Drylands and Oases Cropping Laboratory LACO, Institute of Arid Lands of Medenine (IRA), Sreet El Djorf 22.5 km, 4119, Medenine, Tunisia.
Department of Rural Engineering, Water, and Forests GREF, National Institute of Agronomic Research of Tunis (INAT), 43 Charles Nicolle, 1082, Tunis, Tunisia.
Sci Rep. 2024 Jun 28;14(1):14931. doi: 10.1038/s41598-024-65967-5.
Salinity has become a major environmental concern for agricultural lands, leading to decreased crop yields. Hence, plant biology experts aim to genetically improve barley's adaptation to salinity stress by deeply studying the effects of salt stress and the responses of barley to this stress. In this context, our study aims to explore the variation in physiological and biochemical responses of five Tunisian spring barley genotypes to salt stress during the heading phase. Two salinity treatments were induced by using 100 mM NaCl (T1) and 250 mM NaCl (T2) in the irrigation water. Significant phenotypic variations were detected among the genotypes in response to salt stress. Plants exposed to 250 mM of NaCl showed an important decline in all studied physiological parameters namely, gas exchange, ions concentration and relative water content RWC. The observed decreases in concentrations ranged from, approximately, 6.64% to 40.76% for K, 5.91% to 43.67% for Na, 14.12% to 52.38% for Ca, and 15.22% to 38.48% for Mg across the different genotypes and salt stress levels. However, under salinity conditions, proline and soluble sugars increased for all genotypes with an average increase of 1.6 times in proline concentrations and 1.4 times in soluble sugars concentration. Furthermore, MDA levels rose also for all genotypes, with the biggest rise in Lemsi genotype (114.27% of increase compared to control). Ardhaoui and Rihane showed higher photosynthetic activity compared to the other genotypes across all treatments. The stepwise regression approach identified potassium content, K/Na ratio, relative water content, stomatal conductance and SPAD measurement as predominant traits for thousand kernel weight (R2 = 84.06), suggesting their significant role in alleviating salt stress in barley. Overall, at heading stage, salt accumulation in irrigated soils with saline water significantly influences the growth of barley by influencing gas exchange parameters, mineral composition and water content, in a genotype-dependent manner. These results will serve on elucidating the genetic mechanisms underlying these variations to facilitate targeted improvements in barley's tolerance to salt stress.
盐度已成为农业用地的主要环境问题，导致作物产量下降。因此，植物生物学专家旨在通过深入研究盐胁迫对大麦的影响以及大麦对这种胁迫的反应，从遗传学上提高大麦对盐度胁迫的适应能力。在这种情况下，我们的研究旨在探讨 5 个突尼斯春大麦基因型在抽穗期对盐胁迫的生理生化响应的变化。在灌溉水中用 100 mM NaCl（T1）和 250 mM NaCl（T2）诱导两种盐度处理。发现基因型对盐胁迫的响应存在显著的表型变异。暴露在 250 mM NaCl 下的植物所有研究的生理参数均显着下降，即气体交换、离子浓度和相对水含量（RWC）。观察到的浓度下降范围从不同基因型和盐胁迫水平的 K 浓度的约 6.64%至 40.76%、Na 浓度的 5.91%至 43.67%、Ca 浓度的 14.12%至 52.38%和 Mg 浓度的 15.22%至 38.48%。然而，在盐胁迫条件下，所有基因型的脯氨酸和可溶性糖含量均增加，脯氨酸浓度平均增加 1.6 倍，可溶性糖浓度增加 1.4 倍。此外，所有基因型的 MDA 水平也升高，其中 Lemsi 基因型的增幅最大（与对照相比增加 114.27%）。在所有处理中，Ardhaoui 和 Rihane 与其他基因型相比表现出更高的光合作用活性。逐步回归方法确定钾含量、K/Na 比、相对水含量、气孔导度和 SPAD 测量是千粒重的主要性状（R2=84.06），表明它们在缓解大麦盐胁迫方面具有重要作用。总的来说，在抽穗期，用盐水灌溉土壤中的盐分积累会通过影响气体交换参数、矿物质组成和含水量，以基因型依赖的方式显著影响大麦的生长。这些结果将有助于阐明这些变化背后的遗传机制，从而促进大麦对盐胁迫的耐受性的针对性提高。
