Improving salt resistance of safflower (Carthamus tinctorius L.) through growth regulators: salicylic acid and penconazole

Salinity is one of the most important environmental factor that limits plant growth and its productivity. In addition, salinity has affected a significant part of agricultural lands. Therefore, identifying the methods that reduce the effect of salinity on plants to prevent plant yield loss can be one way to cope with this problem. In this study, the effect of salicylic acid and penconazole was investigated on some physiological and molecular paramethers in safflower under salinity. Sodium chloride (0, 100, 200 mM), salicylic acid (1mM), and penconazole (15mg/l) were applied for 21 days on plants. Results revealed that protein content decreased under salinity while, proline, glycine betaine, H2O2, MDA, phenolics, and DPPH activity increased as well as SOS1 and NHX1 genes expression. Exogenous application of salicylic acid and penconazole increased protein, glycine betaine, H2O2, and phenolic contents, DPPH activity, as well as SOS1 and NHX1 genes expression under salinity. But, proline content decreased by salicylic acid and MDA content decreased by penconazole. Additionally, the results showed that the interaction of these two regulators could have antagonistic or synergist effects in plants. Overall, it seems that the exogenous application of these growth regulators can cause the adaptability of safflower to salinity. Due to the low price and availability, the use of these components can be considered in order to increase the resistance of safflower to salinity.