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1.
Neutral and acidic oligosaccharides were obtained from birchwood xylan by treatment with an endoxylanase, family 10 class, from Thermoascus aurantiacus. The main acidic xylooligosaccharide (aldotetrauronic acid) was separated from the hydrolysate by anion-exchange and size-exclusion chromatography and the primary structure was determined by 13C NMR spectroscopy. The aldotetrauronic yield was 15% (w/w) of the total solubilised sugars. The addition of purified aldoterauronic acid at 1.6–16 mg l–1 growth medium, induced callus and somatic embryogenesis in culture explants of common mallow (Malva silvestris L.) and cotton (Gosssypium hirsutum).  相似文献   
2.
三裂叶野葛毛状根的诱导及其固体培养和液体培养   总被引:6,自引:1,他引:5  
发根农杆菌(Agrobacterium rhizogenes)ATCC15834感染三裂叶野葛(Pueraria phaseoloides)叶片外植体20 d后产生毛状根,毛状根可直接从叶片外植体叶脉处或从叶脉处产生的愈伤组织上产生。感染35d后,约85%的叶片外植体产生毛状根。毛状根能在无外源生长调节剂的 MS固体和液体培养基上自主生长。PCR扩增结果表明,发根农杆菌Ri质粒的rolBrolC基因已在三裂叶野葛毛状根基因组中整合并得到表达。与固体培养的毛状根相比,在液体培养基中培养的毛状根不仅生长迅速,也不会形成愈伤组织。在无外源生长调节剂的液体MS培养基中培养15d的三裂叶野葛毛状根的鲜重、干重、可溶性总糖含量及细胞内活性氧(ROS)含量分别为固体培养毛状根的1.59倍、1.18倍、5.25倍和1.16倍。  相似文献   
3.
The effect of explant age, plant growth regulators and culture conditions on somatic embryogenesis and rosmarinic acid production from leaf explants of Salvia officinalis and S. fruticosa plants collected in Greece was investigated. Embryogenic callus with numerous spherical somatic embryos could be induced on explants derived from both species and cultured for 3 weeks on a Murashige and Skoog (MS) medium supplemented with 1.8–18 μm 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin (Kin) or 10.5–21 μm 1-naphthalenacetic acid and 6-benzyladenine. Only explants from young plants (with six to eight leaves) responded to the culture treatments and, in general, low light intensities (50 μmol m–2 s–1) favoured callus formation and induction of somatic embryos. Somatic embryos were further developed on the same medium. Heart- and torpedo-shaped embryos (1–2 mm long) were subcultured on a growth-regulator-free MS medium for maturation. Maximum rosmarinic acid accumulation in S. officinalis and S. fruticosa callus cultured on 4.5 μm 2,4-D and 4.5 μm Kin was 25.9 and 29.0 g/l, respectively. Received: 17 January 1997 / Revision received: 26 May 1997 / Accepted: 30 June 1997  相似文献   
4.
Anther culture responsiveness of three H. spontaneum derived spring barley lines, RS170-47(A), RS20-1(B) and 1B-152B(C) was investigated using only one type of culture medium and treatment. The line 1B-152B was identified as highly responsive producing 22.4 total and 12.4 green regenerants per 100 anthers plated. 74% of these green regenerants were spontaneous double haploids. A genetic analysis involving F1 and F2 plants derived from crosses A × B and B × C revealed that the factor(s) determining high anther culture responsiveness in line 1B-152B was heritable and behaved as dominant in the F1. There was an indication that genotypic responsiveness in anther culture for green plant regeneration was different from total or albino plant regeneration.  相似文献   
5.
We investigated the effect of genotype, seed maturity and culture medium on the in vitro germination and development of protocorms and plantlets from seeds of 13 different Ophrys species (O. apifera, O. attica, O. cornuta, O. delfinensis, O. ferrum-equinum, O. lutea, O. mammosa, O. speculum, O. spruneri, O. umbilicata, O. argolica, O. irricolor and O. tenthredinifera) collected in Greece, some of which are endemic to this country. Mature seeds (10 months after collection) and immature seeds (2 months after anthesis) were cultured in a coconut milk-enriched or a pineapple-enriched medium (CEM or PEM, respectively). The highest percentage of callogenesis (96%) was observed in immature seeds of O. delphinensis in the CEM, while the highest percentage of protocorm formation (52%) was observed in mature seeds of O. spuneri in the CEM. Protocorm formation was significantly lower in immature seeds than in mature seeds in both culture media. Eventually almost all of the transferred protocorms developed to plantlets, which later formed minitubers. PEM appeared to be the most suitable for the development of minitubers from plantlets. All of the factors investigated—as well as their interactions—significantly affected callogenesis and protocorm formation. The results are discussed with the perspective of applying an improved protocol for in vitro seed germination and plantlet formation in several under-utilized Ophrys species.Abbreviations CEM Coconut milk-enriched medium - CLT Callus-like tissue - PEM Pineapple-enriched medium - PPFD Photosynthetic photon flux density  相似文献   
6.
A novel biosensory method has been developed for the determination of various chemical and biological molecules by assessing their electrophysiological interactions with a group of cells and cell components immobilized in a gel matrix that preserves their 'physiological' functions. The method was applied for the detection of: (i) hepatitis C virus in human blood samples; (ii) plant viruses; and (iii) a herbicide (glyphosate) in aqueous solutions. It was able to rapidly (assay time 3-5 min) and specifically detect the molecules in question at a concentration lower than 100 pg/ml, among other compounds f similar structure. The potential use of BERA biosensors for a rapid and cost-efficient molecule determination without prior knowledge of a specific receptor-molecule interaction is discussed.  相似文献   
7.
Anther culture response of Hordeum spontaneum-derived winter barley lines   总被引:2,自引:0,他引:2  
The anther culture response of 18 Hordeum spontaneum derived winter barley lines, as well as that of the F2 and/or BC1 progeny of the cross between nine of these lines and the winter barley cultivar Triton was assessed. While the majority of lines showed a poor regeneration capacity (4%), two lines, RS 170-A13 × Sonja and RS 120-27 × Sonja demonstrated an outstanding response, producing 26 and 8 green regenerants per 100 anthers plated, respectively. Five further lines, RS 70-30 × Dura, RS L74-11 × Dura, RS 122-19 × Sonja. RS 142-29 × Dura and RS 170-A51 × Sonja were identified as highly responsive in the F2 generation. An average production of 4 green regenerants per 100 anthers plated was observed both in the parental and F2 generation.Abbreviations BA benzyladenine - IAA indole-3-acetic acid  相似文献   
8.
Leaf explants of squash (Cucurbita pepo L.) and melon (Cucumis melo L.) were pretreated initially with 113.1, 226.2 or 452.4 µM 2,4-dichlorophenoxyacetic acid (2,4-D), 46.5, 93 or 186 µM kinetin or a combination of both at the above concentrations, for 6, 24 or 48 h. After pretreatment, explants were transferred to an agar-solidified medium that was not supplemented with growth regulators or to a species-specific standard induction medium. Control explants from each species were incubated directly on the species-specific standard induction medium. Initial pretreatment of squash explants with 186 µM kinetin and of melon explants with 226.2 µM 2,4-D for 48 h significantly promoted the formation of somatic embryos which developed further to the torpedo-shape stage and germinated. Under these conditions at least four plants can be regenerated per square centimeter of explant surface, thus achieving an increase over non-pretreated cultures of 143% and 130% for squash and melon, respectively.  相似文献   
9.
A protocol has been developed for the induction of somatic embryogenesis from flower explants of chamomile (Chamomilla recutita L.). The effects of several plant growth regulators [α-naphthylacetic acid (NAA), 2,4-dichlorophenoxyacetic acid, 6-benzyladenine (BA) and kinetin (Kin), alone or in combination] and the flower type (disk or ray flower) were investigated. Both types of flowers responded to the callus and shoot induction treatments, but formation of globular somatic embryos took place only on disk-flower-derived explants after 2–4 weeks of culture on a Murashige and Skoog (MS) medium supplemented either with 8.87 μm BA and 1.07 μm NAA or with 26.8 μm NAA and 11.5 μm Kin. However, fully developed, cotyledonary-stage somatic embryos could be induced only on the NAA/Kin medium, 10 weeks after culture initiation. Germination of the embryos and plant regeneration took place after subculture for 4–5 weeks onto medium of the same composition. Plantlets regenerated from embryos flowered in vitro on a MS medium supplemented with 8.87 μm BA and 1.07 μm NAA. The significance of the results with respect to chamomile micropropagation and the utilization of wild populations in breeding programs is discussed. Received: 6 April 1998 / Revision received: 12 October 1998 / Accepted: 28 October 1998  相似文献   
10.
The Bioelectric Recognition Assay (BERA) is a whole-cell based biosensing system that detects the electric response of cultured cells, suspended in a gel matrix, to various ligands, which bind to the cell and/or affect its physiology. Previous studies have demonstrated the potential application of this method for rapid, inexpensive detection of viruses in a crude sample. However, the understanding, so far, of the fundamental processes that take place during cell-virus interactions within the probe has been rather limited. In the present study, we combined electrophysiological and fluorescence microscopical assays, so that we can prove that animal and plant cells immobilized in BERA sensors respond to different viruses primarily by changing their membrane potential. The response of immobilized cells against different viruses did not depend on the virus ability to penetrate the cell, but was modified after binding each virus to a virus-specific antibody or removal of its coat protein after treatment with a protease. Consequently, we were able to assay the presence of a virus in its complete form or fragments thereof. Combination of immunological recognition with the electrophysiological response of immobilized cells allows for a considerable increase of the specificity of the BERA biosensory assay. In addition, rather than simply detect the presence of a protein or genomic sequence, the method can help gain information on the bioactivity of a virus.  相似文献   
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