Objective: This study aimed to evaluate the effect of chitosan on germination indicators and the activity of antioxidant enzymes in safflower seedlings under salinity stress.
Method: The experiment was conducted using a factorial arrangement based on a completely randomized design with three replications at the University of Mohaghegh Ardabili in 2024. The experimental treatments included four salinity levels (0, 50, 100, and 150 mM NaCl) and four concentrations of chitosan (0, 0.2, 0.4, and 0.5% w/v), which were dissolved in 1% acetic acid.
Results: The results showed that salinity stress reduced the germination rate, radicle length, plumule length, seedling length, seedling fresh weight, and seedling dry weight. However, priming with different concentrations of chitosan, especially at 0.5%, improved these traits. The highest daily germination rate (0.114) was observed in the control group (distilled water priming) under 150 mM salinity. The activity of catalase and peroxidase enzymes in the control under 150 mM salinity increased by approximately 43% and 70%, respectively, compared to the 0.5% chitosan treatment under non-saline conditions. Similarly, the activity of superoxide dismutase enzyme in the 0.5% chitosan treatment under 150 mM salinity increased by about 67% compared to the control under non-saline conditions. Furthermore, the ascorbate peroxidase enzyme activity in seeds primed with 0.5% chitosan increased by 37% compared to the control (distilled water priming).
Conclusions: The results indicated that seed treatment with different concentrations of chitosan can mitigate the harmful effects of salinity on some traits of safflower seedlings and improve seedling growth. The best results were achieved when 0.5% chitosan was used under salinity conditions.

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