الفهرس 
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Abstract
The present study represents the first that comprises the cytological effects
of the phytochemically analysed plant extracts of Cleome droserifolia and
Portulaca oleracea on Allium cepa root meristem and Viciafaba flower
buds, as observed by light microscopy. In addition, tracing those effects
on the ultramicroscopic level was carried out.
The results of the work can be summarized in the following : -
Phytochemical screening of the aerial parts of C.
droserifolia and P. oleracea plants, and the seieciion•o( a
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substance from each plant to isolate, purify and”p). :. e~r~·io be~ ’ .
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tested for its cytological effects. The experiments .it!V((aJ:OO·that ?: ·
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the two plants contain tannins, sterols, terpenes, glycosid¢s,!m.a I of
carbohydrates, alkaloids and mucilage; C. droserifolia contains
flavonoids and saponins in addition. A mucilaginous substance
was isolated in a pure form from each plant; Compound (1)
(C12Hzo010)n isolated from C. droserifolia and Compound (2)
(C~toOs)n from P. oleracea. Their structures were confirmed
by paper chromatography, infra red and mass spectrum analyses.
Light microscopic examination of A. cepa root tip cells to
investigate effects of the tested material on the mitotic activity,
percentages of phases, induction of abnormalities, the
nucleoplasmic index, and the recovering ability of the induced
effects after 24 hours immersion of the treated tissue in water.
Cleome extract was tested at concentrations of 0.25%, 0.5%, 1%
and 3%, while Portulaca extract at concentrations of 1%, 5% and
100/o; treatment durations were for 4, 8 and 24 hours. The isolated
compounds, Compound (1) and Compound (2), were applied at
aqueous solutions of 100, 300 and 500 J,J.g/ml. In all the conducted
cytological experiments control treatments using tap water, instead
of the tested solution, were carried out The observations proved
the following : -
a- Both of Cleome and Portulaca extracts and the isolated compounds
induced statistically significant, dose-dependent reductions in the
mitotic index. These reductions were recoverable in all the
extracts treatments but those of the highest concentrations and
longest durations, where complete arrest at interphase was
induced.
b- Very weak or no effect of the plant extracts and the isolated
chemicals on the percentages of the mitotic phases was observed.
c- Effects on the percentage of total abnonnalities induced by the two
extracts were highly significant, with more recovery after
treatment with Portulaca extract than Cleome extract. The most
affected stage after direct treatment with either extract seemed to
be prophase. Treatment with Compound (1) and Compound (2)
resulted in highly significant, dose-dependent increase in the
percentage of total abnormalities. Ana-telophase seemed to be the
most affected stage by treatment with either compound. Stickiness
of chromosomes was induced by all the tested materials with very
high percentages amounting to l 00% of the induced abnonnalities
m some treatments. Much lower percentages of spindle
disturbance, chromosome bridge, irregular prophase and
chromosome despiralization were induced by direct and recovery
treatment of Cleome and Portulaca extracts. In addition to
stickiness, Compound (1) and Compound (2) induced very low
percentages ofbridges and spindle disturbance, respectively.
d- Statistically significant reductions in the nucleoplasmic index were
induced by Cleome and Portulaca extracts, specially after high
concentration and long duration treatments, which could not
recover after treatment with Portulaca extract. This may reflect
the existence of a relation between mitotic index decline and
nuclear volume reduction.
Light microscopic examination of poUen mother cells and
poUen grains in V. faba flower buds to test effects of the two
plants extracts on the induction potential of meiotic irregularities
(their total percentages, distribution in the 1st and 2nd divisions,
and types), in addition to effects on pollen grain viability. Cleome
extract solutions were applied at concentrations of 1% and 3% and
those of Portulaca at 2.5% and 10%. Flower buds were covered
with cotton wool pieces moistened with the extract solution for 3
hours, then removed. The flower buds were left intact and two
groups were gathered after 24 and 48 hours of treatment. The data
showed that : -
a- The two extracts induced highly significant increases in the
percentage of total abnormalities which were negatively correlated
to the treatment concentrations.
b- The induced percentages of total abnormalities were diminished
after elapse of 24-48 hours following treatments, meanwhile
percentages of abnormalities of the 1st division were higher than
those of the 2nd one. These observations point to recovery of
P,Ollen mother cells from the induced aberrations.
c- Five types of abnormalities were induced by both plant extracts;
namely, chromosome stickiness (which was the dominant type as
in mitosis), bridges, un-oriented chromatin material and
chromosome lagging, spindle disturbance, and multinucleate cells.
It is obvious that most of the scored abnormalities in meiosis
resemble those observed in mitotic cells.
d- Aberrant spore tetrads were abnormally arranged after treatment
with C/eome extract, while after Portulaca extract treatments they
were sticky or deformed. Aberrant pollen grains were deformed
after C/eome extract treatments, whereas those induced by
Portulaca extract were either deformed, un-stained or sticky. It
was suggested that the induced abnormalities may negatively
affect pollen grains viability.
Electron microscopy of V. faba root meristem treated with
0.5%, I% or 3% C/eome extract, or 1%, 5% or 10% Portulaca
extract, to investigate ultrastructural changes induced in the
cytoplasm. The study showed the following changes in : -
a- Mitochondria : which appeared disrupted after Cleome extract
treatments and slightly deformed after those of Portulaca, thus
disturbance of the cells energetics could be expected.
b- Dictyosomes : appeared with enlarged vesicles after C/eome
extract treatments, whereas Portulaca extract treatments caused
decrease in volwne of the vesicles accompanied by increases in
nwnber, length and electron-density of dictyosomal cisternae,
specially after high concentration treatments.
c- Most treatments of Cleome or Portulaca extracts induced the
fonnation of autophagic vacuoles, which points to injury of the
treated cells.
d- The endoplasmic reticulum cisternae appeared destructed after
Cleome extract treatments, while those of Portulaca extract
induced the formation of whorls which may inclose some
cytoplasmic organelles and acting as autophagic areas.
from the obtained results it was concluded that four main effects were
induced by the tested materials, these are : [ 1] Reduction of the mitotic
activity, [2] high percentages of abnormal mitotic and meiotic figures, [3]
diminution of the nuclear volwne, and [4] disturbed metabolic energetics
expressed as malfonned mitochondria, dictyosomes and endoplasmic
reticulwn.