Analysis of mutations induced by carbon ions in Arabidopsis thaliana.

To investigate the nature of mutations induced by accelerated ions in higher plants, the effects of carbon-ion-irradiation were compared with those of electron-irradiation in Arabidopsis thaliana. Point-like mutations and rearrangements were induced at a similar frequency after carbon-ion-irradiation, whereas point-like mutations were more frequently induced after electron-irradiation. Sequence analysis revealed that carbon-ion-induced point-like mutations were mostly short deletions.

Mutation rate and novel tt mutants of Arabidopsis thaliana induced by carbon ions.

Irradiation of Arabidopsis thaliana by carbon ions was carried out to investigate the mutational effect of ion particles in higher plants. Frequencies of embryonic lethals and chlorophyll-deficient mutants were found to be significantly higher after carbon-ion irradiation than after electron irradiation (11-fold and 7.8-fold per unit dose, respectively).

LET dependence of lethality in Arabidopsis thaliana irradiated by heavy ions.

To clarify the effect of heavy ions in plants, dry seeds of Arabidopsis were irradiated with carbon, neon, and argon ions with various linear energy transfer (LET) values. The relative biological effectiveness (RBE) for lethality peaked at LET values over 350 keV/microns for neon and argon ions. This LET giving the peak RBE was higher than the LET of 100-200 keV/microns which was reported to have a maximum RBE for other types of cells, such as mammalian cells.

An ultraviolet-B-resistant mutant with enhanced DNA repair in Arabidopsis.

An ultraviolet-B (UV-B)-resistant mutant, uvi1 (UV-B insensitive 1), of Arabidopsis was isolated from 1,280 M(1) seeds that had been exposed to ion beam irradiation. The fresh weight of uvi1 under high-UV-B exposure was more than twice that of the wild type. A root-bending assay indicated that root growth was less inhibited by UV-B exposure in uvi1 than in the wild type.