The aim of this study was to investigate the effects of exogenous Melatonin (100, 300 and 500 µM) and L-tryptophan (125, 250, 375 ppm) applications on some growth parameters of lettuce plants grown under salt stress. The study was carried out under semi-controlled greenhouse conditions in spring (March/April) season. The exogenous applications to lettuce plants were carried out two times as foliar spraying. Salt stress was generated by adding NaCl (0 mM, 100 mM, 200 mM) to irrigation water. The complete randomized design was used with three replications in this experiment. At the end of the study, it was found that the highest doses of exogenous applications had the highest effect on the parameters of the number of leaves, salinity necrosis, fresh leaf weight, fresh root weight, and total surface area of lettuce plants under 200 mM salinity condition. When the effects of the subtract on these values were compared, the effect of melatonin was found to be more pronounced. Leaf width, leaf length, and leaf surface temperature values were not affected by the external application. These values only changed depending on salt concentration. As a result of the study, it was concluded that the application of 500 µM melatonin significantly increased salt tolerance in lettuce plants. However, in order to reach a more general conclusion, the dose ranges and genotype/variety numbers should be increased.

Main aim of this study was to determine the effects of different salt contents (75 mM, 150 mM and 225 mM NaCl), heavy metal (0.2 mg/L FeCl3, NiCl2, ZnCl2), lime (2 mg/L CaCO3), drought (50%) and pollution (0.2 mg/L dust of factories) on photosynthetic pigments, malondialdehyde (MDA), hydrogen peroxide (H2O2) levels, the ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (GPOX) and superoxide dismutase (SOD) in Siyez wheat (Triticum monococcum L.). All experiments were carried out under laboratory conditions with 16 hour-day and 8 hour-night photoperiod in an incubator at 23 ± 1°C. Results showed that mean chlorophyll-a concentration was highest in the siyez seedlings treated with the pollution, while both mean chlorophyll-b and total chlorophyll concentrations were highest with 75 mM salt application. Mean total carotenoid was, however, highest with the drought treatment and mean relative water content was highest with NiCl2 application. Mean MDA and H2O2 contents were found to be highest in the siyez seedlings treated with 225 mM salt, whereas they were lowest with NiCl2 treatment. Mean proline content was highest with the NiCl2 treatment compared to the lowest concentration in the control siyez seedlings (82 µmol/g). Mean APX, CAT and GPOX activities were noted to be highest in the siyez seedlings treated with NiCl2. In general, the siyez seedlings showed high tolerance to the pollution, NiCl2 and drought with having highest photosynthetic pigments, proline, protein content and enzymes activities. Among all treatments, 225 mM NaCl and CaCO3 negatively influenced chemical compounds of the siyez seedling. When all data are taken into consideration, it can be said that higher photosynthetic pigments, proline contents, antioxidant enzymes activities and lower MDA and H2O2 levels play an important role in the resistance of siyez seedlings against abiotic stress conditions.

In this study, resistance mechanism of two wheat genotypes against salt, heavy metal, lime and drought (50%) treatments were investigated in summer Cumhuriyet-75 and winter Selimiye-95. According to results chlorophyll a, b, total chlorophyll and carotenoid level increased in FeCl3, drought and 225 mM NaCl in Cumhuriyet-75 but they were higher at NaCl, FeCl3 and ZnCl2 treatments in Selimiye-95 comparison to control. While H2O2 content rose all stres treatments in both varieties but Malondialdehyde (MDA) decreased in Selimiye with all applications. The amount of proline is lower in Cumhuiyet-75 but higher in Selimiye-95. Total soluble protein was found higher at salt concentartion and drought in both varieties. Ascorbate peroxidase (APX), Süperoxide dismutase (SOD) activity increased in salt and FeCl3 in Selimiye-95 but SOD ativity were higher at salt treatments in Cumhuriyet-75. And also in both varieties APX and Guaiacol peroxidase (GuPX) increased at FeCl3 but Catalase (CAT) were higher in only FeCl3 in Cumhuriyet-75. As a result Selimiye-95 showed tolerance to salt and FeCl3 with high photosynthetic pigment, proline and soluble protein content with lower MDA but it is sensitive to NiCl2 and drought. Whereas Cumhuriyet-75 cultivar is resistan to drought, FeCl3 and 225 mM NaCl depended on pigment, protein content and APX, CAT, GuPX and SOD activities. When all the data are taken into consideration, it was concluded that the responses of the varieties to the treatments changed according to the type and concentration of stress, and Selimiye-95 variety was tolerant compared to Cumhuriyet-75 variety.

This study was conducted to investigate the NaCl impacts on germination and emergence performance of common vetch varieties. Seeds of Gülhan, Selçuk, Kubilay, Emir and Nitra were used as materials. Electrical conductivity (EC) values of NaCl solutions were 5, 10, 15 and 20 dS m-1. Distilled water (0 dS m-1) used as control. In this study germination and emergence test were applied to the varieties. In germination and emergence test mean germination time, mean emergence time, germination percentage, emergence percentage shoot length, root length, shoot fresh and dry weight were measured at the end of the 14th day after sowing. The results showed that germination and emergence percentage and the seedling growth of the varieties were inhibited by NaCl stress and NaCl stress led to increase in germination time and emergence time. Cultivars Gülhan and Emir were the least affected compared to other cultivars. Moreover increased NaCl levels gave rise to increase in Na+ content of cultivars and it was evaluated that the significant correlation (r=-0,525) between Na+ and K+. It was also determined that the correlation between two characters had negative relationship.