Greener Journal of Biological Sciences Vol. 10(1), pp. 21-26, 2020 ISSN: 2276-7762 Copyright ©2020, the copyright of this article is retained by the author(s) https://gjournals.org/GJBS

Taxonomic Studies on Telfairia occidentalis Hooker (Cucurbitaceae)

*¹Wahua, Chika; ²Eke, Redeem Chinazam; ³Nichodemus, Cornelius Onyidikachi

*¹Department of Plant Science and Biotechnology, Faculty of Science, University of Port Harcourt, Choba, P.M.B.5323, NIGERIA.

*Email: chika.wahua@ uniport.edu. ng, Phone number: +2348064043448

² Department of Plant Science and Biotechnology, Faculty of Science, University of Port Harcourt, Choba, P.M.B. 5323, NIGERIA. Email: redeemeke8@ gmail. com

³ Department of Plant Science and Biotechnology, Faculty of Science, University of Port Harcourt, Choba, P.M.B. 5323, NIGERIA. Email: cornel4nic@ gmail. com

ARTICLE INFO	ABSTRACT
Article No.: 020120021 Type: Research	This study examined the morphological, anatomical, cytological, phytochemical characteristics of Telfairia occidentalis (Fluted pumpkin) in the family Cucurbitaceae. Observations of plant parts aided by measurements were done and these were sectioned following Wahua’s method; root tips squashed with FLP Orcein and qualitative phytochemical analysis was carried out. T. occidentalis is a dioeciously perennial plant with stem up to 10m long and 3-5 palmately arranged leaflets. The fruit is pale green with waxy deposit strongly ribbed and light yellow fibrous flesh with flattened seeds. The flower is composed of male and female inflorescence. The epidermal studies revealed glandular trichomes, oil glands and anomocytic stomata with polar contiguous stomata on the abaxial layer. The anatomical studies showed various internal structures for the stem, midrib, root, petiole and node with bicollateral vascular bundle arrangements. Diploid chromosome number of 2n=22 was observed. Phytochemical screening revealed presence of alkaloids, flavonoids, tannins, saponins, terpenoids, phenols and cardiac glycosides across the three extracts while steroids was absent. The information generated from this study further aid the delimitation of the species.
Accepted: 02/02/2020 Published: 25/02/2020
*Corresponding Author Wahua, Chika E-mail: chika.wahua@ uniport.edu.ng Phone: +2348064043448
Keywords: Telfairia, morphology; anatomy; cytology; phytochemistry; anomocytic

INTRODUCTION

The genus Telfairia Hooker belongs to the family Cucurbitaceae and contains two (2) species in Africa namely; Telfairia occidentalis Hooker and T. pedata (Sm. ex Sims.) Hooker from West Africa and East Africa respectively (Okoli, 2013). Although T. occidentalis is an herbaceous perennial plant, it is grown as an annual crop due to its importance in parts of West Africa (Irvine, 1969). In Nigeria, Telfairia occidentalis is extensively cultivated in the southern part by the Igbos where it is fast becoming an important vegetable crop (Okoli, 2013) and has become a major component of their diets and can be found in every home. In trado-medicine, it is used as blood booster, improve immune system, aid digestion and convulsion (Kayode et al., 2010).

The antioxidant property of T. occidentalis has been widely reported by several authors (Nwanna and Oboh, 2007; Eseyin et al., 2014; Eseyin et al., 2018). Nutritionally, this leafy vegetable is rich in minerals such as iron, potassium, sodium, phosphorus, calcium and magnesium and some essential amino acids (Fasuyi and Nonyerem, 2007). Major Phytochemicals present include; tannins, saponins, flavanoids and phenolics (Ekpenyong et al., 2012; Adeniyi et al., 2010).

Some taxonomic lines of evidence have been explored in the study of T. occidentalis such as morphology (Hutchinson and Dalziel, 1954), phytochemistry (Adeniyi et al., 2010), cytology (Okoli and Mgbeogwu, 1983).

This present study examines the morphology, anatomy, cytology and phytochemistry of T. occidentalis to further provide useful taxonomic information relevant to its identification and delimitation.

MATERIALS AND METHODS

Morphological Studies

Observations of the morphological characters (vegetative and floral) were made and a meter rule was employed to aid their measurements. The seeds were obtained from Rumuokoro market in Port Harcourt while the plant parts were collected from University of Port Harcourt farm, Rivers State, Nigeria.

Anatomical Studies

Fresh plant parts (stem, midrib, petiole, node and roots) collected were fixed in FAA solution (in the ratio of 1:1:18) for 48 hours, Johansen (1940) with some modifications, and later subjected to free hand sectioning using 5 blades as described by Wahua (2013) with 2 sets (Nacet and Tiger blades) crossed and a central vertical one (Nacet) lying in between the 2 sets crossed. The blades were adjusted until the holes in them synchronized. The plant part to be sectioned was placed in the hole and using the first two fingers of the left hand to hold the vertical blade sets, while pressing down the 2 crossed sets with the first two fingers of the right hand to make a transverse section of about 15 to 25µm in thickness. These were dehydrated in ethanol solution of 30%, 50%, 70% and absolute for 5 minutes in each and further passed through different series of alcohol and chloroform (3:1, 1:1 and 1:3) v/v for 10 minutes in each. Good sections were selected, stained with 1% Alcian blue, rinsed and counter stained with 1% Safranin 0 for 2 minutes. Mounted on glass slides with a drop of glycerol and viewed under the microscope. Microphotographs were taken (Metcalfe and Chalk, 1979; Stace, 1980).

Cytological Studies

The seeds were plated in petri-dishes and allowed to grow roots. The roots were harvested at time intervals (8, 9, 10, 11 and 12), dipped in 8 hydroxylquinoline for 3hours removed and dipped in Carnoy’s fluid for 24hours (Okoli and Mgbeogwu, 1983). The roots were removed and dehydrated in water. 8% HCl was added in a water bath and heated to 60^o, the roots were added to the boiling HCl and allowed for 4minutes to hydrolyze. The roots were removed and placed in 70% ethanol for 10minutes to neutralize the acid. The root tip was placed on a glass slide and cut at 0.2cm, FLP Orcein was added, covered with a cover slip and quashed. Air bubbles and excess stain were removed using filter paper. The slide was viewed under the microscope for observations and chromosomal counts with clear microphotographs taken from good preparations.

Phytochemical Studies

Qualitative analysis was carried out as described by Trease and Evans (1989) and Sofowora (1993). The leaves of Telfairia occidentalis were screened for the presence of flavonoids, tannins, alkaloids, terpenoids, saponins, steroids, phenols and cardiac glycosides.

RESULTS AND DISCUSSION

Morphological Studies

Telfairia occidentalis (fig 1) is a perennial herb, grows up to 10m in length with leafs composed of about 3-5 palmately arranged leaflets, absence of stipules, the petiole length is about 5-12cm with petiolules of 1.4-3.2cm long. The terminal or central leaflet is the largest usually up to 14-18cm X 8-11cm. The leaf margin is dentate with acute leaf apex and base. The fruit is pale green, large, ellipsoid, strongly ribbed at maturity and about 35-50cm X 18-25cm with weight up to 3-6kg. The flower is composed of male racemes about 13cm in length with lobe calyx while corolla is obovate and lobe. The seeds are flattened, yellow and about 3.5cm in diameter. Taxonomic studies of plants provide useful and diagnostic information required for the identification and classification. This work explored four (4) basic lines of evidence namely; morphology, anatomy, cytology and phytochemistry and each proved very important to this study. Morphological investigation of T. occidentalis having palmate leaves (trifoliate), climbing stem, white to purple flowers and pale green fruit corresponds to the findings of Hutchinson and Dalziel (1954) and Okoli (2013). The measurements for the fruit size and weight were similar to the results obtained by Tindall (1983).

Fig 1. Morphology of T. occidentalis (A) Habit (B) Flower (C) Tendril (D) Fruit

Anatomical Studies

The stem anatomy (fig 2A) revealed 1 epidermal layer followed by 4-5 layers of parenchymatous cortex with presence of non-glandular trichomes on the epidermis. The vascular bundles are bicollateral, eleven (11) and arranged in a ring form. Pericycle cells surrounded the vascular bundles and pith at the innermost layer. The midrib anatomy shows presence of non-glandular trichomes on the epidermis, 1 epidermal layer, bicollateral vascular bundles and layers of parenchymateous cortex. The root anatomy shows presence of parenchyma cells, absence of pith and thick walled intercellular spaces. In the petiole anatomy, it revealed a well curved bicollateral vascular bundle. Presence of non-glandular trichomes on the epidermis with 1 epidermal layer with layers of parenchyma cells. The nodal section revealed the presence of 1 epidermal layer, curved vascular bundle and numerous parenchyma cells as shown in fig 2E. The anatomical study further gave an insight into the internal structures by highlighting basic components which distinguishes T. occidentalis from other plant species. The curved arrangements of the bicollateral vascular bundles in the petiole agreed with the reports of Okoli (1987). The epidermal characteristics showed clearly that anomocytic stomata is the dominant stomata type in T. occidentalis and contiguous stomata, only in the adaxial layer. Peltate gland of 5 parts (pentagon) observed only in the adaxial layer provided diagnostic tools relevant to this study.

Fig 2. Transverse section of T. occidentalis (A) Stem (B) Midrib (C) Root (D) Petiole (E) Node

Vb represents vascular bundle, P represents pith, Pc is parenchymatous cortex, Pe is pericycle, NGT is non glandular trichome, INS is xylem vessel, E represents epidermal layer.

Epidermal studies

Telfairia occidentalis is amphistomatic (fig 3). The adaxial layer contains anomocytic stomata with 5 subsidiary cells and peltate glands of 5 parts (pentagon). The epidermal cell shape is irregular while the anticlinal cell wall pattern is regular. The abaxial layer contains anomocytic stomata with 4, 5 and 6 subsidiary cells and tetracytic stomata. Contiguous stomata (polar) phenomenon was observed randomly in the abaxial layer. The epidermal cell shape was irregular while the anticlinal cell wall pattern was wavy.

Fig 3. Epidermal layers of T. occidentalis (A) Adaxial layer, (B) Abaxial layer arrow revealed contiguous stomata.

Cytogical Studies

A diploid chromosome number of 2n=22 was observed in T. occidentalis as shown in fig. 4. The basic chromosome number of T. occidentalis n=11 as reported by Okoli and Mgbeogwu (1983) was confirmed in this study. This shows that the species has diploid chromosome number 2n = 2x = 22 with the chromosome size relatively different.

Fig 4. Chromosomes of T. occidentalis

Phytochemical Studies

The phytochemical results using three different extracts revealed the presence of various metabolites and their relative compatibility to the extracts (methanol, ethanol and aqueous). Saponins, alkaloids and flavonoids were present in the three extracts, terpenoids only present using ethanol extract but absent in others. Phenols were present in methanol and aqueous extracts but absent in ethanol extract. Cardiac glycosides were present using methanol and ethanol extracts but absent using aqueous extracts. Steroids were observed to be absent in all the extracts. These findings were in accordance with the reports of Ekpenyong et al. (2012) and Adeniyi et al. (2010). The level of phytochemicals present further reveals the reason for its high ethnobotanical potentials and usage in treatment of various ailments.

Table 1. Showing the result of the phytochemical screening

Phytoconstituent	Methanol	Ethanol	Aqueous
Alkaloids	+	+	+
Flavonoids	+	+	+
Saponins	+	+	+
Terpenoids	_	+	_
Steroids	_	_	_
Phenols	+	_	+
Cardiac glycosides	+	+	_

Key: += present; - = absent

CONCLUSION

It is worthy of note that the four taxonomic lines of evidence employed in this work has further provided useful diagnostic information required for the delimitation of the species.

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Cite this Article: Wahua, C; Eke, RC; Nichodemus, CO (2020). Taxonomic Studies on Telfairia occidentalis Hooker (Cucurbitaceae). Greener Journal of Biological Sciences, 10(1): 21-26.