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

Abstract

Frequencies of chromosomal aberrations were examined during 3 successive cell generations in the root meristem of 2-rowed barley, Hordeum distichum, following X-ray irradiation of 24 hr. soaked seeds with a moderate exposure of 300 R. Frequencies of such chromosomal aberations as dicentric bridges and acentric fragments at anaphase and dicentrics, rings and chromosomes with obvious deletions at metaphase 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, indicated that elimination of the cells carrying aberrant chromosomes occurred in the meristematic cell population. It was concluded that the elimination seemed 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.