Salt tolerance induced by hydrogen peroxide priming on seed is related to improvement of ion homeostasis and antioxidative defense in sunflower plants

Abstract

Salt-induced redox and ion imbalance may lead to increased oxidative stress and impair the plant growth. However, among the many reactive oxygen species (ROS) produced under stress, hydrogen peroxide (H₂O₂) plays a central role in several signal transduction pathways triggering a series of physiological mechanisms and increase plant tolerance to salt stress. Thus, this study aimed to evaluate the changes in the balance of inorganic and organic solutes induced by seed priming with H₂O₂ in leaves and roots of sunflower plants grown under salt stress. In this study, six treatments were tested: T1 - control (absence of NaCl and absence of H₂O₂); T2 - salt control (presence of 100 mM NaCl and absence of H₂O₂); T3 − 100 mM H₂O₂ (12 h) + 100 mM NaCl; T4 − 10 mM H₂O₂ (12 h) + 100 mM NaCl; T5 − 1 mM H₂O₂ (24 h) + 100 mM NaCl; T6 − 0.1 mM H₂O₂ (36 h) + 100 mM NaCl. Our results show that, the role of H₂O₂ in increase of the salt tolerance is directly associated with reduction on Na⁺ (on average 46%) and Cl^- (on average 24%) contents in the leaves, besides a positive regulation of K⁺ and NO₃^- absorption (for three harvests). In addition, H₂O₂ priming also decreased the oxidative damage, mainly by increasing the activity of catalase enzyme (CAT) in leaves (on average 49% at 2^nd and 3^rd harvests) and roots (on average 39% at 3^rd harvest).

Keywords:

• Cross-tolerance
• Helianthus annuus L
• H₂O₂
• ion balance
• oxidative stress
• salinity
• solutes accumulation

Declaration of interest

The authors declare that there is no conflict of interest on publication of this article.

Additional information

Funding

This study was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); and Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB).