抄録
Gamma irradiation of seeds (100 to 1000 Gy) or inflorescences (3000 Gy) of Nicotiana tabacum L. var. xanthi Dulieu mainly induced chromatoclastic effects affecting the microspore mother cells (MMCs) during meiosis: chromosome fragmentation, chromosome stickiness promoting the formation of chiasmas even between non-homologous chromosomes, single or multiple chromosomal bridges during anaphases and telophases I and II and irregular chromosomal disjunction.
In plants raised from irradiated seeds, the frequency of abnormal meiotic figures and the rate of pollen sterility were directly related to the gamma ray dose. Gamma irradiation also induced the early dysfunction of the tapetum (tapetal degeneration was already visible at pachytene) with nuclear pycnosis or an expanded and sticky chromatin network and this no doubt contributed to pollen sterility.
