The meiotic and postmeiotic consequences of spontaneous chromosome breakage in Najas marina

Abstract

Spontaneous chromosome breaks were analysed in different populations of the plant species Najas marina. The mean value of aberrant cells was 0.7% in the mitotic divisions, 5.1% in the first, and 2.6% in the second meiotic division. In the first pollen mitosis, there were bridges and fragments in 2.1% of the anaphases, and 7.3% of the pollen grains remained unstained after cotton blue treatment. The origins of the spontaneous breaks are believed to be due to viruses, clastogenic products of the normal metabolism, and errors in the repair mechanisms. The vast excess of aberrations in the first meiotic division may be caused by errors in the chiasms formation and possibly also by the persistent chromosomal interconnections.