Effects of radiations on meristematig cells

Abstract

Three main types of cytological change are observed in irradiated plant meristem cells. These are (1) mitotic cycle delay, (2) formation of chromosome aberrations and (3) loss of proliferative capacity due either to premature differentiation or cell death. The importance of these three changes in contributing towards the growth reduction in X-irradiated primary root meristems of Vicia faba is discussed. The data indicate that mitotic delay plays but a minor role in contributing to growth depression, and that the importance of chromosome aberrations in contributing to this effect may be rather less than has generally been assumed. Experiments on roots exposed to a lethal dose (1600 rads) of X-rays reveal that the majority of cells develop through the G 1 and S phases of interphase but rarely enter mitosis, so that death of cells in these roots occurs in late interphase. It is suggested that this type of effect leading to premature differentiation or death of cells in late interphase may be a major contributory factor to growth reduction induced by exposure to sublethal radiation doses.