Comparative study of drought stress and salicylic acid effects on different accessions of saffron (Crocus Sativus L. )

Drought causes osmotic imbalance and inhibits plant growth and productivity. Salicylic acid (SA) is an endogenous growth regulator with phenolic nature, which participates in the regulation of physiological processes in plants. SA is an important plant growth regulator because of its promoting role in plant growth and development under environmental stresses. In this research, we used two concentrations of salicylic acid (0.5 mM and 1 mM) for three accessions of saffron under drought stress in order to study drought resistance improvement. The results showed that fresh weight (FW) reduced in three accessions of saffron under drought stress. Foliar spray of salicylic acid increased FW in three accessions under severe stresses (PEG 10% and 20%). Under drought stress, content of MDA and H2O2 and antioxidant enzymes (CAT, PPO, SOD and POX) activities increased while SA reduced these parameters. Due to foliar spray of SA and decreased parameters of stress (MDA and H2O2), we can conclude that using SA decrease the effects of stress and improve the plants growth. According to our results, among the examined accessions of saffron, Aryanshahr accession had the lowest level of damage in FW and also, antioxidant enzymes in this accession have increased gradually and moderately. So, we can say that, this accession compared to the others, has a more effective mechanism against drought stress but salicylic acid has the same effect in all the three accessions.