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  • Articles  (31)
  • Nicotiana  (16)
  • Hordeum  (15)
  • Springer  (31)
  • American Institute of Physics
  • Oxford University Press
  • Sage Publications
  • 2010-2014
  • 2005-2009
  • 1985-1989
  • 1975-1979  (31)
  • 1945-1949
  • 2007
  • 2005
  • 1978  (31)
  • 1945
  • Biology  (31)
  • Electrical Engineering, Measurement and Control Technology
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  • Articles  (31)
Source
Keywords
Publisher
  • Springer  (31)
  • American Institute of Physics
  • Oxford University Press
  • Sage Publications
Years
  • 2010-2014
  • 2005-2009
  • 1985-1989
  • 1975-1979  (31)
  • 1945-1949
Year
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  • 1
    Electronic Resource
    Electronic Resource
    Observations on the time course of wall development at the surface of isolated protoplasts (1978)
    Springer
    Planta 139 (1978), S. 85-91 
    Details
    ISSN: 1432-2048
    Keywords: Antirrhinum ; Cellulose ; Nicotiana ; Protoplasts ; Scanning microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The formation of cell wall fibres at the surface of isolated leaf protoplasts has been studied by scanning electron microscopy. Fibres are not formed on incubated protoplasts until a lag period has elapsed. This period is about 8 h for leaf protoplasts of Nicotiana tabacum and about 45 h for leaf protoplasts of Antirrhinum majus. In the case of Antirrhinum protoplasts the length of the lag period is dependent on the concentration of osmoticum present during the incubation period. If regenerating protoplasts are briefly treated with dilute cellulase, the newly formed wall is completely digested. Such protoplasts are capable of producing new fibres at the surface within minutes of their return to a nutrient medium. These results are discussed in terms of the likely source of the lag period and its significance in wall regeneration studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00390815
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  • 2
    Electronic Resource
    Electronic Resource
    A comparison of regenerated cell walls in tobacco and cereal protoplasts (1978)
    Springer
    Planta 139 (1978), S. 155-158 
    Details
    ISSN: 1432-2048
    Keywords: Avena ; Cell-wall regeneration ; Electrical potential ; Nicotiana ; Protoplast culture ; Turgor pressure ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four independent kinds of observations indicate that the cell wall regenerated by oat (Avena sativa L.) and corn (Zea mays L.) protoplasts in culture is less well developed than that regenerated by tobacco (Nicotiana tabacum L.) protoplasts. Following wall regeneration the cereal protoplasts remained susceptible to osmotic shock upon transfer to water, showed great enlargement, stained poorly with calcofluor white, and maintained a positive internal electrical potential. The development of a negative membrane potential by tobacco protoplasts in culture often occurred simultaneously with the onset of cell division. Since division was observed only in protoplasts which had regenerated good cell walls and had re-established negative membrane potentials it is suggested that culture conditions which favor these two processes should improve protoplast viability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387141
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  • 3
    Electronic Resource
    Electronic Resource
    Peptide transport by germinating barley embryos: Uptake of physiological di- and oligopeptides (1978)
    Springer
    Planta 138 (1978), S. 211-215 
    Details
    ISSN: 1432-2048
    Keywords: Germination (embryos) ; Hordeum ; Oligopeptides ; Peptide absorption and transport ; Storage protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The uptake of a variety of physiological di- and oligopeptides by germinating barley (Hordeum vulgare L.) embryos is described. Peptides as large as pentaalanine can be absorbed. Evidence is presented suggesting the peptides are absorbed intact and subsequently undergo rapid intracellular hydrolysis. Uptake shows stereospecificity. The transport of peptides is generally faster than the transport of amino acids, making it likely that the former could play an important role in the mobilization of the protein storage reserves during germination. The peptide transport system in barley is compared with similar systems from other groups of organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386813
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  • 4
    Electronic Resource
    Electronic Resource
    Peptide transport by germinating barley embryos: Evidence for a single common carrier for di- and oligopeptides (1978)
    Springer
    Planta 138 (1978), S. 217-221 
    Details
    ISSN: 1432-2048
    Keywords: Germination (embryo) ; Hordeum ; Peptides ; Protein ; Storage protein ; Scutellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Competition for uptake of a range of amino acids and peptides by germinating barley (Hordeum vulgare L.) embryos was studied. Peptides and amino acids show no competition and are apparently absorbed by independent transport systems. However, peptides of widely different structures do compete and it seems that only a single peptide transport system is present in barley embryos, capable of handling both di- and oligopeptides. The ability of physiological peptides to totally inhibit the uptake of glycylsarcosine indicates they share a common uptake system which previously has been shown to have the properties of an active transport process. The characteristics of the barley peptide transport system are compared with those found in other organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386814
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  • 5
    Electronic Resource
    Electronic Resource
    Fatty acid synthesis by slices from developing leaves (1978)
    Springer
    Planta 138 (1978), S. 223-228 
    Details
    ISSN: 1432-2048
    Keywords: Chloroplasts ; Fatty acids ; Hordeum ; Lolium ; Triticum ; Zea leaves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fatty acid synthesis was studied in successive leaf sections from the base to the tip of developing barley (Hordeum vulgare L.), maize (Zea mays L.), rye grass (Lolium perenne L.) and wheat (Triticum aestivium L.) leaves. The basal regions of the leaves had the lowest rates of fatty acid synthesis and accumulated small amounts of very long chain fatty acids. Fatty acid synthesis was highest in the middle leaf sections in all four plants. Linolenic acid synthesis from [1-14C]acetate was highest in the distal leaf sections of rye grass. The labelling of the fatty acids of individual lipids of rye grass was examined and it was found that [14C]linolenic acid was highest in the galactolipids. Synthesis of this acid in the galactolipids was most active in leaf segment C. Only traces of [14C]linolenic acid were ever found in phosphatidylcholine and it is concluded that this phospholipid cannot serve as a substrate for linoleic acid desaturation in rye grass. The synthesis of fatty acids was sensitive to arsenite, fluoride and the herbicide EPTC. The latter was only inhibitory towards those leaf segments which made very long chain fatty acids. Formation of fatty acids from [1-14C]acetate was also studied in chloroplasts prepared from successive leaf sections of rye grass. Chloroplasts isolated from the middle leaf sections had the highest activity. Palmitic and oleic acids were the main fatty acid products in all chloroplast preparations. Linolenic acid synthesis was highest in chlorplasts isolated from the distal leaf sections of rye grass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386815
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  • 6
    Electronic Resource
    Electronic Resource
    Regulation of threonine biosynthesis in barley seedlings (Hordeum vulgare L.) (1978)
    Springer
    Planta 140 (1978), S. 185-192 
    Details
    ISSN: 1432-2048
    Keywords: Homoserine kinase ; Hordeum ; Threonine synthese
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Homoserine kinase was purified 700-fold by fractional ammonium sulfate precipitation, heat treatment, CM-Sephadex C-50 and DEAE-Sephadex A-50 ion exchange chromatography, and Sephadex G-100 gel filtration. The reaction products O-phosphohomoserine and ADP were the only compounds which caused considerable inhibition of homoserine kinase activity. Product inhibition studies showed non-competitive inhibition between ATP and O-phosphohomoserine and between homoserine and O-phosphohomoserine, and competitive inhibition between ATP and ADP. ADP showed non-competitive inhibition versus homoserine at suboptimal concentrations of ATP. At saturating concentrations of ATP no effect of ADP was observed. The homoserine kinase activity was negligible in the absence of K+ and the Km value for K+ was observed to be 4.3 mmol l−1. A non-competitive pattern was observed with respect to the substrates homoserine and ATP. Threonine synthase in the first green leaf of 6-day-old barley seedlings was partially purified 15-fold by ammonium sulfate fractionation and Sephadex G-100 gel chromatography. Threonine synthase was shown to require pyridoxal 5′-phosphate as coenzyme for optimum activity and the enzyme was strongly activated by S-adenosyl-L-methionine. The optimum pH for threonine synthase activity was 7 to 8.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384919
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  • 7
    Electronic Resource
    Electronic Resource
    An in vitro association of soluble phytochrome with a partially purified organelle fraction from barley leaves (1978)
    Springer
    Planta 141 (1978), S. 71-76 
    Details
    ISSN: 1432-2048
    Keywords: Hordeum ; Membranes ; Organelles ; Phytochrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Red light treatment in vitro increases the pelletability of phytochrome in homogenates of etiolated barley (Hordeum vulgare L. cv. ‘Julia’) leaves. When mixtures of soluble phytochrome (100,000 x g supernatant) and partially-purified organelles (Sephadex G-50 eluate) are irradiated the amount of pelletable phytochrome increases by a factor of two. Pre-irradiation treatments show that phytochrome in both components of the mixture must be in the Pfr form for increased pelletability to be observed. Once associated, photoreversion of Pfr to Pr does not result in decreased pelletability. The results are consistent with a non-artifactual in vitro association of soluble phytochrome to organelle membranes. One possible explanation is that Pfr molecules associate to form dimers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387747
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  • 8
    Electronic Resource
    Electronic Resource
    DPX-3778 promotes proliferation of tobacco callus in vitro (1978)
    Springer
    Planta 140 (1978), S. 293-294 
    Details
    ISSN: 1432-2048
    Keywords: Callus culture ; DPX-3778 ; Nicotiana ; Tissue culture ; Triazinone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DPX-3778, the triethanolamine salt of 3-(p-chlorophenyl)-6-methoxy-s-triazine-2,4(1H,3H) dione, at concentrations of 0.124–2.48 μM enhanced ca. 4-5-fold the proliferation of tobacco (Nicotiana tabacum L. cv. Wisconsin 38) callus cultured in the presence of indole-3-acetic acid and kinetin, and retarded its senescence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00390263
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  • 9
    Electronic Resource
    Electronic Resource
    Total protein release from barley aleurone layers as a bioassay for gibberellins (1978)
    Springer
    Planta 142 (1978), S. 37-40 
    Details
    ISSN: 1432-2048
    Keywords: Aleurone ; Gibberellin ; Hordeum ; Protein release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of gibberellic acid on the secretion of proteins from barley (Hordeum vulgare L.) aleurone layers has been investigated for its suitability as a gibberellin bioassay. Concentrations from 10−4 μg/ml to 100 μg/ml of GA3 resulted in the release of proportionally increasing amounts of total protein. The release of proteins is not affected by indoleacetic acid and kinetin. This method has been applied and compared with the α-amylase assay for the estimation of gibberellin in extracts of tomato fruits and maize seedlings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385117
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  • 10
    Electronic Resource
    Electronic Resource
    O-diphenol O-methyltransferases of healthy and tobacco-mosaic-virus-infected hypersensitive tobacco (1978)
    Springer
    Planta 144 (1978), S. 101-108 
    Details
    ISSN: 1432-2048
    Keywords: Hypersensitivity ; Nicotiana ; o-Diphenols ; O-Methyltransferases ; Tobacco mosaic virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three distinct o-diphenol O-methyltransferases (OMTs) were found in leaves of Nicotiana tabacum, variety Samsun NN. They could be clearly distinguished by differences in elution pattern upon chromatography on DEAE-cellulose and in specificity towards 16 diphenolic substrates. The phenylpropanoids caffeic acid and 5-hydroxyferulic acid, whose importance as lignin precursors is well known, were the best substrates of OMT I, but they were also efficiently methylated by the two other OMTs that showed a broader substrate specificity. The highest rates of methylation were observed by assaying these latter enzymes with catechol, homocatechol and protocatechuic aldehyde. The flavonoid quercetin, the major o-diphenol of tobacco leaves, was a good substrate for OMTs II and III, but was also methylated significantly by OMT I. The tobacco OMTs showed both para-and meta-directing activities with protocatechuic acid, protocatechuic aldehyde and esculetin as substrates. Para-O-methylation of the former substrate arose almost exclusively from OMT I whereas that of the two latter substrates from all three enzymes. In healthy leaves the total O-methylating activity varied very much with the batch of plants whereas the relative contributions of the three enzymes were rather constant. On an average, OMTs I, II and III acounted towards caffeic acid, respectively. In tobacco mosaic virus-infected leaves carrying local necrotic lesions we found the same three OMTs with the same substrate specificities, but with increased activities. The degree of stimulation of both OMTs II and III was 2–3 times greater than that of OMT I when the leaves had a moderate number of lesions, and 3–5 times greater with large number of lesions. It is very likely that the changes in both the pattern of the O-methylating enzymes and the concentrations of the naturally occuring o-diphenolic substrates are related to an increased biosynthesis of lignins and of lignin-like compounds. These aromatic polymers could be involved in the cell wall thickening associated with the hypersensitive reaction and with the resistance to virus spread that occur in the cells surrounding the local lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385014
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  • 11
    Electronic Resource
    Electronic Resource
    Chemical inhibition of cell wall formation and cytokinesis, but not of nuclear division, in protoplasts of Nicotiana tabacum L. cultivated in vitro (1978)
    Springer
    Planta 142 (1978), S. 253-262 
    Details
    ISSN: 1432-2048
    Keywords: Cell wall formation ; Cytokinesis ; Inhibitors ; Mitosis ; Nicotiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of cytochalasin B, colchicine, coumarin and 2,6-dichlorobenzonitrile on cell wall formation and cellular division was studied by light and electron microscopy with tobacco mesophyll protoplasts cultivated in vitro. 2,6-dichlorobenzonitrile was found to be the most effective and reversible inhibitor of cell wall formation. The other inhibitors caused irreversible damage and/or inhibited mitosis. In protoplasts cultivated in the presence of 2,6-dichlorobenzonitrile the total inhibition of cell wall formation had no effect on nuclear division, but cytokinesis was totally inhibited so that multinucleate protoplasts were obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385074
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  • 12
    Electronic Resource
    Electronic Resource
    Isolation of somatic hybrids by cloning Nicotiana heterokaryons in nurse cultures (1978)
    Springer
    Planta 143 (1978), S. 29-32 
    Details
    ISSN: 1432-2048
    Keywords: Hybrids (somatic) ; Isoenzymes ; Kanamycin resistance ; Nicotiana ; Somatic hybrids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fusion of Nicotiana knightiana Goodsp. and kanamycin resistant Nicotiana sylvestris Speg. et Com. protoplasts was induced by polyethylene glycol treatment. Heterokaryons were isolated by micropipette and transferred to nurse cultures of albino cells. Colonies originating from the heterokaryons could subsequently be distinguished by their green colour. The somatic hybrid nature of four such colonies was confirmed by isoenzyme pattern, kanamycin resistance and restored morphogenic potential. An additional kanamycin resistant line with characteristic Nicotiana knightiana isoenzymes was also found indicating that the drug resistance in the kanamycin resistant parent is under cytoplasmic control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389048
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  • 13
    Electronic Resource
    Electronic Resource
    The mode of secretion of α-amylase in barley aleurone layers (1978)
    Springer
    Planta 143 (1978), S. 89-99 
    Details
    ISSN: 1432-2048
    Keywords: Aleurone cells ; α-Amylase ; Gibberellin ; Hordeum ; Membrane fractionation ; Secretion (enzymes)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The involvement of the endomenbrane system of barley (Hordeum vulgare L.) aleurone cells in the secretion of gibberellin-induced hydrolases has been investigated at the biochemical level. Our results show that at least 40–60% of the α-amylase activity in homogenates of aleurone layers occurs in a membrane-bound, latent form. The latent α-amylase can be assayed quantitatively following disruption of membranes by treatment with Triton X-100, ethanol, sonication, or osmotic shock and shear. The association of α-amylase with the membrane is not an artifact arising from homogenization of the tissue, and acid protease is also enriched in the same subcellular fraction as the α-amylase. The membrane fraction with which the α-amylase is associated has many properties of the endoplasmic reticulum (ER). When membranebound α-amylase is prepared in buffers containing 3 mM MgCl2 two fractions from a sucrose step gradient contain most of the α-amylase activity. These fractions are enriched in the ER marker enzyme, NADH-dependent cytochrome-c reductase, and show densities characteristic of smooth and rough ER during subsequent purification on continuous gradients. In step gradients prepared with ethylenediaminete-traacetic-acid-treated membranes, α-amylase activity is contained primarily in one fraction having the density of smooth ER. Electron microscopy of the purified fractions is consistent with α-amylase being associated with smooth and rough ER. However, it has not been ruled out that the enzyme is also associated with plasma membrane, Golgi membranes, or tonoplast. Examination of the isoenzyme patterns of secreted, of total-homogenate and of membrane-associated α-amylases, as well as the results from pulsechase experiments using L-[3H]leucine for labeling of α-amylase, are all consistent with the hypothesis that membrane-associated α-amylase is an intermediate in the secretory process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389057
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  • 14
    Electronic Resource
    Electronic Resource
    Metabolism of myo-Inositol and growth in various sugars of suspension-cultured tobacco cells (1978)
    Springer
    Planta 141 (1978), S. 77-82 
    Details
    ISSN: 1432-2048
    Keywords: Cell wall ; myo-Inositol ; Nicotiana ; Polysaccharides (cell wall) ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tobacco (Nicotiana tabacum L.) cells were cultured in a liquid medium which contained sucrose as a source of carbon and energy. Various cell-wall constituents and wall precursors (L-arabinose, D-xylose, D-galactose, D-mannose, D-glucuronate, myo-inositol) were added to cells growing in this medium to by-pass possible rate-limiting steps in the relevant metabolic pathways. None of these compounds stimulated growth as measured by increase in fresh weight; myo-inositol did cause a slight increase and L-arabinose a decrease in dry weight accumulation compared to controls grown on sucrose only. Although myo-inositol was not needed for rapid growth, tracer level amounts of [2-3H]myo-inositol were rapidly absorbed and metabolized. Label was incorporated into the uronide and pentose residues of cell walls and exocellular polysaccharide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387748
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  • 15
    Electronic Resource
    Electronic Resource
    The role of acidification in gibberellic acid- and fusicoccin-induced elongation growth of lettuce hypocotyl sections (1978)
    Springer
    Planta 142 (1978), S. 135-145 
    Details
    ISSN: 1432-2048
    Keywords: Acid growth ; Cell elongation ; Gibberellin ; Fusicoccin ; Lactuca ; Hordeum ; Potasium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The roles of gibberellic acid (GA3) and fusicoccin (FC) in the elongation growth and acidification of the medium by excised hypocotyl sections of lettuce (Lactuca sativa L.) were investigated. Hypocotyl sections incubated in buffer without GA3 elongate optimally at pH 4.0–4.25 while sections incubated with GA3 show the same growth between pH 4.25 and 6.0. Preincubation of sections at pH 6.0 for 6 h does not affect the subsequent elongation response to acidic medium (pH 4.25); however, the sections become refractory to further acid treatment after their initial burst of growth in response to pH 4.25. Sections made refractory to acid are responsive to GA3 application, however, and the rate of growth in response to GA3 of sections pretreated for 6 h at pH 4.25 is 85% of that of sections pretreated at pH 6.0. Although preincubation of sections for 48 h in medium at pH 6.0 abolishes the GA3 response, it does not affect the response to buffer at pH 4.25. FC stimulates elongation growth in letuce hypocotyls at an optimal concentration of 1 μM, and pretreatment of sections at pH 4.25 does not affect this elongation response. Although both GA3 and FC increase elongation of the section, neither causes appreciable acidification of the medium. Addition of KCl or NaCl to FC-treated sections causes rapid medium acidification but addition of salts to GA3-treated tissue does not cause acidification. Abrasion of the hypocotyl to remove the cuticle does not enhance acidification of the medium by the sections nor deos it affect elongation of the sections in response to GA3 or FC. Medium acidification by the sections is not a passive process since it is abolished both by low temperature (2° C) and metabolic inhibitors (carbonyl cyanide-m-chlorophenyl-hydrazone, azide). The acidification of the medium by barley (Hordeum vulgare L.) roots in response to FC is also dependent on the presence of KCl. We conclude that the acid-growth hypothesis does not explain GA3- or FC-induced elongation in lettuce hypocotyls.
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    URL: http://dx.doi.org/10.1007/BF00388204
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  • 16
    Electronic Resource
    Electronic Resource
    Stereospecificity of peptide transport by germinating barley embryos (1978)
    Springer
    Planta 142 (1978), S. 299-305 
    Details
    ISSN: 1432-2048
    Keywords: Germination ; Hordeum ; Peptide absorption ; Peptide transport ; Stereospecificity ; Storage protein mobilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The stereospecific requirements for peptide transport in the scutellum of germinating barley (Hordeum vulgare) embryos are described. Replacement of an L-amino acid residue in a peptide by its D-stereoisomer decreases the affinity of the peptide for the transport site, leading to a reduction in transport. Substitution of a second D-residue reduces affinity still further. The extent to which transport is inhibited depends upon the position of the D-residue in the primary sequence, with D-residues at the C-terminus of the peptide having the greatest effect. Competition between D- and L-peptides indicates that they both enter via the same transport system. Although D-amino acids can be accumulated when presented as a peptide, these same D-residues are not transported when supplied as the free amino acids. L-Leu-D-leu is accumulated intact against a concentration gradient, indicating the operation of an active transport mechanism that can function without the involvement of peptidase activity.
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    URL: http://dx.doi.org/10.1007/BF00385081
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  • 17
    Electronic Resource
    Electronic Resource
    Does abscisic acid influence proline accumulation in stressed leaves? (1978)
    Springer
    Planta 143 (1978), S. 85-88 
    Details
    ISSN: 1432-2048
    Keywords: Abscisci acid ; Hordeum ; Pisum ; Polyethylene glycol ; Proline ; Stress (water) ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Root treatments of barley (Hordeum distichum L.) plants with 10-7 to 10-4 M abscisic acid (ABA) caused an increase in proline content, especially at higher concentrations, within 2–3 h. Even 3 h after the removal of ABA from the medium the plants continued to accumulate proline. The higher the concentration of the ABA, the higher was the proline level at 6 h. When the highest ABA concentration, 10-4 M, was tested with polyethylene glycol (PEG) (-5.0 bars) in the medium, the ABA treatment resulted in a higher proline content than in control plants. The treatments “PEG alone” and “PEG + ABA” resulted in heavy accumulation of proline, especially, 3 h after releasing the plants from the stress. The proline content in PEG+ABA-treated plants was always higher than plants treated with PGE or ABA alone. In peas (Pisum sativum L. cv Alaska) the same trend occurred although to a lesser degree. These findings indicate an influence of ABA on proline accumulation in water-stressed plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389056
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  • 18
    Electronic Resource
    Electronic Resource
    Spectral characteristics of phytochrome in vivo and in vitro (1978)
    Springer
    Planta 142 (1978), S. 225-228 
    Details
    ISSN: 1432-2048
    Keywords: Hordeum ; Phytochrome ; Receptor site
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The absorption maximum of the far-red absorbing form of phytochrome in the difference spectrum for phototransformation (Pfr λmax) was investigated in vivo and in in vitro pellets from dark grown Hordeum vulgare L. primary leaves. Exposure of pellets in Honda medium from tissue pre-irradiated with red light to far red light gave a Pfr λmax of 734 nm, a slightly longer wavelength than was seen in vivo (730 nm). After incubation as the red absorbing form of phytochrome (Pr) for 2 h at 0° C irradiation with red light showed that Pfr λmax had shifted to shorter wavelength (716 nm) in Honda medium. Further incubation as Pfr for 2 h at 0° C and irradiation with far red light showed that Pfr λmax had shifted to longer wavelength (726 nm). Similar shifts were also seen in other media, although the peak positions were different. Phytochrome remained pelletable throughout these experiments and Pfr λmax is compared to that of soluble phytochrome in similar media. The results are interpreted as indicating changes in molecular environment of the putative phytochrome membrane receptor site and that Pfr λmax can be used to probe the nature of this binding.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388217
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  • 19
    Electronic Resource
    Electronic Resource
    Surface charge of protoplasts and their significance in cell-cell interaction (1978)
    Springer
    Planta 142 (1978), S. 235-238 
    Details
    ISSN: 1432-2048
    Keywords: Brassica ; Cell-cell interaction ; Nicotiana ; Petunia ; Protoplasts (surface charge) ; Vigna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract ζ-potential of mesophyll protoplasts of tobacco (Nicotiana tabacum L.), petunia (Petunia hybrida Hort.), turnip (Brassica rapa L.) and cowpea (Vigna unguiculata L. Walpers) was determined by use of a cell electrophoresis apparatus. All protoplasts examined showed a constant negative value of-10 to-35 mV. The addition of CaCl2 nullified the ζ-potential of tobacco protoplasts. This phenomenon is explained by DLVO theory of colloid science, which has been successfully applied to animal cells. Furthermore, positively charged polymers reversed the ζ-potential to positive values. Treatment of the protoplast surface with several enzymes was carried out to characterize the chemical nature of suface charges. The removal of surface charges was most conspicuous by the treatment of acid phosphatase (EC 3.1.3.2), but did not occur upon treatment with α-neuraminidase (EC 3.2.1.18) or Streptomyces griseus pronase. Thus a major part of the surface charge originates from the phosphate groups at the cell membrane. The significance of these studies for the properties of the protoplast surface in cell adhesion is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388219
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  • 20
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    The occurrence of caulonema-specific proteins in different moss species (1978)
    Springer
    Planta 138 (1978), S. 299-301 
    Details
    ISSN: 1432-2048
    Keywords: Bryophytes ; Funaria ; Nicotiana ; Protein pattern ; Pteridophytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Soluble proteins extracted with Tris-buffer pH 8.8 from different mosses are analysed by microgelelectrophoretic method for comparison to the specific proteins present only in the caulonema of Funaria hygrometrica. The protein patterns are also compared with those of liverwort, fern gametophytes and sporophytes and tobacco. It is observed that the “caulonema specific proteins” are only present in the caulonema of these mosses and are absent in other plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386825
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  • 21
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    The effect of aspartate-derived amino acids (lysine, threonine, methionine) on the growth of excised embryos of wheat and barley (1978)
    Springer
    Planta 139 (1978), S. 113-117 
    Details
    ISSN: 1432-2048
    Keywords: Hordeum ; Lysine ; Metabolic control ; Methionine ; Threonine ; Triticum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Excised wheat (Triticum aestivum L. var. Maris Freeman) and barley (Hordeum vulgare L. var. Maris Mink) embryos were grown on medium containing both nitrate and ammonium ions. Addition of lysine (1 mM) plus threonine (1 mM) caused a synergistic inhibition of growth measured by length of first leaf or dry weight. The inhibition was specifically relieved by methionine, homocysteine and homoserine. Threonine at 0.2–0.3 mM caused half-maximal inhibition of growth at all lysine concentrations whereas lysine increased the synergistic inhibition up to 3 mM. The inhibition is explained by a model in which lysine acts as a feedback inhibitor of aspartate kinase and threonine of homoserine dehydrogenase. This is compatible with published studies of the enzymes involved. The implications of these findings for using lysine plus threonine as a selection system for lysine-overproducing cereals are discussed.
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    URL: http://dx.doi.org/10.1007/BF00387135
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  • 22
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    Levels of short-chain fatty acids and of abscisic acid in water-stressed and non-stressed leaves and their effects on stomata in epidermal strips and excised leaves (1978)
    Springer
    Planta 139 (1978), S. 281-287 
    Details
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Beta ; Commelina ; Fatty acids ; Hordeum ; Phaseolus ; Stomata ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Straight-chain saturated fatty acids (C6-C11) and abscisic acid (ABA) accumulate in the leaves of Phaseolus vulgaris L. and Hordeum vulgare L. under water stress. ABA and certain of the fatty acids, particularly decanoic and undecanoic acid, can inhibit stomatal opening and cause stomatal closure in epidermal strips of Commelina communis L. depending on the incubating medium used. 10-4 M (±)-ABA inhibits opening in media containing either high or relatively low concentrations of KCl but causes closure only in the latter medium. The fatty acids (at 10-4 M) prevent opening in both media while significant closure of open stomata was caused only by undecanoic acid in both media and, additionally, by decanoic acid in the low-KCl medium. 10-4 M formic acid also caused stomatal closure and prevented opening to significant extents in the low-KCl medium (it was not tested in the high-KCl medium). The efficacy of undecanoic acid in causing 50% inhibition of opening is about three orders of magnitude lower than that of ABA. At a concentration of 10-3 M, nonanoic, decanoic and particularly undecanoic acid and all-trans-farnesol cause increased cell leakage in Beta vulgaris L. root tissue. Undecanoic acid (10-4 M) also causes some loss of guard cell integrity in C. communis within 1.5 h of treatment. ABA (10-4 M) reduces transpiration rates in barley and C. communis leaves when applied via the transpiration stream but decanoic and undecanoic acids did not have this effect. Transpiration was not affected when ABA or the fatty acids were applied to the leaf surfaces.
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    URL: http://dx.doi.org/10.1007/BF00388642
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  • 23
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    Further observations on cell-wall formation around isolated protoplasts of tobacco and tomato (1978)
    Springer
    Planta 140 (1978), S. 53-58 
    Details
    ISSN: 1432-2048
    Keywords: Cell wall ; Cellulose ; Lycopersicum ; Nicotiana ; Plasmalemmasomes ; Plasma membrane ; Protoplasts ; Raphanus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Freeze-etch observations of protoplasts isolated from tobacco (Nicotiana tabacum L.) mesophyll tissue and tomato (Lycopersicum esculentum Mill.) fruit locule tissue are described which clarify earlier observations (Burgess, J., Fleming, E.N., Planta 131, 173–178, 1976; Planta 133, 267–273, 1977), obtained using scanning electron microscopy. of “fibres” associated with “projections” from these cell surfaces. It is demonstrated (1) that the “fibres” consist of bundles of small numbers of microfibrils which have become artifactually thickened by the deposition of coating materials, and (2) that the apparent association between “fibres” and “projections” results from microfibrils being lifted preferentially from protoplast surfaces in regions rich in “projections” (plasmalemmasomes). With the higher resolution available using freeze-etching it can be demonstrated that microfibril deposition does not occur in discontinuous zones on these protoplast surfaces. Globules associated with microfibril termini in radish (Raphanus sativus L.) roots are illustrated and it is proposed that turgor pressure differences between isolated protoplasts and intact tissue may account for the absence of similar globules from isolated protoplast surfaces.
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    URL: http://dx.doi.org/10.1007/BF00389379
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  • 24
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    Effect of “osmotic stress” on protein and nucleic acid synthesis in isolated tobacco protoplasts (1978)
    Springer
    Planta 141 (1978), S. 33-36 
    Details
    ISSN: 1432-2048
    Keywords: Nucleic acid synthesis ; Nicotiana ; Osmotic stress ; Protein synthesis ; Protoplasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The incorporation of labeled precursors into RNAs and proteins of isolated tobacco (Nicotiana tabacum L.) leaf protoplasts decreases with increasing osmotic pressure in the incubation medium. The incorporation of precursors into RNA and proteins is linear for 15–18 h after the isolation of the protoplasts, irrespective of the osmolarity of the culture media. The uptake of precursors is also affected by the osmolarity of the medium. However, the osmotic stress-induced inhibition of incorporation of precursors into RNA and proteins is also apparent if the differences in uptake are taken into consideration in the calculation. Incorporation of 32P into TMV-RNA is also inhibited by osmotic stress. As assayed by the double labeling ratio technique, osmotic stress has less unequivocal effect on TMV protein synthesis.
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    URL: http://dx.doi.org/10.1007/BF00387741
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  • 25
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    The differential effects of TCA-cycle acids on the growth of plant cells cultured in liquid media containing various nitrogen sources (1978)
    Springer
    Planta 139 (1978), S. 199-202 
    Details
    ISSN: 1432-2048
    Keywords: Cell cultures ; Medicago ; Nicotiana ; Nitrogen sources ; TCA cycle ; Tissue culture ; Triticum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Alfalfa (Medicago sativa L. cv. Canadian No. 1), tobacco (Nicotiana tabacum L. var. humilis) and wheat (triticum monococcum L.) cells were grown in a defined, liquid medium containing either ammonium sulfate, L-glutamine or potassium nitrate as the sole nitrogen source, and the effects of the tricarboxylic-acid (TCA) intermediates, citrate and α-ketoglutarate (5, 10, 15 mM), on the growth (dry-weight increase) of these cells was observed. The three cell suspension cultures exhibited a different growth response to the TCA-cycle intermediate supplied, depending upon the concentration of the additive and the nitrogen source. Citrate (5 mM) greatly enhanced growth of alfalfa and wheat cells in an ammonium-based medium but was less effective at higher concentrations, and in the case of alfalfa cells markedly inhibited growth. Tobacco cell growth was inhibited by all citrate concentrations tested. In contrast, all concentrations of α-ketoglutarate used stimulated the growth of all three cell cultures in an ammonium-based medium. Alfalfa and wheat cells grown in an L-glutamine-based medium were influenced by citrate in a manner similar to that in ammonium-based medium. The growth of tobacco cells was slightly enhanced by 5 mM citrate but inhibited by higher concentrations. α-Ketoglutarate, at all concentrations tested, was stimulatory to the growth of the cells of all three species in a glutamine-based medium, except for alfalfa cells which were inhibited at 15 mM. Both TCA-cycle acids inhibited the growth of alfalfa and tobacco cells grown on a nitrate-based medium whereas the growth of wheat cells was almost unaffected.
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    URL: http://dx.doi.org/10.1007/BF00388630
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  • 26
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    The influence of potassium content on the kinetics of potassium influx into excised ryegrass and barley roots (1978)
    Springer
    Planta 141 (1978), S. 117-119 
    Details
    ISSN: 1432-2048
    Keywords: Hordeum ; Ion influx ; Lolium ; Potassium influx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influx of K+ into excised roots of barley (Hordeum vulgare L.) and ryegrass (Lolium multiflorum L.) previously grown with or without K+ was measured in K+ solutions ranging in concentration from 0.01 to 50 mM. In both species the K+ influx was lower in the roots with high K+ content. The extent of reduction by high internal [K+] decreased with external concentration above 1 mM. These results support the contention that at high external concentrations passive diffusion makes significant contributions to observed fluxes.
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    URL: http://dx.doi.org/10.1007/BF00387753
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  • 27
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    Influence of phosphate-stress on phosphate absorption and translocation by various parts of the root system of Hordeum vulgare L. (barley) (1978)
    Springer
    Planta 139 (1978), S. 47-53 
    Details
    ISSN: 1432-2048
    Keywords: Hordeum ; Phosphate ; Root transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plants of Hordeum vulgare (barley) were grown initially in a solution containing 150 μM phosphate and then transferred on day 6 to solutions with (+P) and without (-P) phosphate supplied. After various times plants from these treatments were supplied with labelled phosphate. Analysis of plant growth and rates of labelled phosphate uptake showed that a general enhancement of uptake and translocation was found, in plants which had been in the-P solution, several days before the rate of dry matter accumulation was affected. Subsequently a detailed analysis of phosphate uptake by segments of intact root axes showed that the enhancement of phosphate uptake by P-stress occurred first in the old and mature parts of the seminal root axis and last in the young zones 1 cm from the root apex. During this transition period there were profound changes in the pattern of P absorption along the length of the root. Most of the additional P absorbed in response to P-stress was translocated to the shoot, particularly in older zones of the axis. Enhancement of phosphate uptake in young zones of nodal axes occurred at an earlier stage than in seminal axes. The results are related to the P-status of shoots and root zones and discussed in relation to the general control by the shoot of phosphate transport in the root.
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    URL: http://dx.doi.org/10.1007/BF00390809
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  • 28
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    Uptake of auxotrophic cells of a heterocyst-forming cyanobacterium by tobacco protoplasts, and the fate of their associations (1978)
    Springer
    Planta 139 (1978), S. 55-60 
    Details
    ISSN: 1432-2048
    Keywords: Anabaena ; Cell uptake ; Cyanobacterium ; Nicotiana ; Polyethylene glycol ; Protoplast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Auxotrophic cells of the filamentous cyanobacterium Anabaena variabilis Kütz. were introduced into protoplasts of Nicotiana tabacum L. in an attempt to engineer a nitrogen-fixing endosymbiosis. Conditions were established to maximize uptake of the cyanobacteria by use of polyethylene glycol. Culture of the novel association was not successful: tobacco protoplasts with Anabaena inside did not appear to divide. Most of the protoplasts expelled the cyanobacteria and simultaneously disintegrated. The reasons for the incompatibility are not known.
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    URL: http://dx.doi.org/10.1007/BF00390810
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  • 29
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    Enrichment for heterokaryocytes by the use of iso-osmotic density gradients after plant protoplast fusion (1978)
    Springer
    Theoretical and applied genetics 53 (1978), S. 49-55 
    Details
    ISSN: 1432-2242
    Keywords: Density gradient ; Nicotiana ; Protoplasts ; Selection ; Somatic hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Buoyant density differences between different types of protoplasts were used in an iso-osmotic density gradient system to enrich protoplast fusion mixtures for heterokaryocytes. Protoplasts of maize stem and wheat mesophyll, as well as epidermis, stem parenchyma and mesophyll protoplasts of two amphihaploid, light sensitive tobacco mutants were fused with polyethylene glycol using conventional methods and a new rolling tube technique. The protoplast combinations used for fusion involved protoplast types with considerably different buoyant densities. Enriched fractions of maize-wheat heterokaryocytes of intermediate density were recovered which contained up to 31% mostly binucleate heterokaryocytes (a 2–7 fold relative enrichment). Tobacco heterokaryocytes recovered analogously from enriched intermediate fractions readily divided and gave rise to an increased number of light resistant calluses when compared with cultures from non-fractionated fusion mixtures. Maize-wheat fusion products, however, failed to divide.
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    URL: http://dx.doi.org/10.1007/BF00274330
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  • 30
    Electronic Resource
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    Enrichment for heterokaryocytes by the use of iso-osmotic density gradients after plant protoplast fusion (1978)
    Springer
    Theoretical and applied genetics 53 (1978), S. 49-55 
    Details
    ISSN: 1432-2242
    Keywords: Density gradient ; Nicotiana ; Protoplasts ; Selection ; Somatic hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Buoyant density differences between different types of protoplasts were used in an iso-osmotic density gradient system to enrich protoplast fusion mixtures for heterokaryocytes. Protoplasts of maize stem and wheat mesophyll, as well as epidermis, stem parenchyma and mesophyll protoplasts of two amphihaploid, light sensitive tobacco mutants were fused with polyethylene glycol using conventional methods and a new rolling tube technique. The protoplast combinations used for fusion involved protoplast types with considerably different buoyant densities. Enriched fractions of maize-wheat heterokaryocytes of intermediate density were recovered which contained up to 31% mostly binucleate heterokaryocytes (a 2–7 fold relative enrichment). Tobacco heterokaryocytes recovered analogously from enriched intermediate fractions readily divided and gave rise to an increased number of light resistant calluses when compared with cultures from non-fractionated fusion mixtures. Maize-wheat fusion products, however, failed to divide.
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    URL: http://dx.doi.org/10.1007/BF00817832
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  • 31
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    Serological reactions of Fraction I proteins from interspecific hybrids in the genusNicotiana (1978)
    Springer
    Plant systematics and evolution 129 (1978), S. 177-183 
    Details
    ISSN: 1615-6110
    Keywords: Solanaceae ; Nicotiana ; Fraction I protein ; interspecific hybrids ; allopolyploids ; serotaxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The serological reactions of Fraction I proteins from interspecific hybrids in the genusNicotiana have been examined by immunodiffusion in agar gels using antisera to crystalline Fraction I proteins fromN. glutinosa, N. gossei, andN. tabacum. The serological reactions of the proteins from the hybrids resembled the reactions of the proteins from the maternal parent species but not from the paternal species. Changes in ploidy level did not affect the serological reactions of Fraction I proteins from hybrids. It is suggested that serological examination of Fraction I proteins from polyploid species and their known progenitors can indicate the direction of the cross giving rise to the polyploid species.
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    URL: http://dx.doi.org/10.1007/BF00990759
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