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1.
用焦锑酸钙沉淀的电镜细胞化学方法 ,研究了低温胁迫下董棕 (GaryotaurensL .)幼苗叶肉细胞内Ca2 + 水平的变化。研究结果表明 ,未经低温处理的董棕幼苗叶肉细胞 ,焦锑酸钙沉淀颗粒大量出现在液泡和细胞间隙中 ,细胞壁中也可见少量沉淀 ,而细胞基质中则看不到焦锑酸钙沉淀 ;经 2℃ 48h低温处理后 ,细胞基质和细胞膜上焦锑酸钙沉淀增加 ,而液泡和细胞间隙中的焦锑酸钙沉淀则显著减少 ,并且超微结构已初步显示出寒害的特征 ,叶绿体外膜部分破损 ,类囊体片层稀疏且排列不规则 ,光合速率明显下降等 ;经 2℃ 1 2 0h低温处理后 ,细胞间隙内的焦锑酸钙沉淀极少 ,有的也紧贴在细胞外壁上 ,而细胞基质和细胞膜上则分布有非常多的焦锑酸钙沉淀 ,在核基质和液泡中也可见到少量的焦锑酸钙沉淀 ,并且超微结构遭到了显著破坏 ,叶绿体结构完全被破坏 ,核膜与液泡膜严重破损 ,内部结构模糊 ,细胞只表现为呼吸作用 ,不进行光合作用。表明Ca2 + 的区域性分布的变化与植物抗寒性存在一定关系。  相似文献   

2.
用焦锑酸钙沉淀的电镜细胞化学方法,研究了低温胁迫下董棕(Caryota urens L.)幼苗叶肉细胞内Ca^2 水平的变化。研究结果表明,未经低温处理的董棕幼苗叶肉细胞,焦锑酸钙沉淀颗粒大量出现在液泡和细胞间隙中,细胞壁中也可见少量沉淀,而细胞基质中则看不到焦锑酸钙沉淀;经2℃ 48h低温处理后,细胞基质和细胞膜上焦锑酸钙沉淀增加,而液泡和细胞间隙中的焦锑酸钙沉淀则显著减少,并且超微结构已初步显示出寒害的特征,叶绿体外膜部分破损,类囊体片层稀疏且排列不规则,光合速率明显下降等;经2℃ 120h低温处理后,细胞间隙内的焦锑酸钙沉淀极少,有的也紧贴在细胞外壁上,而细胞基质和细胞膜上则分布有非常多的焦锑酸钙沉淀,在核基质和液泡中也可见到少量的焦锑酸钙沉淀,并且超微结构遭到了显著破坏,叶绿体结构完全被破坏,核膜与液泡膜严重破损,内部结构模糊,细胞只表现为呼吸作用,不进行光合作用。表明Ca^2 的区域性分布的变化与植物抗寒性存在一定关系。  相似文献   

3.
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 Ca2 水平变化。研究结果表明 ,枇杷幼叶细胞未经低温处理时 ,Ca2 定位分布的沉淀颗粒大量出现在细胞壁、细胞间隙、质膜和液泡 ;叶绿体、细胞质和细胞核中也有一些 Ca2 沉淀颗粒分布。枇杷幼叶经 44h、4℃低温处理后 ,在质膜和液泡膜上 Ca2 的沉淀增多 ,细胞质和细胞核中的Ca2 水平增加。不抗寒品种在低温胁迫条件下可见核孔开口较大 ,有时可观察到核内容物外漏。抗寒品种在低温胁迫条件下核孔未见明显开口 ,叶绿体中类囊体不形成基粒 ,少数片层结合重叠后伸展在整个叶绿体中。而不抗寒品种类囊体则堆积形成明显的颗粒状基粒 ,类囊体片层数量较多。在 2个叶绿体之间还常可见到线粒体紧夹其间 ,但线粒体的内膜模糊不清。不抗寒品种内质网和高尔基体也较多见 ,内膜系统比较发达 ,但低温胁迫条件下膜系统易受破坏 ,膜结构模糊不清。  相似文献   

4.
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。  相似文献   

5.
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  相似文献   

6.
采用改进的焦锑酸钙沉淀的细胞化学方法,探讨了Ca^2+在黄瓜幼苗细胞中超微结构定位分布及在低温逆境条件下Ca^2+水平的动态。结果表明:在适宜温度下生长的黄瓜幼苗,其细胞中Ca^2+主要定位于液泡及细胞间隙内,说明液泡是植物细胞内的主要钙库,并显示质外体中存在大量的Ca^2+分布。当黄瓜幼苗在1℃下冷胁迫28h后,质膜内侧钙沉淀颗粒明显增加,同时观察到液泡内Ca^2+分布变得比较集中,并趋向于液泡  相似文献   

7.
采用改进的焦锑酸钙沉淀的细胞化学方法,探讨了Ca~(2 )在黄瓜幼苗细胞中超微结构定位分布及在低温逆境条件下Ca~(2 )水平的动态。结果表明:在适宜温度下生长的黄瓜幼苗,其细胞中Ca~(2 )主要定位于液泡及细胞间隙内,说明液泡是植物细胞内的主要钙库;并显示质外体中存在大量的Ca~(2 )分布。当黄瓜幼苗在1℃下冷胁迫28h后,质膜内侧钙沉淀颗粒明显增加,同时观察到液泡内Ca~(2 )分布变得比较集中,并趋向于液泡膜内侧。当幼苗在1℃低温下胁迫40h后,胞内Ca~(2 )水平进一步提高,尤其是质膜内侧及细胞核内出现较大的呈同心圆状的钙沉淀颗粒。作者认为,胞内Ca~(2 )水平的提高,尤其是质膜内侧及细胞核内局部区域Ca~(2 )密集分布,势必会引发一系列代谢过程的紊乱,最终导致幼苗的伤害或死亡。  相似文献   

8.
低温胁迫下水稻幼叶细胞内Ca^2^+水平的变化   总被引:17,自引:1,他引:17  
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  相似文献   

9.
以早熟、中熟、晚熟三种不同熟性的6个棉花品种幼苗为试材,分析4℃低温胁迫处理对叶肉细胞超微结构的影响。结果表明:4℃低温处理3 d后,中熟品种N177和N181及晚熟品种K-1和N203的细胞器均受到严重破坏,表现为叶绿体受损严重,部分类囊体解体,线粒体膜模糊,失去完整性,细胞核膜基本消失,染色质凝聚,淀粉粒的数量和体积增大,嗜锇颗粒增多;而早熟品种中50和N52受损较轻,叶绿体变化不明显,线粒体结构完整,细胞壁完整。说明早熟品种中50和N52具有与抗冷性相适应的结构特点,其抗冷性较强。  相似文献   

10.
低温锻炼(10℃)期间翠南报春叶肉细胞线粒体增加并出现质膜内陷现象,低温胁迫(0℃)过程中,低温锻炼植株的细胞超微结构表现相对稳定,叶绿体片层结构和线粒体数目都未发生明显变化。未受低温锻炼植株线粒体数目在低温胁迫第2天增多,第3、4天逐渐减少,并在第3天出现质膜内陷现象。多泡体和囊泡结构有时伴随着质膜内陷出现。这种变化可能是经低温锻炼的翠南报春抗寒性提高的细胞结构基础。  相似文献   

11.
    
It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.  相似文献   

12.
Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.  相似文献   

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正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases  相似文献   

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Han  Zhenzhi  Xiao  Jinbo  Song  Yang  Zhu  Shuangli  Wang  Dongyan  Lu  Huanhuan  Ji  Tianjiao  Yan  Dongmei  Xu  Wenbo  Zhang  Yong 《中国病毒学》2021,36(6):1652-1655
  相似文献   

16.
    
Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.  相似文献   

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Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.  相似文献   

19.
The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.  相似文献   

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