SALT TOLERANCE IN THE TRITICEAE - K/NA DISCRIMINATION IN SOME PERENNIAL WHEATGRASSES AND THEIR AMPHIPLOIDS WITH WHEAT

Perennial wheatgrasses of the genera Thinopyrum, Leymus and Psathyrostachys were subjected to high and low salinities to determine whether the enhanced K/Na discrimination trait was expressed in these members of the Triticeae. At low salinities, where the enhanced K/Na discrimination trait is most evident, the leaf cation concentrations were consistent with the operation of the trait. At higher salinities sodium exclusion and potassium retention were greater than in tetraploid wheat. Experiments with hexaploid or octoploid wheat x Thinopyrum amphidiploids showed that the presence of the D genome of wheat greatly affected cation discrimination, and pointed to the absence of enhanced K/Na discrimination in the perennial wheatgrasses. Results obtained with Thinopyrum elongatum addition lines, and the uptake of Na-22 into 'low-salt' amphiploid seedlings, are consistent with the absence of the trait in Thinopyrum.