Department Of Botany
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Botany was one of the foundation departments of the Faculty of Science at inception in 1964 (the first Vice-Chancellor, Prof Eni Njoku, being a reputable Botanist of international stature) when the faculty was composed of the School of Biological Sciences and the School of Mathematical and Physical Sciences.
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- ItemOpen AccessCytotaxonomy and Breeding System of the Genus Biscutella (Cruciferae)(Springer, 1984) Olowokudejo, J. D.; Heywood, V. H.Chromosome counts were determined for 46 populations of Biscutella representing 28 taxa. The genus was found to contain diploid taxa with 2n = 12, 16 and 18, tetraploid taxa with 2n =36 and hexaploid taxa having 2 n = 54. B. laevigata L. s. 1. consists of diploid and tetraploid populations which are poorly differentiated morphologically. Tetraploid B. laevigata s. 1. and hexaploid B. variegata Boiss. & Reuter (s. 1.) are characterized by chromosomal instability. The variation in" chromosome numbers and the occurrence of polyploidy is discussed in relation to the taxonomy of the genus. An investigation of the breeding system showed that most of the annual species were self-compatible and partly inbreeding and most of the perennial species self incompatible and, therefore, outbreeding, while one annual species, B. cichoriifolia Lotsel., showed both systems
- ItemOpen AccessVariation and taxonomy of Biscutella valentina in Spain(Canadian Science Publishing, 1985) Olowokudejo, J. D.Morphological studies have been made on herbarium specimens and 25 population samples of Biscutella valentina (Cruciferae) in Spain. The discontinuities in morphological characters warrant the recognition of three varieties, var. leptophylla, var. pinnata, and var. valentina, from the mass collections, and a fourth taxon, var. tenuicaulis, based on herbarium material. Experimental cultivation revealed that the combination of distinguishing characters for each taxon is genetically fixed while the observed phenotypic plastic range of the vegetative features is not wide enough to affect their taxonomic importance. Artificial crosses performed reciprocally in various combinations on seven of the populations representing three of the varieties resulted in the production of fertile hybrids. A key for identifying the varieties is presented.
- ItemOpen AccessThe Morphological Variation and Geographical Distribution of Biscutella glacialis (Boiss. etReuter) Jordan in Spain(Springer, 1986) Olowokudejo, J. D.1986): The morphological variation and geographical Biscutella glacialis (Boiss. et Reuter) Jordan in Spain. ? Folia Geobot. Phytotax., Praha, 21: 397 ? 403. ? A study was made of the morphological variation in seven population samples of B. glacialis. Data on quantitative and qualitative characters reveal that one of the populations differs considerably from the rest. Observations on geographical distribution show that this species is not endemic to the peaks of Sierra Nevada but far more widely distributed than previ? ously realized. Two varieties of B. glacialis, one of which is new, are described.
- ItemOpen AccessTaxonomic Studies in the Genus Talinum (Portulacaceae) in Nigeria(Botanischer Garten und Botanisches Museum, Berlin-Dahlem, 1986) Nyananyo, B. L.; Olowokudejo, J. D.Morphological analysis of Talinum triangulare and T cuneifolium showed a general lack of discrete phenetic discontinuities. The taxonomic status ofthe two taxa is evaluated on the basis of comparati- ve palynology, seed morphology and leaf anatomy. These features revealed taxonomically useful dif- ferences between them. A chromosome number of 2n = 24 is reported for both species as new
- ItemOpen AccessThe Infrageneric Classification of Biscutella (Cruciferae)(The New York Botanical Garden Press, 1986) Olowokudejo, J. D.A brief historical taxonomic sketch of Biscutella is given. Revisionary study of the genus throughout its geo- graphic areas has led to an infrageneric classification. Two subgenera are recog- nized, one with two sections.
- ItemOpen AccessVariation in Biscutella sempervirens (Cruciferae) in Spain(Botanischer Garten und Botanisches Museum, Berlin-Dahlem, 1986) Olowokudejo, J. D.Study of 14 living population samples of Biscutella sempervirens from Spain revealed considerable variability in vegetative characters. Two varieties, one of which is new, are recognised. Experimental cultivation showed that the combination of distinguishing characters for each variety remains intact under uniform conditions in the greenhouse
- ItemOpen AccessValue of Petiole Anatomy in the Genus Biscutella L. (Cruciferae)(Botanic Garden Meise, 1987) Olowokudejo, J. D.result of an investigation into the possible taxonomic value of comparative petiole anatomy in 46 taxa of the genus Biscutella (Cruciferae) is presented. The shape of the petioles varies from dorsiventrally flattened to subcircular or circular in transections with abaxial surface convex and adaxial surface convex or concave. In all taxa the vascular structure consists of a single collateral principal bundle accompanied by subsidiary strands in the wings. Shallow crescentiform, deeply crescentiform and U-shaped bundles all occur within the genus. The perivascular tissue may be composed of either sclerenchyma or collenchyma, or both. In some cases the anatomical features have provided characters which are of practical taxonomic use in distinguishing the species. The relative homogeneity of many anatomical characters in other groups of taxa reflected the close genetic relationships existing between them.
- ItemOpen AccessEpidermal and Phytochemical Studies in the Genus Boerhuviu (Nyctaginaceae) in Nigeria(Taylor and Francis Group, 1989) Fadeyi, M. O.; Adeoye, A. O.; Olowokudejo, J. D.Boerhavia species are widely used in African traditional medicine. Four species of the genus occurring in Nigeria have been investigated morphologically and phytochemically. Epidermal cells are either polygonal in shape with straight anticlinal walls or irregular with curved or undulate walls. The cells are variable in size and thickness both within and among species. Anomocytic stomata are found in all species except in B. drum where a mixture of both anomocytic and anisocytic types occur. Trichomes are uniseriate and unbranched but are variable in size, distribution and abundance. These features are discussed in relation to the practical identification of the taxa. Phytochemically, screening showed that all species contain flavonoid or phenolic constituents while only traces of alkaloids and tannins are present. Free or combined anthraquinones and saponins were not detectable in any of the four taxa screened.
- ItemOpen AccessTaxonomy of medicinal plants I. Epidermal morphology of the genus Khaya (Meliaceae) in West Africa(Wiley-VCH Verlag GmbH & Co. KGaA, 1990) Olowokudejo, J. D.; Nyananyo, B. L.Leaf epidermal morphology of four West African species of Khaya (Meliaceae) has been studied using both light and scanning electron microscopy. The cuticle may be striate, reticulate or verrucose. Epidermal cells are either isodiametric or irregular in shape. The anticlinical walls are of variable thickness and their positions are marked by raised ridges or shallow irregular grooves. Periclinal walls may be flat, concave or convex. Anomocytic stomata which are either superficial or slightly sunken occur in all taxa. Stomata1 size and index are variable among all species. A dichotomous key for identifying the species, even if they are in a fragmentary condition, is presented.
- ItemOpen AccessMorphological variation of fruits and infrutescences in Biscirtellcl L. (Cruciferae)(Wiley-VCH Verlag GmbH & Co. KGaA, 1992) Olowokudejo, J. D.The variation of fruits and infrutcscences in 51 taxa of the genus Biscutellu is reported. The basic structure of the fruit is similar in all species - a stalked strongly compressed indehiscent didymous silicula which breaks from the axis into two one-seeded loculi at mnturity. The peculiar and distinctive nature of the fruit constitutes the most important diagnostic feature for separating the genus from other genera. There is considerable variation in fruit size both within and between some species, e.g. the smallest fruits are found in B. microcurpu where they hardly exceed 2.5 mm x 5.0 mni while in B. rnegacarpucu they could be as big ;IS 11.0 mrn long and 18.5 mm wide. Prominent among species with significant intra-specific variation are B. lirsiranicu, B. setpercirens, B. glaciulis and B. crrlentina. The apex of the fruit is notched to varying extents except in B. uiiricirluttr where the margins run continuously with the style and the apex is therefore not notched. Style is persistent and contributes to the distinctive appearance of the fruit and the recognition of some species. Other variable characters include the pedicel. margin. valve shape and pubescence. The infrutescence varies from a simple raceme to a much-branched panicle. The flexuous branches of some taxa constitute an important feature for their preliminary identification. Some of these characters are of value in clarifying the taxonomic relationships among some component taxa.
- ItemOpen AccessTaxonomic Significance of Leaf Indumentum Characteristics of the Genus Biscutella(Cruciferae)(Springer, 1992) Olowokudejo, J. D.Leaf indumentum characteristics of 52 taxa of the genus Biscutella are examined by hand lens, stereo- and scanning electron microscopy. Hairs occur on all vegetative organs of all taxa except B. laevigata subsp. lucida which is completely glabrous and shining. Trichomes are simple unicellular and attenuate but are variable in structure, size and distribution both within and between species. Eight types of indumenta are recognized and these include hispid/hirsute, puberulent, tomentose, villous and velutinous. Each type varies in abundance from sparse to dense within the genus. In a few cases, indumentum is species-specific; for example, the whitish tomentose hair covering of B. frutescens distinguishes this species from the remaining species of the genus. In other taxonomically important species affinities are indicated. The occurrence of indumentum is discussed in relation to the various roles usually ascribed to this feature.
- ItemOpen AccessTaxonomic Significance of Leaf Indumentum Characteristics of the Genus Biscutella(Cruciferae)(Springer, 1992) Olowokudejo, J. D.Leaf indumentum characteristics of 52 taxa of the genus Biscutella are examined by hand lens, stereo- and scanning electron microscopy. Hairs occur on all vegetative organs of all taxa except B. laevigata subsp. lucida which is completely glabrous and shining. Trichomes are simple unicellular and attenuate but are variable in structure, size and distribution both within and between species. Eight types of indumenta are recognized and these include hispid/hirsute, puberulent, tomentose, villous and velutinous. Each type varies in abundance from sparse to dense within the genus. In a few cases, indumentum is species-specific; for example, the whitish tomentose hair covering of B. frutescens distinguishes this species from the remaining species of the genus. In other taxonomically important species affinities are indicated. The occurrence of indumentum is discussed in relation to the various roles usually ascribed to this feature.
- ItemOpen AccessComparative epidermal morphology of West African species of Jatropha L. (Euphorbiaceae)(The Linnean Society of London, 1993) Olowokudejo, J. D.
- ItemOpen AccessTaxonomic significance of epidermal morphology in Nigerian Rhizophoraceae(Amsterdam : North-Holland Pub. Co.,, 1993) Olowokudejo, J. D.; Obi-Osang, T. E.Epidermal morphology of adaxial and abaxial leafsurfaces of five genera of the family Rhizophoraceae in Nigeria were studied by light microscopy. The epidermises are composed of variously shaped cells which, in surface view, range in outline from triangular, rectangular to more commonly hexagonal, polygonal and irregular. Cuticular striations are absent except in Poga oleosa in which conspicuous striae encircle the guard cells and run parallel to the axis of non-specialized epidermal cells. Anticlinal walls are either straight, curved or undulate. Leaves of all genera are hypostomatic. Paracytic stromata occur in Cassipourea and Anisophyllea while all species of Rhizophora possess cyclocytic stomata. The stomata of Anopyxis are of the anisocytic type and those of Poga anomocytic. The morphology of the guard cells and stomatal ledges varies significantly within the family. Evidence is produced to support the suspected hybrid nature of Rhizophora harrisonii. Other features of the epidermis that show variationinclude stomatal size, shape and density, size and density of epidermal cells, and cell wall thickness. Epidermal characters are of some utility in elucidating relationships and identifying some taxa within the family.
- ItemOpen AccessTaxonomic Study of the Biscutella variegata Complex (Cruciferae)(Botanischer Garten und Botanisches Museum, Berlin-Dahlem, 1995) Olowokudejo, J. D.; Heywood, V. H.Taxonomic status and crossing relationships of the four taxa constituting the Biscutella varie- gata complex, i.e. B. variegata, B. megacarpaea, B. foliosa and B. latiorifolia, have been investigated. Herbarium specimens and natural population samples have been examined and analyzed. It is demonstrated that morphological characters vary widely both within and among populations and show considerable intergradation between the taxa. Six of 15 population samples studied, comprising 3 of the taxa, were crossed reciprocally in various combinations resulting in the production of fertile artificial hybrids. Evidence is produced to show that the B. variegata complex consists of a single, variable species, B. variegata, with 3 varieties, var. variegata, var. megacarpaea and var. foliosa, which occupy partially overlapping geographi- cal areas and can be distinguished only to some extent by their cauline leaves and fruit size. B. latiorifolia is not distinct from B. variegata var. megacarpaea and is therefore reduced to synonymy. The recent converse choice of B. megacarpaea, a name simultaneously published with B. variegata, as the name for the species to include B. variegata is shown to be ruled out by the earlier choice of B. variegata.
- ItemOpen AccessLipase activity of fourteen fungi on Cucumeropsis manii seeds(Botanical Society of Nigeria, 1996) Adekunle, A.A.; Uma, N. U.Texts attached
- ItemOpen AccessAncistroguineines A and B as well as Ancistrotectorine-naphthylisoquinoline alkaloids from Ancistrocladus guineensis(Elsevier Science, 1998) Bringmann, G.; Gonther, C.; Busemann, S.; Schaffer, M.; Olowokudejo, J. D.; Alo, B. I.The isolation of three naphthylisoquinoline alkaloids from the leaves of Ancistrocladus guinegnsis is described. Their complete structures were established by spectroscopic, chiroptical and degradative methods. Thus, two hitherto unknown 5,8'-coupled naphthylisoquinolines, named ancistroguineines A and B, were isolated, constituting the first example of a pair of 3-epimeric naphthylisoquinoline alkaloids. Moreover, ancistrotectorine, a 7,3'-coupled alkaloid previously known only from the South-East Asian species Ancistrocladus tectorius, was isolated. Its absolute stereostructure was confirmed by oxidative degradation and by comparison of experimental and calculated CD spectra.
- ItemOpen AccessEffect of some fungi on the anatomy of Cucumeropsis manii Naud-Holl (Melon) seeds(Scholastic Publications, Jos, Nigeria, 1998) Adekunle, A.A.; Uma, U. N.texts attached
- ItemOpen AccessAntifungal property of the crude extract of Brachystegia eurycoma and Richardia brasiliensis(Nigerian Society of Pharmacognosy, 2000) Adekunle, A.A.Texts attached
- ItemOpen AccessPreservation of Cucumeropsis mannii Naud-Holl seeds(Springer, 2000) Adekunle, A.A.; Uma, N. U.Texts attached