Evidence for a sodium influx pump in sunflower roots
- 1 January 1971
- journal article
- Published by Springer Nature in Planta
- Vol. 98 (4), 323-329
- https://doi.org/10.1007/bf00380233
Abstract
Transmembrane electrical potential differences in the cortical cells of the root of the sunflower (Helianthus annuus) have been measured using microelectrodes. The plants were grown in culture solution with a range of sodium concentrations. It was found that increasing the external sodium concentration had virtually no effect on the transmembrane potential. The vacuolar content of sodium did not change significantly with the age of the tissue indicating that sodium was in flux equilibrium in our experiments. This allowed the Nernst equation to be used to calculate the electrochemical potential gradient for sodium between the vacuole and the external solution. It was concluded that sodium was being transported into the vacuole against the electrochemical potential gradient. The location and role of the inwardly directed sodium pump implied by these results is discussed in relation to the efflux pumps for sodium reported for roots of other species. Potassium was also accumulated against the electrochemical potential gradient by these cells. Sodium was found to stimulate the growth of H. annuus when present in the culture solution at very low concentrations.Keywords
This publication has 10 references indexed in Scilit:
- Movement of Ions and Electrogenesis in Higher Plant CellsAmerican Zoologist, 1970
- Evidence for a K+-stimulated Na+ efflux at the plasmalemma of barley root cellsPlanta, 1970
- ELECTROCHEMICAL POTENTIAL GRADIENTS OF IONS IN AN AQUATIC ANGIOSPERM, POTAMOGETON SCHWEINFURTHII (BENN.)New Phytologist, 1968
- Nernst Potential Measurements on the Leaf Cells of the Moss,Hookeria lucensJournal of Experimental Botany, 1967
- Sodium and Rubidium as Possible Nutrients for Sugar Beet PlantsPlant Physiology, 1967
- Active sodium and potassium transport in cells of barley roots.Proceedings of the National Academy of Sciences, 1967
- Mineral Ion Contents and Cell Transmembrane Electropotentials of Pea and Oat Seedling TissuePlant Physiology, 1967
- Partial substitution of sodium for potassium in water culturesPlant and Soil, 1966
- Active and Passive Transport of the Major Nutrient Ions across the Root ofRicinus communisJournal of Experimental Botany, 1966
- Relationship of Cell Transmembrane Electropotential to Potassium and Sodium Accumulation Ratios in Oat and Pea SeedlingsPlant Physiology, 1963