Abstract
Aim:
This study was conducted to assess the mitigation effect of A. vera
leaf ethanolic and water extracts on plant growth, MDA and protein content,
and mitotic index of barley seedlings irrigated with sewage water.
Methodology: The experiment was conducted in a green house in
Al-Ahsa, Saudi Arabia, in plastic bags containing air-dried loam soil and
compost (1:1). Wastewater samples were collected from Al-Ahsa Sewage
Treatment Plant/Al-Ahsa/Saudi Arabia. Seeds of barley were exposed to the
following treatments for three weeks: 100% treated wastewater, treated wastewater
mixed with: 0.05 g ml-1 A. vera alcoholic extract (Alc Ext)
or 0.05 g ml-1 A. vera water extract (Wat Ext), 0.15 g ml-1
Alc Ext or 0.15 g ml-1 Wat Ext. Similar test doses were prepared
for untreated wastewater. A separate set of seeds was prepared using
distilled water as a control. Germination rate, fresh and dry weight, protein
content, MDA content and mitotic index were determined.
Results:
Untreated wastewater caused significant reduction in fresh weight while both
treated and untreated wastewater showed insignificant decrease in dry weight
of barley. No significant change in MDA contents were observed in all
treatments, except for addition of 0.15 A. vera water extract to
untreated wastewater. Protein content showed an increase in both treated
wastewater (insignificant) and untreated wastewater (significant). Addition
of A. vera extracts increased accumulation of protein in both shoot
and root. A. vera alcoholic extract promoted significant increase in
both root and shoot protein of treated wastewater, but only shoot protein of
untreated wastewater. A significant reduction in mitotic index was induced by
wastewater, while addition of A. vera extracts stimulated significant
increase in mitotic index.
Interpretation: A. vera possess reactive oxygen
species scavenging ability and enzyme conservation activity in addition to
stimulatory effects on cell proliferation and cell-cycle process that add a
modulation credit on protein content and mitotic index of barley.
Key words: Aloe vera, Cytotoxicity, Mitotic index,
Wastewater
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