International Research Journal of Plant Science (ISSN: 2141-5447) Vol. 4(8) pp. 272-277, September, 2013
DOI: http:/dx.doi.org/10.14303/irjps.2012.040
Available online http://www.interesjournals.org/IRJPS
Copyright © 2013 International Research Journals
Full Length Research Paper
Ecological influence on selected Aloe vera populations
in two geographical zones in Nigeria
O. T. Okareh*1, David Enesi1 and O.I.Shittu2
1
Department of Environmental Health Sciences, Faculty of Public Health, University of Ibadan, Ibadan, Oyo State,
Nigeria
2
Department of Civil Engineering, Faculty of Technology, University of Ibadan, Ibadan, Oyo State, Nigeria
*Corresponding
Author
E-mail: dapsy2001@yahoo.co.uk
Abstract
Morphological, phytochemical and leaf epidermal studies were carried out on three populations of Aloe
vera (L.) Burm. f. collected from North Central and South West geographical zones of Nigeria with a
view to determining the extent of their environmentally induced variations. Morphological studies based
on qualitative and quantitative features proved useful for determining significant discontinuities.
Phytochemical screening indicated that all the populations have similar chemical constituents. Despite
similar anticlinal wall pattern, epidermal cell size indicated significant difference among the study
groups. Correlation of all the studied parameters employed indicated that the selective forces in their
natural habitat have set in motion an evolutionary process as most of the parameters studied remained
significantly different among the populations after cultivating the populations under the same
conditions.
Keywords: epidermal studies, Aloe Vera, Phytochemical screening, environmental induced variations
INTRODUCTION
Aloe vera Linn. is a monocotyledonous plant belonging to
the family Liliaceace (Subfamily: Asphodelaceae). It is a
perennial herb or shrub exhibiting xerophytic characters
(Akinyele and Odiyi, 2007). Aloe vera is widely grown as
an ornamental plant as well as a medicinal plant. The
medicinal potency of Aloe vera has greatly been
harnessed since ancient times and widely used
throughout the world (Akinyele and Odiyi, 2007; Raj and
Joseph, 2010). Large scale commercial production is also
undertaken to meet up demand of culinary, cosmetic and
pharmaceutical industries (Grindlay and Reynold, 1986).
Aloe vera plant is native to Africa (Anselm, 2004).
However, because of its wide adaptability as well as its
importance as medicinal plants, the crop is well
distributed throughout the entire tropical and sub-tropical
regions, since its water requirement is very low (Raj and
Joseph, 2010).
Plants are greatly influenced by ecological factors.
Much of the phenotypic variations encountered are the
result of the plastic response of the individual to factors of
the environment. However, some of these variations have
been genetically fixed and are of interest in
understanding evolutionary processes. According to
Langlet (1963), Species with wide distribution give clear
evidence
of
hereditary
adaptation
to
varying
environmental conditions as diverse environmental
conditions engender diverse patterns of species variation.
The aim of this study therefore is to determine the
variations in morphology, phytochemistry and leaf
epidermal anatomy of selected Aloe vera populations as
influenced by environmental conditions.
MATERIALS AND METHODS
Representative population samples of Aloe vera species
collected from three selected ecological zones were
brought into cultivation in the Biological garden of
University of Ilorin, Ilorin, Nigeria using strip method. Ten
Aleo vera of each population were planted in three rows.
The plants were allowed to acclimatize for a period of one
year and grow under the same conditions in order to
Okareh et al. 273
Table 1. Designated specimens and places of collection
Specimens
Place of collection
AKG-K01
Behind ECWA church complex, Kuroko, Kogi state.
APL-P01
Around Pankshin dam, Pankshin, Jos, Plateau state.
AON-A01
Ijoka, Akure, Ondo state.
Table 2. Mean Values of Measurements of Vegetative Characters
Specimens
leaf length
(cm)
leaf width
(cm)
number of
leaves/plant
Spine freq.
/10cm
AKG-K01
APL-P01
AON-A01
23.9 ± 1.08
16.4 ± 0.68
26.0 ± 0.71
3.0 ± 0.11
6.7 ± 0.33
5.0 ± 0.17
12.0
11.6
12.2
10.31
13.91
6.32
Mottle frequency/4cm2
Adaxial
Abaxial
41.6 ± 1.077 51.0 ± 1.703
_
_
_
_
Values presented are means ± SEM
Figure 1. AKG-K01
neutralize the phenetic effects conferred on each
population by the climatic and edaphic components of
their respective natural environments.
COLLECTION OF MATERIALS
Specimens’ analysis
Morphology
Vegetative morphology were investigated based on
number of leaves per plant, leaf length, leaf width, spine
frequency and leaf alternate phyllotaxy.
Phytochemical analysis
Fresh leaves of Aloe vera were chopped into small
pieces, air dried and used for the preparation of ethanolic
extract.
The extract was qualitatively analysed as
described by Harborne (1973); and Odebiyi and
Sofowora (1979).
Leaf epidermal anatomy
A thin slice was cut mid-way between the leaf base and
apex from either side of the leaf (adaxial and abaxial)
using a sharp razor blade. The segment was hydrolysed
in dilute HNO3 for few minutes and washed. Slides of
both abaxial and adaxial sides of leaves were prepared
and observed under Olympus microscope.
RESULTS AND DISCUSSION
Morphology
Generally, all the specimens retained their initial
morphological differences after a period of acclimatizing
to their new habitat. All the Aloe vera groups used in this
research exhibited a pentastichous alternate phyllotaxy,
however, they exhibited clear differences in leaf colour,
length and width, nature of the spine, size and shape of
the plant as presented in figure1-3. Details of the
vegetative characteristics are as shown in table 2.
Qualitatively, all specimens of AKG-K01 were reddish
green in colour, those of APL-P01 were distinctly deep
274 Int. Res. J. Plant Sci.
Figure 2. APL-P01
Figure 3. AON-A01
Photographs of Aloe vera Groups (Representative)
Showing Vegetative Morphology
Table 3. Qualitative phytochemical screening
Group sample
AKG-K01
APL-P01
AON-N01
Flavonoids
-
Anthraquinone
+
*
+
Glycosides
+
+
+
Saponin
+
+
+
Steriods
+
+
+
Key: (+) indicates present, (-) absent and (*) indicates a slight and almost undetectable
colour change
green in colour while those of AON-A01 were pale green
in colour. The nature of the spines of AKG-K01 peripheral
upturned white spines, APL-P01 has deep-seated jagged
edges ending in brownish thorns while AON-A01 and
AON-A02 have superficial and succulent white spines.
This is contrary to findings of Akinyele and Odiyi (2007),
which indicated that spine frequency is stable across all
Aloe vera groups. Statistically significant morphological
variations are presented in table 6.
study populations, indicates only a slight colour change
for both APL-P01. The phytochemical analysis indicated
a negative result for flavonoid screening. This is contrary
to the findings of Arunkumar and Muthuselvam (2009),
Ejoba (2012), Nnwaoguikpe et al. (2010) and Yebpella
(2011). This seemingly incongruities maybe traced to the
phenetic effects conferred on each population through
acclimatization process or the qualitative approached
used for the screening process. See details in table 3.
Phytochemistry
Leaf Epidermal Anatomy
The result of the phytochemical analysis showed no
significant
difference
among
all
the
groups
investigated.This is consistent with previous findings of
Anselm (2004), who indicated that all the various species
of Aloe are known to have similar chemical constituents.
The anthraquinone constituent, though present for all
Various studies have emphasized the significance of foliar epidermal anatomy in the systematic of
many plant groups (Stace, 1984; Wilkins and Sabanci,
1990; Mustapha, 2000a; Ahmad et al., 2010), thus
suggesting that leaf surface patterns, anatomical
features and structures are genetically controlled.
. Okareh et al. 275
Table 4. Data from Epidermal Cell Measurements.
Groups
AKG-K01
APL-P01
AON-A01
Surface
Adaxial
Abaxial
Adaxial
Abaxial
Adaxial
Abaxial
Mean length (µm)
53.6 (± 2.347)
51.6 (± 3.491)
73.3 (± 2.160)
78.4 (± 5.182)
55.1 (± 2.434)
52.9 (± 1.466)
Mean width (µm)
36.6 (± 0.928)
34.3 (± 0.844)
49.9 (± 2.072)
52.9 (± 1.599)
33.6 (± 1.918)
37.9 (± 1.631)
Cell Index (w/l)
0.683
0.665
0.681
0.675
0.609
0.716
Values presented are means ± SEM
Table 5. Data from Stomatal Cell Measurements
Groups
AKG-K01
APL-P01
AON-A01
Surface
Adaxial
Abaxial
Adaxial
Abaxial
Adaxial
Abaxial
Stomatal length (µm)
34.3 (± 0.677)
40.3 (± 1.048)
34.7 (± 0.801)
38.6 (± 1.515)
35.6 (± 1.286)
30.4 (± 0.801)
Stomatal width (µm)
23.6 (± 0.677)
33.4 (± 1.091)
18.0 (± 1.091)
28.3 (± 1.048)
29.1 (± 0.525)
28.7 (± 0.525)
Table 6. Statistical Analysis of Quantitative Parameters
Values are means ± SEM. Mean values in the same row followed by different
superscripts are significantly different (p<0.05).
Variables
Mean Chromatin length
Spine frequency
Mean Leaf length
Mean Leaf width
Mottle freq. (Adaxial)
Mottle freq. (Abaxial)
Epidermal cell length
(Adaxial)
Epidermal cell width
(Adaxial)
Epidermal cell length
(Abaxial)
Epidermal cell width
(Abaxial)
AKG-K01
11.61±1.34 b
10.31±1.02 b
23.90±1.08 c
3.00±0.11 d
41.60±1.08 b
51.00±1.70 b
2.50±0.35 bc
1.71±0.14
b
2.41±0.52
b
1.60±0.12
bc
APL-P01
16.61±2.39a
13.91±1.11a
16.40±0.68d
6.68±0.33 a
-d
- d
AON-A01
9.66±1.19
6.32±0.35
26.00±0.71
4.94±0.20
-d
- d
b
c
bc
b
3.42±0.38
a
2.57±0.36
bc
2.33±0.31
a
1.57±0.28
bc
3.66±0.76
a
2.47±0.22
b
2.47±0.24
a
1.77±0.24
b
Values presented are means ± SEM
Photomicrograph of leaf epidermal anatomy
Abaxial surface
Adaxial surface
Figure 4. Leaf epidermal cells of AKG-K01
276 Int. Res. J. Plant Sci
Abaxial surface
Adaxial surface
Figure 5. Leaf epidermal cells of APL-P01
Abaxial surface
Adaxial surface
Figure 6. Leaf epidermal cells of AON-A01
The leaf surfaces of all study populations are glabrous.
Stomatal index indicate that the stomatal cells on the
abaxial surface are more frequent than on the adaxial
surface. Also, the anticlinal wall patterns and shape of the
epidermal cell of all the study populations are similar
except the adaxial surface of members of AKG-K01
population that seemed rectangular. However, APL-P01
has a considerably larger epidermal cell than the others.
Duncan analysis of the epidermal cells both on the
adaxial and abaxial distinctly
separates APL-P01 from the other specimens under
study (See table 4 -5 and figure 4-6).
CONCLUSION
The differences which were retained after cultivation in
the same condition suggest that such differences are
genetically-based. It can therefore be advanced that the
selected ecological zones of the study populations
conferred on them an ample genetic differentiation, which
is evident in their morphology and epidermal leaf
anatomy. This inference however, does not hold true for
the phytochemical constituents of the Aloe vera groups.
Therefore, the geographical distribution of Aloe vera does
not compromise its medicinal importance.
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