Hydrogen peroxide (H2O2) improves ion homeostasis in coriander plants under salt stress

ABSTRACT Priming with hydrogen peroxide (H2O2) contributes positively to the increase of salt tolerance in plants. Thus, this study aims to evaluate the effect of H2O2 as an attenuator of the negative effects induced by salinity on coriander plants grown in a hydroponic system. The coriander seeds were pretreated with different H2O2 concentrations (0.1, 1, 10, and 100 mM). The coriander plants were grown in nutrient solutions without presence of NaCl for control treatment (T1), while the other five treatments received 50 mM NaCl: T2 (absence of H2O2 in seed pretreatment), T3, T4, T5, and T6 corresponding to seed pretreatment with H2O2 at concentrations of 0.1, 1, 10, and 100 mM, respectively, in a completely randomized design with four replicates. In general, salinity reduced the production of shoot fresh and dry mass of coriander plants. However, the pretreatment with H2O2 significantly increased the salt tolerance of plants. H2O2 acted as a metabolic signal, improving the ion homeostasis by decreasing Na+ and/or Cl- contents and increasing K+ content in leaves. The multivariate analysis revealed an opposite effect between the Na+ and K+ contents, in addition, to indicating that these results can directly affect the growth of coriander plants.

摘要：过氧化氢（hydrogen peroxide，H₂O₂）引发处理可有效提升植物的耐盐能力。为此，本研究旨在评估过氧化氢作为盐胁迫负面效应缓解剂，对水培体系中芫荽植株受盐胁迫诱导的负面效应的改善效果。本实验以浓度分别为0.1、1、10和100 mM的过氧化氢溶液对芫荽种子进行预处理。实验设置对照处理组T1：芫荽植株在不含氯化钠的营养液中培养；其余5组处理均施加50 mM氯化钠，其中T2组未进行过氧化氢种子预处理，T3、T4、T5、T6组分别以0.1、1、10、100 mM浓度的过氧化氢进行种子预处理；所有处理均采用完全随机设计，设置4次生物学重复。总体而言，盐胁迫会降低芫荽植株地上部的鲜重与干物质产量。但过氧化氢引发处理可显著提升植株的耐盐性。过氧化氢作为代谢信号分子，通过降低叶片中钠离子（Na⁺）和/或氯离子（Cl⁻）的含量、提升钾离子（K⁺）含量，从而改善离子稳态。多变量分析结果显示，钠离子与钾离子含量呈负相关关系，同时表明上述指标变化可直接影响芫荽植株的生长状况。