Revue internationale d'écologie méditerranéenne International ...

KAMAL H. SHALTOUT, TAREK M. GALAL, THANAA M. EL-KOMI
Table 3 – Variation in the mean organic contents in the above-ground living (L) and dead (D) parts of the studied species in relation
to different seasons. NFE: total carbohydrates, TP: total protein, EE: ether extract, CF: crude fiber, DM: dry matter.
*: P 0.05).
84
NFE TP EE CF Ash
Variable % DM
Echinochloa stagnina
Winter L 53.1 ± 2.7 6.8 ± 1.3 1.6 ± 0.3 24.9 ± 1.7 13.6 ± 0.7
D 56.1 ± 0.4 4.7 ± 0.1 1.6 ± 0.2 25.7 ± 0.8 11.9 ± 1.1
Spring L 54.0 ± 3.8 4.4 ± 1.6 1.0 ± 0.4 27.0 ± 4.0 13.6 ± 1.5
D 54.0 ± 3.2 2.6 ± 1.5 1.4 ± 0.3 25.5 ± 2.6 16.5 ± 1.2
Summer L 53.4 ± 1.7 5.3 ± 2.0 1.2 ± 0.6 27.5 ± 2.2 12.6 ± 0.7
D 52.2 ± 4.5 4.4 ± 1.7 1.5 ± 0.4 27.6 ± 3.6 14.3 ± 1.2
Autumn L 57.0 ± 1.4 5.2 ± 1.4 1.2 ± 0.2 25.0 ± 1.7 11.6 ± 0.4
D 52.5 ± 6.0 3.5 ± 1.7 1.8 ± 0.6 29.4 ± 5.5 12.8 ± 3.7
Annual mean L 54.4 ± 1.8 5.4 ± 1.0 1.3 ± 0.3 26.1 ± 1.3 12.9 ± 0.9
D 53.7 ± 1.8 3.8 ± 0.9 1.6 ± 0.2 27.1 ± 1.8 13.9 ± 2.0
F-value L ns ns ns ns 4.48*
Eichhornia crassipes
D ns ns ns 4.45* ns
Winter L 61.9 ± 3.4 4.2 ± 0.5 0.8 ± 0.2 14.0 ± 1.2 19.1 ± 1.9
D 58.5 ± 4.1 1.0 ± 0.4 1.2 ± 0.2 20.7 ± 1.3 18.7 ± 3.3
Spring L 52.0 ± 3.5 8.1 ± 0.9 1.1 ± 0.3 17.1 ± 1.6 21.7 ± 2.4
D 49.2 ± 2.8 1.8 ± 0.8 1.6 ± 0.1 24.5 ± 1.4 22.8 ± 1.6
Summer L 50.0 ± 6.5 12.3 ± 2.1 1.2 ± 0.5 15.1 ± 2.8 21.4 ± 4.4
D 57.2 ± 4.3 2.1 ± 0.9 1.4 ± 0.1 19.8 ± 3.5 19.5 ± 1.7
Autumn L 50.4 ± 5.8 16.6 ± 5.2 1.8 ± 0.3 11.9 ± 0.9 19.3 ± 1.3
D 51.3 ± 2.4 2.5 ± 0.6 1.3 ± 0.2 22.9 ± 2.8 22.0 ± 3.8
Annual mean L 53.6 ± 5.6 10.3 ± 5.3 1.2 ± 0.4 14.5 ± 2.2 20.4 ± 1.4
D 54.1 ± 4.5 1.6 ± 0.6 1.4 ± 0.2 21.9 ± 2.1 20.8 ± 1.9
F-value L 8.27*** 19.70*** 17.58*** 13.39*** ns
D - - - - -
Ceratophyllum demersum
Winter 31.8 ± 2.3 13.0 ± 0.5 1.6 ± 0.4 23.1 ± 2.1 30.5 ± 1.9
Spring 35.5 ± 2.5 12.8 ± 1.3 1.9 ± 0.2 21.7 ± 1.5 28.2 ± 2.7
Summer 34.6 ± 7.3 15.9 ± 3.4 1.5 ± 0.5 22.9 ± 5.6 24.8 ± 1.7
Autumn 31.6 ± 11.6 15.0 ± 3.0 2.1 ± 0.5 20.4 ± 4.1 30.9 ± 7.4
Annual mean 33.4 ± 1.9 14.2 ± 1.5 1.8 ± 0.3 22.0 ± 1.2 28.6 ± 2.8
F-value ns ns ns ns 8.94***
tiotes. In general, this comparison indicated
that the studied plants had the ability to
absorb heavy metals from the water courses
and act as biofilter for these elements. It was
obvious that Mg and Mn concentrations in C.
demersum exceed the maximum values, while
Ca and P approach the minimum (for animal
nutrition), but Na exceeds the maximum in all
plants (NRC 1975).
Mjelde and Faafen (1997) in their study on
small Norwegian lakes observed that most
macrophytes-dominated lakes with water P
concentration above 30 mg m-3 were dominated
by C. demersum. C. demersum is a useful
indicator of water pollution; it can trap
macro- and micro-elements and accelerate the
removal and biotransformation of herbicides
from contaminated water (Zahran & Willis
2003). In addition, C. demersum can survive
in water of high nurients (Galal et al. 2008).
Yaowakhan et al. (2005) observed that, at high
Pb concentration, C. demersum showed substantial
accumulation, i.e. 1621 mg/kg at
1 mg/l Pb after 6 days and 6982 mg/kg at
10 mg/l Pb after 9 days. The relative growth
of plants generally decreased with increase in
Pb concentration. Keskinkan et al. (2007)
reported that M. spicatum has a better adsorption
capacity than C. demersum for Cu and Pb.
Ministry of Agriculture, Fisheries and Food in
England (Anonymous 1975) reported that
minimum protein in the animal diet ranges
ecologia mediterranea – Vol. 36 (1) – 2010