共查询到20条相似文献,搜索用时 46 毫秒
1.
In the present study, we investigated the role of glucose-6-phosphate dehydrogenase (G6PDH) in regulating the levels of reduced
form of glutathione (GSH) to the tolerance of calli from two reed ecotypes, Phragmites communis Trin. dune reed (DR) and swamp reed (SR), in a long-term salt stress. G6PDH activity was higher in SR callus than that of DR callus
under 50–150 mM NaCl treatments. In contrast, at higher NaCl concentrations (300–600 mM), G6PDH activity was lower in SR callus.
A similar profile was observed in GSH contents, glutathione reductase (GR) and glutathione peroxidase (GPX) activities in
both salt-stressed calli. After G6PDH activity and expression were reduced in glycerol treatments, GSH contents and GR and
GPX activity decreased strongly in both calli. Simultaneously, NaCl-induced hydrogen peroxide (H2O2) accumulation was also abolished. Exogenous application of H2O2 increased G6PDH, GR, and GPX activities and GSH contents in the control conditions and glycerol treatment. Diphenylene iodonium
(DPI), a plasma membrane (PM) NADPH oxidase inhibitor, which counteracted NaCl-induced H2O2 accumulation, decreased these enzymes activities and GSH contents. Furthermore, exogenous application of H2O2 abolished the N-acetyl-l-cysteine (NAC)-induced decrease in G6PDH activity, and DPI suppressed the effect of buthionine sulfoximine (BSO) on induction
of G6PDH activity. Western-blot analyses showed that G6PDH expression was stimulated by NaCl and H2O2, and blocked by DPI in DR callus. Taken together, G6PDH activity involved in GSH maintenance and H2O2 accumulation under salt stress. And H2O2 regulated G6PDH, GR, and GPX activities to maintain GSH levels. In the process, G6PDH plays a central role. 相似文献
2.
Glucose-6-phosphate dehydrogenase (G6PDH) has been implicated in supplying reduced nicotine amide cofactors for biochemical
reactions and in modulating the redox state of cells. In this study, the role of G6PDH in thermotolerance of the calli from
Przewalskia tangutica and tobacco (Nicotiana tabacum L.) was investigated. Results showed that Przewalskia tangutica callus was more sensitive to heat stress than tobacco callus. The activity of G6PDH and antioxidant enzymes (ascorbate peroxidase,
catalase, peroxidase and superoxide dismutase) in calli from Przewalskia tangutica and tobacco increased after 40 °C treatment, although two calli exhibited a difference in the degree and timing of response
to heat stress. When G6PDH was partially inhibited by glucosamine pretreatment, the antioxidant enzyme activities and thermotolerance
in both calli significantly decreased. Simultaneously, the heat-induced H2O2 content and the plasma membrane NADPH oxidase activity were also reduced. Application of H2O2 increased the activity of G6PDH and antioxidant enzymes in both calli. Diphenylene iodonium, a NADPH oxidase inhibitor, counteracted
heatinduced H2O2 accumulation and reduced the heat-induced activity of G6PDH and antioxidant enzymes. Moreover, exogenous H2O2 was effective in restoring the activity of G6PDH and antioxidant enzymes after glucosamine pretreatment. Western blot analysis
showed that G6PDH gene expression in both calli was also stimulated by heat and H2O2, and blocked by DPI and glucosamine under heat stress. Taken together, under heat stress G6PDH promoted H2O2 accumulation via NADPH oxidase and the elevated H2O2 was involved in regulating the activity of antioxidant enzymes, which in turn facilitate to maintain the steady-state H2O2 level and protect plants from the oxidative damage. 相似文献
3.
The reduced coenzyme nicotinamide-adenine dinucleotide phosphate (NADPH) is an important molecule in cellular redox balance. Glucose-6-phosphate dehydrogenase (G6PDH) is a key enzyme in the pentose phosphate pathway, the most important NADPH-generating pathway. In this study, roles of G6PDH in maintaining cell redox balance in rice suspension cells under salt stress were investigated. Results showed that the G6PDH activity decreased in the presence of 80 mM NaCl on day 2. Application of exogenous glucose stimulated the activity of G6PDH and NADPH oxidase under salt stress. Exogenous glucose also increased the ion leakage, thiobarbituric acid reactive substances and hydrogen peroxide (H2O2) contents in the presence of 80 mM NaCl on day 2, implying that the reduction of the G6PDH activity was necessary to avoid serious damage caused by salt stress. The NAPDH/NADP+ ratio increased on day 2 but decreased on day 4 under 80 mM NaCl plus glucose treatment. Diphenyleneiodonium, an NADPH oxidase inhibitor, decreased the H2O2 content under 80 mM NaCl treatment on day 2. These results imply that the H2O2 accumulation induced by glucose treatment under salt stress on day 2 was related to the NADPH oxidase. Western-blot analysis showed that the G6PDH expression was slightly induced by glucose and was obviously blocked by DPI on day 2 under salt stress. In conclusion, G6PDH plays a key role in maintaining the cell redox balance in rice suspension cells under salt stress. The coordination of G6PDH and NADPH oxidase is required in maintaining cell redox balance in salt tolerance. 相似文献
4.
Glucose‐6‐phosphate dehydrogenase (G6PDH) is important for the activation of plant resistance to environmental stresses, and ion homeostasis is the physiological foundation for living cells. In this study, we investigated G6PDH roles in modulating ion homeostasis under salt stress in Carex moorcroftii callus. G6PDH activity increased to its maximum in 100 mM NaCl treatment and decreased with further increased NaCl concentrations. K+/Na+ ratio in 100 mM NaCl treatment did not exhibit significant difference compared with the control; however, in 300 mM NaCl treatment, it decreased. Low‐concentration NaCl (100 mM) stimulated plasma membrane (PM) H+‐ATPase and NADPH oxidase activities as well as Na+/H+ antiporter protein expression, whereas high‐concentration NaCl (300 mM) decreased their activity and expression. When G6PDH activity and expression were reduced by glycerol treatments, PM H+‐ATPase and NADPH oxidase activities, Na+/H+ antiporter protein level and K+/Na+ ratio dramatically decreased. Simultaneously, NaCl‐induced hydrogen peroxide (H2O2) accumulation was abolished. Exogenous application of H2O2 increased G6PDH, PM H+‐ATPase and NADPH oxidase activities, Na+/H+ antiporter protein expression and K+/Na+ ratio in the control and glycerol treatments. Diphenylene iodonium (DPI), the NADPH oxidase inhibitor, which counteracted NaCl‐induced H2O2 accumulation, decreased G6PDH, PM H+‐ATPase and NADPH oxidase activities, Na+/H+ antiporter protein level and K+/Na+ ratio. Western blot result showed that G6PDH expression was stimulated by NaCl and H2O2, and blocked by DPI. Taken together, G6PDH is involved in H2O2 accumulation under salt stress. H2O2, as a signal, upregulated PM H+‐ATPase activity and Na+/H+ antiporter protein level, which subsequently resulted in the enhanced K+/Na+ ratio. G6PDH played a central role in the process. 相似文献
5.
Nitric oxide (NO) is a stress factor or a signal molecule involved in various plant physiological and developmental processes. In the present study, the generation of reactive oxygen species and the metabolism of proline due to different sodium nitroprusside (SNP, an NO donor) concentrations were investigated in callus from halophyte Nitraria tangutorum Bobr. Treatment with SNP led to significant increases of hydrogen peroxide (H2O2) content and cell viability but notable reductions in hydrogen radical level and lipid peroxidation degree, and superoxide onion (O2 ?) content also enhanced in 100 μM SNP-treated calli. Using a chemical inhibitor for plasma membrane (PM) NADPH oxidase diphenylene iodonium (DPI), we found low O2 ? generation in untreated and 25 μM SNP-treated calli, whereas in those treated with 100 μM SNP O2 ? level exhibited a very little alteration, comparable to the absence of DPI. These suggest a high activity of PM NADPH oxidase in untreated calli. H2O2 scavenging enzymes (catalase, peroxidase [POD] and ascorbate peroxidase) and H2O2 forming enzymes (superoxide dismutase [SOD], cell wall-POD and diamine oxidase [DAO]) stimulated significantly in calli treated with different SNP concentrations while glutathione reductase activity decreased. In addition, a reduction in proline content was observed in SNP-treated calli. Moreover, different SNP concentrations stimulated proline dehydrogenase (PDH) and ornithine δ-aminotransferase but inhibited r-glutamyl kinase (GK). In conclusion, our results suggest that the increasing H2O2 generation was associated with the stimulation of SOD, cell wall-POD and DAO, and that the reduction of proline content might be the consequence of increased PDH activity and decreased GK activity in N. tangutorum Bobr. calli under SNP treatment. 相似文献
6.
Yingli Yang Ruxia Shi Xueling Wei Qing Fan Lizhe An 《Plant Cell, Tissue and Organ Culture》2010,102(3):387-395
Nitraria tangutorum Bobr., a typical desert halophyte, plays an important ecological role because of its superior tolerance to severe drought
and high salinity. Very little is known about the physiological adaptative mechanism of this species to environmental stresses.
The aim of this study was to investigate the changes of antioxidant enzyme activities and the regulatory mechanism of ascorbate
peroxidase (APX) activity in the calli from Nitraria tangutorum Bobr. after treatment with different NaCl concentrations. The activities of superoxide dismutase (SOD) and catalase (CAT)
significantly increased in the calli treated with NaCl, while the peroxidase activity decreased. APX activity was also elevated
significantly in response to NaCl, but the increase was partly abolished by H2O2 scavenger dimethylthiourea (DMTU). Furthermore, the excitatory effect of salinity on APX could be alleviated by the addition
of exogenous CAT and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor diphenylene iodonium, indicating
that the modulation of the APX activity in Nitraria tangutorum Bobr. calli might be associated with NADPH oxidase-dependent H2O2 generation. Measurement and analysis using fluorescent dye 2′,7′-dichlorodihydrofluorescein diacetate showed the increase
of H2O2 content in salinity-treated calli. The investigation of NADPH-dependent O2− production in plasma membrane (PM) vesicles isolated from Nitraria tangutorum Bobr. calli revealed that salinity treatment stimulated NADPH oxidase activity. In conclusion, these results suggest that
the higher activities of antioxidant enzymes play an important role in the salt tolerance of Nitraria tangutorum Bobr. calli and that the extracellular production of H2O2, depending on the excitation of PM NADPH oxidase, is responsible for enhancing the APX activity in Nitraria tangutorum Bobr. calli under salinity stress. 相似文献
7.
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
8.
Y. L. Yang Y. Y. Zhang J. Lu H. Zhang Y. Liu Y. Jiang R. X. Shi 《Biologia Plantarum》2012,56(2):330-336
Antioxidative responses and proline accumulation induced by exogenous H2O2 were investigated in the callus from halophyte Nitraria tangutorum Bobr. H2O2-treated callus exhibited higher H2O2 content than untreated callus. The activities of catalase (CAT) and peroxidase (POD) significantly increased in the callus
treated with H2O2, while ascorbate peroxidase (APX) activity decreased. In addition, significantly enhanced proline content was observed in
the callus treated by H2O2, which could be alleviated by H2O2 scavenger dimethylthiourea and calcium (Ca) chelator ethylene glycol bis-(β-aminoethyl ether)-N,N,N′,N′-tetra-acetic acid
(EGTA). Moreover, γ-glutamyl kinase (GK) activity increased in H2O2-treated callus, but proline dehydrogenase (PDH) activity decreased significantly, and the reduction was partly abolished
by EGTA or Ca channel blocker verapamil. Assays using a scanning electron microscope showed significantly enhanced Ca content
in H2O2-treated callus. 相似文献
9.
To investigate the roles of ammonium-assimilating enzymes in proline synthesis under salinity stress, the activities of glutamine synthetase (GS; EC 6.3.1.2) and NADH-dependent glutamate dehydrogenase (NADH-GDH; EC 1.4.1.2) were determined in leaves of wheat (Triticum aestivum) seedlings exposed to salt stress at 150 and 300 mM NaCl for 5d. At the lower salinity, only GS activity increased markedly. At 300 mM NaCl, however, NADH-GDH activity increased while GS activity decreased. A significant accumulation of proline was found only at high-salinity exposure while glutamate, a proline precursor, increased dramatically under both low and high salinity. These data suggests that GS-catalysis might be the main glutamate synthesis pathway under low salinity. At 300 mM NaCl, glutamate seems to be preferentially produced through the process catalyzed by NADH-GDH. The increase of ammonium in salinity-stressed wheat seedlings might have resulted from increased photorespiration, which is responsible for the higher NADH-GDH activity. The activity of Delta(1)-pyrroline-5-carboxylate reductase (P5CR; EC 1.5.1.2) was significantly enhanced at 300 mM NaCl but remained unchanged at 150 mM. Delta(1)-Pyrroline-5-carboxylate synthetase (P5CS) activity did not show a specific response, indicating that P5CR might be the limiting step in proline synthesis from glutamate at high salinity. 相似文献
10.
Marta Libik-Konieczny Robert Konieczny Ewa Surówka Ireneusz ?lesak ?aneta Michalec Piotr Rozp?dek Zbigniew Miszalski 《Plant Cell, Tissue and Organ Culture》2012,110(1):123-131
A comparison of the hydrogen peroxide (H2O2) content, proline and betacyanin concentration and activities of some antioxidant enzymes (catalase, superoxide dismutase, guaiacol and ascorbate peroxidases) was made in Mesembryanthemum crystallinum L. calli differing in rhizogenic potential. Callus was induced from hypocotyls of 10-day-old seedlings on a medium containing 1?mg?l?1 2,4-dichlorophenoxyacetic acid and 0.2?mg?l?1 kinetin, which was either supplemented with 40?mM NaCl (CIM-NaCl medium) or did not contain any salt (CIM medium). The callus obtained on CIM-NaCl was rhizogenic, whereas the callus induced on the medium without salt was non-rhizogenic throughout the culture. The rhizogenic callus differed from the non-rhizogenic callus in lower betacyanin and H2O2 content, but the rhizogenic callus displayed a higher proline level. The activity of H2O2 scavenging enzymes, such as catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (POD), was markedly higher in the rhizogenic callus than in the non-rhizogenic callus, but the total activity of superoxide dismutase (SOD) was higher in the non-rhizogenic callus than in the rhizogenic callus. Aminotriazole (CAT inhibitor) and diethyldithiocarbamate (SOD inhibitor) were added solely to the CIM and CIM-NaCl media to manipulate the concentration of reactive oxygen species (ROS) in the cultured tissues. Both CAT and SOD inhibitors brought about an increase in H2O2 content in calli cultured on CIM-NaCl and the loss of rhizogenic potential. Conversely, the addition of inhibitors to the medium without salt led to a decrease in H2O2 content. This corresponded with a significant decrease in the endogenous concentration of betacyanins, but did not change the lack of rhizogenic ability. 相似文献
11.
Barley (Hordeum vulgare L. cv. Alfa) seedlings were treated for 4 d before UV-B irradiation with 0.05 mM proline or 150 mM NaCl. UV-B exposure induced synthesis of yellow coloured compounds with maximum absorbance at 438 nm. The content of these compounds was increased in proline-treated and decreased in NaCl-treated plants. UV-B radiation reduced chlorophyll/carotenoids ratio, oxygen evolution rate and photochemical efficiency of PS 2 as estimated by chlorophyll fluorescence and increased proline accumulation, H2O2 generation and lipid peroxidation. Exogenous proline had no effect on the parameters studied and did not change the response of plants to UV-B radiation. NaCl inhibited photochemical efficiency of PS 2, reduced oxygen evolution and increased H2O2 concentration and lipid peroxidation. The combination of NaCl and proline treatment led to lowering the inhibitory effect of NaCl in non UV-B irradiated seedlings. There was not relationship between the level of UV-B-induced compounds and UV-B tolerance of barley seedlings. 相似文献
12.
Cell wall peroxidase activity,hydrogen peroxide level and NaCl-inhibited root growth of rice seedlings 总被引:13,自引:0,他引:13
The changes in cell-wall peroxidase (POD) activity and H2O2 level in roots of NaCl-stressed rice seedlings and their correlation with root growth were investigated. Increasing concentrations of NaCl from 50 to 150 mM progressively reduced root growth and increased ionically bound cell-wall POD activity. NaCl had no effect on covalently bound cell-wall POD activities. The reduction of root growth by NaCl is closely correlated with the increase in H2O2 level. Exogenous H2O2 was found to inhibit root growth of rice seedlings. Since ammonium and proline accumulation are associated with root growth inhibition caused by NaCl, we determined the effects of NH4Cl or proline on root growth, cell-wall POD activity and H2O2level in roots. External application of NH4Cl or proline markedly inhibited root growth, increased cell-wall POD activity and increased H2O2 level in roots of rice seedlings in the absence of NaCl. An increase in cell-wall POD activity and H2O2 level preceded inhibition of root growth caused by NaCl, NH4Cl or proline. NaCl or proline treatment also increased NADH-POD and diamine oxidase (DAO) activities in roots of rice seedlings, suggesting that NADH-POD and DAO contribute to the H2O2 generation in the cell wall of NaCl- or proline-treated roots. NH4Cl treatment increased NADH-POD activity but had no effect on DAO activity, suggesting that NADH-POD but not DAO is responsible for H2O2 generation in cell wall of NH4Cl-treated roots. 相似文献
13.
The involvement of Na+, K+,
Cl- or Ca2+ in the regulation
of salinity stress-induced proline accumulation via the inhibition of the
activity of proline dehydrogenase (PDH; EC 1.4.3.1), a catabolic enzyme of
proline, was investigated in the marine green macroalga Ulva
fasciata Delile. After 6 h of exposure to elevated artificial
seawater (ASW) salinity, adjusted either by increasing the NaCl content in
30 ASW (a change in ion ratio) or by concentrating ASW (a
constant ion ratio), the contents of Na+,
K+ and Cl- linearly
accumulated with increasing salinity from 30-90 (parts per
thousand); the accumulation pattern of each ion was similar between the two
treatments. An increase in NaCl content in ASW induced proline
accumulation, but decreased both the PDH activity and the total
water-soluble Ca2+ contents, while concentrated ASW
had no effect. As compared to a constant value at 30, both the
contents of total and water-soluble CA2+ and the
activity of PDH decreased 1 h after exposure to 60 (adjusted by
increasing NaCl content in 30 ASW) and concomitantly the
content of seawater Ca2+ increased, while proline
accumulated after 3 h. The addition of 15 mM ethylene
glycol-bis-(2-aminoethyl ether)
N,N,N-tetraacetic acid (EGTA) in
60 ASW (adjusted by increasing the NaCl content in
30 ASW) enhanced both the proline accumulation and the decrease
in the content of total and water-soluble cellular
Ca2+ and the activity of PDH; the effects of EGTA
were reversed by 10 mM CaSO4. These results indicate that a loss of
cellular Ca2+ is associated with the NaCl induction
of proline accumulation via an inhibition of PDH activity in U.
fasciata. 相似文献
14.
Artemisinin, a natural sesquiterpenoid isolated from Artemisia annua L., is regarded as the most efficient drug against malaria in the world. Artemsinin production in NaCl-treated A. annua seedlings and its relationships with the glucose-6-phosphate dehydrogenase (G6PDH) activity and generation of H2O2 and nitric oxide (NO) were investigated. Results revealed that artemisinin content in the seedlings was increased by 79.3 % over the control after 1-month treatment with 68 mM NaCl. The G6PDH activity was enhanced in the presence of NaCl together with stimulated generation of H2O2 and NO. Application of 1.0 mM glucosamine (GlcN), an inhibitor of G6PDH, blocked the increase of NADPH oxidase and nitrate reductase (NR) activities, as well as H2O2 and NO production in A. annua seedlings under the salt stress. The induced H2O2 was found to be involved in the upgrading gene expression of two key enzymes in the later stage of artemisinin biosynthetic pathway: amorphadiene synthase (ADS) and amorpha-4,11-diene monooxygenase (CYP71AV1). The released NO being attributed mainly to the increase of NR activity, negatively interacted with H2O2 production and enhanced gene expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR). Inhibition of NO generation partly blocked NaCl-induced artemisinin accumulation, and NO donor strongly rescued the decreased content of artemisinin caused by GlcN. These results suggest that G6PDH could play a critical role in NaCl-induced responses and artemisinin biosynthesis in A. annua. 相似文献
15.
Biljana Balen Mirta Tkalec Tea Rogić Matija Šimac Petra Peharec Štefanić Sanda Rončević Lovorka Pitarević Svedružić Marijana Krsnik-Rasol 《In vitro cellular & developmental biology. Plant》2013,49(4):421-432
Effects of iso-osmotic concentrations of NaCl and mannitol were studied in Mammilaria gracilis (Cactaceae) in both calli and tumors grown in vitro. In both tissues, relative growth rates were reduced under osmotic stress, which were accompanied by a decrease in both tissue water and K+ content. However, growth was inhibited to a lesser extent after exposure to NaCl, when accumulation of Na+ ions was observed. In calli, only salinity increased proline content, whereas with tumors proline accumulated after both osmotic stresses. Osmotic stresses also induced oxidative damage in both cactus tissues, although higher oxidative injury was caused by mannitol in calli and by salt in tumors. Low iso-osmotic concentrations of NaCl (75 mM) and mannitol (150 mM) increased peroxidase, ascorbate peroxidase, and esterase activities, whereas elevated catalase activity was recorded only after mannitol treatment in both tissues. High osmotic stress generally decreased enzymatic activities. However, in calli, esterase activity increased in response to high salinity, whereas ascorbate peroxidase activity was enhanced after high mannitol stress. In conclusion, both in vitro-grown cactus tissues were found to be sensitive to osmotic stress caused by either mannitol or NaCl, but accumulation of Na+ ions in response to salt somewhat contributed to osmotic adjustment. However, more prominent oxidative damage induced by NaCl compared to mannitol in tumor could be related to ion toxicity. The mechanisms that mediate responses to salt- and mannitol-induced osmotic stresses differed and were dependent on tissue type. 相似文献
16.
Vylassery Deepthi Bawankar Raksha Singh Pooja Rathinasamy Subashkumar Govindasamy Vivekanandhan Ramamoorthy Siva 《Archives Of Phytopathology And Plant Protection》2013,46(11):1390-1399
Seedlings of cultivated rice variety ADT43 was investigated after challenging with two different abiotic (drought and salinity) and biotic (sheath blight and bacterial leaf blight pathogens) stresses. Salinity and drought stress reduced the growth of seedlings, mainly the higher conditions (100 mM NaCl and 10?days of drought, respectively). Increased level of MDA content was observed in biotic and abiotic-stress treated seedlings. The highest H2O2 content was observed under salinity-stressed seedlings and lower level observed under biotic stress. Superoxide dismutase activity showed a gradual decrease in all stress conditions compared to control. Salinity stress resulted in highest activity of catalase compared to biotic stress. The peroxidase activity of the seedlings was found to be increased under salt and drought stress conditions and the activity decreased under biotic stress. Drought stress resulted in induced expression of POC1 gene whereas the biotic stress showed lower expression level. Suppression of the rice peroxidase would have been the mechanism of overcoming the intrinsic defence in rice by these pathogens. 相似文献
17.
Proline antioxidant role in the common ice plant subjected to salinity and paraquat treatment inducing oxidative stress 总被引:2,自引:0,他引:2
N. I. Shevyakova E. A. Bakulina Vl. V. Kuznetsov 《Russian Journal of Plant Physiology》2009,56(5):663-669
Leaves of 4-week-old (juvenile) and 9-week-old (adult) plants of the halophyte Mesembryanthemum crystallinum L. (the common ice plant), cultured under controlled conditions in the phytotron, were treated with paraquat (0.1 μM), which
produces superoxide radical, and (or) paraquat combined with introduction of NaCl (100 mM) or proline (5 mM) into nutrient
medium. After a 20-h dark period (23°C), plants were transferred into light (4 h at 54.1 W/m2 of photosynthetically active radiation) for stimulation of O°2− formation in plastids. Activities of antioxidant enzymes, the contents of MDA, H2O2, chlorophyll, and free proline were measured in leaves. Plant responses in two age groups, which differed in the type of
photosynthesis (juvenile plants had C3 type of photosynthesis, whereas adult plants were at the transition stage to Crassulacean Acid Metabolism (CAM) photosynthesis),
differed in the levels of constitutive proline and proline, induced by NaCl and paraquat, as well as in activities of superoxide
dismutase (SOD) and catalase. Changes in SOD activity and proline accumulation in response to paraquat treatment combined
with NaCl revealed opposite dependence to accumulation of proline: the more proline accumulated in leaves, the lower activity
of the enzyme. In response to paraquat treatment, the content of chlorophylls a and b most drastically declined in juvenile plants. Negative effect of salinity on the content of chlorophylls was lower than that
of paraquat and was almost the same in plants of both age groups. Protective effect of exogenous proline was most profound
in the case of paraquat treatment. Exogenous proline decreased the rate of lipid peroxidation, the content of superoxide radical
and, consequently, SOD activity (almost fivefold), and increased the content of chlorophylls (a and b) in leaves of adult plants. The obtained data suggest that stress-induced accumulation of proline in the common ice plant
has both osmoprotectory and antioxidant functions. 相似文献
18.
Hamid Sobhanian Ferdous Rastgar Jazii Khadija Razavi Vahid Niknam Setsuko Komatsu 《Russian Journal of Plant Physiology》2010,57(6):784-791
To investigate the salt tolerance mechanisms, Aeluropus lagopoides as a halophytic plant was used. Plants were treated with 0, 150, 450, 600, and 750 mM NaCl and harvested at 0, 4, 8, and
10 days after treatment and 1 day and 1 week after recovery. Optimal growth, measured as fresh and dry weights, occurred at
150 mM NaCl, but it was suppressed by 450, 600, and 750 mM NaCl. Recovery significantly increased fresh and dry weights only
in 750 mM NaCl-treated plants. Water content was decreased after NaCl treatment and increased after recovery. Na+ and proline contents and activity of superoxide dismutase (SOD) were increased after NaCl treatment and decreased after recovery
in all treated plants. In contrast, K+ content and ascorbate peroxidase activity decreased after NaCl treatment and increased after recovery in all treated plants.
Catalase (CAT) was activated only in 750 mM NaCl-treated plants. Total content of soluble protein was slightly changed after
NaCl treatment. It was concluded that proline accumulation for osmotic adjustment, SOD activation for O2·− scavenging, and CAT activation at the higher level of salt stress to detoxify produced H2O2 were main A. lagopoides strategies under salt stress. A. lagopoides salt tolerance was not based on the restriction of Na+ uptake. 相似文献
19.
Barley seedlings were pre-treated with 1 and 5 μM H2O2 for 2 d and then supplied with water or 150 mM NaCl for 4 and 7 d. Exogenous H2O2 alone had no effect on the proline, malondialdehyde (MDA) and H2O2 contents, decreased catalase (CAT) activity and had no effect on peroxidase (POX) activity. Three new superoxide dismutase
(SOD) isoenzymes appeared in the leaves as a result of 1 μM H2O2 treatment. NaCl enhanced CAT and POX activity. SOD activity and isoenzyme patterns were changed due to H2O2 pre-treatment, NaCl stress and leaf ageing. In pre-treated seedlings the rate of 14CO2 fixation was higher and MDA, H2O2 and proline contents were lower in comparison to the seedlings subjected directly to NaCl stress. Cl− content in the leaves 4 and 7 d after NaCl supply increased considerably, but less in pre-treated plants. It was suggested
that H2O2 metabolism is involved as a signal in the processes of barley salt tolerance. 相似文献
20.
The over-expression of Chrysanthemum crassum CcSOS1 improves the salinity tolerance of chrysanthemum
Juan An Aiping Song Zhiyong Guan Jiafu Jiang Fadi Chen Wanghuai Lou Weimin Fang Zhaolei Liu Sumei Chen 《Molecular biology reports》2014,41(6):4155-4162
Soil salinity represents a major constraint on plant growth. Here, we report that the over-expression of the Chrysanthemum crassum plasma membrane Na+/H+ antiporter gene CcSOS1, driven by the CaMV 35S promoter, improved the salinity tolerance of chrysanthemum ‘Jinba’. In salinity-stressed transgenic plants, both the proportion of the leaf area suffering damage and the electrical conductivity of the leaf were lower in the transgenic lines than in salinity-stressed wild type plants. After a 6 day exposure to 200 mM NaCl, the leaf content of both chlorophyll (a+b) and proline was higher in the transgenic than in the wild type plants. The activity of both superoxide dismutase and peroxidase was higher in the transgenic than in the wild type plants throughout the period of NaCl stress. The transgenic plants had a stronger control over the ingress of Na+ into the plant, particularly with respect to the youngest leaves, and so maintained a more favorable K+/Na+ ratio. The result suggests that a possible strategy for improving the salinity tolerance of chrysanthemum could target the restriction of Na+ accumulation. This study is the first to report the transgenic expression of a Na+ efflux carrier in chrysanthemum. 相似文献