Salt Tolerance in Omani Lentil Landraces: Impacts on Growth, Root Architecture, Ion Homeostasis, Proline Accumulation, and Antioxidant Defence System

Salt stress is a critical abiotic factor severely limiting crop productivity globally. Development of salt-tolerant genotypes can help address this challenge. This study was conducted to evaluate the impact of salt stress on morphological, physiological, biochemical, and mineral composition parameters among lentil landraces of Omani origin. Eight lentil genotypes, including six local landraces (Jumah, Yanqul-1, Yanqul-2, Rustaq, Nizwa and Ibri) and two exotic genotypes (Markaz and 14515), were subjected to 100 mM sodium chloride (NaCl) treatment in a controlled glasshouse environment. Salt stress caused significant reduction in plant growth, leaf water content and photosystem efficiency in all tested landraces and genotypes. Root architecture was particularly affected, with a significant increase in Na⁺ and a decrease in K⁺, which enhanced catalase activity and altered the antioxidant defense system in shoots. A significant increase in shoot and root proline contents was noted under salt stress in all tested lentil genotypes, with significant variations among the landraces. The landrace Rustaq had higher salt tolerance than other tested landraces, characterized by robust morphological performance under salt stress. In contrast, the landraces Jumah, Yanqul-1 and Yanqul-2 and the exotic genotypes Markaz and 14,515 showed sensitivity under similar conditions. The study demonstrated significant variations among the tested lentil landraces at morphological, physiological, and biochemical levels under salt stress. These findings highlight the potential of landrace Rustaq for use in breeding programs aimed at developing salt-resistant lentil genotypes. The salt tolerance of landrace Rustaq could be attributed to osmotic adjustment due to the accumulation of proline, Na⁺ exclusion in roots, and root architecture under salt stress.