干旱胁迫对杠柳光合特性及抗氧化酶活性的影响

以盆栽杠柳幼苗为材料,用称重控水的方法设置4个含水量梯度,研究不同程度干旱胁迫对杠柳光合特性和抗氧化系统的影响,为黄河三角洲贝壳堤岛植被恢复过程中的物种培育和种植管理提供依据.结果表明:(1)随着干旱胁迫的加剧,杠柳幼苗叶片净光合速率(Pn)先增后降,蒸腾速率(Tr)和气孔导度(Gs)逐渐下降,胞间CO2浓度(Ci)先降后升,说明杠柳幼苗Pn下降在轻度干旱胁迫下主要是由气孔导度下降引起,而在重度胁迫下主要由非气孔因素引起.(2)随着干旱胁迫程度的加剧,杠柳幼苗瞬时水分利用效率(WUE)、表观光能利用效率(LUE)、羧化效率(CE)均呈现先增加后下降趋势;WUE在重度胁迫下才开始下降,比对照显著下降了39%,LUE(CE)则在中度胁迫下就开始下降,中度和重度胁迫分别比对照下降了48%(33%)、71%(69%).(3)随着干旱胁迫的加剧,杠柳叶片的超氧化物歧化酶(SOD)活性先升高后降低,过氧化物酶(POD)、过氧化氢酶(CAT)活性和MDA含量均逐渐增高,表明POD、CAT抑制杠柳叶片脂质过氧化效应不显著,SOD则抑制作用显著,且12.8%的贝壳沙含水量是SOD的耐受阈值,此时MDA含量比对照显著增加153%.     

Proline Accumulation, Protein Pattern and Photosynthesis in Bacopa Monniera Regenerants Grown under NaCl Stress

Shoots of Bacopa monniera exhibited 100 % regeneration on Murashige and Skoog medium with 2 % sucrose, 0.2 mg dm⁻³ 1-naphthaleneacetic acid, 0.5 mg dm⁻³ 6-benzylaminopurine and 50 mg dm⁻³ glutamine. When the medium was supplied with various concentrations (5 - 15 g dm⁻³) of sodium chloride, proline content in regenerants was six times higher than in the control. With increasing NaCl concentration photosynthetic rate decreased and fresh mass and root length of regenerants declined. NaCl also induced formation of new proteins. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of NaCl and Proline on Polyphenol Oxidase Activity in Bean Seedlings

In this work, the effects of NaCl (0, 50, 100, and 150 mM), proline (0, 5 and 10 mM) and NaCl + proline in combinations on activity of polyphenol oxidase (PPO; E.C. 1.10.3.1) and soluble protein content have been investigated in the root, stem and leaf tissues of bean (Phaseolus vulgaris L.) seedlings grown in embryo culture. PPO activities were higher in all the tissues treated with NaCl, proline and NaCl + proline combinations those that of the control tissues. The protein content was very high in tissues exposed to proline and NaCl + proline combination, but NaCl alone decreased protein contents in root and leaf tissues. The results suggest that proline may play a role as an enzyme-stabilizing agent in salt stress.     

Dopamine Alleviates Chilling Stress in Watermelon Seedlings via Modulation of Proline Content,Antioxidant Enzyme Activity,and Polyamine Metabolism

Journal of Plant Growth Regulation - Dopamine acts as a strong water-soluble antioxidant that mediates many physiological processes in plants. In the present study, we utilized two cultivars to...     

盐胁迫下小麦苗叶片吡咯-5-羧酸还原酶活性和游离脯氨酸积累

受NaCl、KCl或MsCl_2胁迫的小麦幼苗,当外部溶液的渗透势由—160 kPa下降到—900 kPa时,叶片吡咯—5—羧酸还原酶(PSC)活性增高;渗透势由—900 kPa降低到—1500kPa,酶活性下降;胁迫 1d和 2d的幼苗,还原酶活性显著增加;3～6d酶活性无大变化。游离脯氨酸含量随溶液渗透势下降和培养时间的延长而提高。胁迫解除后酶活性和脯氨酸含量均降低。受NcCl胁迫义在ABA影响下的幼苗,P5C还原酶活性和脯氨酸含量高于仅受NaCl胁迫的幼苗。     

Selenium Promotes the Growth and Photosynthesis of Tomato Seedlings Under Salt Stress by Enhancing Chloroplast Antioxidant Defense System

Tomato (Lycopersicon esculentum Miller) cv. Jiahe No. 9 (a salinity-resistant cultivar) and cv. Shuangfeng 87-5 (a salinity-sensitive cultivar) were used as experimental materials to investigate the effects of exogenous selenium (Na₂SeO₃ 0.05 mM) on plant growth, chlorophyll fluorescence, photosynthetic rate, and antioxidative metabolism of chloroplasts in tomato seedlings under NaCl (100 mM) stress. Salt stress significantly inhibited plant growth, net photosynthetic rate (P _n), maximum quantum yield of PSII (F _v/F _m), actual photochemical efficiency of PSII (Φ _PSII), photochemical quenching coefficient (q _P), and non-photochemical quenching coefficient (q _N) of both cultivars, whereas application of Se reversed the negative effects of salt stress. Furthermore, application of Se significantly decreased the levels of hydrogen peroxide (H₂O₂) and malondialdehyde. Application of Se increased the activities of superoxidase dismutase, glutathione reductase, dehydroascorbate reductase, monodehydroascorbate reductase, glutathione peroxidase, and thioredoxin reductase, and the contents of ascorbate, glutathione (GSH) and NADPH, and the ratios of GSH/GSSH, AsA/DHA, and NADPH/ NADP⁺ in the salt-stressed chloroplasts of both cultivars. These results suggest that Se alleviates salt-induced oxidative stress through regulating the antioxidant defense systems in the chloroplasts of tomato seedlings, which is associated with the improvement of the photochemical efficiency of PSII, thereby maintaining higher photosynthetic rates. In addition, the salt tolerance of Jiahe No. 9 is closely related with high reactive oxygen species scavenging activity and reducing power levels in the chloroplasts.     

Effect of Differential Light Quality on Morphology,Photosynthesis, and Antioxidant Enzyme Activity in Camptotheca acuminata Seedlings

Journal of Plant Growth Regulation - Light quality is an important environmental factor for plant growth and development. In this study, the effects of light quality (white, blue, yellow, and red...     

Effects of Melatonin on Growth,Physiology and Gene Expression in Rice Seedlings Under Cadmium Stress

Melatonin (MLT) is a hormonal substance found in many organisms and can improve plant stress resistance. In this study, the japonica rice variety Y32 and indica rice variety NJ6 were cultivated in hydroponics under different concentrations of CdCl₂ at the two-leaf stage. The growth, physiological and biochemical responses of the seedlings and the expression of cadmium (Cd)-related genes under exogenous melatonin (MLT) treatment were assessed. The results indicated that Cd stress destroyed the dynamic balance between reactive oxygen species (ROS) production and removal, resulting in ROS accumulation, membrane lipid peroxidation, and impaired growth and development. Following the application of exogenous MLT to rice seedlings, increases in plant biomass including both underground and above-ground areas were observed. MLT also scavenged the inhibition of superoxide dismutase (SOD) and peroxidase (POD) in a concentration dependent manner in response to Cd stress. Catalase (CAT) activity and malondialdehyde (MDA) expression also decreased following MLT treatment. Amongst the six Cd-related genes assessed, five genes were down-regulated and one was up-regulated in response to MLT treatment. Taken together, these data demonstrate that MLT improves the resilience of rice seedlings at the biochemical, physiological, and molecular levels, and diminishes the damage caused by Cd stress.     

可见分光光度法测定盐胁迫下玉米幼苗抗氧化酶活性及丙二醛含量

采用可见分光光度计法研究了盐胁迫条件下,登海9号及掖丹22两个玉米品种的幼苗中SOD、POD、CAT活性及MDA含量变化。根据这些生理指标在不同玉米品种、不同盐浓度处理下的变化规律,探求盐胁迫下玉米幼苗的抗盐生理机制。研究结果表明,随着NaCl处理浓度的提高,玉米幼苗中SOD、POD及CAT活性均有增加;当盐胁迫浓度达到60mol/L时,两玉米品种的SOD活性均达到最高,然后随NaCl处理浓度的增加,SOD活性逐渐降低;当盐胁迫浓度达到40mol/L时,两玉米品种的POD活性均达到最高,然后随NaCl处理浓度的增加,POD活性逐渐降低;当盐胁迫浓度达到40mol/L时,掖丹22的CAT活性达到最高,当盐胁迫浓度达到60mol/L时,登海9号的CAT活性达到最高,然后随NaCl处理浓度的增加,CAT活性逐渐降低。随着NaCl处理浓度的提高,玉米幼苗叶片中的MDA含量均有增加,当浓度大于40mol/L时,增加幅度加大。     

外源亚精胺对盐胁迫下黄瓜幼苗生长和可溶性蛋白表达的影响

采用营养液水培方法,研究了叶面喷施亚精胺(Spd)对黄瓜幼苗生长和可溶性蛋白的影响.结果表明,外源Spd可使盐胁迫黄瓜幼苗株高、茎粗、叶面积、根长和根表面积显著增加,可溶性蛋白含量明显提高,部分可溶性蛋白的表达量减弱;而对正常生长条件下黄瓜幼苗各生长指标无明显影响,但显著提高了根系中可溶性蛋白的含量.随着Spd处理时间的延续,盐胁迫幼苗至少有7种分子量分别约为67、61.5、50、47、43、29和16 kD的可溶性蛋白表达量发生明显变化,尤其使61.5、47和43 kD蛋白表达量明显减弱,50 kD蛋白甚至消失,这4种蛋白可能与外源Spd缓解黄瓜幼苗盐胁迫伤害效应关系密切.     

盐胁迫下木麻黄幼苗抗氧化酶活性的变化及Ca2+对它的调控

在单纯NaCl处理下,随着NaCl浓度的加大,木麻黄幼苗的蛋白质含量逐渐升高,超氧化物歧化酶(SOD)活性下降,过氧化物酶(POD)活性则逐渐增加,过氧化氢酶(CAT)活性在低盐下下降,高盐下明显升高.加入适量Ca2 后,SOD活性上升,POD活性和蛋白质含量下降.CAT活性低时加Ca2 ,CAT活性增加;CAT活性高时加Ca2 ,CAT活性则降低.     

低温胁迫下氯丙嗪和氯化镧对水稻幼苗脯氨酸积累的影响

低温胁迫下水稻幼苗质膜透性增大、相对含水量(RWC)下降、丙二醛(MDA)含量增加,同时脯氨酸(Pro)积累。以氯丙嗪(CPZ)和氯化镧(LaCl3)对水稻幼苗预处理以阻碍Ca2+·CaM(钙调素)信使传导后,加剧了低温胁迫下水稻幼苗质膜透性的增加、RWC的下降、MDA含量的增加和Pro的积累,说明水稻幼苗受伤害程度将加重。     

NaCl胁迫对番茄嫁接苗生物量及离子含量的影响

以影武者为砧木,宝大903为接穗,研究了NaCl胁迫下番茄嫁接苗与接穗自根苗在生物量及Na 、K 、Ca2 、Mg2 、Cl-等含量方面的差异.结果显示,NaCl胁迫下,嫁接苗生长受抑制程度较轻;嫁接苗和自根苗Na 、Cl-含量增长幅度最大的部位均是叶片,嫁接苗增长幅度小于自根苗;K 、Ca2 、Mg2 含量下降幅度最大的部位均是根系,嫁接苗下降幅度小于自根苗;嫁接苗的K /Na 值、Ca2 /Na 值显著高于自根苗,说明嫁接苗选择性吸收K 、Ca2 能力显著强于自根苗.结果表明,NaCl胁迫下嫁接苗体内离子分布的区域化优于自根苗,耐盐性强于自根苗.     

盐胁迫对红麻幼苗生长及抗氧化酶活性的影响

为研究不同盐胁迫时间和不同盐浓度胁迫对红麻（Hibiscus cannabinusL.）幼苗的生长及抗氧化酶活性的影响,探寻红麻耐盐的生理机制,为盐碱地种植红麻提供科学依据,本研究对红麻幼苗进行了两种不同条件的盐胁迫处理。一种将红麻幼苗在0（对照组）、140 mmol/L NaCl的半强度Hoagland营养液下分别处理3、6、9 d,另一种是在0（对照组）、70、140、200 mmol/L NaCl的1/2 Hoagland营养液下处理6 d,分别测定两种盐胁迫条件下植株的鲜重、根长、茎长、叶片H2O2、丙二醛（MDA）含量、超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）和谷胱甘肽还原酶（GR）活性。结果显示：（1）在第一种处理条件下,随着盐胁迫时间的延长,处理组红麻幼苗的鲜重相对于对照分别减轻了19.63%、19.35%和39.03%,株高则分别降低了25.59%、19.17%和18.48%,处理组的SOD活性先增后减,POD活性先减后增,MDA和H2O2的含量、CAT和GR活性基本随胁迫时间的增长而增高。（2）在第二种处理条件下,随着胁迫盐浓度的增加,处理组鲜重相对于对照分别减轻了16.79%、19.35%和44.73%,株高则分别降低了11.21%、19.17%和23.62%,处理组SOD活性都稍高于对照,但三者无显著差异,POD活性先减后增,MDA和H2O2的含量、CAT和GR活性基本上随着盐浓度增加而增加。实验表明,在两种不同条件的盐胁迫下,红麻幼苗受盐害的程度基本上随胁迫时间和盐浓度的增加而加重。处理组植株的SOD和POD活性较对照组增加不明显,甚至有所降低,而CAT和GR活性则相对较高,CAT和GR可能在红麻幼苗抵御盐害时起较重要作用。     

NaCl对小麦苗叶片脯氨酸氧化酶活性和游离脯氨酸累积的影响

在含NaCl营养液中培养的小麦幼苗较之无NaCl营养液中的幼苗。其脯氨酸氧化酶活性降低,而游离脯氨酸含量则升高;培养液的渗透势越低,培养时间越长,则脯氨酸氧化酶的活性越低,且游离脯氨酸的含量越高。去除胁迫后酶活性恢复,脯氯酸含量下降。不同渗透剂对氧化酶活性抑制强弱顺序为MgCl_2>NaCl>甘露醇,引起脯氨酸累积效应的强度顺序为MgCl_2>NaCl>甘露醇。超微结构显示,高NaCl浓度下部分线粒体结构受损伤,膜和嵴部分消失。     

NaCl 胁迫对甘草生长及抗氧化酶活性的影响

目的:通过分析不同浓度NaCl胁迫下甘草生长和抗氧化酶活性的变化探讨甘草对盐分胁迫的适应性机理;方法:采用不同浓度的NaCl溶液(配成Hoagland液)处理盆栽一年生甘草,分别于35d、70d和105d取样,测定甘草株高、地上部分鲜、干重、根鲜、干重及甘草叶片SOD、POD、CAT活性,分析各生长指标与抗氧化酶活性的相关性;结果:NaCl胁迫70d和105d,0.6%和0.9%处理组的株高、地上部分鲜、干重及根鲜、干重均显著低于CK,SOD、POD及CAT活性均显著高于CK,经相关性分析得知,SOD、POD及CAT活性与各生长指标均负相关,其中POD活性与各生长指标极显著负相关;结论:甘草对NaCl胁迫的响应有胁迫时间和浓度的依赖性,在遭遇胁迫时,通过改变自身的生长和提高抗氧化酶活性,来提高机体的抗盐能力。     

外源亚精胺对Ca(NO3)2胁迫下番茄幼苗合特性和抗氧化酶活性的影响

以耐盐性较弱的番茄品种上海‘合作903’幼苗为试验材料,采用营养液栽培方法,研究了叶面喷施1 mmol·L-1亚精胺( Spd)对75 mmol·L-1 Ca(NO3)2胁迫下番茄幼苗生长、叶绿素含量、光合及荧光参数、叶片抗氧化酶活性的影响,以探讨外源亚精胺缓解Ca( NO3)2胁迫伤害的机制.结果显示:Ca(NO3)2胁迫能够显著抑制番茄幼苗的生长;与Ca( NO3)2胁迫处理相比,叶面喷施外源Spd 9 d后,受胁迫番茄幼苗的株高、茎粗、干重、鲜重分别显著增加70.9％、15.8％、43.4％、41.4％;叶绿素a、b的含量分别提高17.7％、13.8％;净光合速率(Pn)、气孔导度(Gx)、蒸腾速率(T1)、光合电子传递效率(rETR)和光化学猝灭系数(qp)分别升高6.6％、18.0％、31.0％、4.9％、5.0％,而胞间二氧化碳浓度(C1)、非光化学猝灭系数(q、)分别降低21.5％、8.1％;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性分别增加10.7％和37.5％,而丙二醛(MDA)含量和超氧阴离子(O2)产生速率分别显著下降34.5％、17.1％.研究表明,外源Spd通过提高番茄幼苗抗氧化酶活性来有效清除体内活性氧,维持光合机构的稳定性,提高其光合速率,从而缓解Ca( NO3)2胁迫对番茄幼苗的伤害.     

土壤水分胁迫对红砂幼苗叶绿素荧光和抗氧化酶活性的影响

以红砂(Reaumuria soongorica)2年生幼苗为材料,研究不同土壤水分处理下其叶绿素荧光参数、叶绿素含量和抗氧化酶活性等光合生理指标的变化特征。取得如下结果。(1)与对照组(CK)相比,中度胁迫(MS)和重度胁迫(SS)处理下红砂叶绿素含量分别降低了15.3%和25.7%,叶绿素(a/b)含量分别增加了7.4%和36.9%。表明胁迫处理导致色素含量和捕光色素复合体II含量下降,减少了其对光能的捕获,降低了光合机构遭受破坏的风险。(2)随着胁迫的加剧,初始荧光(Fo)呈升高趋势,而最大荧光(Fm)、PSII潜在光化学效率(Fv/Fo)和PSII最大光化学效率(Fv/Fm)呈明显降低趋势。说明胁迫使PSII结构与功能受到一定程度的损伤和破坏。(3)在胁迫处理下,抗氧化酶活性和丙二醛含量也发生了一定程度的变化,反映出红砂对胁迫环境有较强的耐受性。