铝胁迫下小麦根尖分生细胞中Ca2+分布变化

运用透射电镜细胞化学方法对铝胁迫下小麦根尖分生细胞中Ca^2 分布的变化进行了观察,在正常生长条件下,Ca^2 广泛分布于细胞质、细胞核、细胞间隙中,特别是液泡中有大量的Ca^2 沉淀颗粒;在AI^3＋胁迫条件下,细胞质、细胞核中Ca^2 沉淀颗粒明显减少,分布发生改变,细胞质中液泡增多,但其中Ca^2 沉淀颗粒明显减少。结果表明,AI^3 不但抑制了根尖细胞对Ca^2 的吸收,而且引起细胞中原有Ca^2 分布的变化,这很可能引起细胞功能的紊乱,进而影响极系的生长。     

铝胁迫下小麦根尖分生细胞中Ca2+分布变化

运用透射电镜细胞化学方法对铝胁迫下小麦根尖分生细胞中Ca2+分布的变化进行了观察,在正常生长条件下,Ca2+广泛分布于细胞质、细胞核、细胞间隙中,特别是液泡中有大量的Ca2+沉淀颗粒;在Al3+胁迫条件下,细胞质、细胞核中Ca2+沉淀颗粒明显减少,分布发生改变,细胞质中液泡增多,但其中Ca2+沉淀颗粒明显减少.结果表明,Al3+不但抑制了根尖细胞对Ca2+的吸收,而且引起细胞中原有Ca2+分布的变化,这很可能引起细胞功能的紊乱,进而影响根系的生长.     

镉胁迫下小麦根尖分生细胞中Ca2+分布的变化

运用透射电镜细胞化学方法对镉胁迫下小麦极尖分生细胞中Ca^2 分布的变化进行了观察。在正常生长条件下,Ca^2 广泛分布于细胞质,细胞核,细胞间隙中,特别是液泡中有大量的Ca^2 ;在镉胁迫条件下,细胞质基质内Ca^2 减少,而细胞核,质膜与细胞壁之间,细胞壁中Ca^2 明显增多,细胞液泡化,液泡中仍有较多Ca^2 。结果表明,Cd^2 引起细胞中原有Ca^2 分布发生明显变化。这很可能引起细胞生理功能紊乱。进而影响植物的生长。     

低温胁迫下水稻幼叶细胞内Ca^2^＋水平的变化

用焦锑酸钙沉淀的电镜细胞化学方法,研究了低温胁迫下水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）幼苗细胞内Ｃａ２＋ 定位分布的变化。水稻幼苗在适宜温度下生长时,显示Ｃａ２＋ 定位分布的焦锑酸钙沉淀颗粒大量出现在液泡及细胞间隙中,此外,质体和线粒体以及细胞质和细胞核中也有一些Ｃａ２＋ 沉淀分布。说明在正常情况下,细胞质和细胞核中的游离Ｃａ２＋ 水平是较低的;液泡是植物细胞的主要Ｃａ２＋ 库;细胞外的细胞间隙中有大量的Ｃａ２＋ 存在。当水稻幼苗经２４ 小时１℃低温处理后,在质膜内侧几乎形成一圈整齐排列的Ｃａ２＋ 沉淀颗粒,同时,细胞质和细胞核中的Ｃａ２＋ 水平增加;当１℃低温持续到４８ 小时,不仅在细胞质和细胞核中出现大量的Ｃａ２＋ 分布,同时在液泡膜和质体被膜上产生大量的Ｃａ２＋ 沉淀。而此时的细胞超微结构尚保持较正常的状态,看不出明显的改变。作者认为,低温胁迫中细胞质和细胞核内Ｃａ２＋ 水平的提高可能与尔后的许多生理生化过程的改变有联系     

低温胁迫下龙眼(Dimocarpus longana Lour.)幼叶细胞内Ca2+水平及细胞超微结构

用焦锑酸钾沉淀的电镜细胞化学方法研究低温胁迫下龙眼幼叶细胞内Ｃａ＾２＋水平的变化。未经低温处理的幼叶,细胞壁,细胞间隙,质膜和液泡存在大量的Ｃａ＾２＋沉淀颗粒,叶绿体,细胞质和细胞核中也有一些Ｃａ＾２＋沉淀颗粒分布,表明液泡和细胞间隙是植物细胞的钙库。     

低温胁迫下枇杷幼叶细胞内Ca2+水平及细胞超微结构变化的研究

用焦锑酸钾沉淀的电镜细胞化学方法,研究了低温胁迫下枇杷幼叶细胞内Ｃａ＾２＋水平变化。研究结果表明,枇杷幼叶细胞未经低温处理时,Ｃａ＾２＋定位分布的沉淀颗凿在碍出现在细胞壁、细胞间隙、质膜和液泡;叶绿体、细胞质和细胞核中也有一些Ｃａ＾２＋沉淀颗粒分布。楷杷幼叶经４４ｈ、４℃低温处理后,在质膜和液泡膜上Ｃａ＾２＋沉淀颗粒分布。枇杷幼叶经４４ｈ、４℃低处理后,在质膜和液泡膜上Ｃａ＾２＋的沉淀增多,细胞质     

云南紫稻细胞质雄性不育系花药发育过程中Ca2+的分布特点

运用焦锑酸钾沉淀法研究了云南紫稻细胞质雄性不育系和保持系花药在发育过程中Ca^2 的分布特点。结果表明,保持系的花粉母细胞和小孢子的胞质内部基本无Ca^2 的沉淀,后期花粉外壁出现Ca^2 的沉淀;保持系早期的绒毡层细胞形态正常,胞内有少量Ca^2 沉淀,后期绒毡层细胞开始凋亡,胞质凝集,胞内出现大量Ca^2 的颗粒。不育系花粉母细胞在减数分裂时期败育,胞质液泡化,内部出现大量Ca^2 的沉淀;不育系绒毡层细胞形态正常,胞内无Ca^2 的沉淀。绒毡层与花粉母细胞、小孢子之间出现大量Ca^2 颗粒。探讨了不育系花药花粉母细胞中以及与绒毡层细胞之间Ca^2 的异常积累与雄性不育的关系。     

微重力对石刁柏根尖组织和细胞中钙水平及分布的影响

用焦锑酸钾沉淀法进行了组织和细胞中游离钙的化学定位。用光学显微镜和透射电镜观察石刁柏幼苗在太空飞行后Ｃａ２＋沉淀颗粒在根尖组织和细胞内的分布。结果表明,太空飞行１５天后,Ｃａ２＋在各组织内的分布情况与地面对照无明显差异,但Ｃａ２＋的含量明显低于对照。Ｃａ２＋在细胞内不同区域的分布在飞行和对照样品中差异十分明显,对照细胞中Ｃａ２＋集中在液泡内,其它细胞器中很少见到。飞行幼苗的根尖细胞,液泡中Ｃａ２＋很少,并向液泡膜集结,液泡膜内侧和细胞质中的Ｃａ２＋明显增多。细胞壁中的Ｃａ２＋较对照有明显增加,高尔基体中也有少量钙存在。本文着重讨论了飞行幼苗根尖中Ｃａ２＋在细胞内重新分布的可能作用。     

洋葱花药发育中钙离子分布特征

采用焦锑酸钾沉淀钙离子技术,对洋葱（Alliumcepa）花药发育中Ca^2＋分布进行了研究。在小孢子母细胞时期,小孢子母细胞中的钙沉淀颗粒很少,但绒毡层细胞的内切向壁已出现明显的钙沉淀颗粒。在四分体时期,四分体小孢子的胼胝质壁中出现较多的钙沉淀颗粒;绒毡层细胞内切向壁的钙沉淀颗粒消失,而在外切向壁和径向壁部位的钙沉淀颗粒增加。在小孢子早期,小孢子中也出现了钙沉淀颗粒,而绒毡层细胞内切向壁表面出现了很多絮状物,其上附有细小钙沉淀颗粒。到小孢子晚期,小孢子中出现一些小液泡,细胞质中的钙沉淀颗粒有所下降。此时绒毡层细胞已明显退化,但在绒毡层膜上仍有一些乌氏体和钙沉淀颗粒。在二胞花粉早期,营养细胞中的液泡收缩、消失,细胞质中又出现了较多的钙沉淀颗粒,在质体和其内部的淀粉粒表面上附有较多的钙沉淀颗粒。到二胞花粉晚期,花粉中的钙沉淀颗粒已明显下降,仅在花粉外壁中还有一地钙沉淀颗粒．     

毛竹"韧皮部结"发育过程中Ca2+-ATP酶的超微定位

用电镜和细胞化学技术对毛竹[Phyllostachys edulis（Carr.）H.De Lehaie]节部“韧皮部结”发育过程中Ca^2＋-ATP酶进行了超微细胞化学定位研究.结果显示：在“韧皮部结”形成期,仅细胞质膜和细胞核上具有很高的Ca^2＋-ATP酶活性;随着“韧皮部结”的发育,发育期细胞质膜上的Ca^2＋-ATP酶活性较形成期有所降低,而细胞核上仍保持较高的Ca^2＋-ATP酶活性,胞间连丝、运输小泡膜上都具有Ca^2＋-ATP酶活性;发育后期,液泡膜及内质网上也开始出现Ca^2＋-ATP酶沉积物;成熟期的“韧皮部结”细胞质膜上的Ca^2＋-ATP酶活性较发育期有所升高,并且在“韧皮部结”成熟的过程中,细胞核、内质网、胞间连丝、质体膜和细胞质降解物上始终都有较高的Ca^2＋-ATP酶活性.实验结果表明“韧皮部结”细胞具有活跃的生理代谢以及频繁的共质体运输和信息交流.     

Cytochemical and X-ray microanalytical studies of calcium in the extending zone, particularly in the rhizodermis of Zea mays roots

Calcium was detected in CaCl (10 m M )-pretreated roots of Zea mays L. (cv. LG 11) by means of electron probe X-ray microanalysis with energy-dispersive spectrometry (EDS) using embedded samples, fixed by the antimonate staining procedure. A high level of calcium was found where large amounts of antimonate precipitates were observed by light or transmission electron microscopy. In the elongation zone, after 20 h in humid air following a 2 h CaCl₂ pretreatment, the level of calcium was higher in trichoblasts than in atrichoblasts. In these cells it was detected mainly in the walls and nucleus, and antimonate staining was observed in the walls. Abundant precipitates containing calcium were associated with the nucleus, vacuoles, mitochondria and endoplasmic reticulum of non-differentiated cells, whereas they were confined to the walls of these cells just after the CaCl₂ pretreatment. The involvement of calcium in the formation of root hairs is discussed.     

Changes of the Level of Ca2+ in Cells of Rice Seedlings Under Low Temperature Stress

The changes of Ca2+ localization in ceils of rice (Oryza sativa L. ) seedlings under chilling stress were investigated with calcium antimonate precipitate-electromicroscopic-cyto- chemical methods. When rice seedlings grew at the optimum temperature, it was shown that the deposits of calcium antimonate, being the indicator for Ca2+ localization, mainly concen-trated within the vacuoles and intercellular spaces, and that there was also some Caz+ deposits in plastid, mitochondria, cytoplasm and nucleus. This indicates that under the normal condition, the vacuoles are the main pool of Ca2+ in plant cells, and that there is quite an amount of Ca2+ in the intercellular spaces. On the contrary, the free Ca2+ in cytoplasm and nucleus is very low under the normal condition. When the rice seedlings were treated at the temperature of 1 ℃ for 24 h, there nearly appeared a ring of well arranged Ca2+ precipitates in the inner side of plasmalemma. Meanwhile, the level of Ca2+ in cytoplasm and nucleus increased considerably. When the chilling stress of 1 ℃ continued for 48 h, a great amount of Ca2+ distributed within the cytoplasm and nucleus, and there was also a large quantity of Ca2+ deposits on vacuolar membranes and envelope of plastid. However, the ultrastructures of the cells remained normal. Based on the above observations, the authors proposed that the increase of Ca2+ in cytoplasm and nucleus under chilling stress might be related to the ulterior changes of physiological-biochemical processes.     

淹水对玉米不定根形态结构和ATP酶活性的影响

淹水２天后,玉米苗基节内即有不定根原基一进于正常植株。淹水１６天后,从基节部长出的不定根数多于正常植株,但淹水导致根系生长和干物质积累大幅度下降。淹水幼苗不定根伸长区内有发达的通气组织形成,使根内部组织孔隙度大幅提高。电镜细胞化学研究表明,经１５天淹一,不定根根尖细胞内ＡＴＰ酶的分布与正常功苗基本相同,酶活性尽管有一定的下降,但仍保持较高水平。根据实验结果,本文重点讨论了不定根的发生及其内部通气组     

Microgravity and clinorotation cause redistribution of free calcium in sweet clover columella cells

In higher plants, calcium redistribution is believed to be crucial for the root to respond to a change in the direction of the gravity vector. To test the effects of clinorotation and microgravity on calcium localization in higher plant roots, sweet clover (Melilotus alba L.) seedlings were germinated and grown for two days on a slow rotating clinostat or in microgravity on the US Space Shuttle flight STS-60. Subsequently, the tissue was treated with a fixative containing antimonate (a calcium precipitating agent) during clinorotation or in microgravity and processed for electron microscopy. In root columella cells of clinorotated plants, antimonate precipitates were localized adjacent to the cell wall in a unilateral manner. Columella cells exposed to microgravity were characterized by precipitates mostly located adjacent to the proximal and lateral cell wall. In all treatments some punctate precipitates were associated with vacuoles, amyloplasts, mitochondria, and euchromatin of the nucleus. A quantitative study revealed a decreased number of precipitates associated with the nucleus and the amyloplasts in columella cells exposed to microgravity as compared to ground controls. These data suggest that roots perceive a change in the gravitational field, as produced by clinorotation or space flights, and respond respectively differently by a redistribution of free calcium.     

Alterations in ultrastructure and subcellular localization of Ca2+ in poplar apical bud cells during the induction of dormancy

In poplar (Populus deltoides Bartr. ex Marsh), bud dormancyand freezing tolerance were concomitantly induced by short-day(SD) photoperiods. Ultrastructural changes and the alterationin subcellular localization of calcium in apical bud cells associatedwith dormancy development were investigated. During the developmentof dormancy, the thickness of cell walls increased significantly,the number of starch granules increased, and there was a significantaccumulation of storage proteins in the vacuoles of the apicalbud cells. The most striking change was the constriction andblockage of the plasmodesmata. It was demonstrated that antimonate precipitation is a reliabletechnique for studying subcellular localization of calcium inpoplar apical bud cells. Under the long day (LD) photoperiod,electron-dense calcium antimonate precipitates were mainly localizedin vacuoles, intercellular spaces and plastids. Some antimonateprecipitates were also found in the cell walls and at the entranceof the plasmodesmata. However, there were few Ca²⁺ depositsfound in the cytosol and nucleus. After 20 d of SD exposure,when development of bud dormancy was initiated, calcium depositsin intercellular spaces were decreased, whereas some depositswere found in the cytosol and nuclei. From 28–49 d ofSD exposure, while dormancy was developing, a large number ofCa²⁺ precipitates were found in the cytosol and nuclei. Whendeep dormancy was reached after 77 d of SD exposure, Ca²⁺ depositsbecame fewer in both cytosol and nuclei, whereas numerous depositswere again observed in the cell walls and in the intercellularspaces. These results suggest that under the influence of SDphotoperiods, there are alterations in subcellular Ca²⁺ localization,and changes in ultrastructure of apical bud cells during thedevelopment of dormancy. The constriction and blockage of plasmodesmatamay cause the cessation of symplastic transport, limit cellularcommunication and signal transduction between adjacent cells,which in turn may lead to events associated with growth cessationand dormancy development in buds. Key words: Poplar, apical bud cells, Ca²⁺ subcellular localization, dormancy     

枸杞花药发育过程中钙的分布

在枸杞花药发育过程中,用焦锑酸钾沉淀的钙颗粒显示出了一个与花药发育事件有关的分布特征：在孢原细胞时期的花药中钙颗粒很少。在造孢细胞到小孢子母细胞时期,花药中钙颗粒增加。当花粉母细胞进行减数分裂时,花药中的钙颗粒进一步增加,尤其是在小孢子母细胞的胼胝质壁中。在小孢子发育早期,花药药隔部位的绒毡层细胞质中钙颗粒也明显增加并特异性地分布在其内切向壁上。当小孢子被释放出后,钙颗粒开始特异性积累在正在形成的花粉外壁中,尤其在萌发孔的部位聚集了大量的钙颗粒。当小孢子形成大液泡时,其细胞质中的钙颗粒明显减少。在小孢子分裂形成二胞花粉后,在二胞花粉的大液泡中又特异性地出现许多细小钙颗粒。随着二胞花粉的大液泡完全消失,其细胞质中又出现了许多钙颗粒。接近开花时的成熟花粉粒细胞质中,细小的钙颗粒主要分布在营养细胞和生殖细胞中。枸杞花药发育过程中钙的分布特征反映了其参与调控花粉发育过程。     

Structural Association of Endoplasmic Reticulum with Other Membrane Systems in Populus deltoides Apical Bud Cells and Its Alterations During the Short Day-induced Dormancy

A comparative study was carried out on the EM-cytochemical localization of calcium and Ca2+-ATPase activity in the suspension-cultured cells between the chilling-sensitive maize (Zea mays L. cv. Black Mexican Sweet) and chilling-insensitive Trititrigia (Triticum sect. Trititrigia mackey) at 4 ℃ chilling. When maize and Tyititrigia cells were cultured at 26 ℃, electron microscopic observations revealed that the electron-dense calcium antimonate deposits, an indication of the calcium localization, were localized mainly in the vacuoles, and few was found in the cytosol and nuclei. The electron-dense cerium phosphate deposits, an indication of Ca2+-ATPase activity, were abundantly distributed on the plasma membrane (PM). When the cells from both species were cultured at 4 ℃ for 1 and 3 h, an elevation of Ca2+ level in the cytosol and nuclei was observed, whereas the cerium phosphate deposits on the PM showed no quantitative difference from those of the 26 ℃-cultured cells, indicating that the enzymatic activities were not altered during these chilling periods. However, there was a distinct difference in the dynamics of the Ca2+ distribution and the PM Ca2+-ATPase activity between maize and Trititrigia when chilled at 4 ℃ for 12, 24 and 72 h. In maize cells, a large number of Ca2+ deposits still existed in the cytosol and nuclei, and the PM Ca2+-ATPase became less and less active, and even inactive at all. In Trititrigia cells, the increased cytosolic and nuclear Ca2+ ions decreased after 12 h chilling. By chilling up to 24 and 72 h, the intracellular Ca2+ concentration had been restored to a similar low level as those of the warm temperature-cultured cells, while the activity of the PM Ca2+-ATPase maintained high. The transient cytosolic and nuclear Ca2+ increase and the activities of PM Ca2+-ATPase during chilling are discussed in relation to plant cold hardiness.     

NaHCO3胁迫下星星草根中Ca2＋与Ca2＋-ATPase的超微细胞化学定位

利用焦锑酸盐和磷酸铅沉淀技术分别对NaHCO3胁迫条件下星星草（Puccinellia tenuiflora）根中Ca2＋和Ca2＋-ATPase进行超微细胞化学定位研究,旨在进一步探讨Ca2＋在NaHCO3胁迫诱导胞内信号转导过程中的作用,以及Ca2＋-ATPase活性定位变化与NaHCO3胁迫下星星草抗盐碱能力的关系。结果表明：在正常状态下,根毛区细胞质内Ca2＋较少,主要位于质膜附近和液泡中,Ca2＋-ATPase主要定位于质膜和液泡膜,有一定活性。在0.448%NaHCO3胁迫下,根毛区细胞质中Ca2＋增多,液泡中Ca2＋减少,且主要集中于液泡膜附近,质膜和液泡膜Ca2＋-ATPase活性明显升高。在1.054%NaHCO3胁迫下,细胞质中分布的Ca2＋增多,而液泡中Ca2＋极少,Ca2＋-ATPase活性也降低。以上结果表明,Ca2＋亚细胞定位和Ca2＋-ATPase活性变化在星星草响应NaHCO3胁迫的信号传递过程中具有重要作用。