Potential Impacts of the Invasive Ipomoea carnea Jacq.
on Plant Diversity Along Canal and Drain Banks of the
Nile Delta, Egypt
By
Mohamed Abd El-Aal Lotfy Sadek
Lecturer of Plant Ecology
Botany Department, Faculty of Science
Mansoura University, Egypt
 Invasive plant species pose a threat that
negatively
impacting
biodiversity
or
abundance of native plant communities and
ecosystems (McGeoch et al., 2010).
 In Nile Delta, Egypt the introduced invasive
species Ipomoea carnea Jacq. become in pure
and/or mixed stands with poor associates
along banks of canals and drains forming a
dense aboveground patches.
 Perennial
dicot shrub belonging to Family
Convolvulaceae
 It is native to Tropical South America and was
introduced to Egypt in 1932 as an ornamental
plant for its luxuriant vegetative growth and
attractive large pink flowers.
 Recently, it is recorded as a naturalized species
along canals and drains, road sides, railways,
wastelands and field edges in the Nile Delta
(Shaltout et al., 2010).
The problems created by I. carnea
1) block water flow in the open water zone of
2)
3)
4)
5)
6)
drainage & irrigation system
Interfering with fishering & navigation
Polluting water supplies
Increasing sedimentation & water loss
Cause severe nervous disorders when ingested
by cattles & goats or sheep
The growing season of it encompasses most of
the year.
The objective of this work
 1) To demonstrate the impacts of
invasion on plant species diversity.
I. carnea
 2) To identify the reasons for its dominance in
the canal and drain banks.
Study area
Figure. Map of the Nile Delta (Egypt) indicated the location of sampling sites . Source Google Earth
Materials and Methods
 1) Measurement of plant diversity in invaded
and uninvaded stands
 2) Soil analysis
 3)Assessment of allelopathic potential of I.
carnea (root, stem, leaf, fruit) aqueous extracts
with different concentrations (2,4,6,8,10%)
against
a) Portulaca oleracea L.
b) Echinochloa crus-galli (L.) P. Beauv
 4)Phytochemical analyses of I. carnea
Results
 Effect of I. carnea on species diversity
Uninvaded
Invaded
Species Number
50
27
Species Richness
0.940
0.905
Evenness
0.861
0.813
 Effect of I. carnea on soil chemical properties
Two-way ANOVA indicated significant negative effect
for I. carnea invasion on sulphates, phosphorous and
sodium (P≤ 0.05).
Impact of aqueous extracts of I. carnea on seed
germination and seedling growth of the tested species
 All aqueous extracts of I. carnea significantly (P≤ 0.05)
inhibited seed germination and seedling growth of P.
oleracea and E. crus-galli at both high and low
concentrations.
 The leaf aqueous extract was the most effective one where
it completely inhibited the germination of P. oleracea at
concentrations ranged between 6, 8 and 10 gl-1, and at
concentration of 10 g/L for E. crus-galli.
 The decline in germination percentages was a function
of type and concentration of the extract.
 At a concentration of 10% aqueous leaf extract, shoot
length was reduced by 63.57% in P. oleracea and by
48.02% in E. crus-galli, while root length was
reduced by 53.39% in P. oleracea and by 69.44% in
E. crus-galli.
 Bioactive chemical compounds of I. carnea
Phenolics
Flavonoids
Tannins
Alkaloids
Plant organ
concentration (mg/g dry weight plant material)
Root
70.52±0.50
7.78±0.45
22.63±0.75
41.95±0.77
Stem
63.53±1.01
7.60±0.65
20.33±0.38
38.43±0.42
39.30±0.46
50.54±0.71
30.66±0.29
24.27±0.62
Leaf
Fruit
110.16±0.78
79.15±1.43
39.09±0.31
12.29±0.53
Leaf extract contained the highest values of
phenol contents, flavonoids, tannins and
alkaloids, while stem extract showed the lowest
contents of phenols, flavonoids and tannins.
Discussion
 I. carnea invasion has a potential threat to plant
diversity and certain soil chemical properties along
the banks of canals and drains in the Nile Delta.
 The plant I. carnea caused a negative impact on
species richness and evenness of associated species
beneath, as compared with uninvaded stands.
high rate of reproduction, quick
spread, unpalatability and wide
ecological amplitude
I. carnea
abundance
Competition for available
nutrients
Allelopathic Effect
 The root, stem, leaf and fruit of I. carnea extracted in
water have inhibitory effects upon seed germination
and seedlings growth of the tested species, P. oleracea
and E. crus-galli.
 Phytochemical analysis of I. carnea revealed the
presence of some bioactive compounds, particularly
phenolic compounds, flavonoids, tannins and
alkaloids. These bioactive chemical compounds have
been described as allelochemicals (Cheema et al.,
2012).
 In the present study, the inhibitory effects of I. carnea extracts
followed a gradient: leaf > fruit > root > stem. Also, the degree
of inhibition was dependent on the concentration of extracts.
 The high allelopathic activity of leaf extract may be attributed
to the presence of many inhibitory bioactive secondary
metabolites in higher concentration compared to fruit, root and
stem extracts as shown in the results.
 The aqueous leaf extract (10 g/L) was the most potent inhibitor
of seed germination and seedling growth of the assayed
species.
Conclusion
 I. carnea dominated the community in the canal and
drain banks in the Nile Delta, Egypt and become in
pure and/or mixed stands with poor associates.
 The allelopathic effect of I. carnea coupled with its
competitive effect on soil nutrients could contribute to
the successful invasion and attainment of pure
population.
 The management strategy should be focused on
eliminating the population of I. carnea which
currently established in the canal and drain banks for
prevention of biodiversity loss and changes in habitat
conditions.
 The present results suggest that, aqueous leaf extract
of I. carnea could be used at 10 gL-1 for management
of Echinochloa crus-galli and Portulaca oleracea as
an alternative biocontrol method.
 Further work is needed for characterization of the
causative allelochemical (s) of I. carnea water extract.