Comparative adaptations of high-tolerant species and broccoli cultivars to salinity stress during germination and early development stages

Salinity imposes significant physiological and biochemical challenges on plants, disrupting key processes such as germination, involving growth, and water balance. Under saline conditions, plants activate various defense mechanisms to mitigate salinity-induced damage. While many of these mechanisms are well-characterized in mature plants, their role during germination and early seed development remains largely unexplored. In this work, we studied four pre-commercial broccoli ( Brassica oleracea L. var. italica) cultivars previously selected for their enhanced salinity tolerance and compared to the high tolerant Eruca vesicaria subsp. sativa . The results provide insights into key mechanisms involved in salinity tolerance, including osmotic potential regulation, mineral homeostasis, and antioxidant enzymatic activity and ATP concentration. The ATP availability and utilization emerged as critical determinants of the stress response profiles of the seeds during germination. Notably, the BQ1 cultivar demonstrated the most efficient ATP utilization, probably enabling a broader, more sustained, and effective response under saline conditions. These findings highlight ATP as a crucial factor in salinity tolerance during early seeds development.