Biochemical and Metabolomic Insights into the Effects of Salinity on the Endemic Halophyte Limonium irtaense from Eastern Spain

Limonium irtaense is an endemic halophyte from eastern Spain, that naturally grows under saline conditions. However, its physiological and biochemical mechanisms of salt tolerance remain unexplored, despite their potential relevance for understanding adaptive strategies in narrowly distributed coastal species. The present study investigated the effect of increasing concentrations of NaCl (0, 0.05, 0.1, 0.2, 0.3 M) on growth, biochemical traits, ion composition, and metabolic patterns of L. irtaense plants. Flowering and biomass partitioning were maintained under stress treatments. Biochemical adjustments included osmolytes and flavonoid accumulation and ion regulation. Metabolomic profiling revealed a salinity-induced reprogramming of metabolism, with key metabolites such as proline, dopamine, and sugar alcohols showing strong positive correlations with increasing salt levels. Dose-dependent metabolic adjustments were reflected in the enrichment of pathways related to amino acid biosynthesis, carbohydrate metabolism, and antioxidant responses. These findings highlight the physiological resilience of L. irtaense to moderate salinity and identify biochemical markers that not only inform conservation strategies for this endangered endemic species, but also contribute to a broader understanding of halophyte adaptation to increasingly variable environmental conditions.伊特萨补血草（Limonium irtaense）是西班牙东部特有的盐生植物（halophyte），自然生长于盐渍环境中。尽管其耐盐的生理生化机制对于理解狭域分布海岸物种的适应策略具有潜在研究价值，但目前该机制仍未得到系统阐明。本研究探究了梯度浓度氯化钠（NaCl，0、0.05、0.1、0.2、0.3 M）对该植株生长、生化性状、离子组成及代谢模式的影响。结果显示，盐胁迫处理下，植株的开花进程与生物量分配均保持稳定。其生化调控包括渗透调节物质与类黄酮的积累以及离子稳态调节。代谢组学分析揭示了盐胁迫诱导的代谢重编程现象：脯氨酸、多巴胺及糖醇等关键代谢物与盐浓度升高呈现显著正相关。剂量依赖性的代谢调控体现在氨基酸生物合成、碳水化合物代谢与抗氧化应答相关通路的显著富集。本研究结果不仅揭示了伊特萨补血草对中度盐胁迫的生理适应性，还鉴定出一系列生化标记物，这些标记物既可为此濒危特有物种的保护策略提供科学依据，也有助于更深入理解盐生植物对日益多变的环境条件的适应机制。