Hendry J H, Cowie F G, von Wangenheim K H
Radiat Environ Biophys. 1985;24(1):45-56. doi: 10.1007/BF01212652.
In several systems a paradoxical reduction of radiation damage with increasing dose, termed reversion, has been observed. In the fern Osmunda regalis the percentage of cells which does not die but stays alive, although reproductively sterile, increases with dose. The assumed mechanism of this effect is a continuation of cytoplasmic growth during radiation-induced mitotic delay which induces terminal differentiation (early differentiation) thus preventing mitosis and the expression of chromosomal injury. Suppression of cytoplasmic growth after irradiation should abrogate reversion. This was tested using anoxia. Reversion was suppressed by storage of the sporelings in nitrogen for 8 h or more after X-rays, but was not suppressed by storage in 0.27 microM oxygen nor by a 60-min exposure to air after irradiation and before storage in nitrogen. Anoxia before irradiation in air had no effect. Anoxia only during irradiation showed an OER of about 2 for the reversion peak. The partial abrogation of reversion is consistent with the assumed mechanism. Marked reversion also was observed after 14.7 MeV neutrons.
在多个系统中，已观察到随着剂量增加辐射损伤出现反常减少的现象，即所谓的回复现象。在蕨类植物王紫萁中，未死亡但存活下来的细胞（尽管生殖不育）的百分比随剂量增加而升高。这种效应的假定机制是在辐射诱导的有丝分裂延迟期间细胞质生长的持续，这会诱导终末分化（早期分化），从而阻止有丝分裂和染色体损伤的表达。辐射后抑制细胞质生长应能消除回复现象。这通过缺氧实验进行了验证。在X射线照射后将幼苗在氮气中储存8小时或更长时间可抑制回复现象，但在0.27微摩尔氧气中储存或在照射后且在储存于氮气之前暴露于空气中60分钟均不能抑制回复现象。在空气中照射前进行缺氧处理没有效果。仅在照射期间进行缺氧处理时，回复峰值的氧增强比约为2。回复现象的部分消除与假定机制相符。在14.7兆电子伏特中子照射后也观察到了明显的回复现象。
