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| The Relative Biological Effectiveness of 0.5 MeV Neutrons to Induce Micronuclei in the Root-tip Cells of Onion Seedlings After Irradiation as Dry Dormant Seeds |
| ZHANG Wen-yi1, JIAO Ling1, HOSHI Masaharu2 |
| Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, China |
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Abstract Objective To best understand the relative biological effectiveness (RBE) of 0.5 MeV neutrons to induce micronuclei in the root-tip cells after irradiation as dry dormant seeds.Methods To observe the difference of the frequencies of micronuclei induced in the root-tip cells of onion seedlings after irradiation as dry dormant seeds by 0.5 MeV neutrons from an accelerator and by γ rays from a 60Co source.Results The frequencies of micronuclei induced by unit dose of 0.5 MeV mono-energetic neutrons from an accelerator and γ rays from a 60Co source are 4.36 ±0.17 and 0.031 ±0.002 (%Gy-1), respectively. Thus, the RBE value for 0.5MeV mono-energetic neutrons to induce micronuclei in the root-tip cells of onion seedlings irradiated as dry dormant seeds is about 141 ±11.Conclusion The RBE value of 0.5 MeV mono-energetic neutrons to induce micronuclei in the root-tip cells of Allium cepa onion seedlings irradiated as dry dormant seeds is as high as 141 ±11. Our findings suggested that the repair efficiency of DNA damage induced by mono-energetic neutrons may be lower than that by γrays.
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Received: 03 January 2005
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