Salicylic Acid Mitigates the Effects of Drought and Salinity on Nutrient and Dry Matter Accumulation of Linseed

Salicylic acid can mitigate the impacts of salinity and drought stresses in crops. To study the effect of salicylic acid under iso-osmotic drought and salt stresses on nutrients absorption and growth of linseed (Linum usitatissimum L.), an experiment was conducted based on a completely randomized design with three replications in Yasouj University in 2016. Treatments included salinity and drought with similar osmotic potentials (-2, -4, -7 and -9 bar) in 8 levels and control that applied in Hoagland solution. The second factor was salicylic acid (0 and 0.5 mM). Salinity and drought applied using sodium chloride and polyethylene glycol 6000, respectively. The results showed that root and shoot dry weight and Fe, Zn, Mn and Ca content decreased by increasing salinity and drought compared to control, however salicylic acid application significantly increased these traits, especially under salinity conditions. Na content of Shoot significantly raised by increasing salinity compared to control and salicylic acid decreased it. Drought, and also salicylic acid, had no significant effect on shoot and root Na. Shoot and root dry weights were more significantly affected by drought than salinity in mild stress levels, but the effect of drought and salinity were the same at high levels. Generally it found that the negative effects of drought were more destructive than salinity at lower osmotic potentials but at higher osmotic potentials impact of drought and salinity was the same indicating the ionic toxicity of salinity at high Na stress. Salicylic acid significantly mitigated the negative impacts of osmotic stress especially under salinity conditions.