LAUSR

BACKGROUND Aflatoxin B1 is the most dangerous among mycotoxins that naturally contaminate cereal seeds. The stress lignin formation is linked with the accumulation of reactive oxygen species causing a change in the redox status and formation of stable organic radicals, constituting the first layer of defence. The relation between AFB1 and changes in lignin organic free radicals in seeds are not known, as well as which part of the seed is more targeted. We investigated, using optical and electron paramagnetic resonance spectroscopy, AFB1 -induced changes of lignin and organic free radicals in seeds, and whether the inner and outer seed fractions differ in response to the increasing AFB1 . RESULTS Different change in the content of lignin and free radicals with increasing AFB1 concentrations was observed in the two seed fractions. There was a significant positive linear correlation (R = 0.9923, p= 0.00005) between lignin content and AFB1 concentration in the outer fraction, and no correlation between the lignin content and the AFB1 concentration in the inner fraction. We found a positive correlation between area of the green spectral emission component (C4) and the AFB1 concentration in the outer fraction. CONCLUSIONS To the best of our knowledge, the results showed for the first time that maize seed fractions respond differently to aflatoxin concerning the lignin and organic free radicals content. Lignin content and (C4) area may be reliable indicators for the screening of lignin changes against AFB1 content in the seeds, and thus for seed protection capacity. This article is protected by copyright. All rights reserved.