The seaweed Ascophyllum nodosum-based biostimulant enhances salt stress tolerance in rice (Oryza sativa L.) by remodeling physiological, biochemical, and metabolic responses

This study explores the role of a biostimulant derived from the seaweed Ascophyllum nodosum (AN) in mitigating salt stress in rice plants. The weekly (S+W) and biweekly (S+B) biostimulant treatments exhibited enhanced shoot and root biomass, maintained ionic balance, and increased pigment content (total chlorophyll increased by 26.35% and 31%, carotenoids by 11.90% and 16.67% in S+W and S+B treatments, respectively) compared to untreated salt-stressed plants (CS). Improved gas exchange parameters and PSII efficiency were observed in S+W and S+B treatments. AN-biostimulant treatments mitigated salt-induced oxidative stress by positively regulating the antioxidant defense system. Notably, a strong negative correlation was observed between antioxidants and oxidative markers. Furthermore, AN-biostimulant treatments induced key metabolites (organic acids, sugars, amino acids, flavonoids), emphasizing the integrated role of multiple pathways in enhancing salt tolerance in rice. These findings highlight the potential of AN biostimulants as eco-friendly tools for crop enhancement in challenging environments.

本研究探讨了源自海藻泡叶藻（Ascophyllum nodosum，AN）的生物刺激素在缓解水稻盐胁迫中的作用。相较于仅受盐胁迫而未施加生物刺激素的对照组（CS），每周施加一次的生物刺激素处理组（S+W）与每两周施加一次的处理组（S+B）均表现出地上部与根系生物量提升、离子稳态维持以及色素含量提升：其中S+W组与S+B组的总叶绿素含量分别提升26.35%与31%，类胡萝卜素含量分别提升11.90%与16.67%。S+W组与S+B组的气体交换参数与光系统II（PSII）效率均得到改善。AN生物刺激素处理通过正向调控抗氧化防御系统，缓解了盐诱导的氧化应激。值得注意的是，抗氧化物质与氧化标志物之间呈现显著负相关关系。此外，AN生物刺激素处理可诱导关键代谢物（有机酸、糖类、氨基酸、黄酮类物质）的积累，凸显了多条通路协同调控在提升水稻耐盐性中的整合作用。本研究结果表明，AN生物刺激素作为环境友好型作物改良手段，在逆境环境下具备广阔的应用潜力。