الفهرس 
Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
The present study has been conducted in order to investigate the
genotoxicity of two mycotoxins, aflatoxin B1 (AFB1) and
deoxynivalenol (DON), on wheat which is one of the most important
crops. The genotoxic potential of these toxins was evaluated by looking at
their effect on seed germination and tillering. Cytogenetic effects of
different concentrations of both toxins on meiotic cell division was also
investigated. The genotoxic effect of the used toxins was extended to
examine their capacity to induce alterations in the DNA patterns of 5S
rRNA and RAPD fragments of the treated wheat plants. Furthermore,
fluorescence in situ hybridization (FISH) technique was used to study the
effect of both mycotoxins on location and physical distribution of some
DNA fragments on the chromosomes as a result of treating with the used
mycotoxins.
Five different concentrations (5, 10, 15, 20, 25μg /ml) of each toxin were
applied. The results obtained in this study could be summarized as
following:
1- The percentage of germination was reduced from 96% in the
control to 48% in plants treated with the maximum concentration
of AFB1 (25μg/ml). whereas it was reduced to 87% in plants
treated with 25μg/ml DON.
2- The highest number of tillers was found in control plants. The
number of tillers was increased gradually by increasing toxin
concentration up to 15μg/ml, and then tillers number was declined
again at the maximum concentrations. The highest value (4.9) was
scored in plants treated with 15μg/ml AFB1 even so, this value
decreased to 3.7 in plants treated with the maximum concentration used (25μg/ml) of AFB1. Regarding plants treated with DON, the
highest mean number of tillers (5.3) was found in control however;
plants treated with the maximum concentration (25μg /ml) of DON
showed the lowest mean number of tillers (3.8).
3- Concerning the cytogenatical effect of aflatoxin B1, the common
types of chromosomal irregularities which have been recorded in
the present study were stickiness, out-side, laggards, bridges,
fragments, unequal division (lag-division) and micro-nuclei.
Regarding the first meiotic division, PMCs cells of the control
plants exhibit a percentage of aberrations of 2.12% which was
gradually increased and reached to the highest value of 7.92 in
plants treated with the highest concentration (25μg/ml) of AFB1.
In the second meiotic division, control plants exhibit abnormal
cells with a percentage of 2.69% whereas the percentage of
abnormal cells detected from plants treated with the highest
concentration (25μg/ml) of AFB1 was 5.18%.