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1.
以3年生圆柏和祁连圆柏幼苗为材料,采用不同浓度水杨酸(SA)预处理两种圆柏属植物幼苗,测定-4℃低温胁迫处理第6天叶片相对含水量(RWC)、相对电导率(REC)、丙二醛(MDA)、可溶性糖(SS)、可溶性蛋白(SP)、脯氨酸(Pro)和类胡萝卜素(Car)含量及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸氧化酶(APX)和谷胱甘肽还原酶(GR)活性,分析外源 SA 对低温胁迫下圆柏属植物叶片膜脂过氧化、渗透调节物质及抗氧化酶系统的影响,为培育较多品种的抗冷冻常绿植物提供理论依据。结果表明:低温胁迫下,一定浓度的 SA 预处理能有效保护幼苗叶片膜系统的稳定性、增加渗透调节物质含量和提高抗氧化酶活性,其中200 mg/L SA 预处理对提高圆柏抗寒性效果最好,30 mg/L SA 预处理对提高祁连圆柏抗寒性效果最好,且在外源 SA 预处理下,祁连圆柏的抗寒性比圆柏的强。因此,施用适合浓度的 SA 在提高圆柏属植物抗寒性方面具有较好的应用价值。  相似文献   

2.
水分胁迫下扶芳藤幼苗保护酶活性和渗透调节物质的变化   总被引:43,自引:0,他引:43  
扶芳藤(Euonymus fortunei(Turcz.)Hand.-Mazz)作为北方城市园林的新优攀援藤本和地被植物越来越受到重视,新品系的抗逆性筛选工作迫在眉睫。本文采用聚乙二醇(PEG-6000)模拟水分胁迫的方法。测定其生理指标,研究水分胁迫对扶芳藤不同品系幼苗叶片保护酶活性和渗透调节物质的影响。旨在摸索出这些生理指标与植物抗旱性的关系。研究结果表明,随着模拟干旱时间的延长。扶芳藤幼苗叶片中相对含水量(RWC)逐步下降,保护酶活性上升。脯氨酸和可溶性糖含量急剧上升,并且抗旱性强的品系保护酶活性和渗透调节物质含量较高。  相似文献   

3.
翅果油树幼苗对NaCl胁迫的生理生化反应   总被引:1,自引:0,他引:1  
研究了不同浓度NaCl处理对翅果油树幼苗高度、叶绿素含量、膜脂过氧化和保护酶活性的影响.结果表明,随着NaCl浓度的升高和胁迫时间的延长,幼苗高度明显受到抑制,叶绿素含量呈下降趋势.整个处理过程中,丙二醛(MDA)含量逐渐增加,但增加幅度不大,表明脂质过氧化反应水平不高.各处理浓度的叶片相对电导率、超氧化物歧化酶(SOD)、过氧化物酶(POD)活性均呈上升趋势.研究表明,翅果油树幼苗在NaCl胁迫下有活性较高的膜保护酶系统,具有一定的抗盐能力.  相似文献   

4.
低温胁迫下黄瓜幼苗子叶抗坏血酸过氧化物酶活性和GSH含量显著下降,下降幅度随低温胁迫程度增加而递增。不同低温胁迫下酶活性和GSH含量变化与子叶电解质泄漏和MDA的增加呈负相关。幼苗用MV和MDA预处理可加剧由低温引起的抗坏血酸过氧化物酶活性和GSH含量降低,而用苯甲酸钠和α-生育酚预处理则可减轻这种降低,显示出过量的活性氧及其引发的膜脂过氧化产物MDA对抗坏血酸过氧化物酶和GSH均有伤害影响。  相似文献   

5.
为了探讨空心莲子草(Alternantheraphiloxeroides(Mart.)Griseb)的抗盐机理,测定了盐胁迫条件下的空心莲子草和水稻中保护酶活性和渗透调节物质的变化。结果表明,在盐胁迫下,空心莲子草中的脯氨酸、甜菜碱以及SOD、POD等含量增加速度比水稻快,膜脂过氧化产物丙二醛的含量在两种植物中虽亦增加,但在空心莲子草叶中的增加幅度小于水稻。证明盐胁迫下保护酶活性和渗透调节物质含量的迅速增加是空心莲子草具有较强抗盐能力的重要生理学基础。  相似文献   

6.
盐胁迫对低温预处理石榴种子萌发及幼苗生理生化的影响   总被引:5,自引:0,他引:5  
以催芽‘峄城大青皮甜’石榴种子为材料,经2~4℃低温预处理5、10和15d,置于不同盐分梯度下进行种子萌发试验,并测定分析幼苗生长、细胞保护酶活性、可溶性糖和脯氨酸含量及电导率变化,以阐明盐胁迫下低温预处理对石榴种子萌发和幼苗生长及生理生化的影响。结果显示:(1)适当的低温预处理和低盐胁迫能提高石榴种子的发芽率和发芽势,低温处理5d和0.1%低盐环境下有利于壮苗生长。(2)适当时间的低温预处理(5d)可显著提高石榴幼苗的保护酶(SOD、POD、CAT)活性,长时间的低温预处理(15d)却降低了幼苗的保护酶活性;随着盐浓度的升高石榴幼苗的保护酶活性也逐渐升高,并在盐浓度为0.3%时均达到最大值,说明当盐浓度高于0.3%时超出了石榴幼苗保护酶系统的调节范围,从而发生盐害。(3)低温预处理5d和10d降低了幼苗可溶性蛋白和脯氨酸的含量;随着盐浓度的升高幼苗可溶性蛋白和脯氨酸的含量也逐渐升高。(4)5d和10d的低温预处理可以提高石榴幼苗细胞膜透性,随着盐浓度的升高相对电导率也显著升高。研究表明,在低盐环境下,适当时间的低温预处理能显著促进石榴种子萌发生长,其幼苗能通过调整自身渗透调节物质可溶性蛋白和脯氨酸含量以及体内保护酶活性,降低细胞膜脂过氧化程度,保证细胞膜的完整性,维持正常的细胞代谢活性,从而有效减轻盐胁迫对植株的伤害,表现出较强的抗盐性。  相似文献   

7.
目的:研究不同浓度的水杨酸对10%聚乙二醇(PEG-6000)胁迫下野生大豆生理特性的影响。方法:以野生大豆为试验材料,采用盆栽土培法,研究野生大豆幼苗抗氧化酶活性,渗透调解物质及膜质过氧化变化规律。结果:1.5 mmol/L水杨酸明显提高了PEG胁迫下野生大豆过氧化物酶(POD)、超氧化物歧化酶(SOD),减轻了膜脂过氧化。随着水杨酸浓度升高,可溶性糖呈下降趋势,脯氨酸含量呈先上升后下降趋势,和可溶性蛋白呈上升趋势,结论:外源水杨酸可通过POD、SOD活性和渗透调节物质的含量提高幼苗的抗干旱胁迫能力。在本试验中以1.5 mmol/L水杨酸缓解效果最好。  相似文献   

8.
5种卫矛属植物对低温胁迫的生理响应及抗寒性评价   总被引:2,自引:0,他引:2  
以5种卫矛属树种(品系)当年生充分休眠离体带叶枝条为试材,在高低温湿热试验箱内进行0℃、-10℃、-20℃和-30℃共4个梯度低温胁迫处理,考察其叶片解剖结构以及细胞膜透性、渗透调节物质、保护酶活性等生理指标的低温响应特征,并结合隶属函数分析方法综合评价5种卫矛属植物抗寒性。结果表明:(1)‘北海道黄杨6号’叶片有3层紧密的栅栏组织,北海道黄杨、胶州卫矛和大叶黄杨叶片有2层紧密、1层相对疏松的栅栏组织,扶芳藤叶片则只有2层排列紧密的栅栏组织;5个树种叶片组织紧密度表现为‘北海道黄杨6号’北海道黄杨胶州卫矛大叶黄杨扶芳藤。(2)通过Logistic方程拟合叶片相对电导率随温度的变化,获得5种卫矛树种的半致死温度(LT_(50))由低到高依次为‘北海道黄杨6号’(-19.69℃)、北海道黄杨(-17.41℃)、胶州卫矛(-16.03℃)、大叶黄杨(-13.33℃)、扶芳藤(-10.45℃)。(3)各树种叶片渗透调节物质含量随胁迫温度的降低而持续增加,在-30℃低温时,叶片可溶性糖含量以‘北海道黄杨6号’和北海道黄杨的增幅最大,可溶性蛋白含量以胶州卫矛和大叶黄杨增幅最大,但两者含量均以扶芳藤增幅最小。(4)各树种叶片抗氧化酶活性均随胁迫温度的降低而先升高后降低,大叶黄杨和扶芳藤叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、多酚氧化酶(PPO)活性均在-10℃低温胁迫时达到峰值,而‘北海道黄杨6号’、北海道黄杨和胶州卫矛叶中各酶活性在-20℃低温胁迫时才达到峰值,它们酶活性峰值出现的时间及高低与其半致死温度的结果相吻合。(5)隶属函数综合评价结果显示,5种卫矛属植物的抗寒能力表现为‘北海道黄杨6号’北海道黄杨胶州卫矛大叶黄杨扶芳藤。研究发现,在低温胁迫条件下,卫矛属植物一方面通过渗透调节物质的合成来提高细胞内的渗透势,另一方面通过增强抗氧化酶活性来清除细胞内过量的活性氧、酚酸类等有害物质,从而对低温环境具有一定的适应能力,这为卫矛属植物抗寒种质的筛选及其在城市绿化中的合理应用提供了理论依据。  相似文献   

9.
以酿酒葡萄‘雷司令’(Riesling)一年生营养袋扦插苗为材料,采用人工气候室水培试验,考察在聚乙二醇6000(PEG)模拟干旱条件下,不同浓度(0.05、0.10和0.20mg/L)24-表油菜素内酯(EBR)预处理对‘雷司令’幼苗活性氧、抗氧化物质、渗透调节物质含量和抗氧化酶活性的影响,以揭示EBR预处理对干旱胁迫下葡萄幼苗的抗旱机理。结果显示:(1)与正常生长(对照)相比,干旱胁迫显著提高葡萄幼苗叶片中超氧阴离子自由基(■)、过氧化氢(H_2O_2)和丙二醛(MDA)含量;与干旱胁迫处理(PEG)相比,不同浓度EBR预处理均可降低叶片中■、H_2O_2和MDA的含量。(2)与对照相比,PEG处理显著降低葡萄幼苗叶片的抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量;与PEG处理相比,各浓度EBR预处理均可显著提高葡萄叶片AsA与GSH的含量,且以0.10mg/LEBR处理效果最好。(3)随着干旱胁迫时间的延长,葡萄幼苗叶片中的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)与抗坏血酸过氧化物酶(APX)活性均呈先上升后下降的变化趋势,而在正常生长条件下酶活性基本保持不变;EBR预处理的葡萄叶片SOD、CAT、POD和APX活性均始终高于同期PEG处理。(4)PEG处理条件下,渗透调节物质脯氨酸和可溶性蛋白的含量整体高于对照;与PEG处理相比,不同浓度EBR预处理在干旱胁迫中后期均能显著提高葡萄叶片中脯氨酸和可溶性蛋白含量。研究表明,在干旱胁迫下,外源EBR预处理能够提高葡萄叶片抗氧化系统酶活性和渗透调节物质含量,有效降低干旱胁迫诱导的活性氧过度积累及膜脂过氧化程度,提高葡萄幼苗的抗旱能力,且以0.10mg/L EBR处理效果最佳。  相似文献   

10.
通过盆栽控水实验,模拟科尔沁沙地由东至西50年的年均降水量及最大、最小年降水量下的土壤水势,分析了不同水分处理(土壤水势分别为-16.18、-5.09和-4.50 bars,即A、B和C处理)对樟子松2年生幼苗膜脂过氧化产物[丙二醛(MDA)、脂膜相对透性(RC)和超氧阴离子自由基(O2-)产生速率]、渗透调节物质[可溶性糖(SS)、可溶性蛋白(SP)和脯氨酸(Pro)]和膜保护酶(SOD酶和POD酶)的影响.不同水分处理对樟子松幼苗针叶内的保护酶、渗透调节物质及膜脂过氧化的作用影响显著.随着土壤水势的降低,幼苗的SOD酶呈现微下降再升高的趋势;POD酶活性呈逐渐升高的趋势;幼苗的渗透调节物质(SS、SP和Pro)的含量均呈现上升趋势;3种水分处理的可溶性糖和可溶性蛋白含量上升的幅度最大,A处理分别是C处理的1.8倍和2.4倍,脯氨酸的含量持续积累;随干旱胁迫加重,MDA、RC和O2-产生速率均有明显上升趋势,以O2-产生速率上升幅度最大.这表明,樟子松幼苗通过体内的生理生化机制,尤其是增加渗透调节物质的含量,实现对干旱胁迫较强的忍耐性和较好的适应性.A处理针叶内的自由基大量积累和膜脂过氧化程度加重,对植物造成不可逆的损伤.  相似文献   

11.
Proline accumulates in a variety of plant species in response to stresses such as drought, salinity and extreme temperatures. Although its role in plant osmotolerance remains controversial, proline is thought to contribute to osmotic adjustment, detoxification of reactive oxygen species and protection of membrane integrity. In the present study, we evaluated the effects of stress-inducible proline production on osmotic adjustment, chlorophyll fluorescence and oxidative stress protection in transgenic sugarcane transformed with a heterologous P5CS gene. In well-watered conditions, free proline, malondialdehyde (MDA) levels, Fv/Fm ratios and chlorophyll contents (Chls) in transgenic sugarcane were not statistically different from non-transformed control plants. After 9 days without irrigation, proline content in transgenic events was on the average 2.5-fold higher than in controls. However, no osmotic adjustment was observed in plants overproducing proline during the water-deficit period. The photochemical efficiency of PSII observed was higher (65%) in the transgenic events at the end of the water-deficit experiment. The effects of proline on lipid peroxidation as MDA levels and on the decline of Chl in paraquat-treated leaf discs along the drought period suggest that proline protected the plants against the oxidative stress caused by the water deficit. The overall capacity of transgenic plants to tolerate water-deficit stress could be assessed by the significantly higher biomass yields 12 days after withholding water. These results suggest that stress-inducible proline accumulation in transgenic sugarcane plants under water-deficit stress acts as a component of antioxidative defense system rather than as an osmotic adjustment mediator.  相似文献   

12.
The influence of the arbuscular mycorrhizal (AM) fungus, Glomus mosseae, on characteristics of growth, photosynthetic pigments, osmotic adjustment, membrane lipid peroxidation and activity of antioxidant enzymes in leaves of tomato (Lycopersicon esculentum cv Zhongzha105) plants was studied in pot culture under low temperature stress. The tomato plants were placed in a sand and soil mixture at 25°C for 6 weeks, and then subjected to 8°C for 1 week. AM symbiosis decreased malondialdehyde (MDA) content in leaves. The contents of photosynthetic pigments, sugars and soluble protein in leaves were higher, but leaf proline content was lower in mycorrhizal than non-mycorrhizal plants. AM colonization increased the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) in leaves. The results indicate that the AM fungus is capable of alleviating the damage caused by low temperature stress on tomato plants by reducing membrane lipid peroxidation and increasing the photosynthetic pigments, accumulation of osmotic adjustment compounds, and antioxidant enzyme activity. Consequently, arbuscular mycorrhiza formation highly enhanced the cold tolerance of tomato plant, which increased host biomass and promoted plant growth.  相似文献   

13.
Increase of glycinebetaine synthesis improves drought tolerance in cotton   总被引:1,自引:0,他引:1  
The tolerance to drought stress of the homozygous transgenic cotton (Gossypium hirsutum L.) plants with enhanced glycinebetaine (GB) accumulation was investigated at three development stages. Among the five transgenic lines investigated, lines 1, 3, 4, and 5 accumulated significantly higher levels of GB than the wild-type (WT) plants either before or after drought stress, and the transgenic plants were more tolerant to drought stress than the wild-type counterparts from young seedlings to flowering plants. Under drought stress conditions, transgenic lines 1, 3, 4, and 5 had higher relative water content, increased photosynthesis, better osmotic adjustment (OA), a lower percentage of ion leakage, and less lipid membrane peroxidation than WT plants. The GB levels in transgenic plants were positively correlated with drought tolerance under water stress. The results suggested that GB may not only protect the integrity of the cell membrane from drought stress damage, but also be involved in OA in transgenic cotton plants. Most importantly, the seedcotton yield of transgenic line 4 was significantly greater than that of WT plants after drought stress, which is of great value in cotton production.  相似文献   

14.
渗透调节参与循环干旱锻炼提高烟草植株抗旱性的形成   总被引:1,自引:0,他引:1  
对漂浮育苗的烟草幼苗进行控水一半萎焉.复水一恢复的循环干旱锻炼。结果表明,这种干旱锻炼能显著提高烟草幼苗根、茎、叶中的渗透调节物质可溶性糖和脯氨酸的含量,降低细胞渗透势。当干旱锻炼过的烟草植株遭受后续的干旱胁迫时,与未锻炼的对照相比,其根、茎、叶能积累更多的可溶性糖和脯氨酸,从而降低了细胞渗透势,使叶片能维持较高的膨压。这些结果表明渗透调节参与了循环干旱锻炼提高的烟草植株抗旱性的形成过程。此外,干旱锻炼提高了烟草幼苗的根/冠比。循环干旱锻炼过程中烟草植株一方面使其各部位通过渗透调节来对干旱环境进行生理适应,另一方面通过调节光合产物在地上部和地下部的分配以影响根/冠比来对干旱环境进行形态适应,以最终提高其抗旱性。  相似文献   

15.
岷江干旱河谷区典型灌木对干旱胁迫的生理生化响应   总被引:2,自引:0,他引:2  
以岷江干旱河谷区6种典型山地灌木[沙棘(Hippophae rhamnoides)、羊蹄甲(Bauhinia faberi)、白刺花(Sorphora davidii)、锦鸡儿(Caragana arborescens)、三颗针(Berberis sargentiana)、黄栌(Cotinus szechuanensis)]为试材,采用盆栽试验研究了土壤自然干旱胁迫对苗木叶片抗氧化保护酶活性、膜伤害程度以及渗透调节物质的影响,探讨植物应对土壤干旱逐渐加剧的生理生态适应机理。结果表明,植物不同抗氧化保护酶对干旱胁迫及随之而来的氧化胁迫的响应存在一定差异。各灌木的超氧化物歧化酶随着干旱胁迫的增强呈先上升后下降,过氧化物酶在整个胁迫期间表现为逐渐升高,过氧化氢酶的升高则主要发生在胁迫的中后期,表明不同胁迫时期对植物体起主导作用的保护酶不同,三者表现为相互协调的作用方式。随着干旱胁迫的增强,各灌木的丙二醛呈缓慢增加趋势,细胞的膜脂过氧化作用逐渐加强,植物开始遭受一定程度的毒害。沙棘和羊蹄甲叶片的质膜相对透性随胁迫的增强呈现先升后降最终回到初始水平的特点,表明植物可以通过干旱锻炼获得一定的抗旱能力。白刺花和黄栌叶片的质膜相对透性在胁迫的0—4 d保持不变,从8 d开始大幅上升并一直维持在较高水平,说明胁迫初期植物细胞膜的结构和功能还很完整,生理活动仍能正常进行,但从中期开始细胞膜遭受严重破坏。随着干旱胁迫的增强,各灌木叶片的脯氨酸总体均呈增加趋势,表明干旱胁迫下植物通过积累脯氨酸以提高细胞的渗透调节能力。主成分分析表明,6种灌木的抗旱能力由强到弱依次为:羊蹄甲、沙棘、锦鸡儿、黄栌、白刺花、三颗针。综合分析表明,干旱河谷区几种典型灌木可通过提高抗氧化酶活性并积累渗透调节物质对干旱胁迫进行积极的反馈,以减弱逆境胁迫下活性氧的危害,提高细胞的渗透调节能力,减轻细胞遭受的损伤。  相似文献   

16.
Cold stress is among the environmental stressors limiting productivity, yield and quality of agricultural plants. Tolerance to cold stress is associated with the increased unsaturated fatty acids ratio in the plant membranes which are also known to be substrates of octadecanoid pathway for jasmonate and other oxylipins biosynthesis. Accumulation of osmoprotectant, glycine betaine (GB) is well known to be effective in the protecting membranes and mitigating cold stress effects but, the mode of action is poorly understood. We studied the role of GB in cold stress responses of two tomato cultivated varieties; Gerry (cold stress sensitive) and T47657 (moderately cold stress tolerant) and compared the differences in lypoxygenase-13 (TomLOXF) and fatty acid desaturase 7 (FAD7) gene expression profiles and physiological parameters including relative growth rates, relative water content, osmotic potential, photosynthetic efficiency, membrane leakage, lipid peroxidation levels. Our results indicated that GB might have a role in inducing FAD7 and LOX expressions for providing protection against cold stress in tomato plants which could be related to the desaturation process of lipids leading to increased membrane stability and/or induction of other genes related to stress defense mechanisms via octadecanoid pathway or lipid peroxidation products.  相似文献   

17.
Cold temperature acclimation in strawberry (Fragaria virginiana) leaves apparently involves the alteration of cellular osmotic properties. Alterations in leaf osmotic potential were closely correlated with alterations in soluble carbohydrate content of the leaf tissue and changing temperatures. Leaf starch content was inversely related to soluble carbohydrate levels, suggesting that starch is a partial source of osmoticum during osmotic adjustment associated with cold temperature stress. Free amino acid changes were more closely linked to senescence and growth processes while changes in ion content suggested a rapid mobilization of solutes at the onset of freezing temperatures. This was supported by changes in whole plant gradients in leaf osmotic potential before and after exposure to freezing temperatures. In terms of freezing resistance and the role of osmotic adjustment in the development of resistance, it was found that of all leaves undergoing osmotic adjustment only the younger leaves survived, suggesting an age-dependent component to freezing resistance in leaves. Freezing resistance appears to involve alterations in several cellular properties that act in concert to confer a hardy state of the tissue. Although osmotic adjustment may be an important component of the final combination of cellular properties, this study indicates that solute accumulation does not function alone to confer freezing resistance.  相似文献   

18.
以抗旱性不同的小麦品种为材料,在小麦的水分临界期开花期进行缓慢脱水处理,分别在脱水的不同阶段取样测定叶片及根系的渗透调节能力及渗透调节物质。结果表明:随着土壤含水量的降低,叶片与根系的饱和渗透势同步下降,表现出叶片与根系对水分胁迫反应的一致性,但根系的渗透调节能力低于叶片。根系与叶片的渗透调节物质,一方面在物质总含量方面,表现出与渗透调节能力的一致性,另一方面各种物质的相对含量又有一定差异,叶片中可溶性糖与K+的含量及增加量都高于根系,而根系中的游离氨基酸与Ca2+的相对增加量则大于叶片。  相似文献   

19.
以抗旱性不同的小麦品种为材料,在小麦的水分临界期开花期进行缓慢脱水处理,分别在脱水的不同阶段取样测定叶片及根系的渗透调节能力及渗透调节物质。结果表明:随着土壤含水量的降低,叶片与根系的饱和渗透势同步下降,表现出叶片与根系对水分胁迫反应的一到场生,但根系的渗透调节能力低于叶片。根系与叶片的渗透调节物质,一方面在物质总含量方面,表现出与渗透调节能力的一致性,另一方面各种物质的相对含量又有一定差异,叶片中可溶性糖与K+含量及增加量都高于根系,而根系中的游离氨基酸与Ca^2 的相对增加量则大于叶片。  相似文献   

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