Improving salt tolerance in barley by osmopriming and biopriming

Salt stress hinders the plant growth and productivity by inducing changes in physiological and biochemical processes. This 2-years study was conducted to determine the effect of seed priming treatments on tolerance against salinity in barley. Seed priming treatments of two barley genotypes (Haider-93 and Frontier-87) involved hydropriming, osmopriming (1.5% CaCl₂) and biopriming (Enterobacter spp. strain FD17); dry seeds were taken as control. Seeds were sown in pots (30 cm diameter and 45 cm depth) containing soil. After stand establishment, salinity treatment i.e., control (50 mM NaCl), moderate salinity (100 mM NaCl) and severe salinity (150 mM NaCl) were imposed. Salt stress hampered growth, yield, chlorophyll content, water relations and cell membrane stability (CMS) whereby increased osmolytes, leaf malondialdehyde (MDA) and Na accumulation in tested barley genotypes. However, seed priming techniques improved the plant height, leaf area, grain yield, harvest index, chlorophyll a and b contents, accumulation of total soluble phenolics and proteins, proline and glycine betaine, K and relative water contents, water, osmotic and pressure potentials and CMS, while decreased leaf MDA and Na contents under each level of salinity. Seed priming induced improvement in yield and related attributes under salinity was ordered as osmopriming > biopriming > hydropriming. Genotype Haider-93 performed better under each level of salinity than Frontier-87. In conclusion, seed priming induced salinity tolerance in barley was associated with enhanced osmolytes accumulation, improved water relations and decreased lipid peroxidation and Na accumulation.