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  • 1
    Electronic Resource
    Electronic Resource
    Appearance of a State 1 – State 2 transition during chloroplast development in the wheat leaf: Energetic and structural considerations (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 60 (1984), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The ability of developing chloroplasts to dynamically regulate the distribution of excitation energy between photosystem 1 and photosystem 2, and thus perform a State 1 – State 2 transition, was examined from analyses of chlorophyll fluorescence kinetics in 4- and 8-day-old Triticum aestivum L. cv. Maris Dove leaves grown under a diurnal light regime. Chloroplasts at all stages of development in the two leaf systems could undergo a State 1 – State 2 transition, except those found in the basal 0.5 cm of the 4-day-old leaf. The ability to physiologically modify the excitation energy distribution between the chlorophyll matrices of the two photosystems developed after the development of mature, fully photochemically competent photosystem 2 units and the appearance of excitation energy transfer between photosystem 2 and photosystem 1. Also, changes in the degree of energetic interaction between the two photosystems, in vivo rates of electron transport and the chlorophyll a/b ratio could not be correlated with the appearance of a State 1 – State 2 transition. Ultrastructural studies demonstrated a 32% increase in the degree of thylakoid appression in chloroplasts at the base of the 8-day-old leaf compared to the situation in the basal 0.5 cm of the 4-day-old leaf. This difference in thylakoid stacking can account for the differing abilities of these two tissues to perform a State 1 – State 2 transition when considered in the context of the distribution of the two photosystems within appressed and non-appressed regions of thylakoid membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1984.tb04560.x
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  • 2
    Electronic Resource
    Electronic Resource
    Stomatal Response to Humidity and Lanthanum (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 41 (1977), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Lanthanum fed to the base of excised leaves of Sesamum indicum L. and Helianthus annuus L. was used as a tracer to investigate by electron microscopy the path of water in the apoplast of leaves. The generally random distribution of lanthanum in cell walls provided no support for the hypothesis that cuticular transpiration may be greater for guard cells than for adjacent epidermal cells. Occasionally, accumulations of lanthanum were observed in anticlinal walls of epidermal cells and at the outer surface of the plasma membrane but lanthanum was not observed in the symplast.The influx of 86Rb to excised roots of sesame and sunflower was inhibited during incubation with 0.5 mM lanthanum or calcium for 15 or for 180 min. Stomata of sunflower partially closed when 2.5 mM lanthanum was supplied to the base of excised shoots in a potometer, whereas this treatment had little effect on stomatal conductance of sesame shoots maintained in a constant environment. Supplying 2.5 mM lanthanum to the base of sesame shoots strongly inhibited stomatal opening response to increase in ambient humidity but had little effect on stomatal opening response to light. It was concluded that stomatal opening response to increased humidity may be dependent upon some process, such as ion influx, that is inhibited by lanthanum, and that opening response to humidity may differ in mechanism from stomatal opening response to increased irradiance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1977.tb05536.x
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  • 3
    Electronic Resource
    Electronic Resource
    The marginal regions of thylakoid membranes: A partial characterization by polyoxyethylene sorbitan monolaurate (Tween 20) solubilization of spinach thylakoids (1988)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 72 (1988), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The detergent Tween-20 solubilized preferentially portions of the marginal regions of Spinacea oleracea L. thylakoid membranes and, thus, opened the inside of the grana to the external media. Differential centrifugation. following Tween-20 solubilization. enabled separate fractions of grana and stromal-exposed membranes to be isolated. Analysis of Tween-20 solubilized material, after pelleting all membrane material by centrifugation at 100 000 g, revealed polypeptides associated with the coupling factor (CF1) particles, cytochrome b6/f and photosystem II complexes, suggesting that the marginal membranes contain these proteins. Concomitantly, the 100 000 g pellet was depleted in cytochrome b6/f and P700, determined spectroscopically, Thus. our results reveal the margin to be a distinct membrane region, which does not contain the light-harvesting centers of photosystem II (LHC II). The implication of these results, in terms of the energetic interaction of components of granal and stromalexposed membrane regions, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1988.tb05835.x
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  • 4
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of Lucifer Yellow and endocytosis in plant cells (1991)
    Springer
    Protoplasma 160 (1991), S. 115-120 
    Details
    ISSN: 1615-6102
    Keywords: Brocchinia reducta (Bromeliaceae) ; Coated vesicle ; Dictyosome ; Endocytosis ; Lucifer Yellow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The fluorescent dye Lucifer Yellow CH (LYCH) was localized at the ultrastructural level with a precipitation method using barium chloride. Applying this technique, endocytosis of LYCH was examined in the nutrient absorptive trichomes of a carnivorous bromeliad. After a two hour incubation, the electron dense reaction product was localized in the membrane compartments of the endocytotic system. These structures included coated regions of the plasma membrane, coated and smooth vesicles, dictyosomes, partially coated reticulum, and smooth endoplasmic reticulum. This procedure demonstrates for the first time at the ultrastructural level endocytosis in whole plant cells, using a non-toxic compound.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01539963
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  • 5
    Electronic Resource
    Electronic Resource
    The ultrastructure of the plasmodesmata of the salt glands ofTamarix as revealed by transmission and freeze-fracture electron microscopy (1985)
    Springer
    Protoplasma 125 (1985), S. 13-23 
    Details
    ISSN: 1615-6102
    Keywords: Plasmodesmata ; Ultrastructure ; Freeze-fracture ; Salt glands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Numerous plasmodesmata occur in the walls between the secretory cells ofTamarix salt glands. The plasmalemma bounds the plasmodesmata and is continuous from cell to cell. In freeze-fracture, the e-face of the plasmalemma within the plasmodesmata is virtually devoid of intramembranous particles while, in contrast, the p-face is decidedly enriched with particles. The axial components appear to be a tightly curved membrane bilayer, as judged from measurements and their appearance in freeze-fracture, and the e-face of this membrane is also devoid of particles. Observations from both thin sections and freeze-fracture replicas indicate the presence of a circular cluster of six particles around the axial component near the cytoplasmic termini of the plasmodesmata. These particles extend from the p-face of the axial component to the p-face of the plasmalemma. These observations are summarized in a model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01297346
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrastructural and lipid changes associated with the aging of citrus leaves (1978)
    Springer
    Protoplasma 94 (1978), S. 221-233 
    Details
    ISSN: 1615-6102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary During maturation and senescence of leaves of navel orange (Citrus sinensis L.), total lipids per gram of leaf steadily decline. The decline is attributable to the galactolipid and phospholipid partners, while chlorophylls, carotonoids and tocopherols increase during maturation. The phospholipid/galactolipid ratio declines steadily during maturation and senescence but the monogalactosyldiglyceride/digalactosyldiglyceride ratio remains relatively constant. The phospholipid composition remains relatively constant even though the total phospolipid declines markedly. Ultrastructural changes concomittant with changes in lipid composition include the development of an extensive internal membrane system (grana-fretwork system), and several large-plastoglobuli in the chloroplasts of mature green leaves. With the conversions of chloroplasts to chromoplasts in the senescing leave the internal membrane system is reduced and numerous, large plastoglobuli appear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276773
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