Field Crops Research Institute, Agricultural Research Center, Kafrelsheikh, 33717, Egypt.
Department of Agriculture, Higher Technical Teachers' Training College, University of Buea, PO Box 249, Kumba, SWR, Cameroon.
BMC Plant Biol. 2024 Aug 30;24(1):818. doi: 10.1186/s12870-024-05533-3.
This study investigates the differential responses of two maize genotypes, SC180 and SC168, to salt stress, aiming to elucidate the mechanisms underlying salinity tolerance and identify traits associated with improved stress resilience. Salinity stress, imposed by 150 mM NaCl, adversely affected various growth parameters in both genotypes. SC180 exhibited a more pronounced reduction in shoot length (13.6%) and root length (13.6%) compared to SC168, which showed minimal reductions (3.0% and 2.3%, respectively). Additionally, dry weight losses in SC180's leaves, stems, and roots were significantly greater than those in SC168. Under salinity stress, both genotypes accumulated Na in all organs, with SC168 showing higher Na + concentrations. However, K levels decreased more significantly in SC180's leaves than in SC168's. The study also assessed physiological responses, noting that SC180 experienced a substantial reduction in relative water content (RWC) in leaves (22.7%), while SC168's RWC remained relatively stable (5.15%). Proline accumulation, a marker for osmotic adjustment, increased 2.3-fold in SC168 compared onefold in SC180. Oxidative stress indicators, such as electrolyte leakage and hydrogen peroxide levels, were elevated in both genotypes under salt stress, with SC180 showing higher increases (48.5% and 48.7%, respectively) than SC168 (35.25% and 22.0%). Moreover, antioxidant enzymes (APX, CAT, POD, SOD, GR) activities were significantly enhanced in SC168 under salinity stress, whereas SC180 showed no significant changes in these activities. Stress indices, used to quantify and compare salinity tolerance, consistently ranked SC168 as more tolerant (average rank = 1.08) compared to SC180 (average rank = 1.92). Correlation analyses further confirmed that SC168's superior tolerance was associated with better Na + regulation, maintenance of K levels, and a robust antioxidant defense system. In conclusion, SC168 demonstrated greater resilience to salinity stress, attributed to its efficient ion regulation, stable water status, enhanced osmotic adjustment, and strong antioxidant response. These findings provide valuable insights for breeding and developing salinity-tolerant maize varieties.
本研究旨在探究两个玉米基因型（SC180 和 SC168）对盐胁迫的差异响应，以阐明耐盐机制并确定与提高胁迫抗性相关的特征。在 150mM NaCl 胁迫下，两种基因型的各种生长参数均受到不利影响。与 SC168 相比，SC180 的茎长（减少 13.6%）和根长（减少 13.6%）降幅更为显著，而 SC168 的降幅分别为 3.0%和 2.3%。此外，SC180 的叶片、茎和根的干重损失明显大于 SC168。在盐胁迫下，两种基因型均在所有器官中积累 Na，其中 SC168 的 Na+浓度较高。然而，SC180 的叶片中 K 水平下降更为显著。本研究还评估了生理响应，结果表明，SC180 的叶片相对水含量（RWC）显著降低（22.7%），而 SC168 的 RWC 相对稳定（5.15%）。脯氨酸积累作为渗透调节的标志物，在 SC168 中增加了 2.3 倍，而在 SC180 中增加了 1 倍。在盐胁迫下，两种基因型的电解质渗漏和过氧化氢水平等氧化应激指标均升高，其中 SC180 的升高幅度更大（分别为 48.5%和 48.7%），而 SC168 的升高幅度较小（分别为 35.25%和 22.0%）。此外，在盐胁迫下，SC168 中的抗氧化酶（APX、CAT、POD、SOD、GR）活性显著增强，而 SC180 中的这些活性没有显著变化。用于量化和比较耐盐性的应激指数一致将 SC168 评为更具耐盐性（平均等级=1.08），而将 SC180 评为耐盐性较差（平均等级=1.92）。相关性分析进一步证实，SC168 具有更高的耐盐性，与其高效的离子调节、稳定的水分状况、增强的渗透调节和强大的抗氧化响应有关。这些发现为培育和开发耐盐性玉米品种提供了有价值的见解。
