Using the Halopriming in Sunflower Seeds for Alleviation and Tolerance to Salt Stress

The growth and development of sunflower plants ( Helianthus annuus L.) can be limited by salinity stress. The damage and changes caused by this stress can occur from germination to final production, depending on the tolerance of the species and salt concentrations. Therefore, techniques have been developed to promote greater seed vigor and seedling development in these conditions. In this study, we aimed to understand the responses and changes in sunflower seedlings promoted by the application of halopriming in seeds. For this, sunflower seeds were subjected to priming with 50µM NaCl and control (without priming) and, sown in soil containing NaCl at concentrations of 0mM, 60mM, 120mM and 240mM. When presenting four fully expanded leaves, seedlings were collected and evaluated content of pigments of the photosynthetic apparatus, proteins, the marker of oxidative stress (MDA), osmoregulators such as proline and sugars and the enzymes of the antioxidant system ascorbate peroxidase (APX) and superoxide dismutase (SOD). Furthermore, growth parameters in leaves and roots were evaluated. Seedlings from primed seeds presented physiological and growth strategies to tolerate salinity. There was an increase in the length and dry matter of the roots and with the increase in saline concentrations there was consequently an increase in the levels of photosynthetic and accessory pigments. In addition, there was an increase in macromolecules and osmoregulatory molecules. In conclusion, halopriming of seeds promoted greater tolerance of seedlings grown under different salt concentrations.