Salt stress is considered one of the most devastating environmental stresses, affecting barley growth and leading to significant yield loss. Hence, there is considerable interest in investigating the most effective traits that determine barley growth under salt stress. The objective of this study was to elucidate the contribution of osmotic and oxidative stress components in leaves and roots growth under salt stress. Two distinct barley (Hordeum vulgare) salt-stress tolerant genotypes, Barrage Malleg (BM, tolerant) and Saouef (Sf, sensitive), were subjected to 200 mM NaCl at early vegetative stages. Stressed and control leaves and roots tissue were assessed for several growth traits, including fresh and dry weight and plant length, as well as the content of osmoprotectants proline and soluble sugars. In addition, malondialdehyde content and activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), as well as their corresponding gene expression patterns, were investigated. The results showed better performance of BM over Sf for leaf dry weight (LDW), root dry weight (RDW) and root length (RL). The salt-tolerant genotype (BM) had better osmoprotection against salt stress compared with the salt-sensitive genotype (Sf), with a higher accumulation of proline and soluble sugars in leaves and roots and a stronger antioxidant system as evidenced by higher activities of SOD, CAT and APX and more abundant Cu/Zn-SOD transcripts, especially in roots. Stepwise regression analysis indicated that under salt stress the most predominant trait of barley growth was Cu/Zn-SOD gene expression level, suggesting that alleviating oxidative stress and providing cell homeostasis is the first priority.

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评估盐胁迫下渗透和氧化胁迫成分对大麦生长的贡献

盐胁迫被认为是最具破坏性的环境胁迫之一，会影响大麦的生长并导致显着的产量损失。因此，人们对研究决定盐胁迫下大麦生长的最有效性状具有相当大的兴趣。本研究的目的是阐明渗透和氧化胁迫成分在盐胁迫下叶和根生长中的贡献。两种不同的大麦（Hordeum vulgare）耐盐胁迫基因型，Barrage Malleg（BM，耐受）和 Saouef（Sf，敏感），在早期营养阶段受到 200 mM NaCl 的影响。评估了胁迫和对照叶和根组织的几种生长特性，包括鲜重和干重和植物长度，以及渗透保护剂脯氨酸和可溶性糖的含量。此外，研究了超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）的丙二醛含量和活性，以及​​它们相应的基因表达模式。结果表明，BM 在叶片干重 (LDW)、根干重 (RDW) 和根长 (RL) 方面的性能优于 Sf。与盐敏感基因型 (Sf) 相比，耐盐基因型 (BM) 对盐胁迫具有更好的渗透保护能力，在叶和根中脯氨酸和可溶性糖的积累更高，抗氧化系统更强，这由更高的 SOD 活性证明、CAT 和 APX 以及更丰富的 Cu/Zn-SOD 转录物，尤其是在根中。逐步回归分析表明，盐胁迫下大麦生长最主要的性状是Cu/Zn-SOD基因表达水平，