INFLUENCE OF DIFFERENT SEED PRIMING METHODS FOR IMPROVING SALT STRESS TOLERANCE IN LETTUCE PLANTS

Seeds of lettuce, variety Romaine were subjected to different priming treatments such as water, potassium nitrate (KNO₃) and gibberellic acid (GA₃). Seedlings obtained from primed (Pr) and nonprimed (NP) seeds were grown in a hydroponic culture system supplemented with 0, 100 or 200 mM sodium chloride (NaCl). The different physiological and biochemical responses were studied 15 days after treatment. Under NaCl, the dry weight was higher in plants derived from hydro-primed (HP) seeds when compared to NP, osmoprimed (KNO₃P), and hormonal primed (GA₃P) ones. Under control and 100 mM NaCl treatment, malondialdehyde (MDA) content and EL did not show any correlation with activities of gaiacol peroxidase (GPX) and catalase (CAT), but did with the increase in reduced ascorbate (AsA) and total ascorbate contents. The results indicated that plants derived from HP seeds exhibited higher adaptive potential under salinity stress. Our findings suggest that a hydropriming technique can be used as a simple commercial approach to alleviate the effects of NaCl induced stress in lettuce plants.