Liquid-holding-mediated enhancement of the frequency of chromosomal aberrations induced by ethyleneimine in barley embryos cultivated in vitro

Barley embryos, deprived of endosperm, were treated with ethyleneimine (EI) and subjected to liquid holding in various media for 4–24 h. Liquid holding in media lacking a 1% sucrose provision led to manifold increase of the frequency of aberrant metaphases in root-tip meristems of EI-treated embryos, cultivated in vitro in a maximal medium after the cessation of the liquid-holding period. The enhancement of the chromosomal damage was dependent on the duration and temperature of the liquid holding. Autoradiographic studies showed that no semi-conservative DNA replication took place under liquid-holding conditions leading to an enhancement of the frequency of aberrant metaphases in EI-treated embryos.