Study on the cytogenetic effect of benzene on the meristematic cells of Allium cepa var. aggregatum
1998
Laruza, E.C.
This study was conducted to determine if benzene has cytogenetic effects on the merismatic cell of Allium cepa var. aggregatum based on two parameters: macroscopic and microscopic. There is a significant difference on the effect of concentration on the number of dividing cells, normal metaphase, normal anaphase, early anaphase, sticky chromosomes, and formation of bridges and fragments. For the length of exposure, it has a significant effect on the number of dividing cells, normal metaphase and normal anaphase. There is a significant difference in the macroscopic parameters of the experimental and control group, although the concentration level of benzene plays a much significant role in the changes of root length, forms and color. The crhomosomes exposed at different concentrations and length of exposure show an increase in the incidence of early anaphase, sticky chromosomes and formation of bridges and fragments. For this reason, there is a change in the number of chromosomes for each daughter cell. The fragment and bridges formation causes one cell to have a greater number of chromosomes while the other one will have a lesser number of chromosomes. Sticky chromosomes sometimes prevent total separation of the sets of chromosomes leaving the cell with a double number of chromosomes resulting to an abnormal telophase. It has been found that benzene exhibits cell division at high concentration and longer length of exposure which account for the few roots and few dividing cells to be available for macroscopical and microscopical study
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