An Evaluation of EPR Measurements of the Organic Free Radical Content of Individual Seeds in the Non-destructive Testing of Seed Viability

Hepburn, H. A., Goodman, B. A., McPhail, D. B., Matthews, S.and Powell, A. A. 1986. An evaluation of EPR measurements ofthe organic free radical content of individual seeds in thenon-destructive testing of seed viability.—J. exp. Bot.37: 1675–1684. Electron paramagnetic resonance (EPR) spectra of individualintact seeds of a range of legumes and brassicas have been obtainedin order to measure their organic free radical contents. Norelationship was found between free radical content and seedviability or early seedling growth for both legumes and brassicas.The testa had a much greater free radical concentration thaneither the embryo axes or the cotyledons for all cultivars ofseed tested. The general high free radical content of the testasuggests that there is little possibility of EPR being usedto predict the viability of individual seeds. The spectroscopicsplitting factor of g = 2·0045 reported for the intactseeds is consistent with the radicals' arising from melanictype compounds. Key words: Seed viability, free radical content