Improving the drought tolerance in barley by osmopriming and biopriming

Determination of physiological and biochemical changes induced by drought stress can be helpful for induction of stress tolerance in plants. This 2-years study was conducted to determine the potential of different seed priming techniques in improving tolerance of barley against drought stress. Seeds of two barley genotypes (Haider-93 and Frontier-87) were primed with aerated water (hydropriming), and solutions of CaCl₂ (1.5%; osmopriming) or Enterobacter spp. strain FD17 (biopriming) for 12 h keeping seed to solution ratio of 1:5 (w/v) while non-primed (dry) seeds were taken as control. Primed and non-primed seeds were sown in soil-filled earthen pots. After uniformity of seedling establishment, soil moisture was maintained at 80 (well-watered), 60 (moderate drought) and 40% (severe drought) of water holding capacity. Drought stress decreased plant growth, yield, chlorophyll contents, water relations and grain nutrient contents, while increased osmolytes accumulation and lipid peroxidation in both genotypes. Seed priming, biopriming in particular, improved leaf area, grain yield, chlorophyll contents, accumulation of phenolics, proline, glycine betaine, total soluble proteins, relative water contents, water, osmotic and pressure potentials, cell membrane stability, and grain Zn, Mn and B contents, while decreased malondialdehyde contents in both genotypes under drought stress. Improvement in yield and related traits by seed priming under drought stress was in the order biopriming > osmopriming > hydropriming. However, seed priming induced tolerance was more prominent under moderate drought than severe drought stress. Performance of genotype Haider-93 was quite better than Frontier-87. In conclusion, seed priming induced increase in osmolytes accumulation enhanced drought tolerance in barley by improving water relations and decreasing lipid peroxidation. Thus, seed priming, mainly biopriming with Enterobacter spp. strain FD17, may be utilized to improve barley performance under drought stress.