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1994 (1)
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1Author    D. Girlich, H.-D Lüdemann, C. Buttersack, K. BuchholzRequires cookie*
 Title    c , T-Dependence of the Self Diffusion in Concentrated Aqueous Sucrose Solutions  
 Abstract    The self diffusion coefficients D of the water molecules and of sucrose have been deter­ mined by the pulsed field gradient NMR technique over a wide range of temperatures and concentrations (cmax: 70% w/w sue.). All temperature dependencies can be fitted to a Vogel-Tammann-Fulcher equation. The isothermic concentration dependence of D for the sucrose is given by a simple exponential concentration dependence. 
  Reference    Z. Naturforsch. 49c, 258—264 (1994); received December 21993 
  Published    1994 
  Keywords    Diffusion, Sucrose, Water, Aqueous Solution 
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 TEI-XML for    default:Reihe_C/49/ZNC-1994-49c-0258.pdf 
 Identifier    ZNC-1994-49c-0258 
 Volume    49 
2Author    M. Arie-Theres, Hauser, Michael WinkRequires cookie*
 Title    Uptake of Alkaloids by Latex Vesicles and Isolated Mesophyll Vacuoles of Chelidonium ntajus (Papaveraceae)  
 Abstract    Latex vacuoles o f Chelidonium majus (Papaveraceae) naturally sequester protoberberine and benzophenanthridine alkaloids. Isolated vesicles take up a number o f other heterologous alkaloids, such as 9,10-dihydroergocryptine, vinblastine, strychnine, nicotine, colchicine, lupanine, and 13-hydroxylupanine, with a strong preference for the indole alkaloids and for nicotine. Kinetic data clearly show that the uptake proceeds via simple diffusion and not by carrier-mediated transport. The alkaloids are concentrated in the vesicles against a concentra­ tion gradient. M gA TP has no influence on alkaloid uptake. It is likely that alkaloids are trapped in the vesicles by chelidonic acid (concentration in latex 58 mM, in vesicles 661 mM) which com plexes these alkaloids and thus prevents their rediffusion out o f the vesicles. Uptake o f these alkaloids by leaf protoplasts and vacuoles o f Ch. majus, by vacuoles o f suspension-cultured cells o f Lupinuspolyphyllus and by rabbit erythrocytes was studied for comparison. 
  Reference    Z. Naturforsch. 45c, 949 (1990); received January 15/May 18 1990 
  Published    1990 
  Keywords    Chelidonium m ajus, Alkaloid Uptake, Vacuole, Latex, Diffusion, Ion-Trap 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0949.pdf 
 Identifier    ZNC-1990-45c-0949 
 Volume    45 
3Author    Wolfram Hartung, Barbara DierichRequires cookie*
 Title    Uptake and Release of Abscisic Acid by Runner Bean Root Tip Segments  
 Abstract    Uptake o f abscisic acid by 5 mm long decapped root tips is a linear function o f the external ABA concentration in the range o f 2.9 x 10-8 m to 10~4 m and decreases dramatically with in­ creasing pH. At pH 8.0 uptake rate is extremely low, even at high ABA concentrations. This indicated that nearly all o f the ABA is taken up as the undissociated m olecule ABAH. Uptake o f ABA is influenced by agents m odifying the pH gradients between the m edium and the tissue such as salts o f weak acids incubated at low external pH (inhibition o f uptake and stim ulation o f ABA release by abolishing the pH gradients), protonophores such as CCCP (inhibition o f uptake) and fusicoccin (stim ulation o f uptake by increasing the pH between m edium and cytoplasm). It is concluded that ABA distributes between the compartments o f the root cells according to the pH gradients with the undissociated m olecule as the only penetrating species. Uptake and release occur without participation o f a saturable com ponent by diffusion. In contrast IAA permeates the plasm alem m a as both IAAH and IAA-. 
  Reference    Z. Naturforsch. 38c, 719 (1983); received March 31 1983 
  Published    1983 
  Keywords    Abscisic Acid, Diffusion, Indole Acetic Acid, Phaseolus coccineus, Plasm alem m a, Transport 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0719.pdf 
 Identifier    ZNC-1983-38c-0719 
 Volume    38