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

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.