Ornamental cabbage (Brassica oleraceae L.), a member of the Brassicaceae family, is adversely affected by excessive salt accumulation, which is one of the most significant environmental stresses impacting plant growth and development. Therefore, identifying strategies to mitigate salinity stress and enable cultivation in saline soils is essential. To investigate the effect of Spirulina (Arthrospira platensis) and brown algae (Polycladia indica) extracts on reducing the impact of salinity stress in ornamental cabbage, a factorial experiment was conducted in a randomized complete design with four replications in the greenhouse of the Faculty of Agriculture, University of Zanjan. The first factor included salinity levels of irrigation water (4 and 8 dS/m), along with a control (non-saline condition). The second factor included the application of 2% brown algae, 2% Spirulina algae, and a control (no algae). Morphophysiological traits such as leaf number, leaf area index, fresh and dry root weight, fresh shoot weight, total chlorophyll, antioxidant activity, total phenols, electrolyte leakage, proline content, peroxidase enzyme activity, and sodium and potassium concentrations were measured. The results indicated that both salinity stress and algae application had significant effects on all traits, and the interaction between salinity and algae was significant for traits such as leaf number, root fresh and dry weight, total phenols, and sodium and potassium content. According to the mean comparisons, algae treatments resulted in the highest values for leaf area index (42.52 cm²), shoot fresh weight (153.33 g/plant), and root fresh and dry weights (17.42 g and 6.44 g/plant, respectively), compared to the control. Furthermore, under salinity stress, sodium concentration in the aerial parts of the plant increased, but the application of algae moderated this effect and reduced sodium accumulation. Both Spirulina and brown algae significantly decreased sodium content in the aerial parts at higher salinity levels. Overall, salinity stress negatively affected the morphophysiological traits of ornamental cabbage. Among the two algae, Spirulina showed a better response and effectively alleviated the adverse effects of salinity stress. In other words, algae application at higher salinity levels can reduce damage caused by salt stress. |
