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1.
The effect of foliar pretreatment by hydrogen peroxide (H2O2) at low concentrations of 0, 5, 10, and 15 mM on the chilling tolerance of two Zoysia cultivars, manilagrass (Zoysia matrella) and mascarenegrass (Zoysia tenuifolia), was studied. The optimal concentration for H2O2 pretreatment was 10 mM, as demonstrated by the lowest malondialdehyde (MDA) content and electrolyte leakage (EL) levels and
higher protein content under chilling stress (7°C/2°C, day/night). Prior to initiation of chilling, exogenous 10 mM H2O2 significantly increased catalase (CAT), ascorbate peroxidase (APX), glutathione-dependent peroxidases (GPX), and glutathione-S-transferase (GST) activities in manilagrass, and guaiacol peroxidase (POD), APX, and glutathione reductase (GR) activities
in mascarenegrass, suggesting that H2O2 may act as a signaling molecule, inducing protective metabolic responses against further oxidative damage due to chilling.
Under further stress, optimal pretreatments alleviated the increase of H2O2 level and the decrease of turfgrass quality, and improved CAT, POD, APX, GR, and GPX activities, with especially significant
enhancement of APX and GPX activities from the initiation to end of chilling. These antioxidative enzymes were likely the
important factors for acquisition of tolerance to chilling stress in the two Zoysia cultivars. Our results showed that pretreatment with H2O2 at appropriate concentration may improve the tolerance of warm-season Zoysia grasses to chilling stress, and that manilagrass had better tolerance to chilling, as evaluated by lower MDA and EL, and
better turfgrass quality, regardless of the pretreatment applied. 相似文献
2.
Two-month-old healthy seedlings of a true mangrove, Bruguiera parviflora, raised from propagules in normal nursery conditions were subjected to varying concentrations of NaCl for 45 d under hydroponic
culture conditions to investigate the defence potentials of antioxidative enzymes against NaCl stress imposed oxidative stress.
Changes in the activities of the antioxidative enzymes catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POX),
glutathione reductase (GR) and superoxide dismutase (SOD) were assayed in leaves to monitor the temporal regulation. Among
the oxidative stress triggered chemicals, the level of H2O2 was significantly increased while total ascorbate and total glutathione content decreased. The ratio of reduced to oxidized
glutathiones, however, increased due to decreased levels of oxidized glutathione in the leaf tissue. Among the five antioxidative
enzymes monitored, the APX, POX, GR and SOD specific activities were significantly enhanced at high concentration (400 mM
NaCl), while the catalase activities declined, suggesting both up and downregulations of antioxidative enzymes occurred due
to NaCl imposed osmotic and ionic stress. Analysis of the stress induced alterations in the isoforms of CAT, APX, POX, GR
and SOD revealed differential regulations of the isoforms of these enzymes. In B. parviflora one isoform of each of Mn-SOD and Cu/Zn-SOD while three isoforms of Fe-SOD were observed by activity staining gel. Of these,
only Mn-SOD and Fe-SOD2 content was preferentially elevated by NaCl treatment, whereas isoforms of Cu/Zn-SOD, Fe-SOD1 and
Fe-SOD3 remained unchanged. Similarly, out of the six isoforms of POX, the POX-1,-2,-3 and -6 were enhanced due to salt stress
but the levels of POX-4 and -5 remained same as in control plants suggesting preferential upregulation of selective POX isoforms.
Activity staining gel revealed only one prominent band of APX and this band increased with increased salt concentration. Similarly,
two isoforms of GR (GR1 and GR2) were visualized on activity staining gel and both these isoforms increased upon salt stress.
In this mangrove four CAT-isoforms were identified, among which the prominent CAT-2 isoform level was maximally reduced again
suggesting differential downregulation of CAT isoforms by NaCl stress. The results presented in this communication are the
first report on the resolutions of isoforms APX, POX and GR out of five antioxidative enzymes studied in the leaf tissue of
a true mangrove. The differential changes in the levels of the isoforms due to NaCl stress may be useful as markers for recognizing
salt tolerance in mangroves. Further, detailed analysis of the isoforms of these antioxidative enzymes is required for using
the various isoforms as salt stress markers. Our results indicate that the overproduction of H2O2 by NaCl treatment functions as a signal of salt stress and causes upregulation of APX, POX, GR and deactivations of CAT in
B. parviflora. The concentrations of malondialdehyde, a product of lipid peroxidation and lipoxygenase activity remained unchanged in leaves
treated with different concentrations of NaCl, which again suggests that the elevated levels of the antioxidant enzymes protect
the plants against the activated oxygen species thus avoiding lipid peroxidation during salt stress. 相似文献
3.
The aim of this work was to investigate whether Fe reduction and antioxidant mechanisms were expressed differently in five Prunus rootstocks (‘Peach seedling,’ ‘Barrier,’ ‘Cadaman,’ ‘Saint Julien 655/2’ and ‘GF-677’). These rootstocks differ in their tolerance to Fe deficiency when grown in the absence of Fe (−Fe) or in presence of bicarbonate (supplied as 5 or 10 mM NaHCO3). Fe deficiency conditions, especially bicarbonate, were shown to decrease Fe and total chlorophyll (CHL) concentration. In the (−Fe)-treated roots of all rootstocks and in the 5 mM NaHCO3-treated ones of the tolerant ‘GF-677’ the Fe(III)-chelate reductase (FCR) activity was stimulated. On the contrary, apart from the ‘GF-677,’ FCR activity was greatly inhibited by the 10 mM NaHCO3. From the results obtained with decapitated rootstocks, it is not entirely clear whether or not the presence of shoot apex was a prerequisite to induce FCR function in all rootstocks tested. In the leaves of rootstocks exposed to the (−Fe) treatment, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities were enhanced whereas the levels of the non-enzymatic antioxidants (FRAP values) were increased in the Fe-deprived leaves, irrespective of the rootstock. Except for ‘Peach seedling,’ foliar SOD activity was stimulated by the presence of NaHCO3. Furthermore, POD activity was increased in the ‘Saint Julien 655/2’ and ‘GF-677,’ but was depressed in the ‘Barrier’ rootstocks exposed to 10 mM NaHCO3. As a result of 10 mM NaHCO3, the expression of a Cu/Zn-SOD and a POD isoform was diminished in the leaves of ‘Peach seedling’ and ‘Barrier,’ respectively. By contrast, an additional isoform of both POD and Mn–SOD were expressed in the leaves of ‘GF-677’ exposed to 10 mM NaHCO3 suggesting that the tolerance of rootstocks to Fe deficiency is associated with induction of an antioxidant defense mechanism. Although CAT activity was increased in the 5 mM NaHCO3-treated leaves of ‘GF-677,’ specifically the 10 mM NaHCO3 treatment resulted in a decrease of CAT activity and an accumulation of H2O2, indicating that bicarbonate-induced Fe deficiency may cause more severe oxidative stress in the rootstocks, than the absence of Fe. A general link between Fe deficiency-induced oxidative stress and Fe reduction-sensing mechanism is also discussed. 相似文献
4.
Copper accumulation, subcellular localization and ecophysiological responses to excess copper were investigated using pot
culture experiments with two Daucus carota L. populations, from a copper mine and an uncontaminated field site, respectively. Significant differences of malondialdehyde
(MDA) and hydrogen peroxide (H2O2) concentrations and antioxidant enzyme [superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX)] activities
of leaves under Cu treatment were observed between the two populations. At high Cu concentrations (400 and 800 mg kg−1), a significant increase in contents of MDA and H2O2 but a significant decrease in activities of SOD, CAT and APX were observed in uncontaminated population. Contrarily, the
population from copper mine maintained a lower level of MDA and H2O2 but higher activities of SOD, CAT and APX. Copper accumulation in roots and shoots increased significantly with the increase
of copper concentrations in soils in the two populations. No significant difference of the total Cu in roots and shoots was
found between the two populations at same copper treatment. There were also no striking differences of cell wall-bound Cu
and protoplasts Cu of leaves between the two populations. The difference was that Cu concentration in vacuoles of leaves was
1.5-fold higher in contaminated site (CS) population than in uncontaminated site population. Hence, more efficient vacuolar
sequestration for Cu and maintaining high activities of SOD, CAT and APX in the CS population played an important role in
maintaining high Cu tolerance. 相似文献
5.
Rice (Oryza sativa L.) seedlings stressed with CdCl2 (0.5 mM or 50 μM) showed typical Cd toxicity (leaf chlorosis, decrease in chlorophyll content, or increase in H2O2 and malondialdehyde contents). Rice seedlings pretreated with heat shock at 45°C (HS) for 2 or 3 h were protected against
subsequent Cd stress. Rice seedlings pretreated with HS had similar Cd concentration in leaves caused by CdCl2 as those non-HS. The content of H2O2 increased in leaves 1 h after HS exposure. However, APX and GR activities were higher in HS-treated leaves than their respective
control, and it occurred after 2 h of HS treatment. Pretreatment of rice seedlings with H2O2 under non-HS conditions resulted in an increase in APX, GR, and CAT activities and protected rice seedlings from subsequent
Cd stress. HS-induced H2O2 production and protection against subsequent Cd stress can be counteracted by imidazole, an inhibitor of NADPH oxidase complex.
Results of the present study suggest that early accumulation of H2O2 during HS signals the increase in APX and GR activities, which in turn prevents rice seedlings from Cd-caused oxidative damage. 相似文献
6.
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
7.
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
8.
Yan Lu Xinrong Li Mingzhu He Xin Zhao Yubing Liu Yan Cui Yanxia Pan Huijuan Tan 《Acta Physiologiae Plantarum》2010,32(3):583-590
The present study showed the toxicity caused by heavy metal and its detoxification responses in two desert plants: perennial
Peganum harmala and annual Halogeton glomeratus. In pot experiments, 1-month-old seedlings were grown under control and three levels of combined heavy metal stress. Seedling
growth as well as heavy metal accumulation, antioxidative enzymes [superoxide dismutase (SOD), catalase (CAT) and ascorbate
peroxidase (APX)] activities and the contents of malondialdehyde (MDA), and hydrogen peroxide (H2O2) in leaves was examined after 2 months of heavy metal exposure. Compared with H. glomeratus, growth of P. harmala was more severely inhibited. In leaves, the heavy metal accumulation pattern in both the plants was dose-dependent, being
more in H. glomeratus. H. glomeratus exhibited a typical antioxidative defense mechanism, as evidenced by the elevated activities of all the three enzymes tested.
P. harmala exhibited a different enzyme response pattern, with a significant reduction in CAT activity, and elevated SOD and APX activities,
but significantly elevated APX activity was only at the lowest heavy metal concentration. MDA and H2O2 contents were significantly enhanced in leaves of heavy metal-treated P. harmala, but in H. glomeratus were elevated only at the highest heavy metal treatment. These results indicated that H. glomeratus had a greater capacity than P. harmala to adapt to oxidative stress caused by heavy metal stress, and antioxidative defense in H. glomeratus might play an important role in heavy metal tolerance. 相似文献
9.
Kyong-Suk Kang Chang-Jin Lim Tae-Jin Han Joon-Chul Kim Chang-Duck Jin 《Journal of Plant Biology》1999,42(3):187-193
The changes in isozyme profiles of catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase
(GR) during severe deactivation of total CAT activity by aminotriazole (AT) treatment were investigated in the leaves ofArabidopsis thaliana (Columbia ecotype) in relation to H2O2-mediated oxidative stress. In spite of striking deactivation of total CAT activity by 0.1 mM AT, there were no significant
differences in H2O2 levels or total leaf soluble protein contents including a Rubisco in both the control and AT-treated leaves. On the other
hand, one specific protein band (molecular mass, 66 kD) was observed on the SDS-gel from leaf soluble proteins whose staining
intensity was strikingly enhanced by AT treatment for 6 h. However, this band disappeared at 12 h. In the native-gel assays
of CAT, POD, APX and GR isozymes, AT remarkably inhibited the expression of the CAT1 isozyme with no effects on CAT2 and CAT3,
and generally had no effect on POD isozyme profiles. However, AT stimulated the intensity of activities of pre-existing APX1
and GR1 isozymes. In particular, it induced a new synthesis of one GR isozyme. Therefore, these results collectively suggest
that a striking deactivation of total CAT activity by AT inA. thaliana leaves largely results from the suppression of CAT1 isozyme, and that APX1, GR1, and a newly synthesized GR isozyme could
complement the role of CAT1 to metabolize H2O2 into non-toxic water. 相似文献
10.
Indian mustard (Brassica juncea L. cv. Vitasso) plants exposed to 10, 30, 50 and 100 μM of Cd for 5 d in hydroponic culture were analysed with reference
to the distribution of Cd2+, the accumulation of biomass and antioxidants and antioxidative enzymes in leaves. Cd induced a decrease in plant biomass.
The maximum accumulation of Cd occurred in roots followed by stems and leaves. Cd induced a decrease in catalase (CAT) and
guiacol peroxidase (GPX) activities but an increase in ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR)
activities. Enhancement in dehydroascorbate reductase (DHAR) activity was also at 10 μM Cd. Glutathione reductase (GR) activity
showed pronounced stimulation after all treatments, but glutathione S-transferase (GST) and glutathione peroxidase (GPOX)
activities decreased. The effectiveness of ascorbate-glutathione cycle (AGC) was determined by the ratio of ascorbate to H2O2. This ratio decreased in the Cd-treated leaves which indicated that the cycle was disordered. 相似文献
11.
12.
Cadmium toxicity and translocation in rice seedlings are reduced by hydrogen peroxide pretreatment 总被引:1,自引:0,他引:1
A hydroponic experiment was carried out to study the role of hydrogen peroxide (H2O2) in enhancing tolerance and reducing translocation of cadmium (Cd) in rice seedlings. Plant growth (length and biomass of
shoot and root) was significantly repressed by Cd exposure. However, pretreatment with 100 μM H2O2 for 1d mitigated Cd stress by inducing enzyme activities for antioxidation (e.g., superoxide dismutase (SOD), catalase (CAT),
guaiacol peroxidase (GPX), ascorbate peroxidase (APX)) and detoxification (e.g., glutathione S-transferase (GST)) as well as by elevating contents of reduced glutathione (GSH) and ascorbic acid (AsA). As a result, H2O2 and malondialdehyde (MDA) content decreased in plants and the seedling growth was less inhibited. On the other hand, H2O2 pretreatment decreased Cd concentration in shoots, thus lowered the ratio of Cd concentration in shoots and roots (S/R),
indicating that H2O2 may affect Cd distribution in rice seedlings. The improved Cd tolerance is partly due to an enhanced antioxidative system
that efficiently prevents the accumulation of H2O2 during Cd stress. Increased Cd sequestration in rice roots may contribute to the decline of Cd translocation. 相似文献
13.
Yuping Wang Wenliang He Huiying Huang Lizhe An Di Wang Feng Zhang 《Acta Physiologiae Plantarum》2009,31(4):839-848
Mountain environmental stresses result in increased formation of hydrogen peroxide (H2O2) and accumulation of malondialdehyde (MDA) in leaves of Polygonum viviparum. The activities of several antioxidative system enzymes such as superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC
1.11.1.6), peroxidase (POD, EC 1.11.1.7), glutathione reductase (GR, EC 1.6.4.2), dehydroascorbate reductase (DHAR, EC 1.8.5.1)
and the contents of several non-enzymatic antioxidants such as reduced form of ascorbate (ASC), dehydroascorbate (DHA), reduced
glutathione (GSH), and oxidized glutathione (GSSG) were investigated in leaves of P. viviparum, which were collected from three altitudes (2,200, 3,200, and 3,900 m) of Tianshan Mountain in China. The activities of these
four antioxidative enzymes were accompanied by increases of H2O2 levels from 2,200 to 3,200 m. However, the activities of CAT and POD were decreased, whereas the activities of SOD and GR
continually increased at 3,900 m. Analyses of isoforms of SOD, CAT, POD, and GR showed that the leaves of P. viviparum exposed different altitude conditions are capable of differentially altering the intensity. Additionally, two new isoforms
of SOD were detected at 3900 m. A continual increase in the ASC, ASC to DHA ratio, GSH and GSH/[GSH + GSSG] ratio, and the
activity of DHAR were observed in leaves of P. viviparum with the elevation of altitude. These results suggest that the higher contents of ASC, GSH as well as an increase in reduced
redox state may be essential to antioxidation processes in the leaves of P. viviparum, whereas antioxidant enzymes system is a cofactor in the processes. 相似文献
14.
Taha Ramadan Suzan A. Sayed Amna K. A. Abd-Elaal Ahmed Amro 《Physiology and Molecular Biology of Plants》2022,28(2):391
Nanotechnology has become one of the several approaches attempting to ameliorate the severe effect of drought on plant''s production and to increase the plants tolerance against water deficit for the water economy. In this research, the effect of foliar application of TiO2, nanoparticles or ordinary TiO2, on Helianthus annuus subjected to different levels of water deficit was studied. Cell membrane injury increased by increasing the level of water deficit and TiO2 concentration, and both types of TiO2 affected the leaves in analogous manner. Ord-TiO2 increased H2O2 generation by 67–240% and lipid peroxidation by 4–67% in leaves. These increases were more than that induced by Nano-TiO2 and the effect was concentration dependent. Proline significantly increased in leaves by water deficit stress, reaching at 25% field capacity (FC) to more than fivefold compared to that in plants grown on full FC. Spraying plants with water significantly decreased the activities of enzymes in the water deficit stressed roots. The water deficit stress exerted the highest magnitude of effect on the changes of cell membrane injury, MDA, proline content, and activities of CAT and GPX. Nano-TiO2 was having the highest effect on contents of H2O2 and GPX activity. In roots, the level of water deficit causes highest effect on enzyme activities, but TiO2 influenced more on the changes of MDA and H2O2 contents. GPX activity increased by 283% in leaves of plants treated with 50 and 150 ppm Nano-TiO2, while increased by 170% in those treated with Ord-TiO2, but APX and CAT activities increased by 17–197%, in average, with Ord-TiO2. This study concluded that Nano-TiO2 didn’t ameliorate the effects of drought stress on H. annuus but additively increased the stress, so its use in nano-phytotechnology mustn’t be expanded without extensive studies.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-022-01153-z. 相似文献
15.
In response to Clostera anachoreta larvae attack, poplar (Populus simonii × P. pyramidalis ‘Opera 8277’) leaves produced a high level of hydrogen peroxide (H2O2). Histochemical localization revealed that H2O2 was mainly localized in herbivore-wounded zones and might spread through the veins. The activities of three H2O2-scavenging enzymes, i.e., peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT), were also enhanced in herbivore-wounded
leaves, and exhibited an opposite pattern to the accumulation of H2O2. It was found that diphenylene iodonium chloride (DPI, a special inhibitor of NADPH oxidase) treatment significantly inhibited
the accumulation of H2O2 induced by herbivory damage. Moreover, DPI treatment led to an obvious decrease in the activities of POD, APX, and CAT. The
results indicated that NADPH oxidase contributed to the accumulation of H2O2 and the increase in activities of H2O2-scavenging enzymes in poplar leaves induced by herbivory damage. The balance between H2O2-production pathway and H2O2-scavenging enzymes led to the tolerable level of H2O2 acting in P. simonii × P. pyramidalis ‘Opera 8277’ cuttings in response to herbivory damage. 相似文献
16.
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
17.
Effect of high temperature stress on polyamine catabolism and antioxidant enzyme activity in relation to glutathione, ascorbate
and proline accumulation was studied in five wheat (Triticum aestivum L.) genotypes (differently susceptible to temperature stress). High temperature significantly increased the activities of
superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), dehydroascorbate reductase
(DHAR), glutathione reductase (GR) and glutathione S-transferase (GST) in shoots of all genotypes. Higher activities of GPX in C 306, C 273 and APX in PBW 550, PBW 343 and PBW
534 demonstrate their important role in scavenging H2O2. Conversely, high temperature stress led to a significant decline in SOD, CAT, APX and GPX activities of roots with a subsequent
increase in diamine oxidase (DAO) and polyamine oxidase (PAO) activities especially in PBW 550 and PBW 343. The concentration
of ascorbic acid declined with the imposition of heat stress, however, polyamines responded to high temperature stress by
increasing spermidine and spermine levels and decreasing putrescine levels. After exposure to high temperature, proline accumulation
was significantly decreased in roots and increased in shoots though maximum concentration was achieved in C 306 genotype.
Apparently, the wheat seedlings respond to high temperature mediated increase in reactive oxygen species (ROS) production
by altering antioxidative defense mechanism and polyamine catabolism though differentially in five wheat genotypes. Among
five genotypes studied, C 306 and C 273 seem to be better protected against temperature stress. The results suggested that
shoots were more resistant against the destructive effects of ROS as is indicated by low levels of thiobarbituric acid reactive
substances under high temperature stress. 相似文献
18.
Wheat (Triticum aestivum L. cv. ‘Zyta’) seedlings were treated with 10, 100 and 200 μM Ni. Tissue Ni accumulation, length, relative water content
(RWC), proline and H2O2 concentrations as well as the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol
peroxidase (POD) and glutathione S-transferase (GST) were studied in the shoots and roots after 6 days of Ni exposure. Treatment
with Ni, except for its lowest concentration, resulted in a significant reduction in wheat growth. In comparison to the shoots,
the roots showed greater inhibition of elongation, which corresponded with higher accumulation of Ni in these organs. Both
shoots and roots responded to Ni application with a decrease in RWC and enhancement in proline concentration. Greater dehydration
of the shoot tissue was accompanied by more intense accumulation of proline. Treatment of the wheat seedlings with the highest
concentration of Ni led to about 60% increase in H2O2 concentration in both studied organs. Apart from CAT, constitutive activities of antioxidative enzymes were much higher in
the roots than in the shoots. Exposure of the seedlings to Ni resulted in SOD activity decline, which was more marked in the
roots. While the shoots showed a substantial decrease (up to 30%) in CAT activity, in the roots the activity of this enzyme
remained unchanged. After Ni application APX, POD and GST activities increased several-fold in the shoots, whereas in the
roots they were not significantly altered. The results suggest that differential antioxidative responses of the shoots and
roots of wheat seedlings to Ni stress might be related to diverse constitutive levels of antioxidant enzyme activities in
both organs. 相似文献
19.
Role of hydrogen peroxide in regulating glucose-6-phosphate dehydrogenase activity under salt stress
The role of hydrogen peroxide in the regulation of glucose-6-phosphate dehydrogenase (G6PDH) activity in the red kidney bean
(Phaseolus vulgaris L.) roots under salt stress (100 mM NaCl) was investigated. Salt stress caused the increase of the activities of G6PDH and
antioxidative enzymes including ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), superoxide dismutase (SOD),
as well as H2O2 production. The application of H2O2 (1 mM) also enhanced the activities of G6PDH as well as antioxidative enzymes. In the presence of exogenous CAT, H2O2 content was decreased, and the enhanced activities of G6PDH and antioxidative enzymes induced by NaCl or by exogenous H2O2 were also abolished, suggesting that the enhancement of the above enzyme activities under salt stress was a result of the
increased endogenous H2O2 levels. Further results showed that the effects of NaCl and H2O2 on the activities of antioxidative enzymes were diminished by Na3PO4 (a G6PDH inhibitor), suggesting G6PDH activity is required in enhancing the activities of antioxidative enzymes. The enhanced
membrane leakage, lipid peroxidation, H2O2 and O2 — contents, G6PDH and antioxidative enzyme activities under salt stress were all recovered to control level when the red
kidney bean seedlings treated with 100 mM NaCl for 6 d were transferred to the control conditions for 8 d. 相似文献
20.
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