Salinity Stress Mitigation in Durum Wheat via Seed Hormonal Priming

Abstract

Seed priming is a simple, economical, and sustainable technique capable of enhancing crop resilience to abiotic stresses. A plastic greenhouse experiment was conducted on the durum wheat cultivar, Karim, sown in a 375 L volume container under semi-controlled conditions. Plots were arranged in a completely randomized design regarding treatments (control, salinity) and priming agents (indole-3-acetic acid, IAA; gibberellic acid, GA₃; and salicylic acid, SA). Some physiological, biochemical, and morphometric traits were analyzed at vegetative and reproductive stages. The obtained results demonstrated that salinity stress reduced plant growth and the SPAD index, hampered photosynthetic efficiency through disrupted PSII integrity and energy management in the electron transfer chain, and significantly affected ear filling (EF) and grain caliber (marked by mean weight of 100 grains, MW100G). However, seed hormonal priming allowed the alleviation of salinity stress effects on durum wheat growth and yield. Although IAA and GA₃ have shown significant potential in improving durum wheat tolerance to salinity, SA was found to be the most effective priming agent. It promotes the biosynthesis of chlorophyll pigments, restores the functional integrity of PSII, enhances photosynthetic efficiency, increases plant growth, and stimulates ear filling and wheat grain development. The principal component analysis demonstrated the interdependence of the vegetative and reproductive traits and presents SA as the most effective treatment that brings plants close to control conditions, despite the salinity.