The restoring influence of priming treatments on germination of Smooth vetch (Vicia dasycarpa) under drought stress and maintaining this advantage following aging by using post priming heat shock treatment

Seed priming often promotes germination and seedling growth under environmental stresses yet as main negative aspect, primed seeds are vulnerable to aging process. In this regard, the current study was carried out to examine the influence of priming treatments (with water and ascorbic acid) on germination of smooth vetch (Vicia dasycarpa) seeds under osmotic stress (-0.9 MPa). In addition, we examined whether or not post priming heat shock treatment may maintain this possible advantage by reducing primed seeds deterioration during artificial aging. Treatments included: hydro priming, hydro priming plus heat shock, priming with ascorbic acid, priming with ascorbic acid plus heat shock, control or non-primed seeds. Primed seeds after partial drying faced heat shock at 40 0 C for 3h. Following heat shock treatment seeds were exposed to accelerated aging for 0, 2, 4, 6 and 8 days. Priming particularly with ascorbic acid substantially increased germination under osmotic stress. Heat shock treatment significantly improved germination ability of both aged-primed seeds with water and ascorbic acid. The difference between HS treated and non-HS treated primed seeds were more considerable following longer terms (6, 8 days) of artificial aging. The results showed that the restoring effect of heat shock was accompanied with lower lipid peroxidation (assayed as malondialdehyde content), electrolyte leakage and enhanced antioxidant activities including catalase, peroxidase and ascorbate peroxidase.