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1.
The effects of methyl jasmonate (MJ) and salicylic acid (SA) on changes of the activities of major antioxidant enzymes, superoxide anion accumulation (O2
−), ascorbate, total glutathione (TG), malondialdehyde (MDA) content and ginsenoside accumulation were investigated in ginseng roots (Panax ginseng L.) in 4 l (working volume) air lift bioreactors. Single treatment of 200 μM MJ and SA to P. ginseng roots enhanced ginsenoside accumulation compared to the control and harvested 3, 5, 7 and 9 days after treatment. MJ and SA treatment induced an oxidative stress in P. ginseng roots, as shown by an increase in lipid peroxidation due to rise in O2
− accumulation. Activity of superoxide dismutase (SOD) was inhibited in MJ-treated roots, while the activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), SOD, guaiacol peroxidase (G-POD), glutathione peroxidase (GPx) and glutathione reductase (GR) were induced in SA-treated roots. A strong decrease in the activity of catalase (CAT) was obtained in both MJ- and SA-treated roots. Activities of ascorbate peroxidase (APX) and glutathione S transferase (GST) were higher in MJ than SA while the contents of reduced ascorbate (ASC), redox state (ASC/(ASC+DHA)) and TG were higher in SA- than MJ-treated roots while oxidized ascorbate (DHA) decreased in both cases. The result of these analyses suggests that roots are better protected against the O2
− stress, thus mitigating MJ and SA stress. The information obtained in this work is useful for efficient large-scale production of ginsenoside by plant-root cultures. 相似文献
2.
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
3.
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
4.
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
5.
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
6.
Many physiological and biochemical plant processes affected by salt stress trigger premature nodule senescence and decrease
their ability to fix nitrogen. The objective of this study was to evaluate the role of arbuscular mycorrhiza (AM) in moderating
salt-induced premature nodule senescence in Cajanus cajan (L.) Millsp. Greenhouse experiments were conducted in which the plants were exposed to salinity stress of 4, 6, and 8 dSm−1. Various parameters linked to nodule senescence were assessed at 80 days after sowing. Nodulation, leghemoglobin content,
and nitrogenase enzyme activity measured as acetylene-reducing activity (ARA) were evaluated. Two groups of antioxidant enzymes
were studied: (1) enzymes involved in the detoxification of O2− radicals and H2O2, namely, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX), and (2) enzymes that are important components of
the ascorbate glutathione pathway responsible for the removal of H2O2, namely, glutathione reductase (GR) and ascorbate peroxidase (APOX). Exposure of plants to salinity stress enhanced nodule
formation; however, nodule growth suffered remarkably and a marked decline in nodule biomass, relative permeability, and lipid
peroxidation was observed. Leghemoglobin content and ARA were reduced under saline conditions. AM significantly improved nodulation,
leghemoglobin content, and nitrogenase activity under salt stress. Activities of SOD, CAT, APOX, POX, and GR increased markedly
in mycorrhizal-stressed plants. A synthesis of the evidence obtained in this study suggests a correlation between enhanced
levels of antioxidant enzyme activities, reduced membrane permeability, reduced lipid peroxidation, and improved nitrogen-fixing
efficiency of AM plants under stressed and unstressed conditions. These factors could be responsible for the protective effects
of mycorrhiza against stress-induced premature nodule senescence. 相似文献
7.
Changes in the content of reactive oxygen species (ROS) and activity of the antioxidant system were measured in leaves of
Arabidopsis thaliana (L.) Heynh exposed to Cd2+. Mature plants growing in the nutrient solution were treated with Cd2+ at different concentrations (0, 5, 25, 50, 100 μM). An increase of
content in leaves was observed at 5, 25 and 50 μM Cd2+. A strong accumulation of H2O2 was found only at the lowest Cd2+ concentration. The content of OH*. was high at 50 and 100 μM Cd2+. Superoxide dismutase (SOD) activity was always higher in Cd2+-treated plants than in control. Catalase (CAT) activity decreased with increasing Cd2+ concentration in the nutrient solution. Guaiacol peroxidase (POX) activity was particularly high at the lowest and highest
Cd2+ concentrations and ascorbate peroxidase (APX) activity additionally at 50 μM Cd2+. Enhanced activity of monodehydroascorbate reductase (MDHAR) and strong reduction in ascorbate (AA) content were observed
at 25 μM Cd2+. Glutathione reductase (GR) activity was always higher than in control but decreased as Cd2+ concentration increased. However, it was accompanied by gradual content increase of SH-groups.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Pigeonpea [Cajanus cajan (L.) Millsp.] is a waterlogging-sensitive legume crop. We studied the effect of waterlogging stress on hydrogen peroxide
(H2O2) content, lipid peroxidation and antioxidant enzyme activities in two pigeonpea genotypes viz., ICPL-84023 (waterlogging
resistant) and MAL-18 (waterlogging susceptible). In a pot experiment, waterlogging stress was imposed for 6 days at early
vegetative stage (20 days after sowing). Waterlogging treatment significantly increased hydrogen peroxide accumulation and
lipid peroxidation, which indicated the extent of oxidative injury posed by stress conditions. Enzyme activities of peroxidase
(POX), catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and polyphenol oxidase (PPO) increased in pigeonpea
roots as a consequence of waterlogged conditions, and all the enzyme activities were significantly higher in waterlogged ICPL-84023
than in MAL-18. POX activity was the maximum immediately after imposing stress, therefore, it was suggested to be involved
in early scavenging of H2O2, while rest of the enzymes (CAT, APX, SOD and PPO) were more important in late responses to waterlogging. Present study revealed
that H2O2 content is directly related to lipid peroxidation leading to oxidative damage during waterlogging in pigeonpea. Higher antioxidant
potential in ICPL-84023 as evidenced by enhanced POX, CAT, APX, SOD and PPO activities increased capacity for reactive oxygen
species (ROS) scavenging and indicated relationship between waterlogging resistance and antioxidant defense system in pigeonpea. 相似文献
9.
Sunita Sheokand Anita Kumari Veena Sawhney 《Physiology and Molecular Biology of Plants》2008,14(4):355-362
Chickpea plants were subjected to salt stress for 48 h with 100 mM NaCl, after 50 days of growth. Other batches of plants were simultaneously treated with 0.2 mM sodium nitroprusside (NO donor) or 0.5 mM putrescine (polyamine) to examine their antioxidant effects. Sodium chloride stress adversely affected the relative water content (RWC), electrolyte leakage and lipid peroxidation in leaves. Sodium nitroprusside and putrescine could completely ameliorate the toxic effects of salt stress on electrolyte leakage and lipid peroxidation and partially on RWC. No significant decline in chlorophyll content under salt stress as well as with other treatments was observed. Sodium chloride stress activated the antioxidant defense system by increasing the activities of peroxidase (POX), catalase (CAT) superoxide dismutase (SOD) and ascorbate peroxidase (APX). However no significant effect was observed on glutathione reductase (GR) and dehydro ascorbate reductase (DHAR) activities. Both putrescine and NO had a positive effect on antioxidant enzymes under salt stress. Putrescine was more effective in scavenging superoxide radical as it increased the SOD activity under salt stress whereas nitric oxide was effective in hydrolyzing H2O2 by increasing the activities of CAT, POX and APX under salt stress. 相似文献
10.
Fei Chen Fang Wang Hongyan Sun Yue Cai Weihua Mao Guoping Zhang Eva Vincze Feibo Wu 《Journal of Plant Growth Regulation》2010,29(4):394-408
A greenhouse hydroponic experiment was performed using Cd-sensitive (cv. Dong 17) and Cd-tolerant (Weisuobuzhi) barley seedlings
to evaluate how different genotypes responded to cadmium (Cd) toxicity in the presence of sodium nitroprusside (SNP), a nitric
oxide (NO) donor. Results showed that 5 μM Cd increased the accumulation of O2•−, H2O2, and malondialdehyde (MDA) but reduced plant height, chlorophyll content, net photosynthetic rate (P
n), and biomass, with a much more severe response in the Cd-sensitive genotype. Antioxidant enzyme activities increased significantly
under Cd stress in the roots of the tolerant genotype, whereas in leaves of the sensitive genotype, superoxide dismutase (SOD)
and ascorbate peroxide (APX), especially cytosol ascorbate peroxidase (cAPX), decreased after 5–15 days Cd exposure. Moreover,
Cd induces NO synthesis by stimulating nitrate reductase and nitric oxide synthetase-like enzymes in roots/leaves. A Cd-induced
NO transient increase in roots of the Cd-tolerant genotype might partly contribute to its Cd tolerance. Exogenous NO dramatically
alleviated Cd toxicity, markedly diminished Cd-induced reactive oxygen species (ROS) and MDA accumulation, ameliorated Cd-induced
damage to leaf/root ultrastructure, and increased chlorophyll content and P
n. External NO counteracted the pattern of alterations in certain antioxidant enzymes induced by Cd; for example, it significantly
elevated the depressed SOD, APX, and catalase (CAT) activities in the Cd-sensitive genotype after 10- and 15-day treatments.
Furthermore, NO significantly increased stromal APX and Mn-SOD activities in both genotypes and upregulated Cd-induced decrease
in cAPX activity and gene expression of root/leaf cAPX and leaf CAT1 in the Cd-sensitive genotype. These data suggest that under Cd stress, NO, as a potent antioxidant, protects barley seedlings
against oxidative damage by directly and indirectly scavenging ROS and helps to maintain stability and integrity of the subcellular
structure. 相似文献
11.
Yu. V. Ivanov Yu. V. Savochkin Vl. V. Kuznetsov 《Russian Journal of Plant Physiology》2012,59(1):50-58
Functioning of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APO), and guaiacol peroxidases
(GPO)) and low-molecular organic ROS scavengers (proline and phenolic compounds) in various organs (roots, cotyledons, stem,
and needle) of 6-week-old seedlings of pine (Pinus sylvestris L.) developing in the chronic presence of ZnSO4 (50, 100, and 150 μM). Pine seedlings were grown in water culture in the climate-controlled chamber at an irradiance of 37.6
W/m2 with a 16-h photoperiod, an air temperature of 23 ± 1/15 ± 1°C (day/night), and a relative humidity of 55/70% (day/night).
Endogenous Zn content was a key factor determining SOD activity decomposing superoxide into H2O2 and O2. Hydrogen peroxide produced is efficiently destroyed by CAT and also by APO and GPO. At the same time, the content of proline
increased (especially at 150 μM ZnSO4), but the content of phenolic compounds remained unchanged. All these processes help to maintain stable intracellular levels
of O2⊙− and H2O2 at elevated zinc concentrations and to prevent generation of hydroxyl radical and development of oxidative stress. 相似文献
12.
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
13.
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
14.
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
15.
The effect of various hormonal combinations on regeneration of shoots and roots from meristem-derived callus of Crocus sativus L. and activities of antioxidant enzymes have been studied. The most efficient regeneration occurred with 1.0 mg dm−3 1-naphthaleneacetic acid (NAA) + 1.0 mg dm−3 thidiazuron and 1.0 mg dm−3 NAA + 2.0 mg dm−3 kinetin. For sprouting, regenerated shoot were subcultured on Murashige and Skoog medium containing 1.0 mg dm−3 NAA + 1.0 mg dm−3 benzylaminopurine (BAP). Protein content and superoxide dismutase activity decreased in regenerated shoots and roots and
increased in sprouting shoots, while catalase (CAT), peroxidase (POX) and polyphenol oxidase (PPO) activities increased during
organogenesis and decreased in sprouting shoots. High CAT and PPO activities were detected in regenerated roots, whereas high
POX activity was observed in regenerated shoot. 相似文献
16.
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
17.
Manganese-excess induces oxidative stress,lowers the pool of antioxidants and elevates activities of key antioxidative enzymes in rice seedlings 总被引:1,自引:0,他引:1
Manganese (Mn) is an essential element for plant growth but in excess, specially in acidic soils, it can become phytotoxic.
In order to investigate whether oxidative stress is associated with the expression of Mn toxicity during early seedling establishment
of rice plants, we examined the changes in the level of reactive oxygen species (ROS), oxidative stress induced an alteration
in the level of non-enzymic antioxidants and activities of antioxidative enzymes in rice seedlings grown in sand cultures
containing 3 and 6 mM MnCl2. Mn treatment inhibited growth of rice seedlings, the metal increasingly accumulated in roots and shoots and caused damage
to membranes. Mn treated plants showed increased generation of superoxide anion (O2
.−), elevated levels of H2O2 and thiobarbituric acid reactive substances (TBARS) and decline in protein thiol. The level of nonprotein thiol, however,
increased due to Mn treatment. A decline in contents of reduced ascorbate (AsA) and glutathione (GSH) as well as decline in
ratios of their reduced to oxidize forms was observed in Mn-treated seedlings. The activities of antioxidative enzymes superoxide
dismutase (SOD) and its isoforms Mn SOD, Cu/Zn SOD, Fe SOD as well as guaiacol peroxidase (GPX) increased in the seedlings
due to Mn treatment however, catalase (CAT) activity increased in 10 days old seedlings but it declined by 20 days under Mn
treatment. The enzymes of Halliwell-Asada cycle, ascorbate peroxidase (APX) monodehydoascorbate reductase (MDHAR), dehyroascorbate
reductase (DHAR) and glutathione reductase (GR) increased significantly in Mn treated seedlings over controls. Results suggest
that in rice seedlings excess Mn induces oxidative stress, imbalances the levels of antioxidants and the antioxidative enzymes
SOD, GPX, APX and GR appear to play an important role in scavenging ROS and withstanding oxidative stress induced by Mn. 相似文献
18.
The combined effects of drought and low light on biomass partition, foliar nitrogen concentration, membrane stability and
active oxygen species (AOS) and antioxidant system were investigated in dragon spruce (Picea asperata Mast.) seedlings grown at two watering regimes (well-watered, 100% of field capacity and drought, 30% of field capacity)
and light availabilities (HL, 100% of full sunlight and low light, 15% of full sunlight). Under high light condition drought
not only reduced foliar nitrogen concentration (Nmass) and membrane stability index (MSI) but also significantly increased biomass partitioning to roots, AOS, ascorbic acid
(AsA) content and antioxidant enzyme activities including superoxide dismutase (SOD, EC 1.15.1.1), peroxidase (POD, EC 1.11.1.7),
catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase(GR, EC 1.6.4.2). However,
no prominently drought-induced differences in biomass partitioning to root, SOD, GR activities, hydrogen peroxide (H2O2) and MSI were observed in low light seedlings. On the other hand, significant interaction of drought and low light was found
on MSI, the antioxidant enzymes activities (SOD, POD, CAT, APX, GR), H2O2 and superoxide radical (O2
−). These results suggested that seedlings grown at the understory were more sensitive to drought than low light. 相似文献
19.
NADH-dependent NO scavenging in barley extracts is linked to hemoglobin (Hb) expression and is inhibited by SH-reagents. Barley
Hb has a single cysteine residue. To determine whether this cysteine was critical for NO scavenging, barley Hb and a mutated
version, in which the single Cys79 was replaced by Ser, were over-expressed in Escherichia coli and purified to near homogeneity. The purified proteins exhibited very low NO-scavenging activity (12–14 nmol min−1 mg−1 protein) in the presence of NADH or NADPH. This activity was insensitive to SH-reagents. Addition of an extract from barley
roots to either of the purified proteins resulted in high NADH-dependent NO turnover in a reaction that was sensitive to SH-reagents.
A protein was purified from barley roots and identified by mass-spectrometry analysis as a cytosolic monodehydroascorbate
reductase. It efficiently supported NADH-dependent NO scavenging in the presence of either native or mutated barley Hb. Ascorbate
strongly facilitated the rate of metHb reduction. The K
m for Hb was 0.3 μM, for ascorbate 0.6 mM and for NADH 4 μM. The reaction in the presence of monodehydroascorbate reductase
was sensitive to SH-reagents with either form of the Hb. We conclude that metHb reduction and NO turnover do not involve direct
participation of the Cys79 residue of barley Hb. NO scavenging is facilitated by monodehydroascorbate reductase mediating a coupled reaction involving
ferric Hb reduction in the presence of ascorbate and NADH. 相似文献
20.
In the present study, it was aimed to investigate the influence of exogenous mammalian sex hormones (MSH) (progesterone, β-estradiol
and androsterone) on the morphological (root and shoot growth) and biochemical parameters (protein and sugar content, antioxidant
enzyme activities, and lipid peroxidation and H2O2 levels) of chickpea (Cicer arietinum L.) plants growing under control conditions. The solutions of hormones prepared at different concentrations (10−4, 10−6, 10−9, 10−12 and 10−15 M) were sprayed once on the leaves of 7-day plants. The plants were harvested on 18 days after the hormone treatment. Although
all of the hormones at the tested concentrations significantly increased plant growth, soluble protein and sugar contents,
and antioxidant enzyme activities [superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT)], they decreased H2O2 content and lipid peroxidation level when compared with control plants. The activities of SOD, POX and CAT reached to the
highest levels at 10−6 M for progesterone, and 10−9 M for β-estradiol and androsterone, which maximum growth, protein and sugar contents were determined. The same concentrations
also resulted in the lowest levels for H2O2 content and lipid peroxidation. It can be interpreted that the MSH improve plant growth and development by affecting some
biochemical parameters including antioxidative system. 相似文献