Effects of salicylic acid on growth indices and some biochemical markers of wheat (Triticum aestivum L.) seedlings under salinity stress

In order to investigate the effect of salicylic acid on growth parameters (shoot and root fresh weight) and some biochemical markers including proline, soluble protein and malondialdehyde levels in wheat seedlings under salt stress, a factorial experiment based on a completely randomized design was conducted with
three replications. Factors were salinity at three levels (0, 75 and 150 mM. NaCl) and salicylic acid at three levels (0, 200 and 400 mg.l-1). Eight days after planting and in complete bifoliolate stage, salt stress treatments were applied. Concentration of 75 mM NaCl was applied by concentrations of 25 and 50mM during two times with seven days interval. NaCl 150 mM was also applied by concentrations of 25, 50, 25 and 50 mM during four times with seven days interval. Seven days after exerting the salt stress, leaves were sprayed by concentrations of 0, 200 and 400 mg.l-1 salicylic acid, with three replications, during two times with six days interval. Based on the results, the amount of protein, shoot and root fresh weight reduced with salinity increasing, but proline and malondialdehyde amounts increased. Exogenous salicylic acid application increased
protein, shoot and root fresh weight contents, but reduced proline and malondialdehyde in presence of salinity. However, exogenous salicylic acid application in normal condition stress have not any effect on proline and malondialdehyde contents.