Physiological and biochemical mechanisms of salt tolerance in barley under salinity stress

Salt stress poses a significant threat to global crop yield, prompting the need for understanding stress responses in crops like barley (Hordeum vulgare L.). This study investigated four barley genotypes - Giza129, Giza135, Line 1 and Line 2 - under 12 and 16 dS/m salt concentrations over a 30-day period. Results revealed a salinity-induced decrease in plant growth, particularly pronounced in Giza 129 and Giza 135. Ion analyses demonstrated distinct responses, with Giza genotypes accumulating more Na+ and less K+, leading to an increased Na+/K+ ratio, while both lines maintained K+, reducing the Na+/K+ ratio. Proline accumulation emerged as a crucial protective mechanism, evident in Line 1 and Line 2 exhibiting significantly higher proline content under salt stress compared to both Giza genotypes. Antioxidant enzyme activities, including catalase, ascorbate peroxidase and peroxidase, are markedly elevated in both lines, indicating superior salt tolerance mechanisms. This research contributes insights into barley salt tolerance, emphasizing the potential for genetic enhancement programs. Conclusively, the current study elucidated variations in salinity tolerance among new barley lines and their signaling mechanisms under salt stress. Given the global impact of salinity on crop yield, these findings hold promise for enhancing salt tolerance in barley and other crops through genetic advancements.