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1.
以‘津春4号’黄瓜为试验材料,采用灌根的方法研究了外源褪黑素（MT）对硝酸盐胁迫下幼苗抗氧化系统的影响,为MT在设施蔬菜生产中的应用提供参考。结果表明：硝酸盐胁迫处理后,黄瓜幼苗叶片中超氧阴离子（）产生速率、过氧化氢（H2O2）和丙二醛（MDA）含量显著增加;抗坏血酸（AsA）和谷胱甘肽（GSH）含量及活性均下降;超氧化物歧化酶（SOD）、过氧化物酶（POD）、抗坏血酸过氧化物酶（APX）、谷胱甘肽还原酶（GR）活性在硝酸盐胁迫3 d时,过氧化氢酶（CAT）活性在胁迫6 d时,脱氢抗坏血酸还原酶（DHAR）活性在胁迫9 d时均达最高,之后又逐渐下降;单脱氢抗坏血酸还原酶（MDHAR）活性则持续降低。MT处理可有效抑制硝酸盐胁迫条件下黄瓜幼苗中  的产生速率及H2O2和MDA的积累,提高AsA和GSH含量及活性,增强SOD、POD、CAT、APX、MDHAR、DHAR、GR活性,提高叶片的光合速率及干物质积累。这些结果说明,MT可减缓硝酸盐胁迫的危害,提高黄瓜幼苗对硝酸盐的耐性,且100 μmol · L-1 MT处理效果最佳。  相似文献   

2.
以狭叶红景天幼苗为试材,在0℃低温条件下,研究外源SA对狭叶红景天幼苗过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD)3种抗氧化酶活性、MDA含量以及膜伤害的影响,探讨外源SA对低温胁迫下红景天幼苗生理及膜伤害的影响。结果表明:在0℃低温胁迫条件下,不同浓度的外源SA总体上均使红景天幼苗叶片CAT、POD、SOD活性不同程度升高,使叶片MDA含量不同程度降低;使叶绿体膜Ca2+-ATP活性、Mg2+-ATP活性不同程度增强。在低温胁迫下,外源SA通过提高抗氧化酶活性、抗氧化物质含量及渗透调节物质含量,减少了膜脂过氧化产物MDA的产生,叶绿体膜Ca2+-ATP活性、Mg2+-ATP活性的增强,减轻细胞膜的损伤,提高了狭叶红景天幼苗耐低温胁迫的能力;提高狭叶红景天耐寒力的外源物质SA适宜浓度为0.1~0.3mg/L,SA的最适浓度为0.3mg/L。  相似文献   

3.
杨萍  李杰 《北方园艺》2017,(21):7-12
以辣椒品种"湘研16号"为试材,采用人工气候箱模拟低温环境,研究了2,4-表油菜素内酯(EBR)对低温胁迫下辣椒幼苗体内超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性以及抗坏血酸(As A)和谷胱甘肽(GSH)含量的影响,以期为油菜素内酯调控辣椒幼苗耐低温胁迫的机理研究提供参考依据。结果表明:抗氧化酶(SOD、POD、CAT、APX)活性在低温胁迫下高于CK,而EBR处理的叶片酶活性显著增加。同时,EBR提高了低温胁迫下辣椒幼苗叶片中抗坏血酸(As A)和谷胱甘肽(GSH)含量,降低了MDA含量。由此可见,EBR能显著增加保护酶活性和非酶抗氧化物的含量,增强植株抗氧化能力,有效缓解低温胁迫引起的膜脂过氧化伤害,降低了低温胁迫对辣椒幼苗生长的抑制作用。  相似文献   

4.
低温胁迫对草莓叶片SOD和AsA-GSH循环酶系统的影响   总被引：25，自引：1，他引：24  
罗娅  汤浩茹  张勇 《园艺学报》2007,34(6):1405-1410
以草莓试管苗为试材,研究低温胁迫对草莓离体叶片抗坏血酸、脱氢抗坏血酸含量和SOD以及抗坏血酸 -谷胱甘肽（AsA-GSH）循环中4种酶活性的影响。结果表明,低温胁迫导致超氧化物歧化酶、抗坏血酸过氧化物酶和单脱氢抗坏血酸还原酶活性上升,脱氢抗坏血酸还原酶和谷胱甘肽还原酶活性下降;同时使还原态抗坏血酸含量下降而脱氢抗坏血酸含量上升。随着低温处理时间延长,过多活性氧不能被防御体系有效清除,植物受到伤害。试验结果还表明,抗坏血酸过氧化物酶具有较强的氧化还原抗坏血酸的能力,单脱氢抗坏血酸还原酶是AsA-GSH循环再生抗坏血酸的主要酶。  相似文献   

5.
水杨酸对根际低氧胁迫八棱海棠幼苗活性氧代谢的影响   总被引：9，自引：0，他引：9  
 采用营养液水培系统,以苹果砧木八棱海棠(Malus robusta Rehd.)为试材,用叶面喷施的方法,研究了外源水杨酸(salicylic acid ,SA)对根际低氧胁迫下八棱海棠叶片活性氧(ROS)代谢的影响。结果表明：低氧胁迫下八棱海棠叶片丙二醛(MDA)、超氧阴离子 (O2)、过氧化氢(H2O2)、谷胱甘肽(GSH)含量和抗氧化酶活性均高于对照,而抗坏血酸(AsA)含量低于对照;外源SA明显抑制MDA和O2的积累,显著增强超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)的活性。说明SA作为化学诱抗剂,可抑制低氧胁迫下苹果幼苗体内活ROS的产生,提高抗氧化酶的活性,降低膜脂过氧化水平,从而减轻低氧胁迫对植株的伤害。  相似文献   

6.
以长鞭红景天幼苗为试材,喷施不同浓度外源油菜素内酯(brassinosteroids,BR),研究了低温条件下(0℃)BR对长鞭红景天幼苗过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD)3种抗氧化酶活性、可溶性蛋白质含量以及膜伤害的影响,以期为外源BR在栽培长鞭红景天耐低温方面的应用提供参考。结果表明:在0℃低温胁迫条件下,不同浓度的外源BR总体上均使红景天幼苗叶片CAT、POD、SOD活性不同程度升高,使叶片可溶性蛋白质含量不同程度升高,使膜表面电位降低,叶绿体膜Ca2+-ATP酶、Mg2+-ATP酶活性不同程度增强。试验表明,低温胁迫下外源BR通过提高抗氧化酶活性、抗氧化物质含量及渗透调节物质含量,减少了膜脂过氧化产物MDA的产生,降低膜电位,叶绿体膜Ca2+-ATP酶、Mg2+-ATP酶活性的增强,减轻细胞膜的损伤提高了长鞭红景天幼苗耐低温胁迫的能力。  相似文献   

7.
以耐盐性不同的2个加工番茄品种(‘双丰87-5’和‘佳禾9号’)为试材,研究了外源硒(Na2SeO3 0.05 mmol/L)对NaCl(100 mmol/L)胁迫下加工番茄叶片中活性氧清除系统的影响.结果表明:加硒显著降低了盐胁迫下加工番茄叶片的H2O2和丙二醛(MDA)含量,提高了加工番茄叶片中谷胱甘肽(GSH)和抗坏血酸(AsA)含量,降低了过氧化氢酶(CAT)活性,提高了超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性,说明硒能增强盐胁迫下加工番茄活性氧清除能力,降低膜脂过氧化作用,减少盐胁迫对植株的伤害.耐盐性强的加工番茄品种‘佳禾9号’具有强的活性氧清除能力,有效缓解了盐胁迫对加工番茄幼苗的毒害作用.  相似文献   

8.
镉对姜叶片活性氧代谢影响的时间和剂量效应   总被引：1，自引：0，他引：1  
刘灿玉  夏杰  韩敏  曹逼力  徐坤 《园艺学报》2016,43(5):927-934
为探讨姜对镉（Cd）胁迫的生理响应特性,通过外施CdCl2 ? 2.5H2O溶液,研究不同Cd水平对姜叶片活性氧代谢的影响。结果表明,Cd胁迫下,姜叶片中  生成速率和H2O2含量显著升高,且呈剂量和时间效应,同时丙二醛（MDA）含量和电导率持续增加。姜幼苗期,超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）、谷胱甘肽还原酶（GR）、抗坏血酸过氧化物酶（APX）、单脱氢抗坏血酸还原酶（MDHAR）、脱氢抗坏血酸还原酶（DHAR）、抗坏血酸氧化酶（AAO）等抗氧化酶活性均被Cd胁迫所诱导增强,还原型抗坏血酸（AsA）、总抗坏血酸（AsA + DHA）、酸溶性SH、还原型谷胱甘肽（GSH）、植物络合素等抗氧化物质含量显著升高,AsA/DHA、GSH/GSSG比值显著增加;随Cd胁迫浓度和时间的增加,相关保护酶活性及抗氧化物质含量均显著降低,表明姜对Cd较短期（40 d）胁迫或较低浓度Cd胁迫具有适应性,但胁迫120 d或过高浓度的Cd胁迫严重损伤了姜叶片抗氧化系统,使活性氧代谢失调,叶片膜系统遭到严重伤害。  相似文献   

9.
以绣球品种‘无尽夏’盆栽为试材，采用盆栽控水和叶面喷施（ALA）法，研究了不同质量浓度(0、25、50、75、100mg·L-1)的ALA溶液对干旱胁迫下绣球叶片的可溶性糖含量、可溶性蛋白质含量、游离脯氨酸（Pro）含量、抗氧化酶(超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）)活性、丙二醛（MDA）含量、超氧阴离子■产生速率的影响，以期为研究外源ALA增强植物在干旱胁迫下的抗旱能力提供参考依据，为提高绣球对干旱胁迫环境的生理适应性提供可行性方案。结果表明：干旱胁迫下绣球叶片表型失绿、渗透调节物质大量积累、抗氧化酶活性增强，植物生长受到抑制；适宜浓度的ALA溶液可以提高干旱胁迫下绣球渗透调节物质含量、抗氧化酶活性，缓解活性氧伤害，降低干旱胁迫对细胞质膜抗氧化程度，外源ALA可以有效缓解干旱胁迫对绣球的伤害，增强绣球对干旱胁迫的适应能力。  相似文献   

10.
为了探讨叶面喷施5-氨基乙酰丙酸(ALA)在黄瓜苗期的施用浓度和效果,以黄瓜品种津春4号3叶1心期的幼苗为材料,研究了不同浓度ALA对黄瓜幼苗叶片光合色素含量和抗氧化酶系统的影响。试验结果表明,叶面喷施10、30、50 mg/L的ALA可明显提高黄瓜叶片叶绿素(Chl)和类胡萝卜素(Car)含量,降低Chl a/b比值;显著增加超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和过氧化物酶(POD)活性,脯氨酸和可溶性蛋白含量;降低超氧阴离子(O2-·)生成速率、过氧化氢(H2O2)和丙二醛(MDA)含量;当ALA浓度达100 mg/L时,黄瓜幼苗受到一定的氧化胁迫伤害。这些结果说明,喷施浓度不超过100 mg/L ALA可促进黄瓜幼苗叶片光合色素的合成、增加其抗氧化能力,降低膜脂过氧化的程度,综合各项指标,以30 mg/L的ALA叶面喷施浓度在黄瓜幼苗上效果最佳。  相似文献   

11.
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12.
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   

13.
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   

14.
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15.
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16.
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   

17.
Cold stress is one of the most detrimental environmental factors affecting plant growth and development. Melatonin (MEL), a natural indoleamine compound, responds to various environmental cues. To explore the role of MEL in the response of melon (Cucumis melo L.) seedlings to cold stress, the effects of exogenous MEL on the ascorbate–glutathione (AsA–GSH) cycle and proline metabolism were investigated. Melon seedlings were sprayed with various concentrations of MEL (0, 50, 100, 200, or 400 μM), then exposed to cold stress, 12/6°C (day/night) for 7 d, followed by recovery at 28/18°C for another 7 d. The results showed that MEL, especially the 200 μM treatment, dramatically alleviated growth inhibition caused by cold stress, manifested by increased plant growth and decreased O2?¯ production rate and malondialdehyde content. Importantly, exogenous application of MEL enhanced the ratios of reduced and oxidized forms of AsA (AsA/DHA) and GSH (GSH/GSSG), and the activities of ascorbate peroxidase (APX), glutathione reductase (GR), and dehydroascorbate reductase (DHAR) involved in the ascorbate–glutathione (AsA–GSH) cycle in melon seedings grown under cold stress. Besides, MEL pretreatment further increased the contents of proline and soluble protein under cold stress. The results reveal that protective effects of MEL against cold stress in melon seedlings are most likely associated with the regulation of the AsA–GSH cycle and proline metabolism as an effective antioxidant system.  相似文献   

18.
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19.
Summary

Early sown radish seedlings were subjected to heat stress from the middle to late growth stage. Roots exhibiting internal browning (IB) were more prevalent in the susceptible cultivars whose seeds were sown early in the summer compared with those which were sown late. However, IB occurrence in the resistant ones was not nearly so marked regardless of the sowing date. In the IB susceptible cultivars, higher levels of L-phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) activities were detected in roots from the early sown plot (ESP), but these enyzme inductions did not occur to a significant extent in the resistant ones. Roots suffering internal browning were also detected to have pronounced increases in ascorbate peroxidase (APX) activity, but decreases in both dehydroascorbate reductase (DHAR) and glutathione reductase (GHAR) activities. These observations strongly suggest that a decline in H2O2 decomposing capacity of the ascorbate-glutathione cycle by heat stress is responsible for the activation of H2O2 detoxyifying pathway derived from PPO.  相似文献   

20.
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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