Cytogenetic abnormalities caused by extremely low frequency electromagnetic fields in canola

摘要

A meiotic study was performed on Brassica napus exposed to electromagnetic fields. Our investigation used plants grown from dry pretreated seeds with 10 mT for 4 h, wet pretreated seeds with 10 mT for 2 h, and a control line. A lower seed yield was produced in the plants grown from exposed grains. However, the weight of 1000 seeds were higher in the plants grown from exposed grains. The highest value of the weight of 1000 seeds occurred in the plants grown from pretreated dry seeds with 10 mT for 4 h. The size of yielding seeds of plants grown from dry pretreated seeds with 10 mT for 4 h were higher than that of the control seeds and they were of uniform size. A significant difference was observed for meiotic characters studied among genotypes. The mean value of total, terminal, and intercalary chiasmata seems to be reduced significantly in plants grown from exposed seeds, indicating that EM significantly reduces the mean value of the genetic recombination. Other meiotic characteristics including ring bivalent and quadrivalent formation were also reduced significantly in the plants grown from treated seeds. Cytological abnormalities observed are chromosome stickiness, laggards, and micronuclei formation which differed significantly among the genotypes indicating their genetic differences. Cytomixis occurred in treated plants, which led to the formation of aneuploid cells.