Garthwaite Alaina J, von Bothmer Roland, Colmer Timothy D
School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
J Exp Bot. 2005 Sep;56(419):2365-78. doi: 10.1093/jxb/eri229. Epub 2005 Jul 12.
Eight wild Hordeum species: H. bogdanii, H. intercedens, H. jubatum, H. lechleri, H. marinum, H. murinum, H. patagonicum, and H. secalinum, and cultivated barley (H. vulgare) were grown in nutrient solution containing 0.2 (control), 150, 300, or 450 mol m(-3) NaCl. In saline conditions, the wild Hordeum species (except H. murinum) had better Na+ and Cl- 'exclusion', and maintained higher leaf K+, compared with H. vulgare. For example, at 150 mol m(-3) NaCl, the K+:Na+ in the youngest, fully expanded leaf blades of the wild Hordeum species was, on average, 5.2 compared with 0.8 in H. vulgare. In H. marinum grown in 300 mol m(-3) NaCl, K+ contributed 35% to leaf psi(pi), whereas Na+ and Cl- accounted for only 6% and 10%, respectively. By comparison, in H. vulgare grown at 300 mol m(-3) NaCl, K+ accounted for 19% and Na+ and Cl- made up 21% and 25% of leaf psi(pi), respectively. At 300 mol m(-3) NaCl, glycinebetaine and proline together contributed almost 15% to psi(pi) in the expanding leaf blades of H. marinum, compared with 8% in H. vulgare. Decreased tissue water content under saline conditions made a substantial contribution to declines in leaf psi(pi) in the wild Hordeum species, but not in H. vulgare. A number of the wild Hordeum species were markedly more salt tolerant than H. vulgare. H. marinum and H. intercedens, as examples, had relative growth rates 30% higher than H. vulgare in 450 mol m(-3) NaCl. Hordeum vulgare also suffered up to 6-fold more dead leaf material (as a proportion of shoot dry mass) than the wild Hordeum species. Thus, several salt-tolerant wild Hordeum species were identified, and these showed an exceptional capacity to 'exclude' Na+ and Cl- from their shoots.
波格丹大麦（H. bogdanii）、中间大麦（H. intercedens）、芒颖大麦草（H. jubatum）、莱氏大麦（H. lechleri）、海大麦（H. marinum）、鼠大麦（H. murinum）、巴塔哥尼亚大麦（H. patagonicum）和黑麦状大麦（H. secalinum），以及栽培大麦（H. vulgare）在含有0.2（对照）、150、300或450 mol m(-3)氯化钠的营养液中种植。在盐胁迫条件下，与栽培大麦相比，野生大麦品种（除鼠大麦外）对钠离子和氯离子有更好的“排斥”能力，并保持较高的叶片钾离子含量。例如，在150 mol m(-3)氯化钠条件下，野生大麦品种最幼嫩、完全展开叶片的钾离子与钠离子比值平均为5.2，而栽培大麦为0.8。在300 mol m(-3)氯化钠中生长的海大麦，钾离子对叶片渗透势（ψ(π)）的贡献为35%，而钠离子和氯离子分别仅占6%和10%。相比之下，在300 mol m(-3)氯化钠中生长的栽培大麦，钾离子占叶片渗透势的19%，钠离子和氯离子分别占21%和25%。在300 mol m(-3)氯化钠条件下，甘氨酸甜菜碱和脯氨酸共同对海大麦展开叶片的渗透势贡献近15%，而栽培大麦为8%。盐胁迫条件下组织含水量的降低对野生大麦品种叶片渗透势的下降有很大贡献，但对栽培大麦没有影响。许多野生大麦品种的耐盐性明显高于栽培大麦。例如，在450 mol m(-3)氯化钠条件下，海大麦和中间大麦的相对生长速率比栽培大麦高30%。栽培大麦的枯叶量（占地上部干质量的比例）也比野生大麦品种多6倍。因此，鉴定出了几种耐盐野生大麦品种，它们表现出从地上部“排斥”钠离子和氯离子的特殊能力。
