As shown in Figure 3, the K/Na ratio in shoots and roots of both AF and MS
cultivars decreased with increasing concentration of NaCl in the nutrient solution. In
absence of NaCl, SM showed higher values of this ratio than AF. With 50 mM NaCl, the
K/Na ratio in shoots was reduced in 72% in the cultivar AF and 77% in SM. In roots, this
ratio decreased 86 and 88% in AF and MS, respectively. Accordingly, Tester and
Davenport (2003) found that under saline conditions, the retention of K in cells is a
mechanism of tolerance, as well as the ability to restrict the absorption of Na. Therefore,
the cultivars that are able to maintain high K/Na ratios are suitable to grow under saline
conditions. This could indicate that this variable is enough to give clues about tolerance or
susceptibility of the evaluated cultivars.