The Effect of Seed Priming with Chitosan on the Improvement of Physiological and Biochemical Traits of Soybean (Glycine max (L.) Merrill) under Salinity Stress

To investigate the effect of seed priming with chitosan on the improvement of physiological and biochemical traits of soybean under salinity stress, a factorial experiment in the form of a completely randomized design with three replications was conducted at Mohaghegh Ardabili University, Iran in 2023. Treatments included four salinity levels (sodium chloride) with the concentrations of 0, 50, 100, and 150 mM) and four chitosan levels (0, 0.25, 0.50, and 0.75% by weight-volume, all of which were dissolved in 1% acetic acid). The results showed that salinity stress decreased the most indicators of germination and growth. However, priming with different levels of chitosan, especially 0.75%, improved these traits compared to the control. The highest lipase enzyme activity and protein content were observed in pretreatment with 0.75% chitosan and 0 mM salinity. Pretreatment with 0.75% chitosan increased catalase and ascorbate peroxidase activities and proline (P) content by 20, 37, and 53%, respectively, compared to the control. The activity of peroxidase and superoxide dismutase enzymes increased by about 43 and 47%, respectively, in pretreatment with 0.75% chitosan and 150 mM salt compared to the control. The highest the amount of soluble sugars was obtained in the treatment with 0.75% of chitosan and 100 mM salinity. The results showed that seed pretreatment with 0.75% chitosan can be considered as an effective way to improve the physiological and biochemical traits of soybean seeds and can reduce the deleterious effects of salinity stress on some traits in soybean seedlings.