Seed priming with H₂O₂ improves photosynthetic efficiency and biomass production in sunflower plants under salt stress

Abstract

Salinity commonly affects photosynthesis and crop production worldwide. However, some studies have shown that hydrogen peroxide seed priming can increase the tolerance of plants to salt stress. In this context, this study aimed to test the hypothesis that the H₂O₂ seed priming can improve photosynthetic efficiency in sunflower plants under salt stress. The experiment was conducted in a completely randomized design, with four replicates. Six treatments were tested: control (deionized water); salt control (100 mM NaCl); 0.1 mM H₂O₂ (36 h) + 100 mM NaCl; 1 mM H₂O₂ (24 h) + 100 mM NaCl; 10 mM H₂O₂ (12 h) + 100 mM NaCl; and 100 mM H₂O₂ (12 h) + 100 mM NaCl. Compared to the control treatment, leaf, stem and root dry mass of stressed plants showed 73, 76, and 71% reduction, respectively. However, this effect was less pronounced in plants whose seeds were primed with H₂O₂. After five weeks, H₂O₂ seed priming increased the CO₂ assimilation rate by 26%, instantaneous carboxylation efficiency by 38%, potential quantum yield and quantum yield of photochemical quenching of photosystems II by 22%, electron rate transport by 43%, and the chlorophyll b content by 71%. In addition, it reduced the non-photochemical quenching parameters by 22% compared to plants under salt control treatment.

Keywords:

• Cross-talk
• Helianthus annuus L.
• photosynthetic machinery
• salt tolerance

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

We thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB), and Universidade Federal do Recôncavo da Bahia (UFRB) for the financial support over the years.