LET-dependent effects of heavy-ion beam irradiation in Arabidopsis thaliana

Abstract

We irradiated Arabidopsis thaliana with several kinds of heavy-ion beams to investigate the linear energy transfer (LET)-dependent effects of heavy-ion beam irradiation. First, dry seeds were irradiated with C, N, Ne, Ar, or Fe ions at doses ranging from 5 to 400 Gy to compare the flowering and mutation rates among the ion species. The sensitivity of the flowering and mutation rates to irradiation differed markedly among the ion species. Of the ion species, N (30 keV μm⁻¹) was the most effective at inducing albino plants. Second, we examined the effects of LET on mutation induction. The LET of C, N, Ne, and Ar ion beams was controlled at 30–640 keV μm⁻¹. Regardless of ion species, irradiation with the same LET value resulted in the same flowering rate and mutation rate. Thus, the LET of ion beams seems to be an important factor affecting mutagenesis. We found a 440-bp deletion in the hy (elongated hypocotyl) mutant that was isolated from M₂ progeny. These fundamental data on LET-dependence can be used to develop advanced technologies for plant mutagenesis.