Department of Botany-Journal Articles
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- ItemOpen AccessBiomonitoring of environmental pollution in the vicinity of iron and steel smelters in southwestern Nigeria using transplanted lichens and mosses(2019-10) Olise, Felix; Tunde, Ogundele Lasun; Olajire, Mudasiru A.; Oyediran, K. OwoadeThis study identified specific emission sources of atmospheric pollution in the vicinity of two secondary iron and steel smelting factories in Osun state, southwestern Nigeria, using transplanted biomonitors. A total of 120 biomonitors consisting of lichen and moss were grown under a controlled environment and later transplanted to the surroundings of each factory for monitoring of air pollutants for 3 months in both wet and dry seasons. The elemental contents (K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb and Sr) of the biomonitors were determined by X-ray florescence (XRF) spectroscopy. The source identification was performed by applying positive matrix factorization (PMF) receptor modelling approach using the elemental data set from the two smelters. Among the measured elements, Fe had the highest average concentration in the lichen and moss samples as well as in both seasons. The average concentrations of Co, Ni, Cu, Zn, As and Br were low. The varying average elemental concentrations of lichen and moss reflect the pattern of impact of smelting on atmospheric airborne pollution around the factories. The four factors resolved by PMF and their respective contributions were metal processing (39.0%), Fe source (28.0%), crustal/soil (22.0%) and road dust (11.0%) for moss and Fe source (34.0%), crustal/soil (26.0%), coal combustion (25.0%) and road dust (15.0%) for lichen. The study showcases lichen and moss as cheaper and yet efficient uninterrupted monitoring tools of air pollution sources associated with iron and steel smelting industrial activities.
- ItemOpen AccessMorpho-physiological characteristics of Vigna unguiculata [L.] Walp grown in a controlled environment using effluents from a beverage bottling company(Environmental Science and Pollution Research, 2019) Olaitan, Abiodun; Owoade, Oyediran; Oladipo, Olaniran Temitope; Agboola, Oludare OladipoThe use of industrial effluents for agricultural practices due to waste management properties, water scarcity, or cultural belief affects both the physiology and morphology of cultivated crops. This study reports the investigation of the agro-potentiality of the effluents from a beverage bottling company on cowpea (Vigna unguiculata) under a controlled environment. This greenhouse experiment was carried out within Obafemi Awolowo University. The effluents were applied at 0, 10, 20, 30, 40, and 50% concentrations using untreated (A) and treated (B) effluents separately in two groups. Physicochemical properties of the effluents were determined using standard methods. Exchangeable cations present in the effluents were investigated via the ammonium acetate exchange way. Morphological and yield parameters were measured in ten replicates. Transverse sections of the leaf, petiole, and stem were also investigated under a light microscopy. General linear model was used for statistical analysis with means compared using Tukey’s HSD test at p < 0.05. The effluents had pH, electrical conductivity, and total dissolved solids in the range of 7.4–7.5, 599.0–693.0 μS/cm, and 395.0–455.0 mg/l, respectively. The exchangeable calcium and potassium concentrations in the effluents range 1067.00–1937.50 and 190.0–343.50 mg/l. Application of effluent A had no significant effect on number of pods per group, seeds per pod, leaf length, leaf width, and leaf area of cowpea (p > 0.05). There was a significant effect of effluent A on the number of leaves and shoot height (p < 0.05). The application of effluent B had a significant effect on the mean number of leaves and seeds per pod at higher (40–50%) concentrations (p < 0.05). Amendment with effluent B showed no significant effect on the mean shoot height, leaf length, width and area, pods per group, pod length, and girth size (p > 0.05). The frequency of guard cells was observed to decrease with increasing effluents (A and B) concentration on the abaxial epidermis. Likewise, a “black deposit” was observed in the vessels in the stem taken from group amended with effluent A at high concentrations (30–50%). No anatomical differences were observed in the petiole and leaf transverse sections of the control and amended subgroups. The untreated and treated effluents showed agro-potentiality. However, crops grown need to be monitored for the health impacts on man and animal, as risk of crop cellular disruption exist.
- ItemOpen AccessEffect of pesticides on microorganisms involved in litter decomposition in cacao plantation in Ile-Ife, Nigeria(Article in Agroforestry Systems, 2016) Osewole, Afolabi; Muoghalu, I.JosephWide spread use of pesticides by farmers in agro-ecosystems to control pests may cause the disruption of nutrient cycling by adversely affecting the organisms especially microorganisms, namely bacteria and fungi, involved in decomposition processes thus altering normal nutrient cycling pattern in these ecosystems. This study, therefore, identified and determined the dynamics of bacterial and fungal species involved in cacao leaf litter decomposition and the effect of the pesticide, Ridomil Gold 66WP on the species. This was with a view to understanding the effects of pesticides used to control pests and diseases on litter decomposition rate in cacao plantations. Cacao leaf litter decomposition was studied using litterbag method. Freshly fallen leaf litter was thoroughly mixed and divided into two groups, treated and untreated. The treated was sprayed with Ridomil Gold 66WP at the rate of the recommended field rate of 3.3 g/L and air dried. 20 g of treated and untreated litter were weighed, put in separate 15 cm × 15 cm of 1.0 mm mesh size litter bags and randomly placed on the floor of cacao plantations in Ile-Ife, Nigeria. Three litter bags of each group were randomly retrieved from the plantation on monthly intervals for each month and the content of each litterbag was weighed to determine the rate of decomposition of the litter. The litter contents of each group litter were bulked, ground and microbiological analyses carried out to isolate, characterise and identify the species of bacteria and fungi involved in cacao leaf litter decomposition. The rate of decomposition of pesticide treated cacao leaf litter (0.473) was lower than that of untreated litter (0.582). A total of 31 microbial species consisting of 13 bacterial species and 18 fungal species were isolated from decomposing cacao leaf litter during the sampling period. More fungal species (16) than bacterial species (9) were involved in untreated cacao leaf litter decomposition. Species of the genera Klebsiella, Pseudomonas, Aspergillus, Penicillium and Rhizopus were the most common microorganisms involved in decomposition of cacao leaf litter. Ridomil Gold 66WP did not have significant effect on the total heterotrophic bacterial and fungal counts throughout the sampling period though their counts in treated litter were lower than in untreated litter. There were also no significant monthly variations in both total bacterial and fungal counts. It was concluded that the pesticide, Ridomil Gold 66WP, though had adverse effect on the rate of decomposition of cacao leaf litter, it did not have any adverse effect on the species of bacteria and fungi involved in decomposition of cacao leaf litter.
- ItemOpen AccessNine years of climber community dynamics in a Nigerian lowland rain forest 31 years after a ground fire(2016-12-30) Uwalaka, Nelson; Muoghalu, Joseph IkechukwuSuccessional studies in tropical forests have generally emphasized the tree component, ignoring the community dynamics of non-tree life-forms, and so there is a limited understanding of how the plant community as a whole is changing during succession within forests. Thus, this study examined the changes in climber community composition and structure in a regenerating secondary lowland rain forest at Ile-Ife that was ravaged by a ground fire 31 years ago using six sample plots. All individual climbers in each sample plot were identified, enumerated and their girths at breast height were measured. The girths were measured at 1.3 m height or just before the point of branching. Our data were compared with those of previous studies in the forest to determine the changes in floristics and structure of climber community over the years using Sorenson’s similarity index. The mortality and recruitment rates in the forest during the course of succession were determined. Climber species increased from 49 (2005) to 61 (2014). Climber density increased astronomically from 448–1152 ha⁻¹ (2005) to 1712–4492 ha⁻¹ but basal area only increased slightly from 0.37–1.10 m² ha⁻¹ (2005) to 0.40–1.14 m² ha⁻¹. The recruitment rate (8%) was higher than the mortality rate (5.8%). The similarity of the climber species composition calculated using the Sorenson similarity index showed that the similarity between the two periods of study was 0.53 (53%). This study concluded that during the study period, the climber community changed, and climber species abundance and structure increased
- ItemOpen AccessStudies on the Reproductive Biology of Emilia (Asteraceae - Senecioneae) 2. Floret Number, reproductive Propagules and Seed Germination(2006) Adedeji, O.Floret number displayed low variability within each species and is statistically species-specific, and thus considered of great diagnostic value in taxonomic evaluation within the genus Emilia CASS. (Asteraceae-Senecioneae). Two reproductive propagules were identified in the genus Emilia, viz. the seeds and the adventitious roots. The incidence of production of adventitious roots was highest in E. coccinea. E. praetermissa Milne-Redh., the allotetraploid hybrid of E. coccinea (SIMS) G. DON and E. sonchifolia (L.) DC., had the shortest number of days to germination and the highest percentage germination performance. The compensatory balance between the two reproductive propagules in the genus is highlighted.