HIGHLIGHTS:
Seed priming with H2O2 increases salt tolerance in coriander plants subjected to 50 mM NaCl.
H2O2 priming improves ionic balance, contributing to ion homeostasis.
Na+ and Cl- contents have an opposite relationship with the shoot fresh mass and shoot dry mass.
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.
Key words:
Coriandrum sativum L.; reactive oxygen species; salt tolerance; hydroponic system
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Means ± standard deviation. Bars with the same letter do not differ statistically from each other, by the Scott-Knott’s test (p ≤ 0.05). Treatments: T1 - control (absence of H2O2 and absence of NaCl); T2 - salt stress without H2O2 (absence of H2O2 and presence of 50 mM of NaCl); T3 - 0.1 mM H2O2 + 50 mM NaCl; T4 - 1 mM H2O2 + 50 mM NaCl; T5 - 10 mM H2O2 + 50 mM NaCl; T6 - 100 mM H2O2 + 50 mM NaCl
Means ± standard deviation. Bars with the same letters do not differ statistically from each other, by the Scott-Knott’s test (p ≤ 0.05). Treatments: T1 - control (absence of H2O2 and absence of NaCl); T2 - salt stress without H2O2 (absence of H2O2 and presence of 50 mM of NaCl); T3 - 0.1 mM H2O2 + 50 mM NaCl; T4 - 1 mM H2O2 + 50 mM NaCl; T5 - 10 mM H2O2 + 50 mM NaCl; T6 - 100 mM H2O2 + 50 mM NaCl
Treatments: T1 - Control (absence of H2O2 and absence of NaCl); T2 - Salt stress without H2O2 (absence of H2O2 and presence of 50 mM of NaCl); T3 - 0.1 mM H2O2 + 50 mM NaCl; T4 - 1 mM H2O2 + 50 mM NaCl; T5 - 10 mM H2O2 + 50 mM NaCl; T6 - 100 mM H2O2 + 50 mM NaCl