Relation between permeability to potassium and sodium ions and fusicoccin-stimulated hydrogen-ion efflux in barley roots
✍ Scribed by M. G. Pitman; N. Schaefer; R. A. Wildes
- Publisher
- Springer-Verlag
- Year
- 1975
- Tongue
- English
- Weight
- 781 KB
- Volume
- 126
- Category
- Article
- ISSN
- 0032-0935
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✦ Synopsis
Measurements are described of fusicoccin(FC)-stimulated I-I + efflux in barley (Hordeum vulgate L.) roots when K + and Na + concentrations were varied. In low-salt roots H + efflux was stimulated in both 5 mM KC1 and NaC1. In salt-saturated roots H + efflux was stimulated more effectively in KC1 than in NaC1 solution. The stimulation of H + efflux thus is parallel with the selectivity of these different root preparations for K + and Na + and with estimates of permeability ratios (P%a/PK) determined from electrical measurements. It is suggested that the results support electrogenie coupling between FC-stimulated H + efflux and cation uptake.
Universita, Milan, Italy. The material was dissolved in ethanol to give a 20 mM stock solution and this added to KC] solutions to give a final FC concentration of 10 ~zM. Separate measurements (Fig. 1) showed that I~ + effinx and ~bov reached maximum levels at about 5 ~zlYl FC.