首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 125 毫秒
1.
盐胁迫对玉米叶片叶肉细胞生物膜超微结构的影响   总被引:4,自引:0,他引:4  
研究了NaCl胁迫对玉米叶肉细胞生物膜超微结构的影响. 结果表明:NaCl胁迫破坏了玉米叶片叶肉细胞生物膜的正常结构,50 mmol·L-1 NaCl处理胁迫下,玉米叶肉细胞核膜,线粒体膜,细胞膜,叶绿体膜,液泡膜都受到不同程度的破坏,叶绿体基粒类囊体膨胀,间质片层空间增大,片层紊乱。100 mmol·L-1 NaCl处理胁迫下,质膜,液泡膜,线粒体,叶绿体都受到严重的破坏。细胞质膜破坏,破损的叶绿体充斥在细胞间隙中;叶绿体外膜破坏,甚至解体消失,叶肉细胞中充满膜结构,基粒排列方向改变,垛叠层数减少,基粒和基质片层界限模糊不清,有的基粒解体消失,甚至叶绿体完全解体;核膜破坏、解体,核中的染色质高度凝缩;线粒体的数量增多,线粒体膜破坏,脊的数量减少,甚至整个线粒体破损解体;液泡膜破坏;由于各种生物膜的破坏,使细胞内充满许多囊状小泡、多泡体或斑层小体;叶肉细胞发生严重的质壁分离,严重时发生细胞壁断裂;甚至整个细胞溶解。  相似文献   

2.
Cd2+胁迫对石龙尾超微结构的影响   总被引:1,自引:1,他引:0  
赵春 《广西植物》2008,28(5):592-595
以在不同浓度梯度Cd2+溶液中培养48h的石龙尾为实验材料,用透射电镜观察叶细胞超微结构的损伤,结果表明:Cd2+浓度越高,超微结构的损伤越严重。表现为核糖体数目减少;高尔基体膨胀或消失;线粒体出芽或破裂;质膜收缩产生质壁分离,胞间连丝断裂;叶绿体膨胀,类囊体解体,进而影响了细胞的整体功能,造成细胞损伤乃至死亡。  相似文献   

3.
Na2CO3胁迫对星星草叶肉细胞超微结构的影响   总被引:13,自引:1,他引:12  
利用透射电镜技术对Na2CO3胁迫下星星草叶肉细胞超微结构进行了观察。结果表明:未胁迫的叶肉细胞排列疏松,各种细胞器结构完整,叶绿体含少量淀粉粒和脂质球。轻度盐胁迫(2g/L,4g/LNa2CO3)对叶肉细胞超微结构影响较小。中度盐胁迫(6g/L,8g/L Na2CO3)引起叶肉细胞超微结构的变化,叶绿体类囊体肿胀,基粒紊乱,不含淀粉粒,脂质球数量增加,叶绿体由原来的梭形或椭球形变成圆球状;部分线粒体嵴消失,出现晶体结构;中央大液泡破裂;核逐渐降解。高度盐胁迫(10g/L,12g/LNa2CO3)下,叶绿体片层结构消失,脂质球数量增加,体积变大,被大量的膜片层所包围,叶绿体内、外膜消失,叶肉细胞中看不到叶绿体的存在;膜片层包围线粒体;叶肉细胞中可见大量的泡状结构和膜片层,叶肉细胞死亡。上述结果表明,细胞器特别是叶绿体膜结构的破坏与盐胁迫叶肉细胞最终死亡密切相关。  相似文献   

4.
用Cd2+、Hg2+两种重金属离子溶液培育菱(TrapabicornisOsbeck.)植物体后,观察体细胞的细胞核及叶绿体超微结构的变化。处理后第8天,菱浮水叶叶片和不定根细胞中细胞核的染色质与核质遭到破坏,不定根中细胞核的核仁消失。但在各处理浓度(10μmol/L~50μmol/LCd2+或Hg2+)下,核膜均保持完整。叶片细胞的叶绿体基粒数目减少,基粒片层解体,叶绿体双层膜断裂,叶绿体中的质体球流入细胞基质中。两种结构的破坏程度随处理的离子浓度提高而增大。说明菱体细胞超微结构的变化观测可作为监测重金属污染的一种方法。  相似文献   

5.
Cd2+处理对菹草叶片保护酶活性和细胞超微结构的毒害影响   总被引:28,自引:2,他引:26  
以不同浓度Cd^2 处理5d的菹草为实验材料,测定了叶片SOD,POD,CAT等生理生化指标的变化,并用透射电镜观察了Cd^2 对叶细胞超微结构,尤其是对叶绿体,线粒体和细胞核的损伤情况。结果表明:SOD活性,叶绿素含量随Cd^2 处理浓度的增加而下降,而CAT和POD活性都是在1mg/L浓度下达到峰值,而后降低。SOD对Cd^2 毒害最敏感,其次为POD和CAT。电镜观察发现:随Cd^2 浓度的增加,对细胞超微结构的损伤程度也加剧。表现为叶绿体膨大,被膜断裂、消失和叶绿体解体;线粒体变形,脊突膨大和空泡化;细胞核核仁分散,核膜断裂,核空泡化。并探讨了Cd^2 对植物的毒害机制。  相似文献   

6.
甜菊叶愈伤组织诱导过程中叶绿体的超微结构变化   总被引:4,自引:0,他引:4  
观察了甜菊(Stevia rebaudiana Bertoni)叶外植体愈伤组织诱导过程中叶绿体的超微结构变化。结果表明,当叶外植体转移到培养基上培养后,叶绿体的片层结构逐渐退化。在叶绿体发生退化的过程中伴有叶绿体出芽和原质体的形成。推测新产生的原质体来自叶绿体产生的芽状体。而叶绿体本身最后完全解体消失。叶绿体超微结构的这种变化与高度液泡化的叶肉细胞脱分化至分生状态是平行的。随着培养的进行,分生状态的细胞发生液泡化变为薄壁细胞时,在愈伤组织表层的细胞中,质体重新形成片层结构,而内部细胞的质体则充满淀粉粒。  相似文献   

7.
镉污染对水鳖的毒害影响   总被引:7,自引:1,他引:6  
郝怀庆  施国新等 《西北植物学报》2001,21(6):1237-1240,T001
研究分析了不同浓度Cd^2 对水鳖叶片叶绿素含量、SOD、CAT、POD活性以及超微结构的影响。结果表明,叶绿素含量、SOD、CAT、POD添生均随Cd^2 浓度的增加而先升后降。电镜观察发现,Cd^2 处理下,细胞核变形,核仁解体,染色质凝集;类囊体片层膨胀,叶绿体双层膜破裂,线粒体中嵴突减少或消失,线粒体空泡化。  相似文献   

8.
Zn诱导的菹草叶抗氧化酶活性的变化和超微结构损伤   总被引:12,自引:0,他引:12  
本文以培养在不同浓度梯度Zn溶液中的菹草为材料,研究Zn对植物的影响。培养第5天,测定叶内抗氧化酶系统活性等指标的变化,并用透射电镜观察对细胞超微结构的损伤。结果表明,低浓度(<20mg/L)在短期内(5d)未对菹草产生影响,各生理指标呈上升趋势,当培养浓度为50mg/L时SOD和CAT活性表达峰值,而其他指标则下降;其中POD活性和叶绿素含量高于对照,而可溶性蛋白含量则比对照低。100mg/L培养学度各指标均明显降低。同时电镜观察发现过量Zn损伤了细胞的超微结构.培养浓度大于50mg/L,叶绿体被膜断裂,叶绿体解体。线粒体脊突膨大,线粒体空泡化。细胞核核膜断裂,核仁散开,这说明过量Zn削弱了细胞抗氧化酶的活性,同时对细胞超微结构产生致死性损伤,从而导致细胞死亡。  相似文献   

9.
环境激素DBP对拟南芥体外培养叶片超微结构的影响   总被引:4,自引:1,他引:3  
报道了酞酸酯类化合物DBP对拟南芥离体培养叶片超微结构的影响。在DBP(1.0mg·L-1)处理第3天即观察到拟南芥叶片叶绿体的超微结构受到破坏。不同浓度的DBP长期处理植株(40d)出现叶片白化、节间短缩等异常现象。在0.01mg·L-1DBP处理40d植株的叶细胞中,叶绿体出现解体,破碎部分呈颗粒状,散落其间,但细胞结构完整;0.1mg·L-1DBP处理后引起叶绿体的进一步解体,叶绿体中类囊体基粒和片层结构解体,细胞出现空洞现象,其它细胞器很少观察到;1.0mg·L-1DBP和2.0mg·L-1DBP处理植株叶片叶绿体中类囊体基粒和片层结构破碎,叶绿体结构也解体,细胞中其它细胞器数目极少。  相似文献   

10.
利用透射电镜技术对Na2CO3胁迫下星星草叶肉细胞超微结构进行了观察。结果表明:未胁迫的叶肉细胞排列疏松,各种细胞器结构完整,叶绿体含少量淀粉粒和脂质球。轻度盐胁迫(2g/L,4g/L Na2CO3)对叶肉细胞超微结构影响较小。中度盐胁迫(6g/L,8g/L Na2CO3)引起叶肉细胞超微结构的变化,叶绿体类囊体肿胀,基粒紊乱,不含淀粉粒,脂质球数量增加,叶绿体由原来的梭形或椭球形变成圆球状;部分线粒体嵴消失,出现晶体结构;中央大液泡破裂;核逐渐降解。高度盐胁迫(10g/L,12g/L Na2CO3)下,叶绿体片层结构消失,脂质球数量增加,体积变大,被大量的膜片层所包围,叶绿体内、外膜消失,叶肉细胞中看不到叶绿体的存在;膜片层包围线粒体;叶肉细胞中可见大量的泡状结构和膜片层,叶肉细胞死亡。上述结果表明,细胞器特别是叶绿体膜结构的破坏与盐胁迫叶肉细胞最终死亡密切相关  相似文献   

11.
 本研究以水培的烤烟给予不同浓度的Cd、Pb及其复合物处理10d后的烟叶为材料,分析了烟叶过氧化氢酶、硝酸还原酶的活性变化,测试了烟叶可溶性糖含量的变化情况,通过透射电子显微镜观察到了Cd和Pb对烟叶叶肉细胞亚显微结构的改变,特别是对叶绿体、线粒体和细胞核结构的损伤情况进行了详细观察。并探讨其毒害机理。研究结果表明:1)烟叶过氧化氢酶的活性剧烈地被Cd抑制;而随着Pb浓度的增加,其活性则表现为先增加后减弱的变化。2)Cd对硝酸还原酶活性的影响表现为先刺激增强,当Cd浓度超过50mg·L-1后,Cd剧烈地抑制其活性,当Cd浓度为200mg·L-1时,其活性几乎为零;Pb抑制烟叶硝酸还原酶的活性,仅在1000mg·L-1时出现一个低于正常活性的抗性峰。3)烟叶可溶性糖含量对Cd、Pb及其复合污染非常敏感,在较低浓度的污染处理时,其含量就明显下降,烟叶可溶性糖含量的变化可作为监测Cd、Pb污染的指标。4)Cd对烟叶叶肉细胞亚显微结构具有较强的损伤诱变作用,对细胞核、叶绿体和线粒体造成不可逆转的伤害,破坏了细胞正常生理活动所需的结构基础。电镜观察表明Cd严重地破坏细胞的膜结构。这可能是由于Cd离子与蛋白质结合而使蛋白质变性,从而使得以蛋白质为重要组成成份之一的膜的结构改变,功能丧失。5)在细胞膜的外面可以看到大量的Pb沉积粒,细胞膜可以阻止部分Pb进入原生质体内部,但在细胞质和叶绿体中仍可看到Pb沉积粒。Pb同样的损伤叶绿体、线粒体、细胞核的亚显微结构。  相似文献   

12.
六价铬污染对水车前叶片生理生化及细胞超微结构的影响   总被引:31,自引:3,他引:28  
徐勤松  施国新  杜开和 《广西植物》2002,22(1):92-96,T001
以培养在铬 ( VI)浓度梯度的污水中 6 d的水车前为实验材料 ,分析了叶绿素含量和抗氧化酶系统的变化 ,并用透射电镜观察了叶细胞超微结构的损伤。实验结果表明 :( 1 )叶绿素含量在 0 .1 mg/L浓度达到最高 ,而后下降。而可溶性蛋白则一直成下降趋势 ;( 2 ) SOD(超氧化物歧化酶 )、POD(过氧化物酶 )、CAT(过氧化氢酶 )活性影响明显 :三者分别在 0 .1 mg/L、1 0 mg/L、和 1 mg/L处理浓度有抗性峰出现 ,随处理浓度的继续增大则下降 ;( 3)对超微结构造成不可逆损伤 ,特别是对叶绿体、线粒体和细胞核 :叶绿体膨胀 ,被膜破裂和消失 ,叶绿体解体 ;线粒体脊突膨胀和空泡化 ;细胞核变形 ,染色质凝集和核质解体 ,核膜破裂。并根据实验结果初步讨论了重金属对植物的毒害机制  相似文献   

13.
Changes in the ultrastructure of the tegument of Echinococcus multilocularis protoscoleces during complement-mediated lysis in vitro was studied using transmission and scanning electron microscopy. It was found that the total disintegration of protoscoleces by complement proceeds through formation of ‘tegumental bubbles’ and disruption of the external plasma membrane. This sequence of events was evident in the appearance of numerous loose membrane fragments and vesicles, the lifting of the external unit membrane of the microtriches and the release of organelles from the distal cytoplasm. Subsequent events, such as the appearance of a ‘fuzzy’ coat and disruption of the basement membrane, were probably due to autolysis.  相似文献   

14.
Pea plants (Pisum sativum L. cv. Greenfeast) were grown and exposed to supplementary UV-B radiation from day 17 after planting under growth cabinet conditions. The effects of this exposure on the ultrastructure of chloroplasts and the total soluble sugar and starch concentrations were estimated. Supplementary UV-B radiation was shown to damage the structure of chloroplasts, as manifested by dilation of thylakoid membranes, a progressive disruption of the thylakoid structure and disintegration of the double membrane envelope surrounding the chloroplast, accompanied by the accumulation of large starch grains. Diurnal changes observed in starch concentration suggest that the higher concentration of starch in supplementary UV-B-treated leaves is due to its immobilization, rather than to any increase in starch synthesis: soluble sugars accumulated and remained at a higher level and then later declined.  相似文献   

15.
NaCl和Na2SO4胁迫下两种刺槐叶肉细胞叶绿体超微结构   总被引:3,自引:0,他引:3  
二倍体刺槐(diploid Robinia pseudoacacia)是我国水土保持林的先锋树种,具有较强的适应性和抗逆性,对改善生态环境、防治水土流失、调节水文状况有重要作用。四倍体刺槐(tetraploid Robinia pseudoacacia)是二倍体刺槐的加倍品种,也称多倍体刺槐,由韩国引进,具有速生、耐盐碱、耐干旱和耐烟尘等特点。目前,关于四倍体刺槐的研究,主要集中于栽培技术和繁殖技术方面,而关于四倍体刺槐叶片超微结构与其耐盐性的关系尚缺乏报道。比较了二倍体刺槐和四倍体刺槐在NaCl和Na2SO4胁迫下,叶片叶绿体超微结构的变化特点,一方面可以对二者的耐盐性进行鉴定,同时也可以探讨不同盐分胁迫条件下的作用机制。利用NaCl和Na2SO4进行20d的盐胁迫处理,观察叶绿体超微结构的变化特点,发现:NaCl处理前,二者叶肉细胞叶绿体为梭形、形态饱满、结构完整,NaCl处理后10d时,二倍体刺槐的叶绿体出现变形、膜模糊、基粒片层松散、类囊体解体、脂质球增多等现象,NaCl处理后20d时,叶绿体肿胀、变形,基粒片层断裂,膜系统解体。Na2SO4处理后10d时,二倍体刺槐的叶绿体肿胀,膜模糊,基粒片层松散、类囊体解体,Na2SO4盐胁迫处理后20d时,膜系统全部解体,结构破坏更为严重。总体来说,四倍体刺槐在盐胁迫后叶绿体结构变化不明显,只是在Na2SO4处理20d时,四倍体刺槐的叶绿体出现中空、基粒片层松散、膜边缘模糊现象。在处理前,两种刺槐的叶绿体均紧贴细胞壁,分布于细胞壁边缘。在NaCl处理后10d时,二倍体刺槐的叶绿体仍呈有序排列,紧贴细胞壁,但在处理后20d时,大部分叶绿体脱离细胞壁,呈随机分布。在Na2SO4处理后10d时,二倍体刺槐部分叶绿体脱离细胞壁,位于细胞中央。在Na2SO4处理后20d时,二倍体刺槐叶绿体大部分与细胞壁脱离。四倍体刺槐在两种盐胁迫处理前后叶绿体的排列变化不明显,均分布于细胞壁边缘,紧贴细胞壁。所以在盐胁迫下,耐盐植物叶片的叶绿体表现为结构完整,基粒片层清晰,类囊体结构完整,而不耐盐植物则表现为叶绿体超微结构松散、变形,基粒片层模糊,破坏严重时基粒片层扭曲,叶绿体解体,失去完整结构。  相似文献   

16.
The isoelectric points of unbroken chloroplast lamellae and various subchloroplast fractions, including a preparation of inside-out thylakoids, have been determined using aqueous two-phase systems containing dextran and charged polyethylene glycol. When the amounts of material in the top phase in a phase system with the positively charged trimethylamino polyethylene glycol are plotted against pH the curve intersects the corresponding curve obtained from phase systems with the negatively charged polyethylene glycol sulfonate. This cross-point can be correlated with the isoelectric point of the material.The cross-point for unbroken chloroplast lamellae was found to be around pH 4.7. Mechanical disintegration lowered the cross-point to around pH 4.4, probably because of exposure of new membrane surfaces. The disintegrated chloroplasts were fractionated by differential centrifugation to separate the grana and stroma lamellae. The stroma lamellae vesicles showed the same isoelectric point as the unbroken lamellae, while a cross-point at pH 4.3 was obtained for the grana-enriched fraction. For thylakoid membranes destacked under low salt conditions the cross-point was 0.3 pH unit lower than for membranes originating exclusively from the stroma lamellae. The most acidic cross-point (pH 4.1) was observed for the fraction enriched in inside-out grana thylakoids. It is suggested that the differences in isoelectric point between various subchloroplast fractions reflect a heterogeneous arrangement of surface charge along and across the thylakoid membrane.  相似文献   

17.
The isoelectric points of unbroken chloroplast lamellae and various subchloroplast fractions, including a preparation of inside-out thylakoids, have been determined using aqueous two-phase systems containing dextran and charged polyethylene glycol. When the amounts of material in the top phase in a phase system with the positively charged trimethylamino polyethylene glycol are plotted against pH the curve intersects the corresponding curve obtained from phase systems with the negatively charged polyethylene glycol sulfonate. This cross-point can be correlated with the isoelectric point of the material. The cross-point for unbroken chloroplast lamellae was found to be around pH 4.7. Mechanical disintegration lowered the cross-point to around pH 4.4, probably because of exposure of new membrane surfaces. The disintegrated chloroplasts were fractionated by differential centrifugation to separate the grana and stroma lamellae. The stroma lamellae vesicles showed the same isoelectric point as the unbroken lamellae, while a cross-point at pH 4.3 was obtained for the grana-enriched fraction. For thylakoid membranes destacked under low salt conditions the cross-point was 0.3 pH unit lower than for membranes originating exclusively from the stroma lamellae. The most acidic crosspoint (pH 4.1) was observed for the fraction enriched in inside-out granathylakoids. It is suggested that the differences in isoelectric point between various subchloroplast fractions reflect a heterogeneous arrangement of surface charge along and across the thylakoid membrane.  相似文献   

18.
A chlorophyll-deficient xantha mutant of cotton (Gossypium hirsutum L.) was examined with respect to development and structural organization of the chloroplast membrane system as affected by disruption of early stages of chlorophyll biosynthesis in the light. The analysis of early chlorophyll precursors showed that the mutant is unable to synthesize 5-aminolevulinic acid (5-ALA) in the light. The disorders in early stages of chlorophyll biosynthesis arrested the development of chloroplast membrane system at the stage of vesicles and single thylakoids. The accumulation of 2–5% chlorophyll in the mutant was related to the formation of light-harvesting chlorophyll-a/b-protein complexes I and II, whereas pigment-protein complexes composing reaction centers of photosystem I and photosystem II were lacking. It is concluded that the chloroplast membrane system in the mutant with impaired 5-ALA synthesis is incapable of development and is even reduced upon long-term growing under light.  相似文献   

19.
采用砂基培养法,运用CI-340便携式光合测定仪、H-7650透射电子显微镜研究了不同锌浓度如0mg/L(锌缺乏)、0.05mg/L(对照)和0.5mg/L(锌过量)处理下不知火杂柑(简称不知火)和槿柑叶片叶绿体色素含量、净光合速率及超微结构的变化。结果表明:(1)锌缺乏处理的不知火及锌过量处理的槛柑叶片叶绿素(a+b)和类胡萝卜素含量、锌缺乏与锌过量处理的两者叶片净光合速率均相对低于对照。(2)锌缺乏处理下,两者叶片叶绿体出现变形或空室化,其中碰柑叶绿体内淀粉粒和质体小球增多,细胞核及线粒体正常,而不知火淀粉粒少,细胞核中出现许多黑色小颗粒物质。锌过量处理下,两者叶片叶绿体出现空室化或叶绿体膜模糊,线粒体解体,其中槿柑叶绿体内质体小球增多,淀粉粒少;而不知火淀粉粒明显增多、增大,基粒片层膨胀、松弛。可见,锌胁迫对两者叶片叶绿体色素、净光合速率及超微结构有着明显的影响,其影响程度因品种而异。  相似文献   

20.
Chlorella pyrenoidosa Chick cells grown in liquid culture containing 5 × 10?3M sodium 2,4-dichloro-phenoxyacetic acid exhibited vesiculation of the plasma membrane, mitochondrial swelling with disorganization of cristae, disruption of the chloroplast lamellar system, and dictyosomes with irregularly swollen cisternae. Ultrastructural details previously not reported for species of Chlorella were also observed: (1) presence of a crystalline pyrenoid with an 80 A periodicity, (2) a nucleolus made up of ribosome-like particles, and (3) smaller ribosomes in the chloroplast and mitochondria than in the cytoplasm.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号