Abstract
The accelerated heavy ions deposit most of their energy close to the end of their range. Little is known about the mutational effects of ion beams near the range end, especially in plants. To gain insight into the mutagenic effects of accelerated heavy ions in plants, the mutagenic effects of carbon ions near the range end (mean LET: 425 keV/μm) were compared with the effects of carbon ions penetrating the seeds (mean LET: 113 keV/μm). We analyzed the mutations occurred in Arabidopsis GL1 locus with the emphasis on large deletions. Arabidopsis seeds obtained by crossing wild-type Col with the gl1-1 mutant were used as a material, and the polymorphic markers that can distinguish Col and gl1-1 sequence were used to detect deletions. While the frequency of generation of glabrous mutant sectors was not different between the two types of carbon-ion irradiation, large deletions (> ~30 kb) were six times more frequently induced by carbon ions near the range end. The 352 keV/μm neon ions also showed a 6.4-fold increase in the frequency of large deletions compared with the 113 keV/μm carbon ions. These results suggest that the proportion of large deletions increases with LET in plants.
