University of Guilan Iranian Journal of Seed Sciences and Research 2476-3780 11 3 2024 09 22 The effect of ethylene on germination and heterotrophic growth of safflower (Carthamus tinctorius L.) seedlings under salinity stress The effect of ethylene on germination and heterotrophic growth of safflower (Carthamus tinctorius L.) seedlings under salinity stress 37 49 8791 10.22124/jms.2024.8791 FA Negin Amanzadeh Ghoojeh Bagloo M.Sc. Student of Seed Science and Technology, University of Mohaghegh Ardabili, Ardabili, Iran Mohammad Sedghi Professor, Department of Agronomy and Plant Breeding, University of Mohaghegh Ardabili, Ardabili, Iran Raouf Seyed Sharifi Professor, Department of Agronomy and Plant Breeding, University of Mohaghegh Ardabili, Ardabili, Iran Haniyeh Saadat Ph.D. Ecology of Crop Plants, University of Mohaghegh Ardabili, Ardabili, Iran Journal Article 2024 11 24 To investigate the effect of different ethylene levels on germination traits and antioxidant enzyme activity of safflower under salt stress, a factorial experiment was conducted in a completely randomized design with three replications at the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili in 2023-2024. The treatments included four different salt levels (0, 150, 300, 450 mM from sodium chloride) and five different ethylene concentrations (0, 0.5, 1, 1.5, 2 per thousand, ppt). The results showed that salt stress reduced the germination percentage, germination rate, and dry weight of seedlings. However, treatments with different levels of ethylene, particularly at a concentration of 2 ppt, moderated the effects of salt stress on these traits. Salt stress increased the average germination duration, with the highest average duration (2.19 days) observed for treatments with distilled water and 450 mM salt. The treatment with ethylene at 2 ppt, under non-salt stress, increased seedling length, with the maximum seedling length (4.07 cm) recorded in this treatment. The highest activity of catalase and superoxide dismutase enzymes, sodium content, sodium-to-potassium ratio, and malondialdehyde levels were observed in treatments with distilled water and 450 mM salt. The highest activity of the peroxidase enzyme (1.84 units mg^-1 of protein) was found in the ethylene treatment at a concentration of 1 ppt, while the highest amount of potassium (33.45 mg kg^-1 dry weight) was observed at an ethylene concentration of 1.5 ppt. The ethylene treatment enhanced germination indices, growth indices, and biochemical traits of safflower seeds under salt stress, leading to increased seedling growth. To investigate the effect of different ethylene levels on germination traits and antioxidant enzyme activity of safflower under salt stress, a factorial experiment was conducted in a completely randomized design with three replications at the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili in 2023-2024. The treatments included four different salt levels (0, 150, 300, 450 mM from sodium chloride) and five different ethylene concentrations (0, 0.5, 1, 1.5, 2 per thousand, ppt). The results showed that salt stress reduced the germination percentage, germination rate, and dry weight of seedlings. However, treatments with different levels of ethylene, particularly at a concentration of 2 ppt, moderated the effects of salt stress on these traits. Salt stress increased the average germination duration, with the highest average duration (2.19 days) observed for treatments with distilled water and 450 mM salt. The treatment with ethylene at 2 ppt, under non-salt stress, increased seedling length, with the maximum seedling length (4.07 cm) recorded in this treatment. The highest activity of catalase and superoxide dismutase enzymes, sodium content, sodium-to-potassium ratio, and malondialdehyde levels were observed in treatments with distilled water and 450 mM salt. The highest activity of the peroxidase enzyme (1.84 units mg^-1 of protein) was found in the ethylene treatment at a concentration of 1 ppt, while the highest amount of potassium (33.45 mg kg^-1 dry weight) was observed at an ethylene concentration of 1.5 ppt. The ethylene treatment enhanced germination indices, growth indices, and biochemical traits of safflower seeds under salt stress, leading to increased seedling growth. https://jms.guilan.ac.ir/article_8791_2f533731fd6840d0e1888dec8b95ed40.pdf