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Evaluation of biochemical and free radical scavengers of Digitaria exilis L. under osmotic stress
J Plant Biotechnol 2019;46:331-337
Published online December 31, 2019
© 2019 The Korean Society for Plant Biotechnology.

David Oyinade A. · Osonubi Oluwole · Oyetunji Olusola Jacob

Department of Plant Science and Biotechnology, Federal University Oye-Ekiti, Ekiti State, Nigeria
Botany Department, University of Ibadan, Ibadan, Nigeria
Correspondence to: e-mail:
Received June 30, 2019; Revised December 16, 2019; Accepted December 16, 2019.
cc This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Digitaria exilis L. is an under-utilized crop with high nutritional and medicinal values. It thrives in and is well-adapted to arid areas with low soil nutrients. Using biochemical markers, this study investigates the mechanisms by which D. exilis responds to osmotic stress. Three accessions Dinat Iburua (DIN), Jakah Iburua (JAK) and Jiw Iburua (JIW) were collected from National Cereal Research Institute, Niger State. Two accessions, NG/11/JD/061 and NG/11/JD/062 were also collected from National Centre for Genetic Resources and Biotechnology, Ibadan. Murashige and Skoog medium of approximately 1.2 L was supplemented with polyethylene glycol 6000 to create osmotic pressures of -9.29, -13.93, -20.13, -26.32, -32.51, and 0 MPa (control). Sterilized seeds were inoculated in the medium and placed in the growth room for 4 weeks. Proline accumulation was significantly high in all JAK plants under osmotic stress. Proline and ascorbate peroxidase (p<0.05) activities were directly correlated, thus reinforcing the survivability of JAK during stress. Catalase (CAT) activity was also significantly induced in JAK under osmotic stress, which synergistically improved its tolerability. As a result, >50% of OH, H2O2, and NO radicals were scavenged. However, other accessions including DIN, NG061, NG062, and JIW showed variations in their responses to different levels of osmotic stress, although not significant. Therefore, JAK possesses a wellequipped free radical quenching system that is protected by the accumulation of the osmolyte proline; therefore, accession JAK is considered osmotolerant. CAT and superoxide dismutase activities were osmostabilized against oxidative stress by proline.
Keywords : free radicals, D. exilis, antioxidant enzymes, proline accumulation, lipid peroxidation

December 2019, 46 (4)
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