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  • 1
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 109 (2000), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Ornithogalum (chincherinchee) is a genus in the Hyacinthaceae. It is popular as a cut flower or pot plant. However, susceptibility to disease, especially ornithogalum mosaic virus, prevents commercial exploitation of micropropagated hybrids. Provided that it is possible to transform Ornithogalum, this problem might be alleviated by the transfer of genes that code for resistance to the virus. The purpose of this study was to develop a transformation protocol using the pat gene as a selectable marker. Callus, induced on leaf segments of an Ornithogalum thyrsoides×O. dubium hybrid cultured in vitro, was bombarded with a particle gun 4–6 weeks after initiation. We first used β-glucuronidase transient expression to optimise the bombardment parameters and then for stable transformation used both a conventional microprojectile-mediated method as well as a modification that entailed complexing single-stranded p35SAC DNA, containing the pat gene, with histone H1 prior to bombardment. Transgenic plants were regenerated from the bombarded tissues and cultured on a medium containing 15 μM phosphinothricin as selective agent. Rooted plants were tested for the presence of the pat gene by polymerase chain reaction. Integration of the gene into the genomic DNA was verified by Southern blotting. Northern blots, enzyme-linked immunosorbent assay, and leaf paint assays with the herbicide Ignite® (glufosinate ammonium) confirmed expression of phosphinothricin acetyl transferase, the enzyme that detoxifies the herbicide.
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 82 (1991), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Fructose and sucrose were used to investigate cyanide-induced absorption changes after high temperature treatment. By comparing the time-resolved absorbance difference spectra obtained under aerobic conditions with those under aerobic conditions, absorbance changes that are associated with the process of oxygen consumption were identified. The rates of absorbance changes of autoclaved sucrose solution or of autoclaved MS medium (Murashige and Skoog 1962. Physiol. Plant. 15: 473–497) were correlated with those of oxygen consumption measured by polarography and used for determining the toxicity of culture media (Hsiao and Bornman 1991. Physiol. Plant. 81: 55–58). When autoclaved together with sucrose, FeNa-EDTA promotes its degradation. Absorbance change, therefore, is a convenient parameter for measuring not only the extent of carbohydrate breakdown at high temperature but also the relative toxicity of culture media autoclaved under different conditions.
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  • 3
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Jarl, C. I., Ljungberg, U. K. and Bornman, C. H. 1988. Correction of chlorophyll-defective male-sterile winter oilseed rape (Brassica napus) through organelle exchange: Characterization of the chlorophyll deficiency. - Physiol. Plant. 72: 505–510.As is known, the introduction of male-sterile Raphanus sativus L. cytoplasm into Brassica napus L. results in male-sterile oilseed rape plants, which display a temperature-related chlorophyll defect. The influences of temperature and irradiance on this defect were investigated. Compared to a line of normal (green phenotype) male-fertile oilseed rape, the male-sterile line had reduced chlorophyll content, fewer chloroplasts per cell, an altered ultrastructure of the chloroplasts and reduced activities of both photosystems, although the relative amounts of the photosystems and the chlorophyll a/b ratio were similar. The lower activity of the photosystems is explained by a decreased functional antennae size and a reduced efficiency in the interactions between the nuclear-encoded light-harvesting proteins and the reaction centres coded for by the plastome. Some thylakoid polypeptides differed in proportion between the male-fertile line with green phenotype and the male-sterile line with chlorotic phenotype. Characters, in which the two lines exhibited differences, are ascribed to difficulties in molecular communication between the oilseed rape nucleus and the radish cytoplasm, which are combined in the deficient male-sterile line.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 61 (1984), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Primary explants ofPicea abies (L.) Karst. and Pinus sylvestris L. were incubated for various periods in solutions containing different concentrations of [14C]-benzyladenine. Time course analysis showed that uptake was linear for the initial 60 min; after this time linear uptake continued but at a much reduced rate. The amount of benzyladenine taken up by the explants saturated at a concentration about one third of that of the medium, Concentration dependence experiments showed that BA uptake was directly proportional to the external concentration. These results and those from experiments in which uptake was examined at different temperatures are consistent with a passive mode of BA uptake. The results are discussed with respect to in vitro micropropagation.
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 48 (1980), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The effects of cis. trans abscisic acid on response to chilling was investigated in callused Nicotiana tabacum L. pith explants. Explants pretreated with 10-4M ABA underwent approximately 50% less cellular leakage when chilled at 2°C under short-day conditions for 10 d than the comparable non-treated tissue. Growth in terms of fresh and dry weights, although poor in comparison to non-chilled (20°C, long days) treatments, was more than twice that of the non-ABA-treated material. On an absolute dry weight basis proline content increased on chilling from 0.7 to 3.4 mg g-1 in non-ABA-treated explants, but rose to nearly 17 mg g-1 in the tissue treated with ABA. Only in the case of cold-hardened. ABA-treated tissue could some cells survive subzero temperatures and regenerate callus again. It is suggested that at least part of the ameliorating effects of ABA result from an increase in the level of proline.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 70 (1987), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Brassica napus L. and Rosa sp. protoplasts were immobilized on variously treated Biosilon, Cytodex 1, 2 and 3, Separon, Sephadex, Sepharose and Sorfix micro carriers. Best anchorage of protoplasts of both species was obtained with Biosilon and Cytodex 3 coated with polylysine of high molecular weight (55 and 450 kDa), as well as with concanavalin A-coated Cytodex 1. Precoating of micro carriers with bovine serum albumin was generally without effect.
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 61 (1984), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Manipulation of protoplasts via fusion and organelle transfer is expected to be facilitated by the technique known as electric field fusion. Construction and use are described of three flow-through fusion chambers that incorporate flat-sided electrodes in a manner that makes fusion of protoplasts possible througout the chambers’ total volume (4, 49 or 110 μl) under constant electrical, chemical and physical conditions. Brassica napus L. protoplasts subjected to fusogenic conditions, that is, application of voltages that induce reversible membrane breakdown, were capable not only of survival but also of cell wall resynthesis, cell division and subsequent growth and development. Intraspecific (B. napus × B. napus), interspecific. (B. napus × B. campestris L.) and intergeneric (B. napus × Primula acaulis L.) fusion and engulfment events were followed by using on the one hand autofluorescence and fluorescein isothiocynate as respective markers or on the other hand autofluorescence and vacuolar anthocyanin (Primula). Properties and merits of flat-sided versus cylindrical electrodes are discussed.
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 63 (1985), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Somatic embryos were observed as early as six days after subculturing immature embryos of Triticum aestivum L. (cvs Froid-Centurk and Helge) in vitro on 2,4-dichloro-phenoxyacetate-containing nutrient media. Embryo formation followed three pathways, each involving one of the scutellum's three basic tissue systems: dermal, ground and vascular.(1) Single epithelial layer cells divided tangentially to give pseudothallus-like structures which, through radial and oblique divisions, assumed polar, proembryoid symmetry.(2) In actively dividing ground tissues, localized asymmetrical division in some cells resulted in proembryoids. When contiguous with each other, the proembryoids could be identified as a proembryonic mass.(3) Oblique divisions in some cells of the scutellum's procambium resulted in daughter cells of unequal size, from the smaller of which the embryoid's root would eventually form.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 77 (1989), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Protoplasts of Vitis rotundifolia Michx. cv. Summit were isolated from mesophyll of axenic shoot cultures under different enzyme concentrations and digestion times. Viability and plating efficiency were assessed and related to the cortical microtubule network, visualized using immunofluorescence. Higher concentrations of enzyme isolation medium significantly decreased protoplast viability and plating efficiency. However, the cortical microtubule network appeared stable, at all concentrations with dense, continuous microtubule strands in both random and parallel arrays. In contrast, longer vs shorter enzyme incubation duration resulted in significantly lower plating efficiency, which was correlated with changes in cortical microtubule organization. With longer incubation, the frequency of parallel microtubule strands decreased; microtubule organization showed increasing disruption, microtubule strands were shortened, fragmented and exhibited only a weak fluorescence labeling. Both high enzyme concentration and prolonged incubation periods negatively affected protoplast regenerability, but in different ways. Microtubule organization was sensitive to duration of incubation, but not to enzyme concentration. It is concluded that the presence of a well-developed cortical microtubule network does not gurantee regeneration. Other factors related to isolation appear to be involved.
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  • 10
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Petiolar protoplasts of a dihaploid line of winter oilseed rape Brassica napus L. ssp. oleifera were exposed to fusogenic polyethylene glycol (PEG) and electric field treatments. The surface properties and stability of membrane components of the treated protoplasts were investigated by contact angle measurements in aqueous two-phase systems and differential scanning calorimetry, respectively. The leakage of intracellular components was estimated with respect to amino acids, proteins and DNA. Both fusogenic treatments resulted in the same apparent changes in membrane surface hydrophobicity and the same destabilization of membrane components. However, the PEG-treated protoplasts were more leaky than both the control and the electric field-treated protoplasts. The results indicate that the molecular mechanisms of PEG- and electrical field-induced fusion are similar. However, the effects of the latter appear to be less harmful presumably because the parameters for electric field treatment are more easily controlled.
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