Salt tolerance in a Hordeum marinum–Triticum aestivum amphiploid, and its parents

Growth, grain production, and physiological traits were evaluated for Hordeum marinum, Triticum aestivum (cv. Chinese Spring), and a H. marinum–T. aestivum am-phiploid, when exposed to NaCl treatments in a nutrient solution. H. marinum was more salt tolerant than T. aestivum and the amphiploid was intermediate, both for vegetative growth and relative grain production. H. marinum was best able to ‘exclude ’ Na+ and Cl2, particularly at high external NaCl. At 300 mM NaCl, con-centrations of Na+ (153 mmol g21 dry mass) and Cl2 (75 mmol g21 dry mass) in the youngest fully-expanded leaf blade of H. marinum were, respectively, only 7% and 4 % of those in T. aestivum; and in the amphiplolid the Na+ and Cl2 concentrations were 39 % and 36 % of those in T. aestivum. Glycinebetaine and proline con-centrations in the youngest fully-expanded leaf blade of plants exposed to 200 mM NaCl were highest in H. marinum (128 and 60 mmol g21 dry mass, respec-tively), lowest in T. aestivum (85 and 37 mmol g21 dry mass), and intermediate in the amphiploid (108 and 54 mmol g21 dry mass). Thus, salt tolerance of H. marinum was expressed in the H. marinum– T. aestivum amphiploid