Then, plants were transferred to solutions with no K+with 2 levels of Ca2+(0.75 and 5 mM) and 5 levels of Na+(0, 10, 20, 25 and 30 mM) and grown for one additional week. This imposed a K+starvation treatment for all plants and the effects of Ca2+ and Na+on the induction of high-affinity K+ uptake could be evaluated. For this purpose, after 7 d of treatments, plants were transferred to 180 mL containers with 1/10 Hoagland uptake solution that contained 50 M K+