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1.
The present investigation was carried out to decipher the interplay between paraquat (PQ) and exogenously applied nitric oxide (NO) in Azolla microphylla. The addition of PQ (8 ??M) increased the activities of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) by 1.7, 2.7, 3.9 and 1.9 folds respectively than that control in the fronds of Azolla. The amount of H2O2 was also enhanced by 2.7 times in the PQ treated plants than that of control. The supplementation of sodium nitroprusside (SNP) from 8?C100 ??M along with PQ, suppressed the activities of antioxidative enzymes and the amount of H2O2 compared to PQ alone. The drop in the activity of antioxidative enzymes ?? SOD, GPX, CAT and APX was highest (39.9%, 48.4%, 41.6% and 41.3% respectively) on the supplementation of 100 ??M SNP with PQ treated fronds compared to PQ alone. The addition of NO scavengers along with NO donor in PQ treated fronds neutralized the effect of exogenously supplied NO. This indicates that NO can effectively protect Azolla against PQ toxicity by quenching reactive oxygen species. However, 200 ??M of SNP reversed the protective effect of lower concentration of NO donor against herbicide toxicity. Our study clearly suggests that (i) SNP released NO can work both as cytoprotective and cytotoxic in concentration dependent manner and (ii) involvement of NO in protecting Azolla against PQ toxicity. 相似文献
2.
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
3.
F. J. Xu G. Li C. W. Jin W. J. Liu S. S. Zhang Y. S. Zhang X. Y. Lin 《Biologia Plantarum》2012,56(1):89-96
The present study investigated the effects of aluminum on lipid peroxidation, accumulation of reactive oxygen species and
antioxidative defense systems in root tips of wheat (Triticum aestivum L.) seedlings. Exposure to 30 μM Al increased contents of malondialdehyde, H2O2, suproxide radical and Evans blue uptake in both genotypes, with increases being greater in Al-sensitive genotype Yangmai-5
than in Al-tolerant genotype Jian-864. In addition, Al treatment increased the activity of superoxide dismutase (SOD), peroxidase
(POD), catalase (CAT), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), glutathione reductase (GR) and
glutathione peroxidase (GPX), as well as the contents of ascorbate (AsA) and glutathione (GSH) in both genotypes. The increased
activities SOD and POD were greater in Yangmai-5 than in Jian-864, whereas the opposite was true for the activities of CAT,
APX, MDHAR, GR and GPX and the contents of AsA and GSH. Consequently, the antioxidant capacity in terms of 2,2-diphenyl-1-picrylhydrazyl
(DPPH)-radical scavenging activity and ferric reducing/antioxidant power (FRAP) was greater in Jian-864 than in Yangmai-5. 相似文献
4.
Valentina Iori Fabrizio Pietrini Angelo Massacci Massimo Zacchini 《Plant Cell, Tissue and Organ Culture》2012,108(1):17-26
Callus cultures of two parental clones of Populus nigra L., Poli and 58-861, originating from contrasting environments, were exposed to different cadmium concentrations (0, 150
and 250 μM CdSO4). Clones showed different growth responses to cadmium, evaluated by the tolerance index (Ti), with Poli being more tolerant
to the metal at both concentrations. The cadmium concentration at the end of the treatment was very similar between clones
at 150 μM CdSO4, while a higher value in 58-861 compared to Poli was detected at 250 μM CdSO4. The bioconcentration factor evidenced the lowest value in Poli at 250 μM CdSO4. Unlike 58-861, cadmium provoked a strong induction of thiols and phytochelatins in clone Poli. In both clones, organic acid
concentration differed notably in untreated calli and cadmium treatment induced a general lowering of these compounds. A notably
higher antioxidant enzyme activity (ascorbate peroxidase, APX; catalase, CAT; guaiacol peroxidase, GPX) was measured in control
calli of clone Poli compared to 58-861. Cadmium induced a remarkable enhancement of APX and CAT, but not GPX, activity at
150 μM CdSO4 in Poli. Conversely, in 58-861 at 150 μM CdSO4, and in both clones at 250 μM CdSO4, a decrease in the antioxidant activity occurred. This investigation provided evidence that these two contrasting genotypes
of P. nigra are characterised by a different response to cadmium in callus cultures. In particular, in Poli, the higher tolerance to
cadmium is associated with a higher activity of antioxidative enzymes and the ability to strongly increase thiol and PC concentration
in response to metal exposure. 相似文献
5.
Chokri Hafsi María C. Romero-Puertas Luis A. del Río Chedly Abdelly Luisa M. Sandalio 《Acta Physiologiae Plantarum》2011,33(1):193-202
The objective of the present study was to determine the influence of potassium deprivation on the halophyte species Hordeum maritimum grown in hydroponics for 2 weeks. Treatments were with potassium (+K) or without potassium (−K). Growth, water status, mineral
nutrition, parameters of oxidative stress [malondialdehyde (MDA), carbonyl groups (C=O), and hydrogen peroxide concentration
(H2O2) contents], antioxidant enzyme activities [superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), guaiacol
peroxidase (GPX, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11), monodehydroascorbate peroxidase (MDHAR, EC 1.6.5.4),
dehydroascorbate peroxidase (DHAR, EC 1.8.5.1), and glutathione reductase (GR, EC 1.6.4.2)], and antioxidant molecules [ascorbate
(ASC), and glutathione (GSH)] were determined. Results showed that the growth of vegetative organs decreased owing to potassium
deficiency with roots (−36%) more affected than shoots (−12%). Water status was only diminished in roots (reduction of 24%).
Potassium deprivation decreased potassium concentration in both organs, this decrease was more pronounced in roots (−81%)
than in shoots (−55%). In contrast to carbonyl groups, MDA content increased owing to potassium deprivation. Except for CAT
activity that remained unaffected; SOD, GPX, APX, GR, MDHAR, and DHAR activities were significantly increased. H2O2 concentration was negatively correlated with the activities of enzymes and the accumulation of non-enzymatic antioxidants
implicated in its detoxification. In conclusion, a cooperative process between the antioxidant systems is important for the
tolerance of H. maritimum to potassium deficiency. 相似文献
6.
Issam Nouairi Wided Ben Ammar Nabil Ben Youssef Douja Daoud Ben Miled Mohamed Habib Ghorbal Mokhtar Zarrouk 《Acta Physiologiae Plantarum》2009,31(2):237-247
Plant species capable of hyper-accumulating heavy metals are of considerable interest for phytoremediation, and differ in
their ability to accumulate metals from environment. Using two brassica species (Brassica juncea and Brassica napus), nutrient solution experiments were conducted to study variation in tolerance to cadmium (Cd) toxicity based on (1) lipid
peroxidation and (2) changes in antioxidative defense system in leaves of both plants (i.e., superoxide dismutase (SOD EC
1.15.1.1), catalase (CAT EC 1.11.1.6), ascorbate peroxidase (APX EC 1.11.1.11), guaiacol peroxidase (GPX EC 1.11.1.7), glutathione
reductase (GR EC 1.6.4.2), levels of phytochelatins (PCs), non-protein thiols (NP-SH), and glutathione. Plants were grown
in nutrient solution under controlled environmental conditions, and subjected to increasing concentrations of Cd (0, 10, 25
and 50 μM) for 15 days. Results showed marked differences between both species. Brassica napus under Cd stress exhibited increased level of lipid peroxidation, as was evidenced by the increased malondialdehyde (MDA)
content in leaves. However, in Brassica
juncea treated plants, MDA content remained unchanged. In Brassica napus, with the exception of GPX, activity levels of some antioxidant enzymes involved in detoxification of reactive oxygen species
(ROS), including SOD, CAT, GR, and APX, decreased drastically at high Cd concentrations. By contrast, in leaves of Brassica juncea treated plants, there was either only slight or no change in the activities of the antioxidative enzymes. Analysis of the
profile of anionic isoenzymes of GPX revealed qualitative changes occurring during Cd exposure for both species. Moreover,
levels of NP-SH and PCs, monitored as metal detoxifying responses, were much increased in leaves of Brassica juncea by increasing Cd supply, but did not change in Brassica napus. These results indicate that Brassica juncea plants possess the greater potential for Cd accumulation and tolerance than Brassica napus. 相似文献
7.
Pretreatment of radish cotyledons with polyamines (PAs; especially 1 mM spermidine) significantly improved their tolerance
to subsequent 50 μM paraquat (PQ)-induced oxidative damage. Symptoms in the cotyledons, e.g., large accumulations of H2O2, and losses of fresh weight, chlorophyll, and proteins, were remarkably alleviated. Likewise, analysis of several enzymes
belonging to the Superoxide dismutase (SOD)/ascorbate-glutathione cycle showed that pretreatment with PAs prevented typical
PQ-induced declines in the total activities of SOD, ascorbate peroxidase (APX), and glutathione reductase (GR). Dehydroascorbate
reductase (DHAR) activity, which normally decreases sharply under prolonged PQ exposure, was also highly maintained by PA
treatment. In a native gel assay, two SOD isozymes (FeSOD and Cu/ZnSODI), two APX isozymes (APX1 and APX2), and two GSSG-specific
isozymes (GR1 and GR2) proved to be more responsible for PQ tolerance, as manifested by the strong increases in their activities
by spermidine (Spd) pretreatment. In addition, experiments with protein synthesis inhibitors (actinomycin D and cycloheximide)
indicated that Spd could stimulatede novo synthesis of SOD and APX at the translational level. We can conclude that PAs may function as antioxidant protectors by invoking
an efficient SOD/ascorbate-glutathione cycle in radish cotyledons exposed to PQ. 相似文献
8.
The effect of short-term exposure to elevated CO2 concentration and high irradiance on the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidases
(GPX) and catalase (CAT), and on the extent of the lipid peroxidation was studied in bean (Phaseolus vulgaris L.) plants. Plants were exposed for 4 d (8 h a day) to irradiance of 100 (LI) or 1000 (HI) μmol m−2 s−1 at ambient (CA, 350 μmol mol−1) or elevated (CE, 1300 μmol mol−1) CO2 concentration. Four-day exposure to CE increased the leaf dry mass in HI plants and RuBPC activity and chlorophyll content
in LI plants. Total soluble protein content, leaf dry matter and RuBPC activity were higher in HI than in LI plants, although
the HI and CE increased the contents of malonyldialdehyde and H2O2. Under CA, exposure to HI increased the activity of APX and decreased the total SOD activity. Under CE, HI treatment also
activated APX and led to reduction of both, SOD and GPX, enzymes activities. CE considerably reduced the CAT activity at both
irradiances, possibly due to suppressed rate of photorespiration under CE conditions. 相似文献
9.
Copper-induced changes in the growth, oxidative metabolism, and saponin production in suspension culture roots of Panax ginseng in bioreactors 总被引:3,自引:0,他引:3
Roots of Panax ginseng exposed to various concentrations of Cu (0.0, 5, 10.0, 25.0, and 50.0 μM) accumulated high amounts of Cu in a concentration-dependent and duration-dependent manner. Roots treated with 50 μM Cu resulted in 52% and 89% growth inhibition after 20 and 40 days, respectively. Saponin synthesis was stimulated at a Cu concentration between 5 and 25 μM but decreased at 50 μM Cu. Malondialdehyde content (MDA), lipoxygenase activity (LOX), superoxide ion (O2
•−) accumulation, and H2O2 content at 5 and 10 μM Cu-treated roots were not increased but strongly increased at 50 μM Cu resulting in the oxidation of ascorbate (ASC) and glutathione (GSH) to dehydroascorbate (DHA) and glutathione disulfide (GSSG), respectively indicating a clear oxidative stress. Seven well-resolved bands of superoxide dismutase (SOD) were detected in the gel and an increase in SOD activity seemed to be mainly due to the induction of Fe-SOD 3. Five to 10 μM Cu slightly induced activity of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR), guaiacol peroxidase (G-POD) but inhibited monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR) enzyme activities. No changes in catalase (CAT) activity and in activity gel were found up to 25 μM Cu, but both G-POD and CAT activities were inhibited at 50 μM Cu. Glutathione metabolism enzymes such as γ-glutamylcysteine synthetase (γ-GCS), glutathione-S-transferase (GST), and glutathione peroxidase activities (GPx) were activated at 5 and 10 μM Cu but were strongly inhibited at 50 μM Cu due to the Cu accumulation in root tissues. The strong depletion of GSH at 50 μM Cu was associated to the strong induction of γ-glutamyltranspeptidase (γ-GGT) activity. These results indicate that plant could grow under Cu stress (5–25 μM) by modulating the antioxidant defense mechanism for combating Cu induced oxidative stress. 相似文献
10.
Effects of the antioxidant system and chlorophyll fluorescence on drought tolerance of four common bean (Phaseolus vulgaris L.) cultivars were studied. The cultivars were positioned in the order of a decrease in their drought tolerance: Yakutiye,
Pinto Villa, Ozayse, and Zulbiye on the basis of changes in the water potential, stomatal conductance, photosynthetic pigment
content, and lipid peroxidation. Under drought conditions, the level of H2O2 was not changed in cv. Pinto Villa but decreased in other cultivars. Antioxidant enzymes (superothide dismutase (SOD), guaiacol
peroxidase (GPX), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR)) were generally activated in
all cultivars. Interestingly, CAT, APX, and GR activities were not changed in cv. Pinto Villa, APX activity decreased in cv.
Yakutiye, and CAT activity was not changed in cv. Zulbiye. The increases in SOD and GPX activities in cv. Ozayse were higher
than in other cultivars. Drought stress reduced the effective quantum yield of PS2 (ΦPS2) and the photochemical quenching (qp), while it increased nonphotochemical quenching (NPQ) in all cultivars. The reduction or increase was more pronounced in
cv. Zulbiye. There were generally significant correlations between qp, NPQ, and ROS scavenging by SOD and APX. Also, there were significant correlations between SOD and qp in tolerant cultivars and APX and qp in sensitive ones. The results indicate that activation of SOD and APX was closely related to the efficiency of PS2 in common
bean cultivars. This interaction was essential for protection of photosystems and plant survival under drought. 相似文献
11.
Alieu Mohamed Bah Huaxin Dai Jing Zhao Hongyan Sun Fangbin Cao Guoping Zhang Feibo Wu 《Biological trace element research》2011,142(1):77-92
This study investigates the modulation of antioxidant defence system of Typha angustifolia after 30 days exposure of 1 mM chromium (Cr), cadmium (Cd), or lead (Pb). T. angustifolia showed high tolerance to heavy metal toxicity with no visual toxic symptom when exposed to metal stress, and Cd/Pb addition
also increased plant height and biomass especially in Pb treatment. Along with increased Cr, Cd, and Pb uptake in metal treatments,
there was enhanced uptake of plant nutrients including Ca and Fe, and Zn in Pb treatment. A significant increase in malondialdehyde
(MDA) content and superoxide dismutase (SOD) and peroxidase (POD) activities were recorded in plants subjected to Cr, Cd,
or Pb stress. Furthermore, Pb stress also improved catalase (CAT), ascorbate peroxidase (APX), and glutathione peroxidase
(GPX) activities; whereas Cr stress depressed APX and GPX. The results indicate that enzymatic antioxidants and Ca/Fe uptake
were important for heavy metal detoxification in T. angustifolia, stimulated antioxidative enzymes, and Ca, Fe, and Zn uptake could partially explain its hyper-Pb tolerance. 相似文献
12.
Thermotolerance and related antioxidant enzyme activities induced by both heat acclimation and exogenous salicylic acid (SA)
application were studied in grapevine (Vitis vinifera L. cv. Jingxiu). Heat acclimation and exogenous SA application induced comparable changes in thermotolerance, ascorbic acid
(AsA), glutathione (GSH), and hydrogen peroxide (H2O2) concentrations, and in activities of the antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), glutathione reductase
(GR), ascorbic peroxidase (APX) and catalase (CAT) in grape leaves. Within 1 h at 38 °C, free SA concentration in leaves rose
from 3.1 μg g−1 FW to 19.1 μg g−1 FW, then sharply declined. SA application and heat acclimation induced thermotolerance were related to changes of antioxidant
enzyme activities and antioxidant concentration, indicating a role for endogenous SA in heat acclimation in grape leaves. 相似文献
13.
Savita Gangwar Vijay Pratap Singh Prabhat Kumar Srivastava Jagat Narayan Maurya 《Acta Physiologiae Plantarum》2011,33(4):1385-1397
Effects of exogenous gibberellic acid (GA; 10 and 100 μM) application on growth, protein and nitrogen contents, ammonium (NH4
+) content, enzymes of nitrogen assimilation and antioxidant system in pea seedlings were investigated under chromium (VI)
phytotoxicity (Cr VI; 50, 100 and 250 μM). Exposure of pea seedlings to Cr and 100 μM GA resulted in decreased seed germination,
fresh and dry weight and length of root and shoot, and protein and nitrogen contents compared to control. Compared to control,
Cr and 100 μM GA led to the significant alteration in nitrogen assimilation in pea. These treatments decreased root and shoot
nitrate reductase (NR), glutamine synthetase (GS) and glutamine 2-oxoglutarate aminotransferase (GOGAT) activities (except
50 μM Cr alone for GOGAT) while glutamate dehydrogenase (GDH) activity and NH4
+ content increased. Compared to control, the root and shoot activities of superoxide dismutase (SOD) and ascorbate peroxidase
(APX) increased (except APX activity at 250 μM Cr + 100 μM GA) while catalase (CAT), glutathione reductase (GR) and dehydroascorbate
reductase (DHAR) activities were decreased (except GR at 100 μM GA alone) following exposure of Cr and 100 μM GA. Total ascorbate
and total glutathione in root and shoot decreased by the treatments of Cr and 100 μM GA while their levels were increased
by the application of 10 μM GA compared to Cr treatments alone. It has been reported that application of 10 μM GA together
with Cr alleviated inhibited levels of growth, nitrogen assimilation and antioxidant system compared to Cr treatments alone.
This study showed that application of 10 μM GA counteracts some of the adverse effects of Cr phytotoxicity with the increased
levels of antioxidants and sustained activities of enzymes of nitrogen assimilation; however, 100 μM GA showed apparently
reverse effect under Cr phytotoxicity. 相似文献
14.
Harinderjeet Kaur Anil Kumar Gupta Narinder Kaur Jeet Singh Sandhu 《Plant Growth Regulation》2009,57(2):109-114
Two chickpea cultivars PBG-1 and PDG-3 along with a wild species Cicer judaicum were investigated to compare the activities of their antioxidant enzymes in mature seeds and roots, as well as shoots and
cotyledons of seedlings germinated under dark and continuous illumination of 40 μmol m−2 s−1 photosynthetically active radiation (PAR). Seedling biomass of C. judaicum was lower as compared to cultivars of PBG-1 and PDG-3 both under dark and light conditions. Light reduced the biomass of
seedlings. Activities of glutathione reductase (GR) and ascorbate peroxidase (APX) were higher in shoots and roots of C. judaicum compared to the cultivars PBG-1 and PDG-3. In mature seeds, the activities of GR and APX were higher in the cultivated genotypes
whereas catalase (CAT) and peroxidase were higher in C. judaicum. Under illumination, a general upregulation of CAT in both shoots and cotyledons and of GR in shoots was observed in all
the three genotypes. However, superoxide dismutase (SOD) increased in C. judaicum and APX in PBG-1 and PDG-3. The differences in antioxidant enzyme system between wild and cultivated genotypes possibly contribute
to better tolerance of wild Cicer species against abiotic and biotic stresses. 相似文献
15.
Eicosapentaenoic acid (EPA) is one of the major dietary polyunsaturated fatty acids and induces apoptosis in several cancer
cells. In this study, the EPA induced lipid peroxidation and response of antioxidative enzymes have been investigated in rat
pheochromocytoma PC12 cells to elucidate the mechanisms of apoptosis induced by the polyunsaturated fatty acid EPA. We have
analyzed superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities and glutathione (GSH) contents
in PC12 cells after exposure to different concentrations of EPA. Lipid peroxidation was shown to increase in the presence
of EPA as an indication of the oxidative damage. Lipid peroxidation was enhanced by EPA in a dose-dependent manner, and the
loss of cell viability was partially reversed by vitamin E. In the case of antioxidant enzyme activities, SOD and GPX activities
and GSH contents increased significantly at 50 μmol/L EPA and were respectively 2.41-fold (p < 0.01), 3.49-fold (p < 0.05), and 1.43-fold (p < 0.05) higher than controls. The CAT activity at 10 μmol/L had the highest value and was increased by 25.83% (p < 0.05) compared to control. The results suggest that in PC12 cells the mechanism of apoptosis induced by EPA may be partly
due to lipid peroxidation. 相似文献
16.
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
17.
Involvement of oxidative stress and role of antioxidative defense system in growing rice seedlings exposed to toxic concentrations of aluminum 总被引:6,自引:0,他引:6
When seedlings of rice (Oryza sativa L.) cultivar Pant-12 were raised in sand cultures containing 80 and 160 μM Al3+ in the medium for 5–20 days, a regular increase in Al3+ uptake with a concomitant decrease in the length of roots as well as shoots was observed. Al3+ treatment of 160 μM resulted in increased generation of superoxide anion (O2
−) and hydrogen peroxide (H2O2), elevated amount of malondialdehyde, soluble protein and oxidized glutathione and decline in the concentrations of thiols
(-SH) and ascorbic acid. Among antioxidative enzymes, activities of superoxide dismutase (SOD EC 1.15.1.1), guaiacol peroxidase
(Guaiacol POX EC 1.11.1.7), ascorbate peroxidase (APX EC 1.11.1.11), monodehydroascorbate reductase (MDHAR EC 1.6.5.4), dehydroascorbate
reductase (EC 1.8.5.1) and glutathione reductase (EC 1.6.4.2) increased significantly, whereas the activities of catalase
(EC EC 1.11.1.6) and chloroplastic APX declined in 160 μM Al3+ stressed seedlings as compared to control seedlings. The results suggest that Al3+ toxicity is associated with induction of oxidative stress in rice plants and among antioxidative enzymes SOD, Guaiacol POX
and cytosolic APX appear to serve as important components of an antioxidative defense mechanism under Al3+ toxicity. PAGE analysis confirmed the increased activity as well as appearance of new isoenzymes of APX in Al3+ stressed seedlings. Immunoblot analysis revealed that changes in the activities of APX are due to changes in the amounts
of enzyme protein. Similar findings were obtained when the experiments were repeated using another popular rice cv. Malviya-36. 相似文献
18.
We studied the physiological responses to abscisic acid (ABA) when 2-year-old potted plants of kiwifruit (Actinidia deliciosa) were grown under moisture stress. Leaves treated with 60 μM exogenous ABA through various means had less severe damage when
water was limiting, and sprayed plants showed relatively greater drought resistance. This indicates that ABA improves tolerance
in kiwifruit, reducing membrane permeability and enhancing the activities of antioxidant enzymes, e.g., peroxidase (POD),
catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR). Exposure to ABA led
to higher levels of antioxidants, such as ABA and glutathione (GSH), while altering the amounts of endogenous hormones—ABA,
indole-3-acetic acid (IAA), and Gibberellin (GA)—and organic oxalate, malate, and citrate in the leaves. Although daily applications
of ABA were more effective than a single spray event, the effect of treatment, i.e., avoiding tissue damage and increasing
plant resistance, was more apparent on Day 4 than on Day 6. No difference in response was apparent between control plants
(regular irrigation) and those sprayed with ABA on Day 4 of the drought period. 相似文献
19.
Vahid Niknam Ali Akbar Meratan Seyed Mahmood Ghaffari 《In vitro cellular & developmental biology. Plant》2011,47(2):297-308
The changes in lipid peroxidation and the involvement of the antioxidant system in relation to salt stress tolerance were
investigated in the callus of Acanthophyllum glandulosum and Acanthophyllum sordidum. The callus was subjected to NaCl stress (50–200 mM) for 40 d. The callus of A. glandulosum was less sensitive to NaCl stress than that of A. sordidum. Increasing concentrations of NaCl from 50 to 200 mM correlated to increased proline content in A. glandulosum. Total protein content was higher in extracts of A. glandulosum than in extracts of A. sordidum under both control and salinity treatments. Compared with A. sordidum, lipid peroxidation and H2O2 content were lower and the activities of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), ascorbate
peroxidase, and glutathione reductase were higher in A. glandulosum under salt stress. Activity staining of antioxidant enzymes separated by native polyacrylamide gel electrophoresis (PAGE)
revealed that callus of A. sordidum had five Fe-SOD isoforms and one Mn-SOD isoform, all of which were reduced by salinity. In A. glandulosum, two Mn-SOD, three Fe-SOD, and one Cu/Zn-SOD isoforms were detected. Out of these six SOD isoforms, expression of the Mn-SOD
and Fe-SOD isoforms was enhanced at 100 mM and higher NaCl concentrations. Two and six GPX isoforms were detected in A. sordidum and A. glandulosum, respectively. Expression of the single CAT isoform in A. sordidum was preferentially reduced by salinity. In A. glandulosum, the two CAT isoforms showed differential down regulation under NaCl stress, with the CAT2 isoform detected only under control
condition. These results suggest that A. glandulosum callus is better protected against salinity-induced oxidative damage by maintaining higher activities of antioxidant enzymes
than the callus of A. sordidum. 相似文献
20.
Seedlings of rice (Oryza sativa L.) cv. Pant-12 grown in sand cultures containing 200 and 400 μM NiSO4, showed a decrease in length and fresh weight of roots and shoots. Nickel was readily taken up by rice seedlings and the
concentration was higher in roots than shoots. Nickel-treated seedlings showed increased rates of superoxide anion (O2
•−
) production, elevated levels of H2O2 and thiobarbituric acid reactive substances (TBARS) demonstrating enhanced lipid peroxidation, and a decline in protein thiol
levels indicative of increased protein oxidation compared to controls. With progressively higher Ni concentrations, non-protein
thiol and ascorbate (AsA) increased, whereas the level of low-molecular-weight thiols (such as glutathione and hydroxyl-methyl
glutathione), the ratio of these thiols to their corresponding disulphides, and the ratio of AsA to dehydroascorbic acid declined
in the seedlings. Among the antioxidant enzymes studied, the activities of all isoforms of superoxide dismutase (Cu-Zn SOD,
Mn SOD and Fe SOD), guaiacol peroxidases (GPX) and ascorbate peroxidase (APX) increased in Ni-treated seedlings, while no
clear alteration in catalase activity was evident. Activity of the ascorbate-glutathione cycle enzymes monodehydroascorbate
reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR)—significantly increased in Ni-treated
seedlings. However such increase was apparently insufficient to maintain the intracellular redox balance. Results suggest
that Ni induces oxidative stress in rice plants, resulting in enhanced lipid peroxidation and decline in protein thiol levels,
and that (hydroxyl-methyl) glutathione and AsA in conjunction with Cu-Zn SOD, GPX and APX are involved in stress response. 相似文献