Tanaka A, Shikazono N, Yokota Y, Watanabe H, Tano S
Research Group for Plant Genes, Japan Atomic Energy Research Institute (JAERI), Gunma, Japan.
Int J Radiat Biol. 1997 Jul;72(1):121-7. doi: 10.1080/095530097143608.
Inhibition of germination and reduction in survival of Arabidopsis thaliana were investigated to study the effects of heavy ions on a multicellular system. Dry seeds of Col and Ler ecotypes were exposed to He, C, Ar and Ne ions with linear energy transfer (LET) in the range of 17-549 keV/micron and to electrons (LET = 0.2 keV/micron). The relative biological effectiveness (RBE) for the survival of both ecotypes showed the same pattern of variation with a maximum RBE of 11-12 at 252 keV/micron. For germination, RBE increased with increasing LET in Ler but not in Col, showing different sensitivities between the plant ecotypes. Inactivation cross sections of survival increased linearly in the range of 0.2-17 keV/micron and proceeded more steeply in the range of 113-252 keV/micron. At higher LET, cross sections appeared to reach a plateau at a little less than the size of the cell nucleus. When the value for survival was plotted against LET, it decreased steeply in the range about 113-252 keV/micron, indicating that heavy ions may have similar effects on both the shoulder and slope of the survival curve.
为了研究重离子对多细胞系统的影响，对拟南芥的萌发抑制和存活率降低进行了研究。将Col和Ler生态型的干燥种子暴露于线性能量传递（LET）在17 - 549 keV/微米范围内的氦、碳、氩和氖离子以及电子（LET = 0.2 keV/微米）。两种生态型存活率的相对生物学效应（RBE）呈现相同的变化模式，在252 keV/微米时RBE最大值为11 - 12。对于萌发，Ler生态型中RBE随LET增加而增加，而Col生态型则不然，这表明植物生态型之间存在不同的敏感性。存活率的失活截面在0.2 - 17 keV/微米范围内呈线性增加，在113 - 252 keV/微米范围内增加得更为陡峭。在较高的LET下，截面似乎在略小于细胞核大小处达到平台期。当将存活率值与LET作图时，在约113 - 252 keV/微米范围内急剧下降，这表明重离子可能对存活曲线的肩部和斜率都有类似影响。
