Yokota Yuichiro, Funayama Tomoo, Kobayashi Yasuhiko, Sakashita Tetsuya, Wada Seiichi, Hase Yoshihiro, Shikazono Naoya, Tanaka Atsushi, Inoue Masayoshi
Laboratory of Plant Breeding Science, Graduate School of Agriculture, Kyoto Prefectural University, Hangi-cho 1-5, Shimogamo, Sakyo-ku, Kyoto 606-8522 Japan.
Biol Sci Space. 2003 Dec;17(4):298-301. doi: 10.2187/bss.17.298.
An ion microbeam system for irradiating single plant cells was developed to analyze exact biological effects of ion beams. Tobacco BY-2 protoplasts were used as a model of single plant cells. Protoplasts were cultured in thin agarose medium on a specially designed irradiation-vessel, which has a CR-39 nuclear track detector (a 100-micrometer thick sheet). The colony formation rate of unirradiated protoplasts was 22.7 +/- 6.7% (mean +/- SE of 3 different experiments) after a month of culture. Protoplasts were irradiated with programmed numbers of 18.3 MeV/u carbon ions that had been collimated by a 20-micrometer phi micro-aperture. After the irradiation, the positions within the protoplasts that were hit with ions were accurately determined by etching the CR-39 sheet in 13.4M KOH solution at 27 degrees centigrade for 9 h. The hit rate of the carbon ion microbeam, i.e., the percent of the ion particles that hit the protoplast that they were aimed at, was 56.9 +/- 2.4% (mean +/- SE of 7 different replications).
