Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, PO Box 1052, Sevilla 41080, Spain. pardo@cica.es
Plants face a dilemma about sodium metabolism. Uptake of ubiquitous sodium ions is desirable as a way to build osmotic potential, absorb water and sustain turgor, but excess sodium ions may be toxic. Information from a number of plant species about the proteins involved in sodium-ion uptake helps to explain how plants manage to take in just the right amount.