Stephen Oyedeji

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• Doctor of Philosophy
• Associate Professor at University of Ilorin

Savannas are prominent members of tropical terrestrial ecosystems. Leaf and branch litter fractions were sampled from ten isolated, natural tree stands of Azadirachta indica (A. Juss), Daniella oliveri (Rolfe) Hutch & Dalziel, Parkia biglobosa (Jacq.) Benth.,Prosopis africana (Guill.&Perr.) and Vitellaria paradoxa (Gaertner) F.}, in the dry season....

Sorghum is a major staple crop in many parts of semi-arid tropics, but soil nutrient deficiencies and pollution are limiting its performance. The study was carried out to determine the combined effects of elevated levels of manganese and zinc in the soil on the germination and performance of Sorghum bicolor seedlings at the early stage of growth. A...

Tropical savannas are widespread, rich in biodiversity, with nutrient cycling being central to long-term sustainability of its phytodiversity. Understory precipitation (canopyfall and stemflow) and freefall from 13 rainfall episodes were sampled in isolated, naturally growing tree stands of Azadirachta indica (A. Juss), Daniella oliveri (Rolfe) Hut...

The increase in consumption of leafy vegetables and their inclusion in daily diet have necessitated vegetable farming throughout the year on very busy road-side farms and gardens and conventional and non-conventional farming areas without consideration for potential risk to health of the consumers. Therefore, the objective of this study is to deter...

Dry tropical biomes are unique ecosystems that experience a short rainy season followed by a marked dry season that exposes plants in these biomes to drought stress. These biomes are widespread across the globe and constitute the transition zone between the moist tropical rainforest and dry desert. The richness of biodiversity in these biomes and t...

Tropical savannas are biomes with grass-dominated herbaceous cover interspersed with scanty trees in regions with alternating wet and dry conditions. The herbaceous cover in this biome shows seasonality and acts as a driver for fire invasion. Climate change impacts are increasing fire impacts by imposing hot, dry conditions (via drought, strong win...

p class="042abstractstekst">This study evaluates eleven sesame accessions in Nigeria for performance and genetic diversity using morpho-agronomic traits, chlorophyll contents and nutrient composition in a complete randomized experimental design with five replicates. The results showed ‘Igboho Black’, ‘02M’ and ‘Kenan 4’ had the best growth attribut...

Engineered nanomaterials (ENMs) have found important usage in agriculture, especially in the areas of crop improvement and production, and disease control. Due to the special attributives possessed by ENMs especially their nano size and high surface reactivity, they are able to penetrate cells of plants and interact intracellularly with plant proce...

This study characterized, identified and conducted phylogenetic analysis on fungi contaminants in vitro bananas based on the sequence of inter-space (ITS) regions. Genomic DNA was extracted from the pure culture of fungi contaminants, amplified and sequenced using ITS1 and ITS4 markers. Analysis of the sequences using MEGA 7 Software at higher simi...

A field study on the effects of pre-and post-emergence application of herbicide (pendimethalin) on the reproductive yield of five accessions of cowpea (TVu-9092, TVu-16265, TVu-16320, TVu-16323 and TVu-16421) was conducted between June and August, 2018. Pendimethalin was applied both as pre-and early post-emergence herbicide (PE and EPOE) and follo...

Litter deposition is a major pathway for nutrients returns to soils. Despite the importance of trees in savannas, litter production and nutrient releases from scattered tree stands open space in the ecosystem have been overlooked. The study assessed litter production and organic carbon, nitrogen and phosphorus enrichment potentials from isolated st...

This study assessed early-season effects of spontaneous wildfires on soil fertility and weed diversity in two managed plantations – cashew and teak – in Ilorin, Nigeria. Soil pH and nutrients in the topsoils and subsoils of burned and unburned plantations plots after a spontaneous wildfire were analysed. Species diversity and similarity were determ...

Abstract Genetic diversity among Thaumatococcus daniellii populations in the southwestern region of Nigeria were assessed using morphometric and molecular markers to determine the population structure and existing genetic relationship for its improvement, conservation and sustainable utilisation. Populations from five locations in each of the six s...

Nanoparticles (NPs) have gained increased use globally owing to their widespread use in day-to-day human lives, their unique properties, and rapid development in the area of nanotechnology. In the course of their application in various fields, it is proposed that soil the ecosystem, which is a natural matrix, is the final environmental sink of NPs....

This study evaluates the growth and biochemical changes in Aeluropus lagopoidesi (L.) Thawaites. induced by different sodium chloride (NaCl) concentrations to understand the effects and tolerance of the plant to salinity regimes. A. lagopoides stolons were grown on Hoagland media in three replicates. At four weeks after planting, 0, 100, 300, and 5...

This paper assessed biochemical parameters in leaves of selected ornamental species growing in urban areas of southwest Nigeria to obtain the air pollution tolerance index (APTI) and anticipated performance index (API) for classification into tolerant and sensitive species against air pollution. Four sites and three ornamental species (Polyalthia l...

Air pollution is one of the major global tribulations in many developing cities around the world. This study evaluates pollution resistance of Terminalia catappa, Anacardium occidentale and Tectona grandis growing around a metal scrap-recycling factory in Osun state, Nigeria using air pollution tolerance index (APTI) and anticipated performance ind...

This study assessed the genetic diversity of six ornamental ferns in parks and gardens in Nigeria using inter-simple sequence repeat (ISSR) markers. Genomic DNA were extracted from the samples and Polymerase Chain Reaction (PCR) was performed using seven ISSR markers. The elcetrophoregram showed amplicon size ranged from 100bp-1Kb among the ferns....

This paper assessed biochemical parameters in leaves of selected ornamental species growing in urban areas of southwest Nigeria to obtain the air pollution tolerance index (APTI) and anticipated performance index (API) for classification into tolerant and sensitive species against air pollution. Four sites and three ornamental species (Polyalthia l...

The present study characterizes seed-related traits, phytochemical, physiochemical parameters and fatty acid profile of shea (Vitellaria paradoxa) seed collected from the Kosubosu, Fufu and Sare areas of Kwara State, Nigeria to determine the effects of microclimate on seed morphology, biochemical and oil constituents. Seed morphological data were a...

The study assessed the ameliorative potentials of cocoa shell powder and biochar on spent engine oil (SEO) soils using the growth performance of cowpea. Twenty-four polyethylene bags were set up consisting of seven treatments (T1 to T7) contaminated with 2% v/w SEO and control (T0) each replicated three times. Cocoa shell biochar (CSB) was applied...

Evidence of the impacts of land-use change on soil biological activities, a determinant of nutrient cycling in soil, will provide a better understanding of soil health and productivity. The study investigates temporal changes in soil chemical and microbial properties in a forest converted to oil palm plantation. Soil samples from four locations: na...

The study assessed the effectiveness of biochars derived from Daniellia oliveri and Vitellaria paradoxa in ameliorating waste lubricant oil contaminated soils and improving germination of cowpea seeds. Daniellia oliveri and Vitellaria paradoxa biochars were applied at 0.5 and 1.0 % levels to soils contaminated with 2 % v/w waste lubricant oil (WLO)...

The article compared two pretreatment liquid substances (ice water and Paradichlorobenze), duration of pretreatment and fixatives on the root mitosis of Allium cepa to determine the efficiency of the pretreatment and fixatives duration for good and visible mitotic Chromosome spreads.

The study compared two pretreatment liquid substances (ice water and paradichlorobenzene), duration of pretreatment, and fixatives on the root mitosis of Allium cepa to determine the efficiency of the pretreatment and fixatives duration for good and visible mitotic chromosome spreads. A. cepa bulbs were grown on sterile water to initiate root forma...

In order to assess the changes in soil chemical properties’ resulting from conversion of forest to other agricultural land uses a study was conducted in Okomu Forest Reserve (Nigeria). Five soil samples collected from top and sub soils of marked points within the undisturbed forest, farmland, cocoa plantation, oil palm plantation and rubber plantat...

The performance and remediation potential of Chrysopogon aciculatus (Retz.) Trin. grown in nickel contaminated soil was assessed. Six contamination regimes of 50, 100, 150, 200, 250 and 300 mg Ni/kg soil and control were set up in three replicates each. Chrysopogon aciculatus established from tillers were allowed to grow six weeks before data colle...

In this study, nineteen accessions of pea and beans varieties commonly grown for food in Nigeria were assessed for variability and diversity in seed storage protein by sodium-dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The electrophorogram revealed presence of protein in the rage of 11-120 kDa in the accessions. Low intra-specifi...

The functional quality of an aquatic ecosystem is a reflection of the health of the environment. Therefore, the present study evaluates the trace metal contamination (Pb, Cd, Ni and Mn) of water and aquatic macrophytes in Asa, Agba, Unilorin and Sobi (Moro) earthen dams, north-central Nigeria to evaluate the level of anthropogenic impact on the imm...

The upsurge in the prevalence of side effects of many synthetic antimicrobial agents and incidence of multidrug resistant bacteria has spurred scientists on the search for plant based antimicrobial of therapeutic potentials. The study extracted essential oils from the flowers of Tithonia diversifolia (Hemsl) A. Gray (Mexican sunflower) and assayed...

The ecological impact of fire regimes on plant diversity and soil fertility has become a subject of intense discussion, especially in savannas where recurring incidences are common. This study assessed the short-term effects of early-season fire on herbaceous composition, dry matter yield and soil fertility in the Guinea savanna belt of Nigeria. Da...

This study was conducted to evaluate the growth response of three leafy vegetables (Celosia argentea, Amaranthus cruentus and Amaranthus hypochodriacus) to the leaf extract of Vitellaria paradoxa. Forty-five (45) experimental plastic containers were filled with 5 kg of loamy soil each and randomly allocated to the following regimes: control, 20 g,...

This study was conducted to evaluate the growth response of three leafy vegetables (Celosia argentea, Amaranthus cruentus and Amaranthus hypochodriacus) to the leaf extract of Vitellaria paradoxa. Forty-five (45) experimental plastic containers were filled with 5 kg of loamy soil each and randomly allocated to the following regimes: control, 20 g,...

The increased use of vehicles coupled with lack of emission standards have increased the deposition of traffic-related metals in the environment. This study quantified heavy metals concentrations in soils and plants in relation to distances from Ilorin-Ibadan road, in order to determine the contributions of vehicular emissions to the environmental...

The present study considered morphological traits, pollens viability and fruit set among five tomato varieties (Roma, Tropimech, Tima, Tedino and UC-82-B) grown in Nigeria. The seeds were grown in the screen house facility at the Botanical garden, University of Ilorin Nigeria. Growth and fruiting morphological data were collected and analyzed while...

The effectiveness of tree species as bioindicators/biomonitors require appropriate selection based on their tolerance and sensitivity to air pollution which is usually evaluated by Air Pollution Tolerance Index (APTI). Despite the importance of APTI in screening tree species for biomonitoring, there are still limitations to its usefulness in green...

Ten cultivarsof cowpea grown in the screen house facility at Botanical garden, University of Ilorin, Nigeriawereevaluated for genetic similarity and variability. Data were collected on vegetative,fruiting and seed characters. Proximate analysis was conducted to determine variation in nutrient composition of the seeds at harvest. The results showed...

Floristic composition of vegetation communities of 27 plots established along a line transect in the four major directions was investigated in the vicinity of an Iron and Steel factory in Ile-Ife, Nigeria. The aim of the study was to document the plant species composition (biodiversity) of the plant communities found within the 350 m perimeter of t...

Floristic composition of vegetation communities of 27 plots established along a line transect in the four major directions was investigated in the vicinity of an Iron and Steel factory in Ile-Ife, Nigeria. The aim of the study was to document the plant species composition (biodiversity) of the plant communities found within the 350 m perimeter of t...

Mutation has been utilised to improve growth and yield of many food crops, but only little effort has been made to ascertain the nutritional advantages in such improved crops. The present study evaluates the alkylating efficiency of sodium azide of different concentrations on pod yield, nut size and nutritional composition of two groundnut varietie...

The study assessed the performance of Axonopus compressus, Chysopogon aciculatus, Sporobolus pyramidalis, Eleusine indica and Dactyloctenium aegyptium in turf establishment. The five grass species planted in sole and mixed stands were varied with the legume - Desmodium triflorum. Ground cover differed significantly among grass species and their mix...

Digitaria exilis seeds have several economic uses with long shelf life and impressive nutritional qualities. The crop is faced with problems of low yield and small- sized grains among others, thus, the crop is neglected and little information is available on its improvement by mutagenesis. This work assessed effect of Nitrous acid on growth and yie...

Dry seeds of groundnut (Arachis hypogaea) varieties Samnut 10 and Samnut 20 obtained from the Ministry of Agriculture, Ilorin, Nigeria were treated with sodium azide concentrations (10, 20, 30, 40 and 50 mM) to evaluate the vegetative and yield performances of the varieties in response to treatment. Low concentrations (10-30 mM) promoted fast germi...

Litter production and decomposition rates have great importance in maintaining the fertility of the soil. The study was carried out to determine the relationship tree characters (girth size, canopy radius, tree height, leaf area and number of primary branches), litter production and quality, and climatic variables among stands of Daniellia oliveri...

The study compares the growth, yield, and proximate composition of Amaranthus hybridus, Amaranthus cruentus, and Amaranthus deflexus, grown with poultry manure and NPK in relation to the unfertilized soil of Ilorin, Nigeria. Viable seeds of the Amaranths raised in nursery for two weeks were transplanted (one plant per pot) into unfertilized soil (c...

The study was performed to compare the crude oil-remediating potential of Cynodon dactylon and Eleusine indica in a screenhouse. The experimental design was completely randomized. Treatments used were crude oil concentrations: 0 (control), 2.5, 5.0, 7.5, 10.0 and 12.5 mL in 3 kg of soil, denoted as T 0 , T 2.5 , T 5.0 , T 7.5 , T 10.0 and T 12.5 ,...

This study was aimed at assessing atmospheric depositions of heavy metals around Nigerian NNPC depots using the moss (Barbula lambarenensis). Concentrations of 7 elements (Cd, Pb, Ni, Cu, Cr, Fe and Zn) were determined in the moss samples by Flame Atomic Absorption Spectrophotometry analysis. Nickel concentrations in the moss samples across the dep...

An investigation into the potentials of duckweed and water hyacinth as possible biomonitors of aquatic environment was carried out in River Asa. Water, duckweeds and water hyacinths were collected from six different locations along River Asa. The water and plant samples were analysed for physicochemical and heavy metal contents with standard method...

The study was conducted to evaluate the allelopathic influence of leaf powder of Anacardium occidentale under various treatments of 20 g, 40 g, 60 g and 80 g on the growth performance of Amaranthus cruentus and Celosia argentea. Data generated from the measurement of growth parameters were subjected to Analysis of Variance and DMRT after the eighth...

Characterisation of Sphenostylis stenocarpa (Hochst ex A. Rich) Harms (African yam bean) was carried out to determine the degree of diversity in some accessions in Nigeria. Twelve accessions of S. stenocarpa collected from the International Institute for Tropical Agriculture (IITA), Ibadan, Oyo State, Nigeria, were grown for morphological variabili...