Seed Hydropriming Improves Drought Tolerance in Tall Fescue Associated with Changes in Osmotic Adjustment, Ion Regulation, and Photosynthetic Stability

Drought limits sustainable forage production in arid and semi-arid regions, where poor crop establishment is common, especially under inadequate irrigation. To address this challenge, research has turned to simple, rapid solutions that improve crop performance under variable conditions. Among green technologies, seed priming has gained attention as an eco-friendly and cost-effective approach. This study evaluates the effectiveness of seed hydropriming in alleviating the effects of water-deficit stress (40% of field capacity) on tall fescue (Festuca arundinacea Schreb.) at the seedling stage. Without priming, drought stress reduced root and shoot growth, tissue hydration, and nutrient uptake. By contrast, hydropriming improved drought tolerance by improving relative water content and ion supply and sustaining photosynthetic activity. These effects were accompanied by greater accumulation of proline and soluble sugars. Hence, (i) a regulated supply with essential mineral nutrients, (ii) an osmotic adjustment using the absorbed ions (such as K+, Ca2+, and Mg2+) in the vacuole and the accumulated osmotica (such as proline and soluble sugars) in the cytoplasm, and (iii) a maintained photosynthetic machinery together with improved root development are associated with enhanced drought tolerance in F. arundinacea plants issued from hydroprimed seeds. It seems that seed priming emerges more and more as a practical, low-cost technique to enhance drought resilience and support sustainable forage production under limited water conditions.