小麦黄化突变体叶绿体超微结构研究

利用透射电镜对小麦自然黄化突变体及其突变亲本(西农1718)叶片细胞叶绿体的数目、形态及超微结构进行比较分析。结果发现:(1)3种不同黄化程度突变体的叶绿体分布、数目、形状及大小与突变亲本无明显差异;(2)突变体叶绿素含量为野生型58%的黄绿植株与其突变亲本叶绿体超微结构无明显差异,基质类囊体与基粒类囊体高度分化,基粒数目以及基粒片层数目较多;(3)突变体金黄和绿黄植株的叶绿素含量分别为野生型的17%、24%,其叶绿体超微结构与突变亲本明显不同,突变体的叶绿体发育存在明显缺陷,其中突变体金黄植株的叶绿体内无基粒、基质片层清晰可见,有淀粉粒,嗜锇颗粒较多,而突变体绿黄植株的叶绿体内有基粒,但明显少于突变亲本,且基粒片层较少,基质类囊体较发达。结果表明该黄化突变体叶绿体超微结构的改变,是由于叶绿素含量降低造成,推测,该黄化突变是由于叶绿素合成受阻导致的。     

施肥对烟草腺毛叶绿体形态结构的影响

以烤烟K326为材料,在盆栽条件下分别施用纯有机肥和无机肥,在烟株旺长期和成熟期对叶面腺毛进行显微和超微结构观察,以明确肥料对烟草叶面腺毛生长发育的影响,结果显示:移栽后50 d,荧光下观察有机肥处理下腺头细胞叶绿素荧光强度较无机肥强烈,腺头细胞内叶绿体结构完整,类囊体基粒片层发达,嗜锇颗粒大而多;无机肥处理的细胞内叶绿体少,嗜锇颗粒较小,数量也较少.移栽后70 d,有机肥处理腺毛头细胞叶绿体双层膜结构依然完整,但类囊体基粒片层结构已经解体,其中积累大量黑色嗜锇颗粒;此时无机肥处理腺毛头细胞叶绿体结构完整,仍可清晰看到类囊体基粒片层仅含少量嗜锇颗粒.推测有机肥处理在初期促进了烟草腺毛细胞叶绿体的发育和叶绿素的合成、积累,在后期,促进叶绿素及内膜系统的降解,并有利于亲脂类物质的合成和积累,从而对腺毛分泌物积累和烟叶香气品质形成具有积极影响.     

定位于类囊体膜的PPF1在转基因拟南芥中的表达影响叶绿体的发育

PPF1是一个与植物营养生长相关的基因。它编码的产物可能是一个膜蛋白并与拟南芥叶绿体中的类囊体蛋白ALB3有很高的同源性。免疫电镜分析表明PPF1蛋白同样主要定位于类囊体膜 ,而且在短日照G2豌豆开花两周后仍发育良好的叶绿体中有很高的表达 ,在长日照豌豆同时期非正常叶绿体中丰度非常低。对转基因拟南芥和野生型植株的叶片衰老进程比较发现 ,PPF1在拟南芥中的过量表达可以延缓叶片的衰老 ,而用PPF1反义mRNA抑制拟南芥中的同源基因ALB3则明显加快叶片衰老速度。对转基因拟南芥的超微结构分析显示 ,PPF1在拟南芥中过量表达时 ,转基因植株的叶绿体比野生型植株的叶绿体大并含有更多的基粒和基质类囊体膜 ;相反 ,反义PPF1表达抑制其在拟南芥中的同源物时 ,转基因植株的叶绿体比野生型植株的叶绿体小并含有较少的基粒和发育较差的类囊体膜系统。这些数据表明叶绿体的发育状况与PPF1或拟南芥同源物ALB3的表达水平呈正相关。我们的结果提示PPF1基因可能通过控制叶绿体的发育状况来调节植物的发育。     

定位于类囊体膜的PPF1在转基因拟南芥中的表达影响叶绿体的发育

PPF1是一个与植物营养生长相关的基因.它编码的产物可能是一个膜蛋白并与拟南芥叶绿体中的类囊体蛋白ALB3有很高的同源性.免疫电镜分析表明PPF1蛋白同样主要定位于类囊体膜,而且在短日照G2豌豆开花两周后仍发育良好的叶绿体中有很高的表达,在长日照豌豆同时期非正常叶绿体中丰度非常低.对转基因拟南芥和野生型植株的叶片衰老进程比较发现, PPF1在拟南芥中的过量表达可以延缓叶片的衰老,而用PPF1反义mRNA抑制拟南芥中的同源基因ALB3则明显加快叶片衰老速度.对转基因拟南芥的超微结构分析显示,PPF1在拟南芥中过量表达时,转基因植株的叶绿体比野生型植株的叶绿体大并含有更多的基粒和基质类囊体膜;相反,反义PPF1表达抑制其在拟南芥中的同源物时,转基因植株的叶绿体比野生型植株的叶绿体小并含有较少的基粒和发育较差的类囊体膜系统.这些数据表明叶绿体的发育状况与PPF1或拟南芥同源物ALB3的表达水平呈正相关.我们的结果提示PPF1基因可能通过控制叶绿体的发育状况来调节植物的发育.     

水稻温敏型突变体叶片间断失绿的超微结构

在短时降温诱导下,水稻温敏型突变体１１０３ｓ（Ｏｒｙｚａ　ｓａｔｉｖａ　ｓｓｐ．ｉｎｄｉｃａ）植株间断失绿性状表达（临界温度２３．１℃）过程中,叶绿体含量的增减与叶色变化相符。电镜观察发现,性状表达时叶片间断失绿区叶绿体内部结构发生退化,呈现基粒垛叠片层数的异常减少,或基粒消失仅剩基粒残迹,有的甚至整个叶绿体为高电子密度的囊泡状结构。但在同一叶片的绿区,叶绿体仅表现基粒片层数减少、排列不规则,嗜锇小球聚集。在叶片失绿区的复绿过程中,叶绿体的这些变化又可逆转,内部结构重建,最后整个叶绿体结构基本恢复正常。水稻温敏突变体１１０３ｓ叶片间断失绿性状表达过程,实质上是一个由温度调控的叶绿体结构退化与修复的可逆过程。     

环境激素DBP对拟南芥体外培养叶片超微结构的影响

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。     

不同叶色水稻叶绿体密度及基粒结构的计算机图象分析

水稻叶绿体计算机图象分析表明,随着叶片色级的提高,叶绿体表面积密度、体积密度以及两者的比值都相应增加。深色稻叶基粒堆直径与高度、类囊体垛叠数与类囊体厚度、叶绿素与类胡萝卜素含量、气孔导度与净光合率均大于浅色叶片。深色叶片基粒堆密集,有些基粒类囊体出现沿叶绿体长轴方向排列整齐现象;浅色叶片基粒堆稀疏,其中较大的基粒类囊体与长轴呈倾斜排列。     

甜菊质体发育过程的超微结构研究

观察了甜菊(Steviarebaudiana Bertani)质,本发育过程的超微结构变化、黄化幼芽质体的原片层体,为小管组成的网状“晶格体”,“质体中心”逐渐弥散,形成放射状排列的片层结构。质体的被膜出现突起的芽体,可能是质体增殖的一种方式。至幼叶转绿后,“质体中心”弥散消失,类囊体基本形成,原片层体转化为片层结构。随着叶片的成长变绿,基粒片层和基质片层的明显分化,基粒垛叠层增多,光合膜系十分发达。在幼叶和正在伸展的叶片细胞内,可以观察到叶绿体的分裂成为哑铃形,这是叶绿体增殖的主要途径。     

水稻温敏叶绿素突变体叶片超微结构的研究

对温敏转绿型叶绿素突变体1103S和武金4B“斑马叶”性状表达过程中叶绿素含量、叶绿体超微结构的变化进行了比较研究。结果表明,在一定条件下,叶片的失绿、复绿与叶绿素含量的下降、上升变化趋势一致;叶绿体结构在失绿区表现为严重退化,基粒和基粒片层减少,淀粉粒和嗜锇粒增多;复绿后,其叶绿体结构重建和恢复     

油菜叶片及其脱分化和再分化中质体的电镜观察

我们用电镜观察了油菜叶片植株再生中质体的超微结构变化。在油菜叶肉细胞中,叶绿体的基粒,基质片层发育良好,偶尔有淀粉粒。在来自叶片的愈伤组织细胞中,质体体积变小,类囊体已经消失或部分消失,有的质体含有淀粉粒,但很少有质体小球。经培养分化后的愈伤组织,特别是在表层细胞中,质体数量急剧增多,形态变化很大,贮藏淀粉明显减少。基质内已有泡状或管状结构。有的质体已出现长的基质片层,但未见到基粒;质体中常有质体球。由此可见,质体是一个十分敏感的细胞器,它的变化与细胞分化有关,变化最大的部分是片层系统,贮藏淀粉,质体小球。片层系统中尤以基粒片层变化最为显著。     

ULTRASTRUCTURAL CHANGES OF CHLOROPLASTS IN ATTACHED AND DETACHED,AGING PRIMARY WHEAT LEAVES

Degradation of chloroplasts is shown in mesophyll cells of primary leaves of wheat. The sequence of ultrastructural changes in chloroplasts of naturally senescing leaves is compared with that of detached, aging leaves. In chloroplasts of naturally senescing leaves, the first indications of aging are the appearance of osmiophilic globuli and reorientation of the thylakoidal system. The membranes of the grana and intergrana lamellae then become distended and later dissociate into distinct vesicles. Concurrent with these membrane changes, osmiophilic globuli increase in size and number, and the stroma breaks down. Finally, the chloroplast envelope ruptures and plastid contents disperse throughout the cell's interior. In chloroplasts of mesophyll cells in detached, aging leaves, initial changes also include appearance of osmiophilic globuli, but later stages of chloroplast degradation are different. The chloroplast envelope ruptures before the lamellae break down. Swelling of grana and intergrana lamellae is not pronounced and, additionally, the thylakoidal system degenerates without forming vesicles or numerous osmiophilic globuli. These differences in the sequence of chloroplast degradation indicate that naturally senescing leaves rather than detached, aging leaves should be used in studies of chloroplast senescence.     

Effects of drought on photosynthetic characteristics of flag leaves of a newly-developed super-high-yield rice hybrid

We investigated responses of chloroplasts from flag leaves of a newly-developed super-high-yield rice (Oryza sativa L.) hybrid LiangYouPeiJiu (LYPJ) to water stress (withholding irrigation) during the grain-filling period. In the early stage of water stress (0–6 d) only the activity of Hill reaction was inhibited, whereas activities of photophosphorylation and Ca²⁺-ATPase, and ATP content were increased and peaked in the day 6 of withholding irrigation. In the late stage of water stress (6-12 d), the activities of photosynthetic O₂ evolution, Hill reaction, photophosphorylation, and Ca²⁺- ATPase, and ATP content were significantly reduced. The membrane lipid content was sharply decreased, especially of sulfoquinovosyl-diacylglycerol (SQDG) and phosphatidylglycerol (PG). The changes in the ultrastructure of chloroplasts included mainly a decrease in number of grana and increase in number of osmiophilic granules.     

水稻叶色突变体叶绿体发育规律研究

从温敏核不育系水稻'810S'中筛选出一个生长发育正常的淡黄绿叶色自然突变株'标810S',其叶绿素含量约为'810S'的50%,光合速率比野生型高.以'810S'为对照,对'标810S'进行叶片形态、叶肉细胞和叶绿体超微结构以及叶绿体蛋白研究.结果显示,'标810S'的叶长、宽和面积与'810S'相似;叶肉细胞和叶绿体发育稍迟缓,片层结构减少;叶绿体蛋白约为对照的55%,并初步鉴定出与光合作用相关的差异蛋白点13个,其中4个缺失蛋白,包括1个RuBP大亚基缺失.推测该水稻突变体叶色变浅与叶绿体基粒片层减少有关.     

Effects of drought on photosynthetic characteristics of flag leaves of a newly-developed super-high-yield rice hybrid

We investigated responses of chloroplasts from flag leaves of a newly-developed super-high-yield rice (Oryza sativa L.) hybrid LiangYouPeiJiu (LYPJ) to water stress (withholding irrigation) during the grain-filling period. In the early stage of water stress (0–6 d) only the activity of Hill reaction was inhibited, whereas activities of photophosphorylation and Ca²⁺-ATPase, and ATP content were increased and peaked in the day 6 of withholding irrigation. In the late stage of water stress (6-12 d), the activities of photosynthetic O₂ evolution, Hill reaction, photophosphorylation, and Ca²⁺- ATPase, and ATP content were significantly reduced. The membrane lipid content was sharply decreased, especially of sulfoquinovosyl-diacylglycerol (SQDG) and phosphatidylglycerol (PG). The changes in the ultrastructure of chloroplasts included mainly a decrease in number of grana and increase in number of osmiophilic granules.This revised version was published online in March 2005 with corrections to the page numbers.     

The Ultrastructure of Chloroplasts in Mineral-deficient Maize Leaves

The ultrastructure of mesophyll chloroplasts in full-nutrient and mineral-deficient maize (Zea mays) leaves was examined by electron microscopy after glutaraldehyde-osmium tetroxide fixation. Nitrogen, calcium, magnesium, phosphorus, potassium, and sulfur deficiencies were induced by growing the plants in nutrient culture. Distinctive chloroplast types were observed with each deficiency. Chloroplasts from nitrogen-deficient plants were reduced in size and had prominent osmiophilic globules and large grana stacks. Magnesium deficiency was characterized by the accumulation of osmiophilic globules and the progressive disruption of the chloroplast membranes. In calcium deficiency, the chloroplast envelope was often ruptured. Chloroplasts from potassium- or phosphorus-deficient plants possessed an extensive system of stroma lamellae. Sulfur deficiency resulted in a pronounced decrease of stroma lamellae, an increase in grana stacking, and the frequent occurrence of long projections extending from the body of the chloroplast. These morphological changes were correlated with functional alterations in the chloroplasts as measured by photosystem I and II activities. In chloroplasts of the nitrogen- and sulfur-deficient plants an increase in grana stacking was associated with an increase in photosystem II activity.     

虹吸输铁对黄化苹果叶片光合参数及细胞器结构的影响

该研究以红富士苹果品种为材料,通过虹吸输入铁肥的方式,设置输铁液(600倍FeS04·7H20)处理并以输离子水和不输液为对照,观察了处理后苹果树的复绿情况,测定了叶绿素含量、光合参数、进行了叶绿体、线粒体超微结构的电镜扫描。结果表明:输铁后10 d,树体复绿情况明显,复绿等级由2.01变为0.53,复绿的叶片叶绿素含量有显著增加,增幅达到200%。同时,净光合速率提高了68%、蒸腾速率提高了21%、气孔导度提高了49%,胞间CO2浓度降低了100%。输铁处理后的单个细胞叶绿体个数比对照有显著增加,且个体更饱满,淀粉粒和嗜锇颗粒有明显减少;基粒片层结构规律整齐,基质清晰,被膜结构完整,线粒体内嵴清晰度高,数量增多。在输铁处理后,苹果树体复绿明显,叶绿素合成能力恢复,叶绿体、线粒体被膜结构均得到修复,表明用虹吸的方法将铁肥输入树体对苹果缺铁黄化病有很好的疗效。     

花粒期光照对夏玉米光合特性和叶绿体超微结构的影响

在大田条件下,以夏玉米品种‘登海605’为试验材料,研究花粒期不同光照强度(正常光照、开花至收获期遮阴和开花至收获期增光)对夏玉米叶片光合、荧光性能和叶绿体超微结构的影响.结果表明:与对照相比,花粒期遮阴影响叶绿体排布及内部结构发育,基粒个数和基粒片层数均有不同程度减少,叶片的净光合速率、蒸腾速率、气孔导度、叶绿素含量下降,PSⅡ反应中心的实际光化学效率和最大光化学效率降低,非光化学淬灭系数数值增加,导致产量降低;增光后叶绿体结构良好,基粒片层排列紧致、清晰且数量增加,PSⅡ反应中心的实际光化学效率增加,净光合速率、蒸腾速率、气孔导度、叶绿素含量上升,叶片光合性能增强,产量增加.即花粒期遮阴破坏了夏玉米叶片叶绿体超微结构,降低了叶片光合能力,产量下降;花粒期增光增加了叶肉细胞中叶绿体的基粒和基粒片层,导致基粒片层排列紧密有序,有利于增加作物产量潜力.     

ACID PHOSPHATASE ACTIVITY AND ULTRASTRUCTURE OF AGED CELLS OF EUGLENA GRANULATA1,2

Ultrastructure and acid phosphatase activity of aged calls of Euglena granulata are reported. Cells are spherical, quiescent, and nonflagellated. The most conspicuous attribute of aged cells is the accumulation of cyloplasmic vacuoles and lysosome-like structures containing heavily stained, pigmented bodies and membrane fragments. In chloroplasts, portions of whorled lamellae arc abscised and subsequently incorporated into lysosome-like structures; osmiophilic granules increase in number. Membranes surrounding eyespot granules disappear and the granules themselves become diffuse; the usual association with microtubules is not seen in aged cells. Acid phosphatase precipitation accumulates largely at the maturing face of dictyosomes and associated vesicles; there is also activity in multivesicular and lysosome-like vacuoles.