Growth and physiological responses of Grammosciadium platycarpum seed treated with seaweed bio-stimulant under salinity stress

Improving seed germination indices is one of the factors for achieving high yields in agriculture, which is affected by environmental stresses, especially salinity. Seed priming is one of the methods for improving seed germination parameters to cope with salinity stress. Seaweeds can maintain plant growth under stressful conditions due to their bioactive compounds, including hormones, vitamins, nutrients, and secondary metabolites. The aim of the present study was to investigate the effect of seed pretreatment with seaweed extract (0, 10, 20, and 30 g L^{- 1}) on germination, growth, and biochemical indices of Grammosciadium platycarpum seedlings under salinity stress (0, 2, and 4 dS m^{- 1}). The results showed that seaweed extract priming enhanced key germination traits, under non-salinity conditions. For seedling growth traits, although conditions were better in the absence of salt stress, seed pretreatment significantly reduced the effects of salt stress compared to the control condition. The highest levels of chlorophyll a and b were observed at 30 g L^{- 1} in seeds treated with seaweed extract. The highest levels of MDA and antioxidant enzymes occurred under 4 dS m^{- 1} salinity. Overall, seaweed extract, with its bioactive compounds as an organic, cheap, and accessible input, appears to be an effective strategy to mitigate plant in low-fertility and saline lands.