title: LET dependence of lethality in Arabidopsis thaliana irradiated by heavy ions.
abstract: 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. Furthermore, sterility showed a higher RBE at an LET of 354 keV/microns with neon ions than that at an LET of 113 keV/microns with carbon ions. Lethality and sterility are both considered to be caused by damage to DNA. The results indicate that the LET having a maximum of RBE for lethality is higher in Arabidopsis seeds than in other unicellular systems. The most likely explanation for this shift of LET is that the DNA in dry seeds has a different chemical environment and/or hydration state than the DNA in cells in culture.
authors.affiliation: Department of Radiation Research for Environment and Resources, Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute (JAERI), Takasaki, Gunma, 370-1292, Japan. naoya@taka.jaeri.go.jp
authors.forename: Naoya
authors.initials: N
authors.lastname: Shikazono
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tanaka
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kitayama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Shigemitsu
authors.initials: S
authors.lastname: Tano
mesh_terms: D017360:Arabidopsis / Q000254:growth & development / Q000528:radiation effects*; D001128:Argon; D002244:Carbon; D004307:Dose-Response Relationship, Radiation; D018525:Germination / Q000528:radiation effects*; D020450:Heavy Ions; D018499:Linear Energy Transfer; D009356:Neon; D011829:Radiation Dosage; D012062:Relative Biological Effectiveness; D012639:Seeds / Q000254:growth & development / Q000528:radiation effects*; D012680:Sensitivity and Specificity
chemical_list: D009356:Neon; D001128:Argon; D002244:Carbon