Seed Priming With Seaweed Extract Modulates the Germination and Seedling Growth of Passiflora edulis Sims Under Salinity Stress

Saline stress impairs the germination and initial establishment in passion fruit seeds, necessitating to minimize its effects. Therefore, this study aimed to evaluate the potential of a commercial seaweed‐based product for seed priming in Passiflora edulis as an alternative to reduce the effects of salinity during germination. The experiment was conducted in a completely randomized design in a 3 × 3 factorial scheme, with three salinity levels (0, 4, and 8 dS m −1 ) and three concentrations of seaweed extract (0, 4, and 8 mL L −1 ). Germination, seed vigor, and biochemical parameters related to osmotic adjustment were evaluated. Salinity and seaweed extract affected germination and vigor variables ( p < 0.05), whereas a significant interaction between salinity and seaweed extract was observed for biochemical parameters ( p < 0.05). Salinity reduced germination, seed vigor, and germination speed, while it increased mean germination time. Seed priming with 4 mL L −1 of Natubio Algas improved seed physiological performance, increasing the germination speed index (GSI) and the coefficient of velocity of germination, while reducing mean germination time, particularly under moderate salinity. Biochemical responses were influenced by the interaction between salinity and seaweed extract, with increases in reducing sugar and amino acid contents, indicating osmotic adjustment in seedlings. Principal component analysis showed that the first two principal components explained 78.5% of the total variation, with salinity being the main factor associated with changes in seed germination and vigor. Overall, seed priming with 4 mL L −1 of seaweed extract partially mitigated the effects of salt stress during P. edulis germination.