glutathione reductase activity increased in all but Rsch, while ascorbate peroxidase and superoxide dismutase were unchanged and catalase decreased in all but Rsch. Under high light, the Scandinavian accession Te had elevated levels of H2O2. Te appeared most sensitive to oxidative stress, having higher malondialdehyde (MDA) levels in the cold and under high light, while only high light caused elevated MDA in the other accessions. Although the most freezing‐tolerant, Te had the highest sensitivity to oxidative stress. No correlation was found between freezing tolerance and activity of antioxidant enzymes in the four accessions investigated, arguing against a key role for antioxidant defence in the differential cold acclimation capacities of Arabidopsis accessions. 相似文献
16.
17.
S Ben Khedir D Moalla N Jardak M Mzid Z Sahnoun T Rebai 《Biotechnic & histochemistry》2016,91(7):480-491
We investigated the efficacy of Pistacia lentiscus fruit oil (PLFO) for protecting human skin from damage due to oxidative stress. PLFO contains natural antioxidants including polyphenols, sterols and tocopherols. We compared the antioxidant potential of PLFO with extra virgin olive oil (EVOO). Explants of healthy adult human skin were grown in culture with either PLFO or EVOO before adding hydrogen peroxide (H2O2). We also used cultured skin explants to investigate the effects of PLFO on lipid oxidation and depletion of endogenous antioxidant defense enzymes including glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) one day after 2 h exposure to H2O2. We found that PLFO scavenged radicals and protected skin against oxidative injury. PLFO exhibited greater antioxidant and free radical scavenging activity than EVOO. Skin explants treated with PLFO inhibited H2O2 induced MDA formation by inhibition of lipid oxidation. In addition, the oil inhibited H2O2 induced depletion of antioxidant defense enzymes including GPx, SOD and CAT. We found that treatment with PLFO repaired skin damage owing to its antioxidant properties. 相似文献
18.
In this study, we examined the modulation of Cu toxicity-induced oxidative stress by excess supply of iron in Zea mays L. plants. Plants receiving excess of Cu (100 μM) showed decreased water potential and simultaneously showed wilting in the
leaves. Later, the young leaves exhibited chlorosis and necrotic scorching of lamina. Excess of Cu suppressed growth, decreased
concentration of chloroplastic pigments and fresh and dry weight of plants. The activities of peroxidase (EC 1.11.1.7; POD),
ascorbate peroxidase (EC 1.11.1.11; APX) and superoxide dismutase (EC 1.15.1.1; SOD) were increased in plants supplied excess
of Cu. However, activity of catalase (EC 1.11.1.6; CAT), was depressed in these plants. In gel activities of isoforms of POD,
APX and SOD also revealed upregulation of these enzymes. Excess (500 μM)-Fe-supplemented Cu-stressed plants, however, looked
better in their phenotypic appearance, had increased concentration of chloroplastic pigments, dry weight, and improved leaf
tissue water status in comparison to the plants supplied excess of Cu. Moreover, activities of antioxidant enzymes including
CAT were further enhanced and thiobarbituric acid reactive substance (TBARS) and H2O2 concentrations decreased in excess-Fe-supplemented Cu-stressed plants. In situ accumulation of H2O2, contrary to that of O2
·− radical, increased in both leaf and roots of excess-Cu-stressed plants, but Cu-excess plants supplied with excess-Fe showed
reduced accumulation H2O2 and little higher of O2
·− in comparison to excess-Cu plants. It is, therefore, concluded that excess-Cu (100 μM) induces oxidative stress by increasing
production of H2O2 despite of increased antioxidant protection and that the excess-Cu-induced oxidative damage is minimized by excess supply
of Fe. 相似文献
19.
In the present investigation, we studied the possible potentiating effect of salicylic acid (SA) under Cd toxicity in Oryza sativa L. leaves. Cd treatments for 24 h reduced the shoot length, dry biomass and total chlorophyll content followed by high Cd
accumulation in shoots. About 16 h presoaking with SA resulted in partial protection against Cd, as observed by minor changes
in length, biomass and total chlorophyll. SA priming resulted in low Cd accumulation. Enhanced thiobarbituric acid reactive
substances (TBARS), hydrogen peroxide (H2O2) and superoxide anion (O2
−) content were seen when Cd was applied alone, while under SA priming the extent of TBARS, H2O2 and O2
− were significantly low, suggesting SA-regulated protection against oxidative stress. The antioxidant enzymes like Catalase
(CAT), guaiacol peroxidase (GPx), glutathione reductase (GR) and superoxide dismutase (SOD) showed varied activities under
Cd alone. CAT activity increased after Cd treatment, followed by a decline in GPX and GR activity. SOD also declined at the
highest concentrations with an initial increase. Under SA-priming conditions, the efficiency of the antioxidant enzymes was
significantly elevated. GPx and SOD activity showed significant increase in activity. The ascorbate activity increased after
Cd treatment, followed by a decline in glutathione under SA-free condition. SA priming showed gradual increase in these non-enzymic
antioxidants. Our results indicate that Cd-induced oxidative stress can be regulated by SA. 相似文献