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  • 1
    Electronic Resource
    Electronic Resource
    Cyanobacterial Tintenstrich Communities and their Ecology (1997)
    Springer
    Naturwissenschaften 84 (1997), S. 526-534 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Notes: Tintenstrich communities receive their name from the black strips on rocks, which are particularly spectacular on the background of white limestone and dolomite. They are dominated by cyanobacteria, green photosynthesizing procaryotes. However, cyanobacterial crusts are ubiquitous and much more widespread. On bare substratum on walls and rocks in temperate, arid, and tropical zones they are subject to severe stress by insolation, heat, and either too little or too much water. An array of ecophysiological traits allow them to endure this multifactorial stress. Particular features of their photosynthetic membranes may facilitate dissipation of surplus photosynthetically active radiation; special sun-screen pigments protect them from UV radiation, they are desiccation tolerant, concentrate inorganic carbon for photosynthetic fixation, and assimilate atmospheric dinitrogen. With their own success on bare substratum they become pioneers for other organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001140050439
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  • 2
    Electronic Resource
    Electronic Resource
    Funktion und Struktur pflanzlicher Drüsen (1966)
    Springer
    Naturwissenschaften 53 (1966), S. 96-103 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00601466
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  • 3
    Electronic Resource
    Electronic Resource
    The effect of light levels on daily patterns of chlorophyll fluorescence and organic acid accumulation in the tropical CAM treeClusia hilariana (1996)
    Springer
    Trees 10 (1996), S. 359-365 
    Details
    ISSN: 1432-2285
    Keywords: Chlorophylla fluorescence quenching ; Citric acid ; Malic acid ; Photochemistry ; Photosynthetic electron transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Sandy plains are characteristic of the coastal region of Brazil. We investigated the diel patterns of changes in organic acid levels, leaf conductance and chlorophylla fluorescence for sun-exposed and shaded plants ofClusia hilariana, one of the dominant woody species in the sandy coastal plains of northern Rio de Janeiro state. Both exposed and shaded plants showed a typical CAM pattern with considerable diel oscillations in organic acid levels. The degradation of both malic and citric acids during the midday stomatal closure period could lead to potential CO2 fixation rates of 28 μmol m-2 s-1 in exposed leaves. Moreover, exposed leaves exhibited large increases in total non-photochemical quenching (qN) accompanied by a substantial decrease in effective quantum yield during the course of the day. However, these potential high rates of CO2 fixation and the increases inqn of exposed plants were not enough to maintain the primary electron acceptor of photosystem II (qA) in a low reduction state, similar to that of shaded plants. As a result, there was a moderate increase in the reduction state of qA throughout the day. Most of the decline in photochemical efficiency of exposed leaves ofC. hilariana was reversible, as evidenced by the high levels of pre-dawn potential quantum yields (Fv/Fm) and their rapid recovery after sunset. However, the depletion of the organic acid pool in the afternoon resulted in an accentuated subsequent drop in Fv/Fm, suggesting that prolonged periods of water stress accompanied by high irradiance levels may expose plants ofC. hilariana in unprotected habitats to the danger of photoinhibition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185639
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  • 4
    Electronic Resource
    Electronic Resource
    Comparative measurements of chlorophyll a fluorescence, acid accumulation and gas exchange in exposed and shaded plants of Clusia minor L. and Clusia multiflora H. B. K. in the field (1997)
    Springer
    Trees 11 (1997), S. 240-247 
    Details
    ISSN: 0931-1890
    Keywords: Key words Chlorophyll a fluorescence ; Clusia ; Crassulacean acid metabolism (CAM) ; Electron transport rate through photosystem II ; Malate decarboxylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Changes in chlorophyll a fluorescence during the day and diurnal-changes of net CO2-exchange and organic acid contents were determined in two species of the genus Clusia during the dry season in Venezuela. The investigations included plants of the C3/CAM intermediate species Clusia minor and the C3 species C. multiflora growing at exposed and shaded sites. Both species showed a C3 pattern of net CO2-exchange at the exposed site. In the shade under extreme drought stress C. minor showed a weak expression of CAM without CO2-uptake during the afternoon (phase IV of CAM). C. multiflora growing in the shade exhibited a C3-pattern of net CO2-exchange and a small but significant nocturnal accumulation of citrate. Shaded plants of C. minor were able to double their light utilisation for electron transport and to reduce non-photochemical quenching during phase III compared to phase II of CAM. Furthermore, increase of electron transport rate through photosystem II in phase III of CAM is correlated to decarboxylation of malate. At the exposed site C. multiflora was less negatively affected by high PPFD than C. minor. This was shown by a lower reduction of potential electron quantum yield (Fv/Fm) and higher light utilisation of electron transport of C. multiflora compared to C. minor. At the exposed site C. minor did not make use of the CAM option to increase light utilisation of electron transport and to reduce non-photochemical quenching as did the plants growing in the shade.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009670
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  • 5
    Electronic Resource
    Electronic Resource
    Generation of rhythmic and arrhythmic behaviour of Crassulacean acid metabolism in Kalanchoë daigremontiana under continuous light by varying the irradiance or temperature: Measurements in vivo and model simulations (1996)
    Springer
    Planta 198 (1996), S. 110-117 
    Details
    ISSN: 1432-2048
    Keywords: Circadian rhythm ; Crassulacean acid metabolism ; Kalanchoe ; Model simulations ; Phase setting ; Tonoplast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Leaves of Kalanchoë daigremontiana Hamet et Perr. at a photon flux density (PFD) above 220 μmol·m−2s−1 (400–700 nm) or at leaf temperatures above 27.0 °C showed a rapid loss of rhythmicity, and a more or less pronounced damping-out of the endogenous circadian rhythm of CO2 exchange under continuous illumination. This rhythm was reinitiated after reduction of the PFD by 90–120 μmol·m−2·s−1 or reduction of leaf temperature by 3.5–11.0 °C under otherwise unchanged external conditions. The reduction in the magnitude of the external control parameter of the Crassulacean acid metabolism (CAM) rhythm (i.e. PFD or leaf temperature) set the phase of the new rhythm. The maxima of CO2 uptake occurred about 5, 28, 51, 75 h after the reduction. Simulations with a CAM model under comparable conditions showed a similar behaviour. The influence of temperature on the endogenous CAM rhythm observed in K. daigremontiana in vivo could be simulated by incorporating into the model temperature-dependent switch modes for passive efflux of malate from the vacuole to the cytoplasm. Thus, the model indicates that tonoplast function plays an important role in regulation of the endogenous CAM rhythm in K. daigremontiana.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197593
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  • 6
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Physiologie der Carnivoren-Drüsen (1966)
    Springer
    Planta 68 (1966), S. 269-285 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Sekretion von 36Cl- durch Gewebescheiben, die aus dem drüsentragenden Teil von Nepenthes-Kannen ausgestanzt worden waren, wurde mikroautoradiographisch untersucht. Nach der Applikation von 1–10 mM Chloridlösungen von der der Kannenaußenseite entsprechenden Fläche her waren die Drüsenzellen, die Zellgrenzen im Mesophyll (also die Zellwände einschließlich des dünnen Plasmabelags), Plasmaansammlungen und die Leitbündel besonders stark markiert. Die Drüsenzellen sind dicht mit Plasma erfüllt und wenig vacuolisiert. Die Kornzählungen zeigen, daß die Radioaktivität der verschiedenen plasmareichen Bereiche (der Drüsenzellen, der Zellgrenzen und der Plasmaansammlungen) nicht statistisch signifikant verschieden ist, während die Vacuolen viel weniger markiert sind. Diese Befunde werden im Lichte von Arisz' Theorie des symplasmatischen Transportes diskutiert. Eine artefizielle Übertragung der in den großen Vacuolen der Mesophyllzellen enthaltenen Radioaktivität auf das Cytoplasma während der Präparation kann allerdings nicht völlig ausgeschlossen werden.
    Notes: Summary The secretion of 36Cl- by tissue isolated from Nepenthes pitchers was investigated with microautoradiographic techniques. The tissue was transferred into ether at-30°C or embedded in the vacuum, following procedures described earlier (Lüttge and Weigl, 1965). The microautoradiographs which we obtained after application of 1–10 mM chloride solutions to the surface corresponding to the outside of the pitchers showed a high labelling of the gland cells, the cell borders in the mesophyll (i.e. the cell walls including the thin plasmatic layers), plasmatic particles and the conductive tissue. The gland cells have only very small vacuoles and are densely filled with cytoplasm. The grain counts show that the radioactivity in the parts of the tissue which are rich in cytoplasm (glands, cell borders, plasmatic particles) did not differ within the statistical error. The activity of the vacuoles, however, was much less. These findings are discussed in the light of Arisz' theory of symplasmatic transport. However, an artificial transfer of the radioactivity contained in the large vacuoles of the mesophyll cells to the cytoplasm during the preparation can not be entirely excluded.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385287
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  • 7
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Physiologie der Carnivoren-Drüsen (1966)
    Springer
    Planta 68 (1966), S. 44-56 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Der Cl--Transport durch isolierte Gewebescheiben aus dem die überdachten Drüsen tragenden Teil von Nepenthes-Kannen wurde untersucht. An der der Kannenaußenseite entsprechenden Fläche, deren cutinisierte Epidermis durch oberflächliches Anschneiden mit einer Rasierklinge entfernt wurde, nehmen die Gewebescheiben aus den Versuchslösungen Cl- durch metabolischen Trägertransport auf, während die Cl--Abgabe passiv ist. Die Cl--Sekretion durch die drüsentragende Oberfläche hängt von der Bereitstellung energiereicher Phosphate durch den Stoffwechsel ab. Zwischen dem Chloridgehalt und der caseinspaltenden Aktivität des Kannensekretes konnte eine Korrelation nachgewiesen werden.
    Notes: Summary The transport of chloride in isolated tissue from Nepenthes pitchers was investigated using 36Cl-, an Aminco-Cotlove chloride-titrator for the determinations of Cl- concentrations, and KCN and AsO 4 - -as metabolic inhibitors. The tissue was brought in contact with different experimental solutions (=medium). The surface corresponding to the outside of the pitchers was cut with a razor blade to remove the cutinized epidermal layer. At this surface the Cl- uptake from the medium is a metabolic process which depends on the Cl--concentration of the medium in a manner that corresponds to the Michaelis-Menten kinetics. The Michaelis-constant of this transport step was 3×10-2M. The Cl--efflux into the medium, however, is a passive process. The opposite surface of the tissue slices (corresponding to the inside of the pitchers) carries the glands. The chloride secretion taking place here is also dependent on metabolism. In vitro it occurs even when a high gradient of chloride concentration has been set up between the medium and the solution which is in contact with the glands. In vivo the Cl--concentration of the pitcher fluid and the amount of Cl- per gram of tissue water are almost equal. The rôle of chloride in the physiology of Nepenthes is still under investigation, A correlation between the chloride content of the pitcher fluid and its enzymatic activity (Casein-test), however, could already be demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385370
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  • 8
    Electronic Resource
    Electronic Resource
    Die Salzdrüsen von Limonium vulgare (1967)
    Springer
    Planta 74 (1967), S. 1-17 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Durch eine Kombination von mikroautoradiographischem Chloridnachweis und elektronenoptischer Lokalisierung von Silberfällungen wurde versucht, die intracelluläre Verteilung des Chlorids und den Weg des Ions im Blatt zu verfolgen. Dabei ergaben sich unter anderem folgende Ergebnisse: 1. Es konnte ein Auftreten des Chlorids in Chloroplasten sichergestellt, im Zellkern wahrscheinlich gemacht werden. 2. Es ergaben sich Hinweise für einen apoplastischen und eine symplastischen Chloridtransport. 3. Für einen Konzentrationshub des Ions zwischen dem Plasma der Parenchymzellen und dem der Drüsenzellen konnten keine Anhaltspunkte erhalten werden.
    Notes: Summary Using a combination of microautoradiographic detection of chloride and an electronmicroscopic localisation of silver precipitation an attempt was made to elaborate the intracellular distribution of chloride and the pathway of this ion in the leaf. The main results were as follows: 1. It was shown that chloride occurs in the chloroplasts and probably also in the nuclei. 2. There are indications for an apoplastic and a symplastic transport of the chloride. 3. The findings do not suggest a rise of the chloride concentration in the cytoplasm between the parenchyma and the gland cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385168
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  • 9
    Electronic Resource
    Electronic Resource
    Absorption and long distance transport by isolated stele of maize roots in relation to the dual mechanisms of ion absorption (1967)
    Springer
    Planta 74 (1967), S. 173-187 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Ionenaufnahme durch intakte Wurzeln, isolierte Rinde und isolierte Zentralzylinder und der Ferntransport durch intakte und entrind ete Wurzeln wurden verglichen, und zwar kurz nach der Isolierung und nach Altern der Gewebe. Frisch isolierte Zentralzylinder akkumulieren Io nen nur in ganz geringem Maße oder überhaupt nicht. Von den beiden Systemen der metabolischen Ionenaufnahme, die in einem niedrigen (System 1: bis 0,5 meq/l) und in einem hohen Konzentrationsbereich (System 2: 1-50 meq/l) die Geschwindigkeit der Ionenaufnahme durch intakte Wurzeln und isolierte Wurzelrinde bestimmen, entwickelt sich während des Alterungsprozesses in isolierten Zentralzylindern System 1, nicht aber System 2. In Übereinstimmung mit diesem Befund zeigt die Analyse der Einzelfluxe am Plasmalemma und am Tonoplasten, daß nur der Influx aus der Außenlösung in das Cytoplasma beim Altern der Zentralzylinder beträchtlich ansteigt. Veränderungen beim Altern von abgeschnittenen, intakten Wurzeln und isolierter Rinde sind viel weniger ausgeprägt. Obwohl die Ionenaufnahme beim Altern isolierter Zentralzylinder steigt, verringert sich der Ferntransport, der bei frisch isolierten Zentralzylindern rein passiv ist. Die mitgeteilten Ergebnisse zeigen die ausgeprägte Permeabilität frisch isolierter Zentralzylinder und demonstrieren die Bedeutung der Wurzelrinde als ein Gewebe, das Ionen für den Ferntransport “sammelt”. Auf diese Weise werden neue Anhaltspunkte für die Theorie des symplasmatischen Transportes der Ionen in die Gefäße gewonnen.
    Notes: Summary Ion absorption and transport by intact roots, isolated cortex and isolated stele were compared shortly after tissue isolation and after aging. Absorption isotherms in the low and in the high concentration range show that in stripped-stele, which absorbs at a very low rate immediately after isolation, the capacity of system 1 but not system 2 is built up with aging. In agreement with this result analysis of individual fluxes across plasmamembrane and tonoplast reveals that only the influx from the medium into the cytoplasm increases considerably with aging of stele. Changes observed in aging excised roots and in isolated cortex are much less significant. In spite of the increase of absorption with aging by isolated stele, long distance transport, which is essentially passive through freshly stripped stele, decreases with aging. The reported results reflect the marked permeability of the plasmamembrane of fresh isolated stele, and demonstrate the importance of the cortex as a tissue “collecting” ions for long distance transport. New evidence for the theory of symplasmatic transport of ions into the xylem vessels is thus provided.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388327
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  • 10
    Electronic Resource
    Electronic Resource
    Evaluation of ion uptake isotherms and analysis of individual fluxes of ions (1968)
    Springer
    Planta 80 (1968), S. 52-64 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Mit Hilfe der von Pitman (1963) beschriebenen Methode wurde die Abhängigkeit der einzelnen Ionenfluxe am Plasmalemma und am Tonoplasten und des Ionengehaltes im Plasma und in der Vacuole von der Außenkonzentration untersucht. Die erhaltenen Kurven wurden mit Ionenaufnahmeisothermen aus der Literatur verglichen. Dabei zeigte sich, daß der Flux aus der Außenlösung in das Cytoplasma dem sogenannten System 1 und der Flux aus dem Cytoplasma in die Vacuole dem System 2 der Isothermenkinetik entspricht. Dies ist ein weiterer Beleg für die Richtigkeit der Theorie von Torii und Laties (1966a) über die Lokalisierung von System 1 und System 2 innerhalb der Zelle. Die Veränderung der im Cytoplasma und in der Vacuole enthaltenen Ionenmenge mit steigender Außenkonzentration läßt deutlich werden, daß das Plasmalemma seine Barrierenfunktion bei Konzentrationen über 1 mM verliert. Es wird diskutiert, welche Aussagen über Transportprozesse mit den beiden Methoden der Isothermenkinetik und der Effluxanalyse gemacht werden können.
    Notes: Summary The dependence of individual ion fluxes at the plasmalemma and at the tonoplast and of the amounts of ions in the cytoplasmic and vacuolar phases on external concentration was investigated using the method outlined by Pitman (1963). The results are compared with ion uptake isotherms from the literature. It is concluded that flux from the solution into the cytoplasm corresponds to system 1 and flux from the cytoplasm to the vacuole is congruent with system 2. The hypothesis of Torii and Laties (1966a) regarding the location of system 1 and system 2 within the cell is thus reemphazised. The changes of the amounts of internal ions with external concentration clearly demonstrate that the plasmalemma loses its function as a barrier at concentrations above 1 mM. The conclusions which can be drawn from investigations of isotherm kinetics and flux analysis are examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387189
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