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1.
植物叶片原生质体分离的可能机制   总被引:1,自引:1,他引:0  
分析了植物叶片在分离液环境中形成原生质体的过程,文中提出,分离液配方中的酸性物质使植物叶片处于酸性环境中并导致植物正常细胞首先发生细胞壁酸性降解,随后出现原生质体脱离细胞壁进入分离液,继而又进一步发生质膜的酸性降解,使细胞核和细胞器进入分离液中,最终分离液中的细胞器以细胞核为中心进行细胞器重组,最后产生外貌形态一致的新的原生质体.植物细胞壁和质膜是植物细胞的包被系统.植物细胞包被系统的酸性降解使植物细胞器重组并产生新的原生质体成为可能.  相似文献   

2.
观察了拟南芥叶片细胞包括细胞壁和质膜在内的细胞包被系统在酸性条件下酶促降解的过程.观察发现,处于酸性酶解液中的拟南芥叶片,最初细胞壁完整,细胞排列有序,其后细胞壁开始部分降解,细胞排列逐渐进入无序状态,随后细胞壁完全降解,去壁的原生质体完全进入游离状态,游离原生质体的质膜也随之降解,细胞器溢出后以细胞核为核心积聚、重组为新的原生质体.进一步观察了这一过程中细胞pH值的改变,结果发现,酸性酶解过程中细胞倾向于pH值降低,而细胞器重组产生的新原生质体pH值向正常水平恢复.因此,酸性环境对拟南芥叶片细胞包被系统的降解产生重要的影响.  相似文献   

3.
组织培养条件下喜树叶片细胞壁酸性降解的pH值观察   总被引:1,自引:1,他引:0  
喜树叶片外植体经组织培养第13 d和23 d后进行解剖学观察,同时比较正常叶片的解剖学特征,发现在pH值为5.8的酸性培养基中,喜树叶片外植体中的海绵组织和栅栏组织等薄壁细胞相继发生明显的细胞壁降解,而表皮细胞发生较微弱的细胞壁降解现象;进行组织培养前,正常叶片的各类细胞未观察到细胞壁降解现象发生.应用BCECF-AM pH荧光探标记并采用激光共聚焦在480 nm波长下进行pH值测定发现,喜树叶片外植体经组织培养第13 d和第23 d后的海绵组织和栅栏组织等薄壁细胞部位的pH值均为5.2,但表皮细胞部位的pH值则为5.7~5.8,而正常叶片各类细胞的pH值平均为5.7.这说明,pH值为5.8的酸性培养基和喜树叶片薄壁细胞内的酸性成分自泌可能共同诱导了其细胞壁的酸性降解.  相似文献   

4.
酸性培养基对喜树叶片细胞壁降解的影响   总被引:3,自引:3,他引:0  
在组织培养过程中对喜树叶片外植体进行解剖学观察.发现在组织培养条件下,喜树叶片在培养基的酸性环境中细胞壁呈现模糊微弱降解、明显降解和完全降解直至消失的解剖学特征.在同样的组培条件和相同的时间内,同一喜树叶片不同部位出现细胞壁程度不同的降解和消失现象,可能是喜树叶片因上表皮凸凹不平进而导致其不同部位与酸性培养基接触的程度不同,因而使培养基中的酸性物质对喜树叶片上表皮的不同部位影响出现异质化.本文对培养基中的酸性成分对喜树叶片细胞壁降解的影响有了进一步的认识和理解.  相似文献   

5.
一、前言植物原生质体就是除去细胞壁以后的裸露细胞。英国植物生理学家Cocking(1960)首先用酶解的方法降解番茄根尖的细胞壁,获得大量而完整的原生质体。植物原生质体可直接从植物各种器官、如根、茎、叶、花、果实的细胞中获得,也可以从培养细胞中获得。一般认为由叶肉组织分离的原生质体遗传性状较一致。而一般  相似文献   

6.
植物原生质体培养方法   总被引:3,自引:0,他引:3  
1 植物原生质体培养的简史植物细胞原生质体 ,在植物学上指植物细胞通过质壁分离后 ,可以和细胞壁分开的那部分细胞物质。原生质体分离纯化后 ,须在适当的培养基上应用适当的培养方法 ,才能再生细胞壁 ,并启动细胞持续分裂 ,直至形成细胞团、长成愈伤组织或胚状体、分化和发育成苗 ,最终再生完整植株。其中 ,选择合适的培养方法始终是原生质体培养中最基础也是最关键的一环。植物原生质体培养方法起源于植物单细胞培养方法。早在 190 2年 ,Haberlant通过实验就预言 :体外培养单个细胞可通过其分裂得到培养组织。直到 1954年 ,植物单细胞培…  相似文献   

7.
植物原生质体培养   总被引:1,自引:0,他引:1  
六十年代初英国植物生理学家 Cocking首先用酶解方法降解细胞壁,获得了蕃茄根尖细胞的原生质体。由于酶解方法能获得遗传性状和生理性状较一致的原生质体群体,为从植物细胞获得大量原生质体开辟了新的途径,并已为国内外科研工作者广泛采用。现用酶解法  相似文献   

8.
绝大多数植物细胞的质膜外都有细胞壁,这是区别予动物细胞的显著特征之一。由于细胞壁的存在,使原生质体的膨胀受到限制,细胞成熟后,使其形态和大小变为固定。细胞壁有保护作用,厚而硬的细胞壁还有支持植物器官的机械作用,同时,细胞壁能影响植物组织的吸收、蒸腾、运输和分泌等功能。  相似文献   

9.
秦明波  云月 《生物学通报》1993,28(11):26-27
植物原生质体是指通过质壁分离,能够和细胞壁分开的那部分细胞物质。换言之原生质体就是除去全部细胞壁的“细胞”,或是一个为原生质膜所包围的“裸露细胞”。植物原生质体由于失去细胞壁,更由于单个原生质体即包含一个物种的  相似文献   

10.
细胞壁作为植物细胞重要的组成部分,在决定细胞形状、维持机械支撑、吸收养分等方面发挥重要功能。因此,揭示植物细胞壁合成的调控机制具有重大的生物学意义。基于植物组织水平研究细胞壁的生物合成具有难以控制时间尺度、观察空间狭小等局限性。原生质体作为去除细胞壁的单个细胞是研究细胞壁再生的理想系统。在过去的几十年里报道了大量关于植物原生质体再生细胞壁的研究,但是关于细胞壁再生的机制尚不清楚。该综述介绍了目前应用于植物原生质体再生细胞壁研究的主要技术和取得的研究进展,并且对该领域的后续发展进行了展望,为进一步阐明植物细胞壁生物合成的机制提供理论参考。  相似文献   

11.
This study investigated the inhibitory effects of NaCl on tracheary element (TE) differentiation in light-grown callus of ice plant Mesembryanthemum crystallinum L., a halophyte which adaptes well to saline environments. When ice plant callus was grown in a modified Linsmaier-Bednar and Skoog culture medium containing no NaCl (control medium), up to 20% of ice plant cells differentiated into tracheary elements during in vitro culture. Close examination of callus tissues stained with potassium permanganate revealed that tracheary elements were aggregated as discrete nodules. Some strikingly elongated tracheary elements were found in the macerated tissues. Experimental results indicated that adding 200 mM NaCl to the control medium reversibly inhibited the formation of tracheary element in the halophytic cells. The rate of tracheary element formation increased accordingly as the rate of cell growth in control medium. In the presence of high salt, the degree of tracheary element differentation remained low through the growth cycle. The inhibitory effect of salt on tracheary element differentiation was overcome by adding 10 mg l−1 salicylic acid, a known signaling compound that induces a diverse group of defense-related genes, including genes involved in reinforcing the host cell wall. Furthermore, microscopic examination revealed that most tracheary elements formed under this treatment (200 mM NaCl plus 10 mg l−1 salicylic acid) were round shaped. The results suggest that high salt inhibits both the biosynthesis of secondary wall components and cell elongation ice plant in vitro culture. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

12.
The effects of proline additions to culture systems of Miscanthus x ogiformis Honda Giganteus' were investigated. Proline was added in concentrations of 0, 12.5, 25, 50, 100 or 300 mM to the callus induction and suspension culture media containing either Murashige and Skoog or N6 basal salts and 22.6 μM 2,4-dichlorophenoxyacetic acid. Shoot apices and leaves from in vitro-propagated shoots, and immature inflorescences from greenhouse-grown plants were used as explants for callus induction and formation. Suspension cultures initiated from embryogenic callus of immature inflorescences were used to test the effect of proline in suspension cultures. The proline additions affected the formation of embryogenic callus and the growth of suspension cultures. Improvements depended on the proline concentration and the basal salts of the medium. Addition of 12.5 to 50 mM proline to callus induction medium with Murashige and Skoog salts increased embryogenic callus formation on shoot apices and leaf explants while proline had no effect on embryogenic callus formation in medium with N6 salts. Increased growth with increasing proline concentration was obtained in suspension aggregates grown in medium with N6 salts, whereas proline only increased growth of suspension aggregates grown in medium with Murashige and Skoog salts at concentrations of 12.5 or 25 mM. A stimulating effect of proline on plant regeneration was observed in short-term cultures of callus as well as in long-term cultures of suspension aggregates. An optimum proline concentration for plant regeneration was found at 12.5 mM. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

13.
Callus and cell suspension cultures were initiated from leaf segments of G. paniculata. Fresh and dry weights measurements of callus showed that callus growth was optimal on MS medium supplemented with 1.0 mg l–1 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.2 mg l–1 benzyladenin (BA). Calli cultured on this medium, showed a two-fold increase in fresh weight by the fourth week of incubation. The initiated hard green callus was repeatedly subcultured on MS medium containing increasing concentrations of 2,4-D in order to increase its friability. The friable callus was then used for establishment of a cell suspension culture. Maximum growth of the suspension culture was on medium supplemented with 1.0 mg l–1 2,4-D and 0.2 mg l–1 BA.The suspension culture was used for studying plant host attachment in both electron and light microscopy. Upon infection with E. herbicola, plant cells showed aggregate formation within 24 h of infection. In the presence of the pathogenic Ehg,the number of aggregates formed was 342 aggregates ml–1, in the presence of the non-pathogenic Ehg154 aggregates ml–1 and in the control 115 aggregates ml–1. These results show that the pathogenic strain causes formation of cell aggregates 5.8 times greater than the non-pathogenic one. Based on these results, it can be hypothesized that bacterial cells of the pathogenic strains bind to the plant cells and may form a bridge for attachment of plant cells to one another. Observations by electron microscope show that bacterial cells do attach to plant cells and that this attachment might be via formation of a bridge between the bacteria and the plant cell.  相似文献   

14.
An embryogenic suspension culture of Zea mays, genotype 4C1, was obtained from friable callus that was cultured on solid medium and had been obtained from zygotic embryos. The suspension contained non-dividing elongated cells, clusters of dividing isodiametric cells, and globular, ovoid, and polar stages of somatic embryos. The single somatic embryos were blocked in shoot meristem formation: when transferred to regeneration medium they developed a root and, at the shoot side, a green cap with meristematic cells, but a scutellum and leaf primordia were not formed. In medium containing 2,4-dichlorophenoxy acetic acid, somatic embryos formed embryogenic callus aggregates, consisting of globular stage somatic embryos attached to each other via undifferentiated callus cells. These somatic embryos developed into mature embryos with the zygotic histological characteristics, such as scutellum and leaf primordia, in maturation medium, and then regenerated into plants in regeneration medium. By omitting the maturation phase, regeneration occurred via organogenesis. Polyembryos, i. e. embryos attached to each other without callus tissue in between, behaved as single somatic embryos. It is concluded that the attached callus tissue provides a factor that stimulates scutellum and leaf primordia formation.Abbreviations CMM callus maintenance medium - 2,4D 2,4-dichlorophenoxy acetic acid - PCV packed cell volume - MS Murashige and Skoog medium  相似文献   

15.
Several kinds of precursors obtained by natural polymer hydrolysis of leaves, cell walls, cellulose and hemicelluloses have been tested on in vitro cultures. Interesting preliminary results were obtained with strawberry callus culture whereby all the tested hydrolysates were able to induce differentiation and organogenesis without addition of any plant growth regulators to the culture medium. This suggests the existence of one or more compounds, enzymatically released from the cell wall, which play a role on plant differentiation and organogenesis.Abbreviations AH agar hydrolysate - BA 6-benzyladenine - CH cotton hydrolysate - 2.4-d 2.4-dichlorophenoxyacetic acid - LH leaf hydrolysate - MS Murashige & Skoog medium - NAA -naphthalene-acetic acid - WH cell wall hydrolysate  相似文献   

16.
Summary The culture conditions for direct embryo formation in leaves of Camellia japonica L. were established. An auxin treatment followed by incubation during 11 days in darkness on diluted Murashige and Skoog modified basal medium induced direct morphogenesis. The number of subcultures, subculture interval and leaf age affected in vitro leaf response. The results showed that the cells from a cultured leaf respond differently to the same culture conditions by forming embryos, roots, and non-morphogenic as well as organogenic callus. Direct embryo formation occurred only in the marginal leaf regions. Direct root formation only occurred in a well-defined region of the midrib whereas callus was preferentially formed on the leaf basis. The results suggest the existence of differences in morphogenic competence according to leaf regions. Plantlet regeneration was successfully achieved from somatic embryos and from leaf basisderived callus, via shoot bud induction.Abbreviations BA 6-benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - DTT dithiothreitol - IAA indole-3-acetic acid - IBA indole-3-butyric acid  相似文献   

17.
For centuries Hypericum perforatum has been used in natural medicine. In the last decades, it has also attracted the attention of pharmaceutical industry due to its promising anti-depressant properties. The important factor in pharmaceutical application of plant material is its stable content of active compounds. Such stability requires standardized conditions of growth, e.g. an in vitro culture. Our aim was to establish a medium allowing for an effective regeneration of shoots from the standardized leaf explants in in vitro conditions. Cultures of the leaf explants carried out in darkness, on Murashige and Skoog agar medium, supplemented with auxins (2,4-dichlorophenoxyacetic acid, 2-metoxy-3,6-dichlorobenzoic acid, α-naphtaleneacetic acid, indole-3-acetic acid) and cytokinins (kinetin, N6-(benzyl)adenine, thidiazuron) resulted in callus formation. The callus produced roots on media containing indole-3-acetic acid or α-naphtaleneacetic acid alone. On media supplemented with auxins and cytokinins, indirect shoot organogenesis was also observed. The most efficient shoot formation was observed with 2.85 μM of indole-3-acetic acid and 4.44 μM of benzyladenine. Regenerated shoots were rooted on Murashige and Skoog without plant growth regulators medium or on a medium supplemented with indole-3-acetic acid. From a single leaf explant (one fifth of the leaf) after a month of the culture, 35 regenerated shoots were obtained (allowing for the formation of about 180 vegetative shoots per leaf). Successful multiplication of shoots from a standardized explant makes it possible to obtain a great quantity of uniform plant material for biotechnological purposes.  相似文献   

18.
When leaf disks from haploid plants of Nicotiana plumbaginifolia Viv. were transformed with T-DNA and cultured on shoot-inducing medium, nonorganogenic callus. designated nolac (for non-organogenic callus with loosely attached cells), appeared on approximately 7% of leaf disks. In contrast, normal callus was generated on T-DNA-transformed leaf disks from diploid plants and on non-transformed leaf disks from haploid and diploid plants. Transmission electron microscopy revealed that the middle lamellae and the cell walls of one line of mutant callus (nolac-H14) were barely stained by ruthenium red. even after demethylesterification with NaOH, whereas the entire cell wall and the middle lamella were strongly stained in normal callus. In cultures of nolac-H14 callus, the level of sugar components of pectic polysaccharides in the hemicellulose fraction was reduced and that in the culture medium was elevated, as compared with cultures of normal callus. These results indicate that pectic polysaccharides are not retained in the cell walls and middle lamellae of nolac-H14 callus. In nolac-H14, the ratio of arabinose to galactose was low in the pectic polysaccharides purified from all cell wall fractions and from the medium, in particular, in the hemicellulose fractions. The low levels of arabinofuranosyl (T-Araf, 5-Araf, 2,5-Araf, and 3,5-Araf) residues in the pectic polysaccharides of the hemicellulosic fraction of nolac-H,14 indicated that no neutral-sugar side chains, composed mainly of linear arabinan. were present in nolac-H14. Arabinose-rich pectins. which are strongly associated with cellulose-hemicellulose complexes, might play an important role in intercellular attachment in the architecture of the cell wall.  相似文献   

19.
The effect of various plant growth substances as single agents was evaluated in a complex tissue culture system: whole embryo culture of early differentiating barley embryos. Callus formation in unsupplemented medium derives from the mesocotyl and is uniquely characteristic of cultures initiated at this stage of embryonic development. This phenomenon could be prevented or reversed by incorporation of gibberellic acid in the medium resulting in plantlet formation. Indoleacetic acid enhanced callus growth, whereas kinetin did not promote either callus or meristematic development. Callus tissue markedly accumulated starch, effectively lowering the cellular osmolarity, while inducing a corresponding rise in the osmolarity of the culture medium. This osmotic pattern was reversed by gibberellic acid induction of shoot formation. These osmotic-hormonal interactions are interpreted relative to in vivo, in situ normal embryogeny or developmental lesions such as tumors.  相似文献   

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