Effect of strıgolactone on enzyme system of ascorbate-glutatione cycle in salt stress tolerant and sensitive wheat varıetıes

As a result of normal metabolic activities of plants under salt stress damages by increasing the level of reactive oxygen species and it's especially the yield of cultivated plants and the environmental factors that limit the equality of the product. Strigolactones (SL) are known to affect plant growth positively by external applications due to the potential of adapting plants to the tolerance system under stress conditions as well as signal compounds produced by plants. In this thesis, the effect of GR24 application on the seeds of salt-tolerant (Tosunbey) and sensitive (Sultan-95) wheat varieties on the effects of ascorbate-glutathione cycle enzymes (SOD, APX, GR) and the expression levels of the genes (FeSOD, MnSOD, CuZnSOD, t-APX, cAPXI, cAPXII, cGR ve chlGR) in different salt stress conditions (0, 200 and 300 mM NaCl) were investigated. In the study, the shoot length, shoot fresh weight and shoot dry weight decreased on the 7th and 14th days of the Sultan-95 varieties in the morphological parameters made in the pre-treated GR24; root length, root fresh weight and root dry weight increase was observed. In Tosunbey variety, the shoot length and shoot fresh weight decrease on day 7; root length, root fresh weight, shoot dry weight and root dry weight were observed to increase. On the 14th day of Tosunbey variety, shoot length, root length and shoot weight decrease; root fresh weight, shoot dry weight and root dry weight was determined to increase. In the biochemical parameters, the total protein amount and SOD activity decreased on the 7th day of the Sultan-95 variety; APX and GR activities were increased. On day 14, reduction in SOD and APX activities; it was observed that total protein content and GR activity increased. In Tosunbey variety, the total amount of protein decreased on the 7th day; SOD, APX and GR activities were observed to increase. On day 14, total protein content and SOD activity decreased; APX and GR activities increased. When the gene expressions were examined, it was observed that the response of MnSOD, FeSOD, CuZnSOD, cAPXI, cAPXII, tAPX, cGR and chlGR gene expressions decreased in Sultan-95 variety. In Tosunbey variety, there was a decrease in the expression of FeSOD, cAPXI, tAPX and cGR genes, and the increase in cAPXII, chlGR, MnSOD and CuZnSOD gene expression. According to the results, it can be said that GR24 pre-treatment has an encouraging role in tolerance against salt in wheat by stimulating the ascorbate-glutathione cycle enzyme system.