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  • Zea  (31)
  • Springer  (31)
  • American Association for the Advancement of Science
  • American Physical Society
  • 1980-1984
  • 1975-1979  (31)
  • 1950-1954
  • 1979  (19)
  • 1977  (12)
  • 1952
Collection
Keywords
Publisher
  • Springer  (31)
  • American Association for the Advancement of Science
  • American Physical Society
Years
  • 1980-1984
  • 1975-1979  (31)
  • 1950-1954
Year
  • 1
    Electronic Resource
    Electronic Resource
    Ion measurements by X-ray microanalysis in unfixed, frozen, hydrated plant cells of species differing in salt tolerance (1977)
    Springer
    Planta 134 (1977), S. 35-38 
    Details
    ISSN: 1432-2048
    Keywords: Hordeum ; Salt tolerance ; Scanning electronmicroscope ; X-ray microanalysis ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A technique is described for X-ray microanalysis of unfixed, frozen, hydrated higher plant cells using a scanning electron microscope in conjunction with a cryostage. Freezing in liquid N2 is the only preparative step required. Using this method, ion distribution was compared in the roots of Zea mays L. (termed a salt excluder) and Hordeum vulgare L. (which is rather more tolerant), both grown in the presence of NaCl. Distinct differences were observed between the two species in Na, K and Cl distribution. Evidence is presented to support the hypothesis that reabsorption of Na from the xylem sap in the mature regions of the root may occur in salt-sensitive glycophytes such as Z. mays.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00390091
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  • 2
    Electronic Resource
    Electronic Resource
    Heterogeneity of storage proteins in maize (1977)
    Springer
    Planta 136 (1977), S. 115-123 
    Details
    ISSN: 1432-2048
    Keywords: Protein ; Storage protein ; Zea ; Zein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The extensive charge heterogeneity of maize (Zea mays L.) zeins observed in isoelectric focusing (IEF) (about 15 bands with pI's in the pH range 6–9) has been found to be independent of extraction procedures or of endosperm development. Zeins do not stain for glycoproteins and exhibit only one lipoprotein component, with pI 3, representing 3–5% of the total protein. Zeins are very resistant to in vitro deamidation, at both acidic and alkaline pH, at high temperatures, and for rather prolonged times. On the basis of the zein content in acidic and basic amino acids, and of the respective pI's exhibited in IEF (mostly in the pH range 7–8) it has been calculated that at least 90% of the glutamic and aspartic acids (≈52 residues out of a total of ≈ 190) are present as asparagine and glutamine. Amino acid analysis of zein fractions isolated by preparative IEF has demonstrated changes in the composition of 18 amino acid residues. However, since these changes affect only neutral and hydrophobic residues, it is concluded that the observed zein heterogeneity is partly based on in vivo deamidation of glutamine and asparagine and partly to spot mutations in some of the genes responsible for zein synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396186
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  • 3
    Electronic Resource
    Electronic Resource
    Early responses to gibberellic acid in a dwarf maize mutant (Zea mays L. d 1) (1977)
    Springer
    Planta 137 (1977), S. 25-28 
    Details
    ISSN: 1432-2048
    Keywords: Gibberellin ; Ion ratio ; Microprobe analysis ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Early effects of gibberellic acid (GA3) (1–4 h treatment) on the ion ratios in a dwarf maize mutant (Zea mays L. d 1) showing normal growth after hormone treatment, have been investigated by electron microprobe analysis. GA3 exerts a different effect on the ion ratios in plastids, cytoplasm and vacuoles in short term experiments. The Cl content of chloroplasts and cytoplasm increases without a lag phase after GA3 treatment. The K content of plastids increases after a lag phase of 2 h, whereas in the cytoplasm an increase can be observed immediately after GA3 addition. The hormone has only little influence on the Ca content of the cell compartments investigated. Control experiments with water and the physiologically inactive GA3 methylester confirm the specifity of the short-term actions of GA3 on the ion ratios. The primary action of GA3 at the membrane level is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00394430
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  • 4
    Electronic Resource
    Electronic Resource
    Specificity of 1-triacontanol as a plant growth stimulator and inhibition of its effect by other long-chain compounds (1979)
    Springer
    Planta 144 (1979), S. 277-282 
    Details
    ISSN: 1432-2048
    Keywords: Growth stimulation and inhibition ; Long-chain compounds ; Lycopersicon ; Oryza ; Zea ; 1-Triacontanol (TRIA)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of several analogs of 1-triacontanol (TRIA), differing in C-chain length (16–32), the position of the hydroxyl group and the terminal functional group, were tested alone and in combination with TRIA on the growth of rice (Oryza sativa L.), maize (Zea mays L.) and tomato (Lycopersicon esculentum Mill.) seedlings. Applied alone, none of the compounds caused an increase in growth; thus, chain length (30 C) and presence and position (terminal) of the hydroxyl group appear to be specific for the growth-promoting activity of TRIA. When applied simultaneously with TRIA, all analogs inhibited the response to the latter in all three test plants, whether applied in the nutrient solution, as foliar spray or by seed soaking. 1-Octacosanol inhibited the response of rice seedlings to 2.3 x 10-8 M TRIA at concentrations as low as 2.4 x 10-12 M. Thus preparations of TRIA and application equipment must be free from trace amounts of other long-chain compounds if they are to be used to increase plant growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388770
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  • 5
    Electronic Resource
    Electronic Resource
    Kinetic characterization of N-1-Naphthylphthalamic acid binding sites from maize coleoptile homogenates (1979)
    Springer
    Planta 145 (1979), S. 119-127 
    Details
    ISSN: 1432-2048
    Keywords: Coleoptiles ; Naphthylphthalmic acid binding ; Rate constants ; Temperature ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The association of NPA with particulate material from corn coleoptile homogenates and the dissociation of the complexes formed are characterized. Using a filtration method, a single rate constant for the association at 0° C was determined as 2.7×10-6 M-1 min-1, and for the dissociation of the complex a rate constant of 0.086 min-1 was obtained with the same method. From these a dissociation constant of the complex of 3.4×10-8 M can be calculated, which is in good agreement with the dirct determination of this constant in equilibrium measurements. This is taken as an indication for a simple reaction schema describing the reaction of NPA with its particle-bound receptor, and it can be inferred that membrane permeation does not impose a limitation on this reaction under the conditions used in this investigation. This view is strengthened by the absence of any indication for a carrier mechanism in “counterflow” experiments. A few minor deviations from quantitative predictions of the simple binding reaction schema are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388707
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  • 6
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    Fractionation of particulate material from maize coleoptile homogenates with polyethylene glycol (1979)
    Springer
    Planta 145 (1979), S. 129-135 
    Details
    ISSN: 1432-2048
    Keywords: Coleoptile ; Naphthylphthalamic acid binding ; Polyethylene glycol ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polyethyleneglycol (PEG) has been used to sediment particulate material from maize coleoptile homogenates at low centrifugal forces. The resuspended sediments were used for N-1-naphthylphthalamic acid (NPA)-binding studies. Binding activity was influenced by monovalent cations in the resuspension medium, but even at concentrations of up to 1.2 M NaCl or 0.5 M LiCl or CsCl, half of the binding activity was still recovered. Binding activity was influenced by divalent cations, because it decreased when Ca2+ and Mg2+ ions in the medium were complexed with EDTA. Fractionated sedimentation using increasing concentrations of PEG resulted in two peaks of NPA-binding activity at about 3% and 6% PEG. The 3% peak cintained enzymatic markers for mitochondria and endoplasmatic reticulum while the 6% peak contained NPA-binding activity only. Possible explanations for the bimodal distribution of NPA binding after fractionated PEG precipitation are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388708
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  • 7
    Electronic Resource
    Electronic Resource
    Cytokinin biosynthesis in roots of corn (1979)
    Springer
    Planta 145 (1979), S. 315-321 
    Details
    ISSN: 1432-2048
    Keywords: Cytokinins ; Quiescent center ; Root apex ; Root growth ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Removal of the quiescent center (QC) from the root apex of maize (Zea mays L., cv. Kelvedon 33) initiates a set of events which culiminate in the regeneration of an intact apex with a newly formed QC. Concomitant with the formation of a new QC is a marked reduction in extractable cytokinins in the tissue of the proximal meristem. Replacing the excised QC with a Dowex (acidic cation-exchange resin) bead affects both root growth and QC regeneration. Root growth is inhibited by “plain” Dowex beads and Dowex beads treated with zeatin; this inhibition is reversed if the beads have been treated with CaCl2 (±zeatin). Dowex beads treated with zeatin delay the formation of a new QC; this effect is the same whether or not the beads also contain CaCl2. The results of this investigation support the notions that cytokinin biosynthesis in roots is a result of activities of both the QC and the proximal meristem, and that cytokinins, at least if supplied exogenously, can play a role in root morphogenesis by delaying the regeneration of the QC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388355
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  • 8
    Electronic Resource
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    Distribution of growth regulators in relation to the light-induced geotropic responsiveness in Zea roots (1979)
    Springer
    Planta 145 (1979), S. 323-329 
    Details
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Auxin ; Geotropism ; Inhibitor ; Light and geotropism ; Root geotropism ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth regulators were measured in extracts from the upper and lower halves of 7-mm apical segments of horizontally oriented, red-light-irradiated and non-irradiated roots of Zea mays L. cv. Golden Cross Bantam 70 which exhibit a georesponse only after an exposure to light. Abscisic acid (ABA) was measured by gas-liquid chromatography, auxin (indole-3-acetic acid, IAA) by the Avena straight-growth assay, and an unidentified growth inhibitor by a Zea root-growth assay. The ratio of ABA in the upper and lower halves was 1.6 in the irradiated roots and 1.0 in the non-irradiated ones. The total amount of ABA after irradiation was increased by a factor of ca. 1.8. The ratio of IAA in the upper and lower halves of irradiated and non-irradiated roots was 1:3.4 and 1:2.9, respectively. The content (or activity) of an unidentified growth inhibitor was highest in the lower halves of horizontally oriented roots which had been irradiated with red light. The unidentified growth inhibitor, rather than IAA or ABA, may be the major factor in the light-induced geotropic responsiveness in Zea roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388356
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  • 9
    Electronic Resource
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    Two forms of NADP-dependent malic enzyme in expanding maize leaves (1979)
    Springer
    Planta 144 (1979), S. 283-289 
    Details
    ISSN: 1432-2048
    Keywords: C4 Species ; Isozymes ; Malic enzyme ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Etiolated maize leaves (Zea mays L.) contain a major isozyme of NADP-dependent malic enzyme (L-malate dehydrogenase, decarboxylating, EC 1.1.1.40) having an isoelectric point of 5.28±0.03, a Km (L-malate) 0.3–0.6 mM at pH 7.45; a broad pH optimum around pH 6.9 under the conditions of assay; a molecular weight of 280,000 (sometimes accompanied by a minor component of 150,000); and an NAD-dependent activity about 1/50 the NADP-dependent activity. This isozyme, resembling the NADP-malic enzyme of vertebrates, is labeled type 1. The dominant isozyme of young green leaves (type 2) has, however, a pI 4.90±0.03, a Km (L-malate) 0.10–0.15 mM, a pH optimum of 8, and a molecular weight of 280,000. It is also more stable and exhibits an appreciable NAD-dependent activity (1/5–1/7 the NADP activity). Both isozymes show linear kinetics, dependence on Mn or Mg ions, similar Km (NADP+), and the typical increase of Km for L-malate with increasing pH values. Type 1 isozyme of maize is assumed to be cytosolic. Type 2 corresponds in each property to the chloroplast enzyme of bundle-sheath cells. It is present at a low level in etiolated leaves and develops to a high specific activity (up to 100 nmol min-1 mg protein-1 by 150 h illumination) during photosynthetic differentiation, replacing the type 1 form.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388771
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  • 10
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    Solute regulation and growth by roots and shoots of water-stressed maize plants (1979)
    Springer
    Planta 147 (1979), S. 43-49 
    Details
    ISSN: 1432-2048
    Keywords: Growth ; Roots ; Shoots ; Solute accumulation ; Water stress ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Potted maize seedlings were subjected to a single period of water stress. As the severity of water stress increased, measurements were made of leaf and root solute and water potentials, leaf diffusive conductance and leaf and root growth. After day four of the drying cycle, the rate of leaf extension and the development of leaf area were reduced. This reduction correlated well with a reduction in leaf turgor which occurred at this time. A significant accumulation of solutes in the root tips of the unwatered plants resulted in the maintenance of root turgor for the duration of the water stress treatment. Root growth of the unwatered plants was also maintained as the severity of water stress increased. A mild degree of water stress resulted in a net increase in root growth compared to the situation in well-watered plants. The significance of solute regulation and continued root growth for plants growing in drying soil is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384589
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  • 11
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    Ethylene-promoted adventitious rooting and development of cortical air spaces (aerenchyma) in roots may be adaptive responses to flooding in Zea mays L (1979)
    Springer
    Planta 147 (1979), S. 83-88 
    Details
    ISSN: 1432-2048
    Keywords: Adventitious roots ; Air spaces (aerenchyma) ; Ethylene ; Oxygen ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The roots and stem base of intact, 10 day old maize (Zea mays L. cv. LG11) plants, grown in nutrient solution, were continuously aerated either with ethylene (5 μl l-1) in air or with air alone. Ethylene treatment hastened the emergence of adventitious (nodal) roots from the base of the shoot, but slowed their subsequent extension. Ethylene also promoted the collapse of cells in the cortex of these roots, with lysigenous development of prominent air spaces (aerenchyma). Non-aeration of the nutrient solution caused endogenously produced ethylene to accumulate in the roots, and stimulated both the emergence of adventitious roots and the formation of cortical air spaces in them. With non-aeration the concentration of oxygen did not fall below 1% in the equilibrium gas phase (air=20.8%). Complete deoxygenation of the nutrient solution, produced by passing oxygen-free nitrogen gas, prevented both air space formation and the evolution of ethylene by root segments. These results suggest that adventitious rooting and cortical air space formation in nodal roots in Zea mays may be stimulated by enhanced concentrations of endogenous ethylene arising either from entrapment of the gas by unstirred water layers around the roots and/or by increased biosynthesis. These responses are considered conducive to survival in waterlogged soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384595
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  • 12
    Electronic Resource
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    The influence of externally supplied sucrose on phloem transport in the maize leaf strip (1977)
    Springer
    Planta 137 (1977), S. 145-151 
    Details
    ISSN: 1432-2048
    Keywords: Phloem transport ; Sucrose ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sucrose (2,5–1000 mmol l−1), labeled with [14C]sucrose, was taken up by the xylem when supplied to one end of a 30-cm-long leaf strip of Zea mays L. cv. Prior. The sugar was loaded into the phloem and transported to the opposite end, which was immersed in diluted Hoagland's nutrient solution. When the Hoagland's solution at the opposite end was replaced by unlabeled sucrose solution of the same molarity as the labeled one, the two solutions met near the middle of the leaf strip, as indicated by radioautographs. In the dark, translocation of 14C-labeled assimilates was always directed away from the site of sucrose application, its distance depending on sugar concentration and translocation time. When sucrose was applied to both ends of the leaf strip, translocation of 14C-labeled assimilates was directed toward the lower sugar concentration. In the light, transport of 14-C-labeled assimilates can be directed (1) toward the morphological base of the leaf strip only (light effect), (2) toward the base and away from the site of sucrose application (light and sucrose effect), or (3) away from the site of sucrose application independent of the (basipetal or acropetal) direction (sucrose effect). The strength of a sink, represented by the darkened half of a leaf strip, can be reduced by applying sucrose (at least 25 mmol l−1) to the darkened end of the leaf strip. However, equimolar sucrose solutions applied to both ends do not affect the strength of the dark sink. Only above 75 mmol l−1 sucrose was the sink effect of the darnened part of the leaf strip reduced. Presumably, increasing the sucrose concentration replenishes the leaf tissue more rapidly, and photosynthates from the illuminated part of the leaf strip are imported to a lesser extent by the dark sink.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387551
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  • 13
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    Development of aleurone and sub-aleurone layers in maize (1977)
    Springer
    Planta 137 (1977), S. 185-193 
    Details
    ISSN: 1432-2048
    Keywords: Aleurone ; Protein bodies ; Spherosomes ; Endosperm ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Electron-microscope studies indicate that the aleurone tissue of maize (Zea mays L.) starts developing approximately 10–15 days after pollination in stocks that take ca. 40 days for the aleurone to mature completely. Development commences when specialized endosperm cells adjacent to the maternal nucellar layer start to differentiate. Differentiation is characterized by the formation of aleurone protein bodies and spherosomes. The protein bodies of the aleurone layer have a vacuolar origin whereas the protein bodies of the immediate underlying endosperm cells appear to develop from protrusions of the rough endoplasmic reticulum. Thus, two morphologically and developmentally distinct types of protein bodies are present in these adjacent tissues. The spherosomes of the aleurone layer form early in the development of this tissue and increase in number as the tissue matures. During the final stages of maturation, these spherosomes become closely apposed to the aleurone grains and the plasma membrane. No further changes are apparent in the structure of the aleurone cells after 40 days from pollination when the caryopsis begins to desiccate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388149
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  • 14
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    Short-term effects of plant hormones on membrane potential and membrane permeability of dwarf maize coleoptile cells (Zea mays L. d 1) in comparison with growth responses (1977)
    Springer
    Planta 137 (1977), S. 293-298 
    Details
    ISSN: 1432-2048
    Keywords: Auxin ; Calcium ions ; Cell growth ; Gibberellin ; Membrane permeability ; Membrane potential ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The membrane potential difference of dwarf maize coleoptile cells is increased by both 10-5moll-1 gibberellic acid (GA3) and indoleacetic acid (IAA) a few minutes after application. A final level is reached after 10–20 min. The membrane permeability ratio P Na:P K is altered by both hormones during the first 15 min after application, indicating a rapid effect on the membrane. Elongation growth of coleoptile segments, however, is only stimulated by IAA. The auxin-induced growth as well as the auxin effect on membrane permeability depends on the calcium ion concentration of the medium. It is concluded that IAA acts via a proton extrusion pump that is electrically balanced by a potassium ion uptake, driven by the electromotive force of the pump. The mode of action of GA3 on elongation growth is assumed to involve a process that depends on the physiologic state of the tissue and/or metabolic energy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388165
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  • 15
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    Kinetics of the light-induced georeactivity of maize roots (1979)
    Springer
    Planta 145 (1979), S. 403-404 
    Details
    ISSN: 1432-2048
    Keywords: Geotropism ; Growth inhibitors (root) ; Light and geotropism ; Root (geotropism) ; Root cap ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Apical root segments of Zea mays L. cv. Orla 264 undergo some geotropic curvature in complete darkness but the curvature increases considerably if prior to geostimulation the segments are given a light pretreatment. If the light treatment is follwed by a dark treatment before the root is geostimulated the light-induced response is not changed by dark periods up to 2 h but declines with longer ones, and disappears completely after 5 h of darkness.
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    URL: http://dx.doi.org/10.1007/BF00388370
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  • 16
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    Enzymes of asparagine synthesis in maize roots (1979)
    Springer
    Planta 146 (1979), S. 237-241 
    Details
    ISSN: 1432-2048
    Keywords: Asparagine ; Cyanide pathway ; Root (asparagine synthesis) ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An asparagine synthetase which is active with either glutamine or NH 4 + has been found in maize (Zea mays L.) roots. Unlike the enzyme obtained from legume cotyledons, the maize-root enzyme is only slightly more efficient with glutamine (Km, 1.0 mM) than with NH 4 + (Km, 2.0–3.0 mM). The activity of this enzyme is higher in the mature root than in the root-tip region, i.e. root cells develop a capacity to make asparagine from glutamine or NH 4 + as they mature. β-Cyanoalanine synthetase is also present in maize roots. The apparent Km for cysteine is 2.6 mM and for cyanide is 0.57 mM. The enzyme is more active in the root tip than in mature root tissue. Thus, if asparagine were made in the root tip, the cyanide pathway could represent the mechanism of synthesis. It is our contention, however, that this potential is not realized under normal conditions because 14C-experiments performed previously have indicated a limited availability of both CN and cysteine in the maize root.
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    URL: http://dx.doi.org/10.1007/BF00388238
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  • 17
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    Solubilized auxin-binding protein (1979)
    Springer
    Planta 146 (1979), S. 263-270 
    Details
    ISSN: 1432-2048
    Keywords: Auxin binding ; Endoplasmic reticulum ; Hormone binding sites ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Discontinuous sucrose gradient fractionations indicate that the high-affinity auxin binding protein which can be solubilized from the microsomes of coleoptiles and primary leaves of Zea mays L. seedlings is probably located in the endoplasmic reticulum (ER). Since aromatic hydroxylations are enzymatic activities typical of the ER of plant cells, we have examined the effects of several electron-transport inhibitors on the binding of 1-naphthylacetic acid (NAA). NaN3 strongly inhibits this binding, but KCN and CO do not. Trans-cinnamic acid and trans-p-coumaric acid, which are the substrates of ER hydroxylase activities in plants (but which are themselves not auxins), also inhibit this binding. Supernatant fractions from corn shoots contain factors inhibitory to the binding of NAA to the intact membranes and solubilized Site I auxin-binding protein. Here we show that these factors are competitive inhibitors of the binding of [14C]NAA but do not change the apparent affinity of the protein for indoleacetic acid, 2,4-dichlorophenoxyacetic acid or naphthoxyacetic acid. Several tissues were assayed for factors inhibitory to auxin binding to the solubilized protein, but only supernants from corn shoots were markedly inhibitory at low concentrations.
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    URL: http://dx.doi.org/10.1007/BF00387796
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  • 18
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    Effects of ophiobolin B on cell enlargement and H+/K+ exchange in maize coleoptile tissues (1979)
    Springer
    Planta 146 (1979), S. 271-274 
    Details
    ISSN: 1432-2048
    Keywords: Cell enlargement ; Fusicoccin ; Ophiobolin ; Potassium ; Protons ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ophiobolin B (OPH B), a sesterpene metabolite of Helminthosporium oryzae, inhibits proton extrusion from maize coleoptiles. Moreover OPH B counteracts the biological activity of fusicoccin (FC), another terpenoid toxin produced by Fusicoccum amygdali having a similar basic chemical structure: OPH B inhibits FC-promoted proton extrusion, potassium uptake and cell enlargement. The findings suggest that the effect of OPH B in stimulating electrolites, glucose and aminoacid leakage, reported in a previous paper, can be explained by the capacity of the toxin to inhibit proton extrusion.
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    URL: http://dx.doi.org/10.1007/BF00387797
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  • 19
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    The occurrence of both C3 and C4 photosynthetic characteristics in a single Zea mays plant (1979)
    Springer
    Planta 147 (1979), S. 257-263 
    Details
    ISSN: 1432-2048
    Keywords: Carboxylating enzymes ; C4 photosynthesis ; Photosynthesis (C3-C4) ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The activities of the carboxylating enzymes ribulose-1,5-biphosphate (RuBP) carboxylase and phosphoenolpyruvate (PEP) carboxylase in leaves of three-week old Zea mays plants grown under phytotron conditions were found to vary according to leaf position. In the lower leaves the activity of PEP carboxylase was lower than that of RuBP carboxylase, while the upper leaves exhibited high levels of PEP carboxylase. Carbon dioxide compensation points and net photosynthetic rates also differed in the lower and upper leaves. Differences in the fine structure of the lowermost and uppermost leaves are shown. The existence of both the C3 and C4 photosynthetic pathways in the same plant, in this and other species, is discussed.
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    URL: http://dx.doi.org/10.1007/BF00388748
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  • 20
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    Identical embryonal proteins in intact and isolated tissues of maize (Zea mays L.) (1979)
    Springer
    Planta 145 (1979), S. 245-251 
    Details
    ISSN: 1432-2048
    Keywords: Antigen ; Callus ; Cell suspension culture ; Dedifferentiation ; Meristem ; Proliferation proteins ; Proteins (in differentiation) ; Tissue culture ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Minor antigens characteristic of developing and mature embryos were not found in the shoot and root meristems of the seedlings. Some of these embryonal antigens (EA) were present, however, in callus and cell-suspension cultures, irrespective of their tissue origin, and were maintained throughout repeated subcultures, in some cases for more than 2 years. These EA were distinct both from the meristematic antigens found in the intact seedlings and in callus cultures, and from organ-specific antigens found only in intact plants. The EA of callus tissues derived from several maize genotypes were serologically identical. We therefore assume that these EA are “proliferation proteins” or “early proteins” expressed by cells that have not undergone any determination and lack any tissue or organ specificity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454448
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    Changes in ultrastructure and transcription induced by elevated temperature in Zea mays embryonic root cells (1979)
    Springer
    Planta 146 (1979), S. 7-18 
    Details
    ISSN: 1432-2048
    Keywords: Germination ; Temperature (elevated) ; Transcription inhibition ; Ultrastructural cytochemistry ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A study has been made of the changes occurring in Zea mays kernels exposed to thermal shock at the 48th h of soaking at 16°C, i.e., just before the protrusion of the root. Heat shock of 5 h at 46°C temporarily inhibits the resumption of root growth and consequently retards the protrusion of the root. On the ultrastructural level, it is the nucleolus which undergoes the most dramatic changes. Total loss of the granular component occurs and new electron opaque corpuscles with diameters ranging from 80 to 140 nm appear. These corpuscles contain RNA and proteins. Microstereology shows that the vacuolation of the nucleolus is increased whereas its volume is decreased. Autoradiographical and biochemical studies of RNA synthesis show that the heat shock induces an inhibition of pre-rRNA synthesis. Only RNAs of low molecular weight are still synthesized. After 19 h of a return to 16°C, the ultrastructural changes of the nucleolus are reversed. Nevertheless, increased nucleolar vacuolation persists up to that time. Exposure of maize kernels to 46°C also produces the appearance of corpuscles in some areas of the cytoplasm and in the matrix of mitochondria. Disappearance of these structures is complete within 19 h, except in some mitochondria.
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    URL: http://dx.doi.org/10.1007/BF00381249
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  • 22
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    The effect of cytochalasin B on the rate of growth and ultrastructure of wheat coleoptiles and maize roots (1979)
    Springer
    Planta 144 (1979), S. 373-383 
    Details
    ISSN: 1432-2048
    Keywords: Auxin ; Cell elongation ; Cytochalasin B ; Dictyosomes ; Secretion ; Triticum ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cytochalasin B (CB) inhibits the elongation growth of maize roots, and that of wheat coleoptile segments incubated in indolyl-3-acetic acid, by over 30% after a lag period of about 60 min. This long lag is not due to poor tissue penetration by the inhibitor, but seems to reflect a property of the process inhibited by CB. The only visible ultrastructural change accompanying growth inhibition is the accumulation of secretory vesicles in the vicinity of dictyosomes, which occurs between 90 and 300 min. However, a massive accumulation of vesicles is seen after 120 min in root cap cells which possess very active dictyosomes. The results indicate that CB does not inhibit elongation growth by interfering with cytoplasmic streaming. Instead, they indicate that the drug acts to inhibit the secretion of cell wall components at some stage after vesicle production, but prior to their transport.
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    URL: http://dx.doi.org/10.1007/BF00391581
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  • 23
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    Cation-activated ATPase activity of plasmalemma-enriched membrane preparations from maize coleoptiles (1979)
    Springer
    Planta 146 (1979), S. 387-391 
    Details
    ISSN: 1432-2048
    Keywords: ATPase (activators, inhibitors) ; Plasmalemma (ATPase) ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ATPase activity present in plasmalemma-enriched preparations from maize coleoptiles shows an optimum at pH 6, a strong dependence on Mg2+, and is stimulated by K+ and other monovalent cations, both organic and inorganic. The activation of ATPase by K+ obeys Michaelis Menten kinetics, saturation being reached at 50 mM K+ concentration. K+, Mg2+-stimulated ATPase activity is strongly inhibited by N,N′-dicyclohexylcarbodiimide and by diethylstilbestrol and, to a lesser extent, by octylguanidine.
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    URL: http://dx.doi.org/10.1007/BF00380849
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    Endogenous and exogenous auxin in the control of root growth (1979)
    Springer
    Planta 146 (1979), S. 405-408 
    Details
    ISSN: 1432-2048
    Keywords: Auxin ; Growth ; Root growth ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The endogenous indol-3yl-acetic acid (IAA) of detipped apical segments from roots of maize (cv ORLA) was greatly reduced by an exodiffusion technique which depended upon the preferential acropetal transport of the phytohormone into buffered agar. When IAA was applied to the basal cut ends of freshly prepared root segments only growth inhibitions were demonstrable but after the endogenous auxin concentration had been reduced by the exodiffusion technique it became possible to stimulate growth by IAA application. The implications of the interaction between exogenous and endogenous IAA in the control of root segment growth are discussed with special reference to the role of endogenous IAA in the regulation of root growth and geotropism.
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    URL: http://dx.doi.org/10.1007/BF00380852
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    Phytochrome-mediated germination control of maize caryopses (1979)
    Springer
    Planta 146 (1979), S. 415-417 
    Details
    ISSN: 1432-2048
    Keywords: Germination (seeds) ; Osmotic stress ; Phytochrome ; Seed germination ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Maize caryopses sown in water germinate equally well either in darkness or under any light regime. However, when they are imbibed in mannitol solutions, continuous far-red light proves to be strongly inhibitory on the final germination as compared to darkness. Similar but less pronounced inhibition is also exhibited by continuous red or blue light. Intermittent far-red light can partially substitute for continuous far-red light in inhibiting maize caryopsis germination, and its effect is reversed to the intermittent red light level when red light is given immediately after each far-red illumination. These results are interpreted as a proof of existence and involvement of phytochrome in the germination control of maize caryopses, though its manifestation is realized only under osmotic stress.
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    URL: http://dx.doi.org/10.1007/BF00380854
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    Tubular extensions of the plasmalemma in leaf cells of Zea mays L. (1977)
    Springer
    Planta 135 (1977), S. 203-205 
    Details
    ISSN: 1432-2048
    Keywords: Apoplast ; Leaf cells ; Plasmalemma extensions ; Symplast ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Leaf tissues of Zea mays were examined with a transmission electron microscope and a high-voltage electron microscope. Tubular extensions (invaginations) of the plasmalemma were found in vascular parenchyma cells and thick-walled, lateformed sieve elements of intermediate and small veins, and in epidermal, mesophyll, and sheath cells of all leaves examined. No continuity seems to exist between the tubules and other cellular membranes.
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    URL: http://dx.doi.org/10.1007/BF00387172
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  • 27
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    Embryonal antigens in maize caryopses: The temporal order of antigen accumulation during embryogenesis (1977)
    Springer
    Planta 135 (1977), S. 225-231 
    Details
    ISSN: 1432-2048
    Keywords: Antigen accumulation ; Embryogenesis ; Globulins ; Proteins ; Seed proteins ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sequential appearance of a specific group of embryonal antigens (EA), presumably globulins, was demonstrated in developing maize (Zea mays L.) caryopses using a double immunodiffusion test with absorption of common antigens. Cross immunoelectrophoresis was employed to follow the differential pattern of EA accumulation in the growing scutellum and embryonic axis. The transient nature of two predominant EA seems to indicate their role as specific protein reserves of embryonal tissues. Another presumably organ-specific EA was maintained in callus obtained from a 28-day-old culture of scutellum isolated from the mature non-germinated caryopsis.
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    URL: http://dx.doi.org/10.1007/BF00384894
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  • 28
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    Development of maize caryopses resulting from in-vitro pollination (1977)
    Springer
    Planta 134 (1977), S. 91-93 
    Details
    ISSN: 1432-2048
    Keywords: Embryo development in vitro ; Fertilization in vitro ; In vitro pollination ; Pollination in vitro ; Seeddevelopment in vitro ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Intact maize (Zea mays L.) ovaries were excised from unpollinated ears (pistillate inflorescences of field-grown plants and placed on defined, agar-based media in Petri dishes. Application of pollen to the end of silks (styles) positioned outside the Petri dish resulted in fertilization of 46% of the ovaries. The extent of subsequent kernel (caryopsis) development varied. After 40 days some kernels had only embryo development while others had embryo and variable endosperm development. About 5% of the initial ovaries developed into normal kernels; 60% of the kernels with some endosperm germinated under laboratory conditions, and 70% of the embryos excised from the embryo-only kernels germinated on culture media.
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    URL: http://dx.doi.org/10.1007/BF00390100
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    Distribution and structure of the plasmodesmata in mesophyll and bundle-sheath cells of Zea mays L. (1977)
    Springer
    Planta 136 (1977), S. 77-89 
    Details
    ISSN: 1432-2048
    Keywords: Apoplast ; Bundle sheath ; Mesophyll ; Plasmodesmata ; Suberin lamella ; Symplast ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In leaf blades of Zea mays L. plasmodesmata between mesophyll cells are aggregated in numerous thickened portions of the walls. The plasmodesmata are unbranched and all are characterized by the presence of electron-dense structures, called sphincters by us, near both ends of the plasmodesmatal canal. The sphincters surround the desmotubule and occlude the cytoplasmic annulus where they occur. Plasmodesmata between mesophyll and bundle-sheath cells are aggregated in primary pit-fields and are constricted by a wide suberin lamella on the sheath-cell side of the wall. Each plasmodesma contains a sphincter on the mesophyll-cell side of the wall. The outer tangential and radial walls of the sheath cells exhibit a continuous suberin lamella. However, on the inner tangential wall only the sites of plasmodesmatal aggregates are consistently suberized. Apparently the movement of photosynthetic intermediates between mesophyll and sheath cells is restricted largely or entirely to the plasmodesmata (symplastic pathway) and transpirational water movement to the cell walls (apoplastic pathway).
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    URL: http://dx.doi.org/10.1007/BF00387929
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    Rapid-growth responses of corn root segments: Effect of auxin on elongation (1977)
    Springer
    Planta 135 (1977), S. 1-5 
    Details
    ISSN: 1432-2048
    Keywords: Auxin ; Cell elongation ; Elongation ; Root growth ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of indole-3-acetic acid (IAA) on the elongation rates of 2 mm corn (Zea mays L.) root segments induced by citrate-phosphate buffer (or unbuffered) solutions of pH 4.0 and 7.0 was studied. At pH 7.0, auxin initially reduced the elongation rate in both buffered and unbuffered solutions. Only in buffer at pH 7.0 was auxin at a concentration of 0.1 μM found to promote the elongation rate though briefly. THis promoted rate represented only ca. 20% of the rate achieved with only buffer at pH 4.0. Auxin in pH 4.0 buffered and unbuffered solutions only served to reduce the elongation rates of root segments. Some comparative experiments were done using 2 mm corn coleoptile segments. Auxin (pH 6.8) promoted the elongation rate of coleoptile segments to a level equal or greater than the maximal H ion-induced rate. The two responses of root segments to auxin are compared to auxin action in coleoptile growth.
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    URL: http://dx.doi.org/10.1007/BF00387967
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  • 31
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    Inhibition of oxygen release by anoxia in a C3-plant (Nicotiana tabacum cv. Wisconsin 38). Comparison with C4-plants (1977)
    Springer
    Planta 135 (1977), S. 39-43 
    Details
    ISSN: 1432-2048
    Keywords: Anaerobiosis inhibition ; C3/C3 plants ; Nicotiana ; Oxygen-release ; Photosynthesis ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tobacco leaves (Nicotiana tabacum var. Wisconsin 38) submitted to anaerobic conditions behave in a manner similar to that of maize, sugarcane, or sorghum leaves (C4-plants); more precisely, a lag time in O2 release is exhibited when the leaves are exposed to light after treatment in the dark under pure nitrogen. Although the conditions for the appearance of this phenomenon in tobacco are somewhat different, the main features are identical to those observed with maize: abolition of the lag time upon immediate exposure to light, release of CO2 under light (illumination burst of CO2), photochemical nature of the reactions involved in the abolition of the lag time, activation of oxygen release by far-red light, and the antagonistic effect of red and far-red light on the lag time. The high CO2 compensation point of tobacco leaves permits the classification of this plant among the C3 group. A comparison of these experimental results with others from the literature suggests than the distinguishing features between C3- and C4-plants are not as sharp as generally thought.
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    URL: http://dx.doi.org/10.1007/BF00387973
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