Chromosome number and cytomorphological characterization of a polyploid Abrus

Chromosome counts from natural populations of Abrus pulchellus in Nigeria were carried out. Tetraploid (2n = 44) chromosome number was constant in all the samples investigated. The 44 chromosomes fall into three cytomorphological categories: eight metacentric and eight submetacentric pairs, and six acrocentric pairs. The chromosomes are relatively small in length ranging from 0.5 to 1.4m. The polyploid (tetraploid) cytotype is reported for the first time for this taxon.African Journal of Biotechnology Vol. 4 (7), pp. 607-610, 200

Utilization of conserved genic SSR markers for phylogenetic analysis of Nigerian Ipomoea species

Ipomoea, with enormous economic importance, is a large genus with species that are highly evolutionarily diverged. There is dearth of information regarding the phylogenetic relationships of the Nigerian species of the genus Ipomoea. It is therefore imperative to use contemporary taxonomic evidences to understand the diversity of its distribution in a region and provide enhanced delimitation of the taxa. In this study, 6 genic simple sequence repeat (SSR) markers whose cross transferability have been established among the plant species were selected to appraise their level of polymorphism and used to study the phylogenetic relationships among 11 indigenous Nigerian Ipomoea species. The 6 SSR loci showed varying levels of polymorphism among the genotypes of all 11 species assessed and demonstrated 100% polymorphism when examined across the 11 species. A total of 55 alleles were produced. The PIC of the primers ranged between 0.2223 and 0.874 with an average value of 0.71885. Phylogenetic analysis clustered species into 3 major and 6 sub clusters wherein the species were clearly separated. This study has shown the effectiveness of developed genic SSR markers for establishing phylogenetic relationship in Ipomoea species

Breeding system and pollination ecology of two Abrus species (Fabaceae) from tropical West Africa

The pollination and breeding strategies of two Abrus species (A. precatorius L. and A. pulchellus Wall. ex Thw.) were comparatively investigated in Nigeria, West Africa. Observations were made on the phenology, floral morphology and architecture, breeding and pollination system, as well as flower-insect interactions. During 1999–2000, Abrus precatorius was observed to flower twice a year (April to June and September to November) while A. pulchellus flowered only once, from October to December. Flowers of A. precatorius never opened, which indicted obligate cleistogamy in this species. The study has produced evidence showing that the type of breeding strategy in A. pulchellus is of the facultative type. There was no evidence of agamospermy in the two species. Fourteen insects and an arachnid belonging to eleven families in six orders were observed visiting flowers of the two species. Among these visitors, Chrysops longicornis, Riptortus dentipes, Rhinocoris bicolor and Rhinocoris rapax were the most likely to aid cross-pollination and hence are legitimate visitors. Our study suggests that low outcrossing rate occurs in both species despite the predominant cleistogamous characteristics in the genus. Occurrence of low outcrossing is a kind of evolutionary homoeostasis in both species for perpetuating healthy offspring

Anatomical and Phytochemical Studies on Benincasa hispida (Thunb.) Cogn. (Cucurbitaceae)

The morphological and anatomical studies of Benincasa hispida (Thunb.) Cogn. from Nigeria was carried out with the view to reporting morphological and anatomical characteristics for the first time. Physical and microscopic (microtomy) observations were used. B. hispida is a monoecious climbing or trailing herb, stem hairy, 5-angled, with suborbicular stipuliform bract at the petiole-base; leaves simple, very hairy on both surface, alternate, blade palmately or ovate in young plant, base cordate. Flowering occurs between April and May. Female flowers solitary, male flowers solitary or in a slender-pedunculate racemes, petals-5, cream, yellow or pale yellow, ovary ellipsoid, ovules many, stigma 3-lobed and stamen 3. Fruits are large, weighs 8.5 - 9.0 kg, succulent, densely hairy when young, with a thick waxy deposit when mature, cylindrical to oblong with hairy stalk. Seeds are ovate-obovate, cream. Leaves and petals of male flower are amphistomatic with anomocytic, tetracytic and anisocytic stomata while petals of the female flower are hypostomatic with anomocytic stomata only on the abaxial surface. It has glandular and non-glandular trichomes with uniseriate stalk, clavate and multicellular gland heads. The midrib, petiole, stem, tendril, male and female flower stalks and tendril have hollow pith with 3, 9, 6-7, 16, 14 and 10 bicollateral vascular bundles respectively. The percentage crude protein, ash, carbohydrate, lipid, crude fibre, alkaloid, flavonoid, tannin and phytate could account for the numerous medicinal properties

The value of morpho-anatomical features in the systematics of Cucurbita L. (Cucurbitaceae) species in Nigeria

Comparative studies on the morphology and anatomy of the three species of Cucurbita L. (C. moschata, C. maxima and C. pepo) in Nigeria were carried out. The morphological features of significance include variations in the number of tendrils, fruit size, shape, nature of fruit stalk, leaf shape and flower colour. Seed-coat anatomy revealed four distinct zones, which varied in thickness and tissue layers. Similarities were observed in the distribution, differentiation and number of layers of cells and tissues in the leaf, petiole and stem sections. There were, however, variations in number of bicollateral vascular bundles in their petiole. While the number is 10 in C. moschata, 14 in C. pepo, it is 16 in C. maxima. Parietal placentation and 15 anther-lobes are reported for these species for the first time. The usefulness of these parameters in the taxonomic delimitation of these species is discussed

The value of leaf micromorphological in the taxonomic delimitation of Emilia cass. (Asteraceae) species

Studies were carried out on the leaf epidermis of the three species of Emilia: E. coccinea (Sims) G. Don, E. praetermissa Milne-Redhead, and E. sonchifolia (L) DC using light microscope. Epidermal cells in the species are irregular with anticlinal wall pattern sinuous in E. coccinea, sinuous in E. sonchifolia, and straight to arcuate in E. praetermissa. Epidermal cell dimensions were highest in E. praetermissa with 52.50µm and 49.64µm for the length and breadth respectively. The epidermis is hypostomatic with anomocytic stomata in all species, semi-contiguous to contiguous stomata in E. coccinea, and E. sonchifolia. Stomata index (S.I), frequency and size differed in all species. While S.I of 34.80 in E. sonchifolia was the highest in the genus, E. coccinea had the lowest S.I of 21.90. Stomata ledges occur in E. coccinea and E. praetermissa. Simple unicellular trichomes were observed only on the abaxial surface of E. coccinea. The usefulness of these data to the taxonomic delimitation of the Emilia is discussed. Keywords: Emilia, epidermis, stomata, taxonomy, trichomeGlobal Journal of Pure and Applied Sciences Vol. 12(2) 2006: 183-18

Interspecific Separation Of Gnetum L. (Gnetaceae) Based On Macro And Micro Morphological Features

The study confirmed the occurrence and distribution of two species of Gnetum (G. africanum and G. buchholzianum) in southeastern Nigeria. A new collection, Gnetum species, which is clearly distinguishable from the other two by the peculiar structure of its male strobili is reported. Macro morphological variation was observed in characters like leaf form, leaf margin, inflorescence type, fruit shape and colour. Entire and lanceolate leaves are peculiar to G. buchholzianum while bead-like inflorescence of the new collection distinguishes it from the other species. Morphometric features like length of leaf, length of internode and length of spike varied among the species. However, analysis of variance on these features showed no significant difference (P < 0.05) in their mean values. The species are hypostomatic with amphibrachy-paracytic type of stomata. Pollens are generally spherical and acolpate. Pollen fertility values were high in the three species with the new collection having the highest value of 96%. Though difference was observed in pollen diameter, the generality of micro morphological characters suggest close affinity of the species. These results are discussed with a view to providing good description and taxonomic separation of the species. KEY WORDS: Gnetum, male-strobili, pollen, stomata, vegetative-character Global Journal of Pure and Applied Sciences Vol.11(1) 2005: 23-2

<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Comparative efficiency of SRAP, SSR and AFLP-RGA markers in resolving genetic diversity in pigeon pea (<i style="mso-bidi-font-style:normal">Cajanus</i> sp.)</span>

486-495Three different marker systems, <i style="mso-bidi-font-style: normal">viz., sequence related amplified polymorphism (SRAP), simple sequence repeat (SSR) and resistance gene analogue anchored amplified fragment length polymorphism (AFLP-RGA) were employed to analyze genetic diversity among 29 pigeon pea genotypes. Furthermore, relative efficiencies of these marker systems were compared in relation to polymorphism information content (PIC), marker index (MI) and resolving power (RP). A total of 21 primers (4 SRAP, 15 SSR and 2 AFLP-RGA) screened on the genotypes that produced 258 fragments, of which 254 were polymorphic. High percentage polymorphism and average PIC were observed for SSR (97%, PIC 0.24), followed by SRAP (94%, PIC 0.21) and AFLP-RGA (93%, PIC 0.21). MI and RP values were observed to be the highest in SRAP (MI=7.30, RP=12.93), decreasing through AFLP-RGA (MI=6.05, RP=12.66) to as low as 0.71 and 1.04, respectively in SSR. Higher ranges of genetic distances were observed for AFLP-RGA (0.13-0.90), followed by SRAP (0.18-0.87) and SSR (0.28-0.97). Mantel test for matrix correspondence among the marker systems revealed SSR and SRAP matrices having good correlation (r=0.86) compared to SRAP and AFLP-RGA (r=0.68), and AFLP-RGA and SSR (0.62). UPGMA clustering based on individual and combined marker data clearly distinguished the 29 genotypes into two broad groups (cultivated and wild) mostly in relation to their pedigree. Overall ability to resolve diversity in pigeonpea as observed using these markers follows the sequence: SRAP &gt; AFLP-RGA &gt; SSR

Assessment of the Impact of Land-Use Change on the Abundance, Composition and Diversity of Mangrove Insects in Bundu-Ama, Niger Delta

Mangrove insect abundance, richness and diversity are currently experiencing a huge decline due to human activities especially in developing nations. In this study, we set out to assess the impact of land use change on the abundance, composition and diversity of mangrove insects in Bundu-Ama, Niger Delta, between the year 2017 and 2023. For this to be achieved, sampling exercise was conducted every other week for a period of three months. Insects were collected and documented with reference to the particular tree species where it was foraging at the point of collection. Insect identification was conducted in the field and later verified in the lab. A Geographic information systems software was used to determine the change in mangrove vegetation between both study periods. The result showed that about 3.39Ha of mangrove in the immediate surroundings of the sample site have been lost to infrastructure development during the period. This also resulted in a huge decline in the insect biodiversity of the mangrove ecosystem. In Avicennia, the insect population reduced from twenty-two to nine insect species, twenty-one to nine insect families, with a shift in dominance from Formicidae to Tabanidae. More so, diversity reduced to 1.766, evenness reduced to 80% and a dissimilarity value of 58% was recorded during the period. Meanwhile in Rhizophora, the insect community reduced from seven to three insect species; the family also reduced from seven to three, with Formicidae retaining its dominance. The ecological indices showed that diversity was very low (0.874), evenness increased slightly to 80% and the dissimilarity index was 41%. The study asserts that consequence of the loss of insect communities in the area would result in the decline in ecosystem services such as food provision, diseases control, loss of gene pool, plus an alteration in the natural, biological and environmental cycles. Hence, there is an urgent need for action from stakeholder groups to halt this menace and rehabilitate the mangrove ecosystem halting the detrimental impact on insect biodiversity. Moreover, there is an imminent need to educate the citizens on the consequences of their activities on the environment. Keywords: Mangrove, Insect, Land use, Niger Delta, Biodiversity DOI: 10.7176/JEES/14-4-01 Publication date: June 30th 202