Determination of the effects of progesteron on tomato under salinity and drought stress in terms of certain physiological and molecular parameters

This study was carried out to determine the effects of salinity and drought stress and the effects of progesterone application in tomato seedlings. When the literature was examined, no findings were found regarding the physiological and molecular effects of progesterone application in tomato. For this purpose, progesterone hormone was applied to the plants by adding 1 μM progesterone to the Hoagland solution beginning with the seed sowing stage and the application continued during the stress applications. After the application, anatomical effects such as stem/root tissue length, stem/root dry weight and water content, physiological effects such as relative water content, ion leakage, proline amount and MDA amount, and gene expressions of SOD, APX, CAT, GR1, P5CS, ACS2 antioxidative defense enzymes were examined. As a result of the study, it was found that salinity and drought stress significantly decreased the stem dry weight and root dry weight of the plants, whereas the use of progesterone against salinity and drought stress increased these values. In addition to these findings, it was also observed that there was a decrease in the amount of MDA with the application of salinity+progesterone, and a decrease in the amount of ion leakage and proline with the application of drought+progesterone. When the results were examined, it was determined that progesterone application had a mitigating effect on the negative consequences of drought stress. When the antioxidative enzyme gene expressions of plants under salinity and drought stresses were examined, it was observed that, progesterone application under salt stress did not cause a significant change in SOD gene expression. While there were increases in the ACS2, GR1 and P5CS gene expressions, there were decreases in the APX and CAT expressions. Also, while progesterone application under drought stress increased SOD, CAT, GR1 and P5CS gene expressions, it decreased the expressions of ACS2 and APX genes. When all these values were examined, it was concluded that the application of progesterone to plants under salinity and drought stress may have an effect in reducing stress.