Investigation of salicylic acid on antioxidant enzymes activities of safflower under drought stress

Drought is one of the abiotic stresses that limit plant growth and crop production. Salicylic acid is one of growth regulators plays an important role in biotic and abiotic stresses.  In this study the effect of salicylic acid on reduction of drought stress in safflower (Carthamus tinctorius L.) were studied. The effect of the concentrations of SA (0, 0.25 mM) and water stress (levels 100%, 75%, 50% and 25% FC) on antioxidant enzymes activities and expression of the SOD gene were studied. When plants had three expanded leaves, they were sprayed with SA and after 2 days, ther were exposed to drought. After seven days, plants again were sprayed by SA. After two weeks plants were harvested for studying of physiological and molecular parameters. The results showed that drought stress 25%FC increased leaves and roots antioxidant enzyme activity, H2O2 and malondialdehyde contents, leaf Mn-SOD and leaf and root Fe-SOD. Interaction of SA and drought increased root antioxidant enzyme activity and reduced leaf antioxidant enzyme activity, root and  leaf gene expression of Fe-SOD and Mn-SOD, leaf and  root  H2O2 and  malondialdehyde contents  . As a result, salicylic acid had a significant role in the reduction of damage of drought stress in safflower plants