Ecological influence on selected Aloe vera populations in two geographical zones in Nigeria

7/29/2019 Ecological influence on selected Aloe vera populations in two geographical zones in Nigeria

1/6

International Research Journal of Plant Science (ISSN: 2141-5447) Vol. 3(5) pp. 88-93, July, 2012Available online http://www.interesjournals.org/IRJPSCopyright 2012 International Research Journals

Full Length Research Paper

Ecological influence on selectedAloe vera

populationsin two geographical zones in Nigeria

O. T. Okareh*1, David Enesi1and O.I.Shittu2

1Department of Environmental Health Sciences, Faculty of Public Health, University of Ibadan, Ibadan, Oyo State,

Nigeria2Department of Civil Engineering, Faculty of Technology, University of Ibadan, Ibadan, Oyo State, Nigeria

Abstract

Morphological, phytochemical and leaf epidermal studies were carried out on three populations of Aloevera (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 basedon qualitative and quantitative features proved useful for determining significant discontinuities.Phytochemical screening indicated that all the populations have similar chemical constituents. Despitesimilar anticlinal wall pattern, epidermal cell size indicated significant difference among the studygroups. Correlation of all the studied parameters employed indicated that the selective forces in theirnatural habitat have set in motion an evolutionary process as most of the parameters studied remainedsignificantly different among the populations after cultivating the populations under the sameconditions.

Keywords: Epidermal studies, Aloe Vera, Phytochemical screening, environmental induced variations.

INTRODUCTION

Aloe veraLinn. is a monocotyledonous plant belonging tothe family Liliaceace (Subfamily: Asphodelaceae). It is aperennial herb or shrub exhibiting xerophytic characters(Akinyele and Odiyi, 2007). Aloe verais widely grown asan ornamental plant as well as a medicinal plant. Themedicinal potency of Aloe vera has greatly beenharnessed since ancient times and widely usedthroughout the world (Akinyele and Odiyi, 2007; Raj andJoseph, 2010). Large scale commercial production is alsoundertaken to meet up demand of culinary, cosmetic andpharmaceutical industries (Grindlay and Reynold, 1986).

Aloe vera plant is native to Africa (Anselm, 2004).

However, because of its wide adaptability as well as itsimportance as medicinal plants, the crop is welldistributed throughout the entire tropical and sub-tropicalregions, since its water requirement is very low (Raj andJoseph, 2010).

Plants are greatly influenced by ecological factors.Much of the phenotypic variations encountered are the

*Corresponding Author E-mail: [email protected]

result of the plastic response of the individual to factors ofthe environment. However, some of these variations havebeen genetically fixed and are of interest inunderstanding evolutionary processes. According toLanglet (1963), Species with wide distribution give clearevidence of hereditary adaptation to varyingenvironmental conditions as diverse environmentaconditions engender diverse patterns of species variation

The aim of this study therefore is to determine thevariations in morphology, phytochemistry and leafepidermal anatomy of selected Aloe verapopulations asinfluenced by environmental conditions.

MATERIALS AND METHODS

Representative population samples of Aloe veraspeciescollected from three selected ecological zones werebrought into cultivation in the Biological garden oUniversity of Ilorin, Ilorin, Nigeria using strip method. TenAleo vera of each population were planted in three rowsThe plants were allowed to acclimatize for a period of oneyear and grow under the same conditions in order to


2/6

Okareh et al. 89

Table 1. Designated specimens and places of collection

Specimens Place of collection

AKG-K01Behind ECWA church complex, Kuroko, Kogi state.

APL-P01

Around Pankshin dam, Pankshin, Jos, Plateau state.

AON-A01Ijoka, Akure, Ondo state.

Table 2. Mean Values of Measurements of Vegetative Characters

Values presented are means SEM

Figure 1. AKG-K01

neutralize the phenetic effects conferred on eachpopulation by the climatic and edaphic components oftheir respective natural environments.

COLLECTION OF MATERIALS

Specimens analysis

Morphology

Vegetative morphology were investigated based onnumber of leaves per plant, leaf length, leaf width, spinefrequency and leaf alternate phyllotaxy.

Phytochemical analysis

Fresh leaves of Aloe vera were chopped into smallpieces, air dried and used for the preparation of ethanolicextract. The extract was qualitatively analysed asdescribed by Harborne (1973); and Odebiyi andSofowora (1979).

Leaf epidermal anatomy

A thin slice was cut mid-way between the leaf base andapex from either side of the leaf (adaxial and abaxial)using a sharp razor blade. The segment was hydrolysedin dilute HNO3 for few minutes and washed. Slides oboth abaxial and adaxial sides of leaves were preparedand observed under Olympus microscope.

RESULTS AND DISCUSSION

Morphology

Generally, all the specimens retained their initiamorphological differences after a period of acclimatizingto their new habitat. All the Aloe veragroups used in thisresearch exhibited a pentastichous alternate phyllotaxyhowever, they exhibited clear differences in leaf colourlength and width, nature of the spine, size and shape ofthe plant as presented in figure1-3. Details of thevegetative characteristics are as shown in table 2.

Qualitatively, all specimens of AKG-K01 were reddishgreen in colour, those of APL-P01 were distinctly deep

Specimens leaf length(cm)

leaf width(cm)

number ofleaves/plant

Spine freq./10cm

Mottle frequency/4cm

Adaxial AbaxialAKG-K01 23.9 1.08 3.0 0.11 12.0 10.31 41.6 1.077 51.0 1.703APL-P01 16.4 0.68 6.7 0.33 11.6 13.91 _ _AON-A01 26.0 0.71 5.0 0.17 12.2 6.32 _ _


3/6

90 Int. Res. J. Plant Sci.

Figure 2. APL-P01

Figure 3. AON-A01

Photographs of Aloe veraGroups (Representative)Showing Vegetative Morphology

Table 3. Qualitative phytochemical screening

Group sample Flavonoids Anthraquinone Glycosides Saponin SteriodsAKG-K01 - + + + +

APL-P01 - * + + +AON-N01 - + + + +

Key: (+) indicates present, (-) absent and (*) indicates a slight and almost undetectable

colour change

green in colour while those of AON-A01 were pale greenin colour. The nature of the spines of AKG-K01 peripheralupturned white spines, APL-P01 has deep-seated jaggededges ending in brownish thorns while AON-A01 andAON-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 allAloe vera groups. Statistically significant morphologicalvariations are presented in table 6.

Phytochemistry

The result of the phytochemical analysis showed nosignificant difference among all the groupsinvestigated.This is consistent with previous findings ofAnselm (2004), who indicated that all the various speciesof Aloe are known to have similar chemical constituents.The anthraquinone constituent, though present for all

study populations, indicates only a slight colour changefor both APL-P01. The phytochemical analysis indicateda negative result for flavonoid screening. This is contraryto the findings of Arunkumar and Muthuselvam (2009)Ejoba (2012), Nnwaoguikpe et al. (2010) and Yebpella(2011). This seemingly incongruities maybe traced to thephenetic effects conferred on each population throughacclimatization process or the qualitative approachedused for the screening process. See details in table 3.

Leaf Epidermal Anatomy

Various studies have emphasized the significance of foliar epidermal anatomy in the systematic ofmany plant groups (Stace, 1984; Wilkins and Sabanci1990; Mustapha, 2000a; Ahmad et al., 2010), thussuggesting that leaf surface patterns, anatomicafeatures and structures are genetically controlled


4/6

Okareh et al. 91

Table 4. Data from Epidermal Cell Measurements.

Groups Surface Mean length (m) Mean width (m) Cell Index (w/l)

AKG-K01 Adaxial 53.6 ( 2.347) 36.6 ( 0.928) 0.683Abaxial 51.6 ( 3.491) 34.3 ( 0.844) 0.665

APL-P01 Adaxial 73.3 ( 2.160) 49.9 ( 2.072) 0.681Abaxial 78.4 ( 5.182) 52.9 ( 1.599) 0.675

AON-A01 Adaxial 55.1 ( 2.434) 33.6 ( 1.918) 0.609Abaxial 52.9 ( 1.466) 37.9 ( 1.631) 0.716

Values presented are means SEM

Table 5. Data from Stomatal Cell Measurements

Groups Surface Stomatal length (m) Stomatal width (m)AKG-K01 Adaxial 34.3 ( 0.677) 23.6 ( 0.677)

Abaxial 40.3 ( 1.048) 33.4 ( 1.091)

APL-P01 Adaxial 34.7 ( 0.801) 18.0 ( 1.091)Abaxial 38.6 ( 1.515) 28.3 ( 1.048)

AON-A01 Adaxial 35.6 ( 1.286) 29.1 ( 0.525)

Abaxial 30.4 ( 0.801) 28.7 ( 0.525)

Table 6. Statistical Analysis of Quantitative ParametersValues are means SEM. Mean values in the same row followed by differentsuperscripts are significantly different (p


5/6

92 Int. Res. J. Plant Sci.

Abaxial surface Adaxial surfaceFigure 5. Leaf epidermal cells of APL-P01

Abaxial surface Adaxial surfaceFigure 6. Leaf epidermal cells of AON-A01

The leaf surfaces of all study populations are glabrous.Stomatal index indicate that the stomatal cells on theabaxial surface are more frequent than on the adaxialsurface. Also, the anticlinal wall patterns and shape of theepidermal cell of all the study populations are similarexcept the adaxial surface of members of AKG-K01population that seemed rectangular. However, APL-P01has a considerably larger epidermal cell than the others.Duncan analysis of the epidermal cells both on theadaxial and abaxial distinctlyseparates APL-P01 from the other specimens understudy (See table 4 -5 and figure 4-6).

CONCLUSION

The differences which were retained after cultivation inthe same condition suggest that such differences aregenetically-based. It can therefore be advanced that theselected ecological zones of the study populationsconferred on them an ample genetic differentiation, whichis evident in their morphology and epidermal leafanatomy. This inference however, does not hold true forthe phytochemical constituents of the Aloe veragroups.

Therefore, the geographical distribution of Aloe vera doesnot compromise its medicinal importance.

REFERENCES

Ahmad K, Khan MR, Ahmad M, Shaheen N, Nazir A (2010).TaxonomicDiversity in Epidermal Cells of some Sub-tropical Plant Species. IntJ. Agric. Biol., 12: 115118

Akinyele BO, Odiyi AC (2007). Comparative study of vegetativemorphology and existing taxonomic, nutritional and medicinal statusof Aloe vera L. African Crop Science Conference Proceedings. 81567 1570

Arunkumar S, Muthuselvam M (2009). Analysis of PhytochemicaConstituents and Antimicrobial Activitiesof Aloe vera L. AgainsClinical Pathogens. World J. Agric. Sci., 5 (5): 572-576.

Ejoba R (2012). Phytochemical constituents of some leaves extract ofAloe vera and Azadirachta indica plant species . Global AdvancedResearch Journal of Environmental Science and Toxicology. 1(2) 014-017.

Grindlay D, Reynolds T (1986). The Aloe veraphenomenon: A review othe properties and modern uses of leaf parenchyma gelJ.Ethnopharmocol. 16: 117-151

Harborne JR (1973). Phytochemical methods. A guide to moderntechniques of Antitumour chemograph microbiology. 3

rdEd. Hol

Saunders International edition CBS college publishing New York. Pp263 285

Langlet O (1963). Patterns and terms of Intraspecific ecologicavariation. Nature, 200:347-348.


6/6

Mustapha OT (2000a). Cytotaxonomy of the genus Urginea Stein III:The Taxonomic value of foliar anatomical featuers in Urginea indica(Roxb.) Kunth complex. Biosci. Res. Comm. 12(2): 201-206.

Nwaoguikpe RN, Braide W, Ezejiofor TIN (2010). The effect of aloevera plant (aloe barbadensis) extracts on sickle cell blood (hbss).African Journal of Food Science and Technology. 1(3): 058-063.

Odebiyi A and Sofowora AE (1979). Phytochemical screening of NigeriaMedicinal Plants (part III). Lloydia. 41: 234 246.

Raj SJ, Joseph B (2010). Pharmacognostic and phytochemicalproperties of Aloe veraLinn an overview. Int. J. Pharm. Sci. Reviewand Research, 4(2): 106-110.

Okareh et al. 93

Stace CA (1984). The taxonomic importance of leaf surface. InHeywood, V.H. and D.M. Moore (eds.), Current Concepts in PlanTaxonomy, pp: 6794. London: Academic Press, London.

Wilkins PW and Sabanci CO (1990). Genetic variation in leaf epidermacell size and shape in Lolium perenne. Euphytica, 47: 233 239.

Yebpella GG, Adeyemi HMM, Hammuel C, Magomya AM, Agbaji ASOkonkwo EM (2011). Phtyochemical screening and comparativestudy of antimicrobial activity of Aloe vera various extracts .African J

Microbiol. Res. 5(10), pp. 1182-1187.

Ecological influence on selected Aloe vera populations in two geographical zones in Nigeria

Documents

Transcript of Ecological influence on selected Aloe vera populations in two geographical zones in Nigeria