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Journal of Environmental BiologypISSN: 0254-8704 ; eISSN: 2394-0379 ; CODEN: JEBIDP |
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Abstract - Issue Mar 2009, 29 (2) BackAccumulation,
tolerance and impact of aluminium, copper and zinc on
growth and nitrate reductase activity of Ceratophyllum demersum (hornwort) C.E.
Umebese* and A.F. Motajo Department
of Botany and Microbiology, University of Lagos, P.M.B. 1029 Unilag Post Office, Akoka Yaba, Lagos, Nigeria (Received:
May 01, 2006 ; Revised received: February 23, 2007 ;
Accepted: May 17, 2007) Abstract:
Ceratophyllum demersum (hornwort) was
subjected to toxic concentrations of Al (3 and 9 mg l -1),
Zn (3 and 9 mg l -1) and Cu (2.5
and 7 mg l -1) in culture solutions for 15 days. The
higher dose of Al enhanced the chlorophyll content significantly (p<0.05) in
the first 6 days of treatment while other treatments caused marked reductions.
Nitrate reductase activity (NRA) was significantly
reduced (p<0.05) by Al, Cu and Zn toxicity and ceased completely in plants
treated with Cu by the 6th day of
treatment. Dry biomass and relative growth rate were reduced significantly
(p<0.05) by metal treatment. Tolerance index of the plant was low for Cu
(21.62 and 13.43% at low and high doses, respectively) and moderate for Zn
(63.74 and 54.85%) and Al (72.83 and 68.79%). Accumulation of Al, Zn and Cu was
threefold at higher doses compared with the lower doses but the bioconcentration factors (BCF) were very low indicating
that this plant is not a hyper accumulator of these metals. Key words: Al,
Zn Cu, Tolerance index, Chlorophyll, Growth, Nitrate reductase activity. PDF
of full length paper is available with author (cumebese@yahoo.com) Copyright
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