共查询到20条相似文献，搜索用时 31 毫秒
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Zhong-Jing Liu Xiao-Long Zhang Ji-Gang Bai Bang-Xia Suo Pei-Lei Xu Lin Wang 《Scientia Horticulturae》2009
In order to examine whether paraquat modifies the functioning of antioxidants and oxidative stress levels in drought-stressed plants, a cucumber cultivar (Cucumis sativus cv. Yuexiu no. 3) was grown hydroponically for 2 days. Drought stress, which was induced by polyethylene glycol (PEG), increased the contents of malonaldehyde (MDA), superoxide radical (O2−) and hydrogen peroxide (H2O2) in cucumber leaves, while pretreatment of paraquat decreased them. Under drought stress induced by PEG, we observed the decreased contents of MDA, H2O2 and O2− in paraquat-pretreated plants in comparison to unpretreated stressed plants. Drought stress and paraquat both increased the activities of antioxidants such as 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), dehydroascorbate reductase (DHAR, EC 1.8.5.1), monodehydroascorbate reducatase (MDHAR, EC 1.6.5.4), glutathione reductase (GR, EC 1.6.4.2), reduced glutathione (GSH) and reduced ascorbate (AsA). But the combined effect of paraquat application and drought stress resulted in the highest activities of antioxidants. So paraquat is able to moderate the activities of scavenging system enzymes and to influence oxidative stress intensity under drought stress induced by PEG. 相似文献
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The beneficial effect of compost, the final product of aerobic biodegradation of organic matter, on growth, lipid peroxidation [as malondialdehyde (MDA], hydrogen peroxide (H2O2) and superoxide anion (O2•−), activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), as well as reduced ascorbate (ASC) and glutathione (GSH) and their oxidized forms was investigated in squash (Cucurbita pepo L. cv. Eskandarany) plants exposed to normal and low temperature (LT) conditions. LT stress of 8 °C significantly reduced the plant growth of untreated plants, but compost alleviated the adverse effect of stress and significantly increased the fresh and dry weights under normal and stress conditions. LT also induced accumulation of H2O2 and O2•− and resulted in increased lipid peroxidation, pointing out to cellular oxidative stress. Under compost application, such reactive oxygen species (ROS) and peroxidized lipids were markedly reduced, but SOD, CAT, APX and GR activities, key enzymes of ROS-scavenging systems, were significantly increased. Data also indicated that there were general reductions in total ascorbate and glutathione pool in LT control plants, but compost-treated ones considerably have maintained higher levels of such redox metabolites. Significantly higher ratios of ASC/DHA (dehydroascorbate) and GSH/GSSG (glutathione disulfide) were generally found in compost-treated plants than in untreated-ones. It is evident that compost induced enhancement of LT tolerance was related to up-regulation of enzymatic and non-enzymatic antioxidant systems. Such enhancement would eventually protect plant cells from LT-induced oxidative stress reactions via scavenging ROS. 相似文献
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To elucidate the physiological mechanism of heat stress mitigated by exogenous hydrogen peroxide (H2O2) further, seedlings of Cucumis sativus cv Lvfeng no. 6 were subjected to two temperatures (42/38 and 25/18 °C) after pretreatment with 1.5 mM H2O2. We investigated whether exogenous H2O2 could protect chloroplast ultrastructure under heat stress (42/38 °C) and whether the protective effect was associated with the regulation of antioxidant enzymes. The heat condition disintegrated the membranes of 71.4% chloroplasts in the leaf cells and resulted in the elevated levels of malondialdehyde (MDA) and endogenous H2O2. When H2O2 pretreatment was combined with the heat stress, the abnormal chloroplasts occurred at a rate of 33.3%, and the contents of MDA and endogenous H2O2 were decreased. Heat stress and exogenous H2O2 both increased the activities of antioxidant enzymes such as glutathione peroxidase (GSH-Px, EC 1.11.1.9), dehydroascorbate reductase (DHAR, EC 1.8.5.1), monodehydroascorbate reducatase (MDHAR, EC 1.6.5.4), and glutathione reductase (GR, EC 1.6.4.2). The combined effect of heat stress and H2O2 pretreatment led to higher activity of antioxidant enzymes including superoxide dismutase (SOD, EC 1.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), GSH-Px, DHAR, MDHAR and GR in comparison to the heat treatment alone. We propose that exogenous H2O2 increases antioxidant enzyme activities in cucumber leaves, decreases lipid peroxidation, and thus protects the ultrastructure of chloroplasts under heat stress. 相似文献
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Exposure of Satsuma mandarin (Citrus unshiu Marc.) and Navel orange (Citrus sinensis Osbeck) plants to high temperature (38 °C) led to reductions of the net photosynthetic rate (Pn), the photorespiration rate (Pr), the quantum efficiency CO2 assimilation (ΦCO2), the maximal photochemical efficiency of PS2 (Fv/Fm), the photochemical quenching (qP) and the quantum efficiency of PS2 photochemistry (ΦPS2), whereas the minimal fluorescence yield (Fo) and the non-photochemical quenching (qN) increased. Increase in the value of Pr/Pn and ΦPS2/ΦCO2 was attributed to the greater decrease in Pn and ΦCO2 than Pr and ΦPS2. In addition, the superoxide radical (O2−) production, the H2O2 concentration and the activities of antioxidant enzymes such as the superoxide dismutase (SOD, EC 1.15.1.1), the ascorbate peroxidase (APX, EC 1.11.1.11), the dehydroascorbate reductase (DHAR, EC 1.8.5.1) and the catalase (CAT, EC 1.11.1.6) were raised. On the other hand, the chlorophyll concentration in leaves decreased during high temperature stress. These results suggest that decline in Pn related to inactivation of PS2 reaction centers may be due to the enhanced number of active oxygen species in the citrus leaves. The water–water cycle may play a role in limiting the degree of photodamage caused by high temperature. Lower O2− production rate, the H2O2 concentration and the antioxidant enzymes activity were observed in high temperature tolerant species of citrus. The exogenous active oxygen scavenger ascorbic acid (Asc) enhanced the ability to clear the O2− in citrus plants, and quicken the recovery of photosynthetic apparatus. 相似文献
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The objective of this work was to evaluate how disease resistance and reactive oxygen species (ROS) metabolism in harvested navel oranges (Citrus sinensis L. Osbeck) may be affected by chitosan. Fresh navel oranges were treated with 2% chitosan or 0.5% glacial acetic acid (control) solution for 1 min, and some were inoculated with Penicillium italicum and Penicillium digitatum. Then, the fruit were stored at 20 °C and 85–95% RH. Treatment with 2% chitosan significantly reduced the disease incidence and the lesion diameter compared with control fruit. This treatment effectively enhanced the activities of peroxidase (POD) and superoxide dismutase (SOD), and levels of glutathione (GSH) and hydrogen peroxide (H2O2), inhibited the activities of catalase (CAT) and the decreases of ascorbate (AsA) content during navel orange fruits storage. Ascorbate peroxidase (APX) activity in the navel orange fruit was induced slightly by the chitosan treatment during 14–21 days storage. However, glutathione reductase (GR) activity in the fruit was not enhanced by the chitosan treatment. These results indicated that chitosan treatment could induce the navel orange fruit disease resistance by regulating the H2O2 levels, antioxidant enzyme and ascorbate–glutathione cycle. 相似文献
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The effect of 80 mmol L−1 stress by excess of calcium nitrate [Ca(NO3)2] on biomass production, oxidative damage, antioxidant enzymes activities and polyamine contents in leaves of grafted and non-grafted eggplant (Solanum melongena L.) seedlings were studied, in which grafted plants were grafted on a salinity tolerant rootstock (Solanum torvum Swartz). The results showed that on the 15th day of treatment, the biomass production reduction of non-grafted seedlings was significantly higher than that of grafted seedlings. Under stress by excess of Ca(NO3)2, superoxide anion radical (O2−) producing rate, electrolyte leakage percentage, contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA) of non-grafted seedlings were significantly higher than those of grafted seedlings, but activities of superoxide dismutase (SOD, EC 1.15.1.1), peroxidase (POD, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) of grafted seedlings were significantly higher than those of non-grafted seedlings, moreover, contents of free, soluble conjugated and insoluble bound polyamines of grafted seedlings were significantly higher than those of non-grafted seedlings, and activities of diamine oxidase (DAO, EC 1.4.3.6) and polyamine oxidase (PAO, EC 1.5.3.3) of grafted seedlings were significantly lower than those of non-grafted seedlings. The possible roles of antioxidant enzymes and polyamines in protective mechanism of grafted eggplant seedlings to stress by excess of Ca(NO3)2 were discussed. 相似文献
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We compared three kinds of habitats: small remnants of native forests, recent hedges and barley crops, in order to investigate their respective roles in the maintenance of carabid-beetle diversity in a 950-ha area of an intensive agricultural landscape. Carabid faunas in remnants differed weakly from these found in hedges and crops. In particular, small remnants had few typical forest carabid species and a large number of open-area or ubiquitous species. Different approaches in the measurement of and -diversity (classical indices, and additive partitioning of Simpson's index) showed similar results: hedges supported a high -diversity but habitat types were quite similar overall, with weak differences between open and closed or disturbed and undisturbed habitats.A comparison of species dispersal powers in the various habitat types showed that species with a low dispersal power were rare in all habitats. However, wing development measured on two dimorphic species revealed, surprisingly, that brachypterous individuals were mainly present in hedges, which were expected a priori to be more disturbed, than remnants hence less suitable for the establishment of populations with a low dispersal power.These results suggest that small remnants do not behave as 'climax' habitats in this intensive agricultural landscape, probably because of their small size and strong isolation. We discuss the interest of new undisturbed habitats, such as recent hedges, for the maintenance of carabid diversity at both the local and landscape scale. 相似文献
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The Andean seed crop quinoa (Chenopodium quinoa Willd.) is traditionally grown under drought and other adverse conditions that constrain crop production in the Andes, and it is regarded as having considerable tolerance to soil drying. The objective of this research was to study how chemical and hydraulic signalling from the root system controlled gas exchange in a drying soil in quinoa. It was observed that during soil drying, relative gs and photosynthesis Amax (drought stressed/fully watered plants) equalled 1, until the fraction of transpirable soil water (FTSW) decreased to 0.82 ± 0.152 and 0.33 ± 0.061, respectively, at bud formation, indicating that photosynthesis was maintained after stomata closure. The relationship between relative gs and relative Amax at bud formation was represented by a logarithmic function (r2 = 0.79), which resulted in a photosynthetic water use efficiency WUEAmax/gs of 1 when FTSW > 0.8, and increased by 50% with soil drying to FTSW 0.7–0.4. Mild soil drying slightly increased ABA in the xylem. It is concluded that during soil drying, quinoa plants have a sensitive stomatal closure, by which the plants are able to maintain leaf water potential (ψl) and Amax, resulting in an increase of WUE. Root originated ABA plays a role in stomata performance during soil drying. ABA regulation seems to be one of the mechanisms utilised by quinoa when facing drought inducing decrease of turgor of stomata guard cells. 相似文献
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Effect of brassinosteroids on drought resistance and abscisic acid concentration in tomato under water stress 总被引：1，自引：0，他引：1
Gao-Feng Yuan Cheng-Guo Jia Zhen Li Bo Sun Li-Ping Zhang Na Liu Qiao-Mei Wang 《Scientia Horticulturae》2010
The effect of brassinosteroid (BR) on relative water content (RWC), stomatal conductance (gs), net photosynthetic rate (PN), intercellular CO2 concentration (Ci), lipid peroxidation level, activities of antioxidant enzymes and abscisic acid concentration (ABA) in tomato (Lycopersicon esculentum) seedlings under water stress was investigated. Two tomato genotypes, Mill. cv. Ailsa Craig (AC) and its ABA-deficient mutant notabilis (not), were used. Water stress was achieved by withholding water and both the AC and not plants were treated with 1 μM 24-epibrassinolide (EBR) or distilled water as a control. The RWC, gs, Ci and PN were significantly decreased under water stress. However, EBR treatment significantly alleviated water stress and increased the RWC and PN. EBR application also markedly increased the activities of antioxidant enzymes (catalase, ascorbate peroxidase and superoxide dismutase) while it decreased gs, Ci and the contents of H2O2 and malondialdehyde (MDA). Interestingly, ABA concentration in AC and not plants was markedly elevated after EBR treatment although the increasing rate and amplitude of ABA in not plants treated by EBR was significantly lower than those in AC plants. Our study suggested that amelioration of the drought stress of tomato seedlings may be caused by EBR-induced elevation of endogenous ABA concentration and/or the activities of antioxidant enzymes. 相似文献
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Antioxidative activity associated with chilling injury tolerance of muskmelon (Cucumis melo L.) rind
‘Galia’ melon (Cucumis melo L. var. reticulatus) is a climacteric fruit with a short storage life. To prevent over-ripening, fruits are stored at 4–6 °C, which also results in chilling injury (CI) that appears as numerous brown spots on the surface of the fruit. It has been suggested that exposure of ‘Galia’ fruits to high growth temperatures in the field renders them sensitive to low storage temperatures. Activity profile of the antioxidative enzymes catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) was monitored in the rind of ‘Galia’ fruits during low-temperature storage, to associate each enzyme's activity with CI incidence. Experiments were performed with low-temperature-sensitive and tolerant varieties, 5080S and 1537T respectively, and included a pre-storage treatment of hot-water wash of 5080S fruits. 相似文献
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Dr. L. Grope 《Erwerbs-Obstbau》2004,46(2):29-34
Zusammenfassung Der Pomologe Franz Hermann Müschen begann vor 200 Jahren mit der Prüfung und Verbreitung von Obstsorten in Mecklenburg. Er selbst beschrieb ab 1821 über 500 Sorten. Der Sohn Johann Georg Bogislav Müschen setzte das Werk seines Vaters fort und beschrieb 1876 weitere 317 Sorten. Beide betrieben eine konsequente Auslese, förderten lokale Sorten und schufen wesentliche Grundlagen für den Obstanbau in ihrer Heimat. Der Beitrag analysiert das Werk beider aus heutiger Sicht. Es werden auch Hinweise zu Müschens Rosenapfel gegeben. Franz Hermann Müschen wird anlässlich seines 230. Geburtstages am 9. Mai 2004 an seinem Wirkungsort Belitz mit einem 2-tägigen Symposium geehrt. 相似文献
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Drought and salinity are two of the most important factors limiting the lemon yield in south-eastern Spain. The effects of drought and salt stress, applied independently, on water relations, osmotic adjustment and gas exchange in the highest evapotranspiration period were studied to compare the tolerance and adaptive mechanisms of 13-year-old ‘Fino 49’ lemon trees, in immature and mature leaves. The study was carried out in an experimental orchard located in Torre Pacheco (Murcia). Three treatments were applied: Control, well-irrigated; drought-stress (DS), non-irrigated from 15th May to 7th July and salinity, irrigated with 30 mM NaCl from 1st March to 7th July. At the end of the experiment, only DS trees showed a decreased leaf stem water potential (Ψmd). Under DS conditions, both types of leaf lost turgor and did not show any osmotic or elastic mechanism to maintain leaf turgor. Osmotic adjustment was the main tolerance mechanism for maintenance of turgor under salt stress, and was achieved by the uptake of Cl− ions. Gas-exchange parameters were reduced by DS but not by salinity, stomatal closure being the main adaptive mechanism for avoidance of water loss and maintenance of leaf turgor. Salinity gave rise to greater Cl− accumulation in mature than in immature leaves. The increase of proline in immature leaves due to DS indicates greater damage than in mature leaves. 相似文献
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In order to screen almond genotypes for drought tolerance, three different irrigation levels including moderate and severe stress (Ψs = −1.2 and −1.8 MPa respectively) and a control treatment (Ψs = −0.33 MPa) were applied for five weeks to six different cultivated almond seedlings. A factorial experiment was conducted with a RCBD which included 3 irrigations factors, 6 genotype factors and 3 replications. Seeds were prepared from controlled pollination of the bagged trees (after emasculation and flower isolation using isolator packets in the previous year). Genotypes included: homozygote sweet (Butte), heterozygote sweet (SH12, SH18, SH21 and White) and homozygote Bitter (Bitter Genotype). Leaf and root morphological and physiological traits including; midday relative water content, midday leaf (xylem) water potential, shoot dry weight and growth, total leaf area, leaf size, total leaf dry weight, specific leaf area, leaf greenness (SPAD), stomatal size and density, root and leaf nitrogen content and chlorophyll fluorescence were measured throughout the study. Results showed the six genotypes had different reactions to water stress but all genotypes showed an ability to tolerate the moderate and severe stresses and they showed different degrees of response time to drought stress. Almond seedling leaves could tolerate Ψw between −3 and −4 MPa in short periods. Water availability did not significantly affect stomatal density and size of young almond plants. The analysis of leaf anatomical traits and water relations showed the different strategies for almond genotypes under water stress conditions. Although almond seedlings even in severe stress kept their leaves, they showed a reduction in size to compensate for the stress effects. All genotypes managed to recover from moderate stress so Ψw = −1.2 could be tolerated well by almond seedlings but Ψw = −1.8 limited young plant growth. Leaf greenness, leaf size, shoot growth, shoot DW, TLDW and stomatal density were not good markers for drought resistance in almond seedlings. Root DW/LA, lower stomatal size and lower SLA might be related to drought resistance in cultivated almonds. Butte had the least resistance and White showed better performance during water stress while other genotypes were intermediate. Bitter seedlings showed no superiority in comparison with other genotypes under water stress conditions except for better germination and greater root DW which might make them suitable as rootstocks under irrigation conditions. 相似文献