Ionic Diffusion Through theNitellaCell Wall in the Presence of Calcium
- 1 October 1978
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Experimental Botany
- Vol. 29 (5) , 1155-1159
- https://doi.org/10.1093/jxb/29.5.1155
Abstract
Diffusion potentials (concentration and bi- or multi-ionic potentials) in KC1, NaCl, or LiCl solutions have been measured across an isolated cell wall of Nitella, with or without the same concentration of CaCl2 on either side of the cell wall. The absolute value of the potentials decreases as the external Ca2+concentration increases and it may happen that an inversion of the sign of the concentration potentials results when the external Ca2+ solution reaches 1 mM. Dosages of K+ and Ca2+ in the cell wall have shown that Ca2+ easily displaces the monovalent ion from the exchange sites and tends to neutralize the cationic exchanger. However, in most cases, the measured potentials are still more negative than the theoretical potentials which would be set up by a neutral-site membrane in the same conditions. These results suggest that Ca2+ largely reduces the discrimination properties of the cell wall between cations and anions.This publication has 3 references indexed in Scilit:
- Nature des liaisons de l'ion calcium dans la paroi de Nitella flexilisCanadian Journal of Botany, 1978
- The Membrane Potential ofNitella translucensJournal of Experimental Botany, 1967
- Cell Growth and the Structure and Mechanical Properties of the Wall in Internodal Cells ofNitella opaca: II. MECHANICAL PROPERTIES OF THE WALLSJournal of Experimental Botany, 1962