Enhancing the Tolerance of safflower Seedlings to Osmotic Stress through Seed Priming using Glutathione, Epibrassinolide, Chitosan and Folic Acid

The aim of the research was to compare priming methods on the physiology of colorful seedlings under osmotic stress conditions. Seeds were treated with priming including distilled water, folic acid, glutathione, epibrassinolide and chitosan and then subjected to osmotic stresses including no osmotic stress, mild osmotic stress (4 bar) and severe osmotic stress (8 bar) for germination and seedling growth. Severe osmotic stress increased soluble leaf proteins, this increase was observed in all priming treatments except distilled water and the highest increase of 35% was related to folic acid, chitosan and epibrassinolide treatments. Mild osmotic stress led to an increase in leaf proline in glutathione, epibrassinolide and chitosan treatments. In severe stress, proline increase was also observed in all treatments except epibrassinolide and chitosan treatment had the best proline level under all stress conditions. Catalase also increased in all priming treatments except distilled water under stress conditions, and in severe stress folic acid treatment showed the highest increase in catalase. SOD levels increased in different treatments under non-stress and mild stress conditions. Soluble sugars were also affected under different osmotic stress conditions by all treatments. MDA decreased under stress conditions with glutathione and chitosan treatments. Plant length was also affected by the treatments and in severe stress, chitosan treatment showed the highest length of 25% increase compared to the control. Therefore, it can be concluded that chitosan treatment overall showed better performance in improving plant tolerance to osmotic stress.