Salt Tolerance in the Triticeae: K/Na Discrimination in Barley

Concentrations of ions were measured in the youngest fully-expandedleaves of Triticum aestivum, T. durum, Hordeum vulgare, H. spontaneum,Secale cereale, and Aegilops squarrosa accessions grown in hydroponicculture in the presence of salt (NaCl+CaCl₂). Triticum aestivum,Secale cereale, and Ae. squarrosa had the low leaf Na and highleaf K concentrations typical of plants which contain the enhancedK/Na discrimination character originally found in Ae. squarrosa.T. durum and the Hordeum species did not have this character.The better growth of H. vulgare than of T. durum with similarsalt concentrations in the youngest fully-expanded leaves maybe a result of better compartmentation of Na, Cl, and K betweendifferent tisssues or between different compartments withincells. The enhanced K/Na discrimination character was expressedin disomic addition lines of H. vulgare chromosomes in Triticumaestivum. The H. vulgare variety Herta and its slender mutantboth had similar leaf cation concentrations, although they differedin growth rate when grown at 60 mol m^–3 NaCl. H. vulgareand T. durum seedlings grown in the absence of monovalent cationsaccumulated more ²²Na in their shoots than seedlings of otherspecies when incubated in 1.0 mol m^–3 NaCl labelled with²²Na. Key words: Salt, ion transport, I genome, barley, wheat