Comparison of shoot dry weight, Na+ content and δ13C values of ari-e and other semi-dwarf barley mutants under salt-stress

Four breviaristatum (short awned and semi-dwarf) barley mutants; ari-e.1, ari-e.119, ari-e.156 and ari-e.228 were compared with other semi-dwarf mutants; Golden Promise, Alf, Pallas and Diamant along with their non-mutant parents; Bonus, Foma, Maythorpe, Bomi and Valticky, for response to salt stress. Plants were exposed to hydroponic salt treatments (NaCl at 25 and 175 mol m-3) for 4 weeks, after which response was measured in terms of shoot dry weight, sodium content and δ13C. In general ari-e mutants and Golden Promise had significantly lower Na+ contents than the other mutants. They also had significantly more negative δ13C values than the other lines in stressed (175 mol m-3 NaCl) conditions. There was a positive correlation (r = 0.71, p < 0.01) between shoot Na+ and δ13C values so that δ13C became less negative with increasing Na+ content. Shoot dry weights were compared to shoot Na+ and δ13C values. The ari-e and Golden Promise mutants showed less reduction in dry matter production in salt stress relative to the control treatment than all the other lines. The data suggest that ari-e mutants and Golden Promise are better adapted to salt stressed environments than the other lines examined. Tests for gibberellic acid sensitivity revealed that ari-e mutants and Golden Promise responded weakly to GA3, while other dwarf mutants Pallas, Diamant and Alf along with their parents Bonus, Foma, Maythorpe, Valticky and Bomi were highly sensitive. Our results support previous findings that ari-e mutants and the GPert mutant are allelic.