FACULTY OF SCIENCE

Permanent URI for this communityhttps://repository.ui.edu.ng/handle/123456789/266

Browse

End date: 2009Subject: search.filters.subject.Taxonomy

Search Results

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Scanning electron microscopy of leaves in the West African polygonaceae
    (2008-12) Ayodele, A. E.; Zhou Z. K.
    The leaf surfaces of the West African taxa of the Polygonaceae were studied using the Scanning Electron Microscope (SEM). Leaf epidermal cells arc polygonal, isodiametric and rarely irregular. Anticlinal walls are straight, curved, undulate or sinuate. Striae are present in a few taxa such as Polygonum plebeium. Rumex abysinaicus, R. bequaertii, Oxygonum sinuatum, Persicaria nepalensis and Afrobrunnichia erecta. The striae may be parallel, radiate, or randomly distributed. Trichomas are unicellular, uniseriate, aggregating together in some species of persicaria, while they may be flagelliform, interwoven and woolly in Persicaria senegalensis forma albotomentosa hence diagnostic for the species. Peltate glands are characteristic of A. arena. Stomata are mainly paracytic or anomocytic although diacytic. cyclocytic and anisocytic types may also be found in some taxa sometimes together with the main types. Stoma’s are sunken in a few species such as Polygonum plebeium and Persicaria attenuata subsp. pulchra, raised or at the same level with epidermal cells in other taxa. Wax deposits arc associated with the stomata in Persicaria attenuata subsp. africana. These characters are discussed in relation to the taxonomy of the family in West Africa.
  • Thumbnail Image
    Item
    Comparative Studies on Khaya. A. Juss.(meliaceae) in Nigeria
    (2006-06) Ibrahim, A. I.; Ayodele, A. E.; Jegede, A. I.; Kunle, Y. F.
    Comparative phytochemical, microscopical and chemomicroscopica! studies were carried out on the genus Khaya with the aim of obtaining useful characters for the identification and delimitation of species boundaries. Tannins and saponins were present In all the species while phenols were detected in all except K. grandlfollola. Protein and anthraquinones were present in the bark of all. iba species. Carbohydrate is present in all the species except in the hark of K. Ivoriensls. Flavonoids and phlobatannins were absent in all the taxa. Microscopical examination of the powdered bark revealed different types and shapes of lignified sclerelds, abundant distribution of prismatic calcium oxalate crystals, druses, lignified cork-cells, fibres, medullary rays and parenchyma cells which may contain starch grains.
  • Thumbnail Image
    Item
    The morphology and taxonomic significance of pollen in the West African polygonaceae
    (2005) Ayodele, A. E.
    The pollen of Polygonaceae in West Africa was studied by light microscopy. Three pollen types are recognized. Type A is typical of Polygonum represented by P. plebeium. These pollen grains are small, 17.5 x 12.5 µm to 22.5 x 15 µm, quadrangular and prolate with thin exine walls (1.5 - 2.5 µm). The Pollen type B is restricted to the Persicaria group. The pollen is of medium size, 34.3 - 45.5 µm polypantoporate, spheroidal with germ pores on the entire surface. Type C pollen is possessed by other genera studied. The grains range from small to large, 19.2 x 19.9 µm in Symmeria paniculata to 51.6 x 44 µm in Antigonon leptopus. They are subprolate, prolate-spheroidal to oblate-spheroidal, triangulate in polar view and oblong, elliptic to round in equatorial view. Palynological evidence supports the segregation of Persicaria from Polygonum as well as revealed that Harpagocarpus is better placed in the tribe Coccolobeae than in the tribe Persicareae.
  • Thumbnail Image
    Item
    Comparative leaf micromorphological characters of the Nigerian species of rauvolfia linn (apocynaceae)
    (Klobex Academic Publishers, 2003-12) Kadiri, A. B.; Ayodele, A. E.
    Leaf micromophological characters of Rauvolfia Linn. (Apocynaceae) have been studied and compared. The leaf is usually glabrous and hypostomatic. Stomatal type is mostly paracytic but epidermal cell shape is either polygonal or irregular while epidermal cell number is lower on the abaxial surface. Mean stomatal size varies from 1.40.µm x 0.60µm in R. macrophylla to 2.30µm x 0.60µm in R. vomitoria and mean cell wall thickness is either identical on both surfaces in R. macrophylla and R. caffra or dissimilar on either surface in other species. Other features that show variation are anticlinal wall pattern, stomatal and cell inclusions. Using these micro-characters, the species can be recognised even when the leaves are fragmentary. Rauvolfia has therapeutic properties for the treatment of neuropsychiatric disorder and it can be used as aphrodisiac and genital excitant.