title: Chemical modification of postirradiation damage under varying oxygen concentrations in barley seeds.
abstract: The influence of ascorbic acid, potassium permanganate and caffeine on the postirradiation seedling injury of dry barley seeds was studied, irradiated (350 Gy 60Co gamma-rays) in vacuo and post-hydrated with varying oxygen concentrations in the soaking medium. The oxygen concentration in the post-hydration medium (OCHG) was adjusted at 0%, 10%, 30%, 50%, 80% and 100%. A linear response between the seedling injury and O2 concentration in the range of 0-80% was observed. These chemicals potentiated, protected or exerted no effect, depending upon the OCHG. Thus, ascorbic acid did not exert any effect on seeds post-hydrated at OCHG of less than or equal to 30%, but afforded radio-protection at OCHG of greater than or equal to 50%. Caffeine, on the other hand, potentiated the postirradiation injury at OCHG of less than or equal to 30%, exerted no influence at OCHG of approximately 50% and afforded radioprotection at OCHG of greater than or equal to 80%. Potassium permanganate enhanced the injury at OCHG of less than or equal to 10%, exerted no effect at OCHG of approximately 30% and afforded radioprotection at OCHG of greater than or equal to 50%. The possible radiation-chemical events in the dry irradiated seeds following their post-hydration containing different OCHG and the three test chemicals which are known free radical scavengers are discussed.
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
authors.forename: P C
authors.initials: PC
authors.lastname: Kesavan
authors.forename: S P
authors.initials: SP
authors.lastname: Singh
authors.forename: N K
authors.initials: NK
authors.lastname: Sah
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology; D002110:Caffeine / Q000494:pharmacology; D003037:Cobalt Radioisotopes; D005720:Gamma Rays; D010100:Oxygen / Q000502:physiology*; D011196:Potassium Permanganate / Q000494:pharmacology; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D012639:Seeds / Q000187:drug effects / Q000528:radiation effects
chemical_list: D003037:Cobalt Radioisotopes; D011837:Radiation-Protective Agents; D011196:Potassium Permanganate; D002110:Caffeine; D001205:Ascorbic Acid; D010100:Oxygen