ELIMINATION OF X-RAY INDUCED ABERRANT CHROMOSOMES IN THE ROOT MERISTEMS OF TWO-ROWED BARLEY

抄録

Frequencies of chromosomal aberrations were examined during three successive cell generations in the root meristem of two-rowed barley following X-ray irradiation of 24-hr soaked seeds with a moderate exposure of 300R. Dicentric bridges and acentric fragments observed at anaphase and dicentrics, rings and chromosomes with obvious deletions detected at metaphase were scored. Frequencies of these chromosomal aberrations decreased rapidly with the progress of cell generation. Their rapid reduction in number, especially of the dicentric bridges which decreased much more rapidly than expected, indicates that elimination of the cells carrying aberrant chromosomes occurs in the meristematic cell population. The elimination seems to be attributable to the loss of reproductive integrity of the cells carrying such aberrations, probably as a result of the loss of chromosome segments.