The effects of hydrogen peroxide and nitric oxide on ion contents and lipid peroxidation levels of pepper callus tissues under salt stress

Some chemical compounds such as calcium, hydrogen peroxide (H(2)O(2)), abscisic acid, jasmonic acid, ethylene, salicylic acid, and nitric oxide (NO) have been suggested to be signal molecules or messengers that are required for stimulating specific responses against various biotic and abiotic stresses. In this research, the effects of hydrogen peroxide and nitric oxide on ion contents and lipid peroxidation levels of pepper callus tissues under salt stress were investigated. Hypocotyl explants from 4- week-old pepper seedlings were cultivated with 1:1 mg L‑1 2,4-D: Kinetin to form callus. Afterward, 100 μM H(2)O(2), 100 μM SNP (NO donor) and their combinations with 150 mM NaCl were applied for 48 h. Changes in ion and MDA (lipid peroxidation) contents were examined in calluses. In salt treated callus, while Na+ contents of tissues were induced, Ca2+ and K+ levels were lowered. Na+ intake was less in H(2)O(2)+150 mM NaCl, SNP+150 mM NaCl, and H(2)O(2)+SNP+150 mM NaCl treatments when compared with only salt treatment while there was no significant difference in K+ contents. The lowest Na+ content was found in SNP+150 mM NaCl when these 3 groups were compared with each other. The lipid peroxidation levels of pepper calli was increased under salt stress conditions. For the groups that had H(2)O(2) and NO applied, one by one or in combination, it was seen that lipid peroxidation level decreased when compared to the groups that were treated only with salt. When H(2)O(2)+150 mM NaCl, SNP+150 mM NaCl, and H(2)O(2)+SNP+150 mM NaCl treatments were compared with each other, the lowest MDA content was found in H(2)O(2)+SNP+150 mM NaCl treatment. The derived data shows that hydrogen peroxide and nitric oxide is given together with salt have healing effects when applied even one by one or together.