Use of electron spin resonance technique for the detection of irradiated rice seeds (Oryza sativa L.)

In the present work, a detailed electron spin resonance (ESR) investigation of characteristic features, time stability and temperature dependence of the free radicals produced in a species of rice seeds cultivated in Turkey and irradiated at doses of up to 5 kGy by a gamma-source, is reported. Unirradiated rice seeds did not exhibit any ESR signal. Irradiation produces three different radicals tentatively identified as hydroxyalkyl (I), aldehydalkyl (II) and an unknown species (III). Room temperature dose-response curves and variations of different spectral parameters with temperature were investigated in the range of 130-390 K. The decay characteristics and the spectral parameters of the proposed radical species were also determined by simulating experimental spectra recorded following the irradiation.