Sodium-coupled symports in the plasma membranes of plant cells
Walker, N.A.
Symposia of the Society for Experimental Biology 48: 179-192
1994
ISSN/ISBN: 0081-1386 PMID: 7597642 Document Number: 437412
It has been a dogma since the success of chemiosmotic theory that plants use protons as a membrane-coupling mechanism--it has come to be implied that they use no other ion for the purpose. Following the finding that potassium can be taken up by sodium symport in Chara australis, we have established that urea is also taken up by sodium symport in the same organism. use of electrical and flux methods for finding sodium-driven symport are described; using these methods, sodium symport is also found for three solutes in Nitella translucens. Extending the search to higher plants has shown indications of sodium-driven uptake of potassium in Elodea canadensis roots, and Egeria sp. and Vallisneria leaves. Sugar and potassium uptake in Zea mays roots, and sugar uptake in Elodea canadensis showed no sodium requirement.