2.International Antalya Scientific Research and Innovative Studies Congress, Antalya, Turkey, 17 - 21 March 2022, pp.2-14
Ionizing irradiation (IR) is one of important environmental factor affecting plant growth at the molecular, morphological and physiological levels. In addition to the radiation present in the environment due to cosmic radiation or naturally occurring radionuclides, human activities further increase the levels of surrounding radiation. IR possesses sufficient energy to ionize any atom. Exogenous application of salicylic acid (SA), a hormone known for its potential ameliorative effect in other abiotic stresses, and gallic acid (GaA), an antioxidant, can protect plants against the deleterious effects of IR stress or bestow resistance on them. The
aim of this study is to determine and compare cell wall phenolic acids, the plant’s first stress defence barrier, and lignin contents. Wheat (Triticum aestivum L. 'Ceyhan-99') seedlings were exposed to increasing doses of gamma rays (100, 200, 300 and 400 Gy), followed by irradiated seeds grown for 10 days in Hoagland’s nutrient solution containing SA and GaA. Ester-bound phenolic acid compounds (EBPHAs) and lignin content were analysedat the chromatographic (HPLC-DAD) and spectrophotometric levels (UV-Vis) in roots and leaves obtained from gamma-irradiated wheat seeds. The presence of seven different phenolic acids (p-HBA, SyA, CaA, p-CoA, o-CoA, m-CoA, FeA) in esterbound form was detected in root and leaves of the wheat. The SA and GaA treatments resulted in increased EBPHAs content in the leaves and root induced by IR exposure. Notable increases in lignin content were also determined with SA and GaA treatments. Total hydroxybenzoic acid (∑HBA), hydroxycinnamic acid (∑HCA) and phenolic acids (∑PHAs) contents were significantly correlated with the lignin content. In conclusion, exogenous SA and GaA alleviated the stress effect of IR.