Abstract
Mitotic cells from root and leaf tips of seedlings treated with sodium fluoride at the concentration levels of 1x10⁻², 1x10⁻⁴, and 1x10⁻⁶ M were examined. Cytological analyses showed the occurrence of chromosomal gaps and micronuclei. The rate of cellular multiplication was also reduced. The highest frequencies of these aberrations were induced by the 1x10⁻² M concentration. Mitotic index of the lateral root tip cells treated with the concentration 1x10⁻² M for period of 0-72 hours with 12 hour increments indicated a negative linear response to the treatment duration. On the contrary, the frequency of total chromosomal aberrations showed a quadratic response curve. The recovery treatments indicated the sodium pyrophosphate at the concentration of 2x10⁻³ M was capable of completely curing the different types of mitotic aberrations caused by sodium fluoride treatment. This suggested the validity of the hypothesis that fluoride may form an inactive fluoro-pyrophosphate complex in which the pyrophosphate groups of the nucleoside triphosphate, and probably magnesium, are involved. Such a complex may inhibit the release of the needed free energy which arises from the splitting of the high energy pyrophosphate group which is formed simultaneously with the biothynesis of the high-energy phosphodiester bond of the polymer DNA. This would be expected to cause chromosome gaps, chromosome breaks, and inhibit the mitotic rates as a result of DNA depolymerization.
Mouftah, Samir Pacha Mohamed Sabri (1968). Mitotic aberrations in V̲i̲c̲i̲a̲ f̲a̲b̲a̲ L. chromosomes induced by sodium fluoride. Doctoral dissertation, Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -175979.