Irradiation effects of MeV protons on dry and hydrated Brassica rapa seeds

Publication date: Available online 21 August 2018Source: Life Sciences in Space ResearchAuthor(s): Naresh T. Deoli, Karl H. HasensteinABSTRACTAlthough space radiation is a known risk for space travel and eventual colonization of Moon or Mars, relatively few data exist on radiation effects on potential crop plants. We studied Brassica rapa to assess the tolerance of seeds and seedlings to radiation by exposing dry and hydrated B. rapa seeds to 1, 2 and 3 MeV proton ions of various fluences and examined the effect on germination and root growth. Modeling penetration depth with SRIM code indicated that the applied energy was insufficient to penetrate the seeds; therefore, all energy was deposited into the tissue. Subsequent germination varied based on the incident ion energy and fluence (dose). Dry and hydrated seeds germinate after ion fluence (1013 ions cm−2) irradiation, but the germination percentage decreased with increasing fluence for ions that could penetrate the seed coat (> 1 MeV). Despite their greater volume and mass, hydrated seeds were more sensitive to irradiation than dry seeds. Damage of the seed coat after irradiation led to faster germination and initial seedling growth. Our results suggest that the seed coat represents a valuable natural radiation protection and that low energy protons, the prevailing solar radiation, are suitable for studying radiation effects in seeds and plants.

Source: Life Sciences in Space Research - August 21, 2018 Category: Biology Source Type: research