Electrocatalytic behahiour of cobalt tetraamino-phthalocyanine in the presence of a composite of reduced graphene nanosheets and of multi-walled carbon nanotubes
- Nyoni, Stephen, Nyokong, Tebello
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189784 , vital:44931 , xlink:href="https://doi.org/10.1016/j.electacta.2014.05.093"
- Description: A composite of multi-walled carbon nanotubes (MWCNT) with reduced graphene nanosheets (rGNS-2) was developed in order to minimize the restacking of the latter. The composite was used to modify a glassy carbon electrode (GCE). GCE was further modified with cobalt tetraamino phthalocyanine (CoTAPc). The modified electrode is represented as rGNS-2-MWCNT-CoTAPc-GCE. X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electrochemical microscopy and Raman spectroscopy were used to explore into surface functionalities, morphology and topography of the nanocomposite. The rGNS-2-MWCNT-CoTAPc-GCE had a low limit of detection of 3.32 × 10−8 M towards the detection of paraguat as a test analyte. A mechanism for paraquat detection using an rGNS-2-MWCNT-CoTAPc-GCE is also proposed in this work.
- Full Text:
- Date Issued: 2014
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189784 , vital:44931 , xlink:href="https://doi.org/10.1016/j.electacta.2014.05.093"
- Description: A composite of multi-walled carbon nanotubes (MWCNT) with reduced graphene nanosheets (rGNS-2) was developed in order to minimize the restacking of the latter. The composite was used to modify a glassy carbon electrode (GCE). GCE was further modified with cobalt tetraamino phthalocyanine (CoTAPc). The modified electrode is represented as rGNS-2-MWCNT-CoTAPc-GCE. X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electrochemical microscopy and Raman spectroscopy were used to explore into surface functionalities, morphology and topography of the nanocomposite. The rGNS-2-MWCNT-CoTAPc-GCE had a low limit of detection of 3.32 × 10−8 M towards the detection of paraguat as a test analyte. A mechanism for paraquat detection using an rGNS-2-MWCNT-CoTAPc-GCE is also proposed in this work.
- Full Text:
- Date Issued: 2014
Improved l-cysteine electrocatalysis through a sequential drop dry technique using multi-walled carbon nanotubes and cobalt tetraaminophthalocyanine conjugates
- Nyoni, Stephen, Mugadza, Tawanda, Nyokong, Tebello
- Authors: Nyoni, Stephen , Mugadza, Tawanda , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193813 , vital:45398 , xlink:href="https://doi.org/10.1016/j.electacta.2013.10.023"
- Description: Voltammetry, chronoamperometry, scanning electrochemical microscopy and electrochemical impedance spectroscopy methods are used for characterization of a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs)–cobalt tetraaminophthalocyanine (CoTAPc) mixture or sequential drop dry modification technique whereby the MWCNTs are first placed on to the electrode followed by CoTAPc. The sequential drop dry CoTAPc–MWCNTs modified surface gave better catalytic responses with a catalytic rate constant of 2.2 × 105 M−1 s−1, apparent electron transfer rate constant of 0.073 cm s−1, and a limit of detection of 2.8 × 10−7 M. Scanning electrochemical microscopy (SECM) surface characterization (topography and reactivity) further gave proof the better catalytic perfomance of the sequential drop dry CoTAPc–MWCNTs modified surface.
- Full Text:
- Date Issued: 2014
- Authors: Nyoni, Stephen , Mugadza, Tawanda , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193813 , vital:45398 , xlink:href="https://doi.org/10.1016/j.electacta.2013.10.023"
- Description: Voltammetry, chronoamperometry, scanning electrochemical microscopy and electrochemical impedance spectroscopy methods are used for characterization of a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs)–cobalt tetraaminophthalocyanine (CoTAPc) mixture or sequential drop dry modification technique whereby the MWCNTs are first placed on to the electrode followed by CoTAPc. The sequential drop dry CoTAPc–MWCNTs modified surface gave better catalytic responses with a catalytic rate constant of 2.2 × 105 M−1 s−1, apparent electron transfer rate constant of 0.073 cm s−1, and a limit of detection of 2.8 × 10−7 M. Scanning electrochemical microscopy (SECM) surface characterization (topography and reactivity) further gave proof the better catalytic perfomance of the sequential drop dry CoTAPc–MWCNTs modified surface.
- Full Text:
- Date Issued: 2014
Development of Graphene/CdSe Quantum Dots‐Co Phthalocyanine Nanocomposite for Oxygen Reduction Reaction
- Nyoni, Stephen, Nyokong, Tebello
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189944 , vital:44950 , xlink:href="https://doi.org/10.1002/elan.201400372"
- Description: Nanocomposites containing CdSe quantum dots, tetra(4-(4,6-diaminopyrimidin-2-ylthio) phthalocyaninatocobalt(II)) (CoPyPc) and reduced graphene nanosheets (rGNS) were devoloped and used for the modification of a glassy carbon electrode. Characterization of the nanocomposites was done by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses. Cyclic voltammetry (CV) was used for electrochemical characterization of the prepared nanocomposite for oxygen reduction reaction. The oxygen reduction activity for rGNS/CdSe-CoPyPc nanocomposite was found to be superior over the individual nanomaterials in this study. The activity of the nanocomposite towards oxygen reduction was also tested for tolerance to methanol crossover effect using chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) studies.
- Full Text:
- Date Issued: 2014
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189944 , vital:44950 , xlink:href="https://doi.org/10.1002/elan.201400372"
- Description: Nanocomposites containing CdSe quantum dots, tetra(4-(4,6-diaminopyrimidin-2-ylthio) phthalocyaninatocobalt(II)) (CoPyPc) and reduced graphene nanosheets (rGNS) were devoloped and used for the modification of a glassy carbon electrode. Characterization of the nanocomposites was done by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses. Cyclic voltammetry (CV) was used for electrochemical characterization of the prepared nanocomposite for oxygen reduction reaction. The oxygen reduction activity for rGNS/CdSe-CoPyPc nanocomposite was found to be superior over the individual nanomaterials in this study. The activity of the nanocomposite towards oxygen reduction was also tested for tolerance to methanol crossover effect using chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) studies.
- Full Text:
- Date Issued: 2014
Career success for women academics in higher education: choices and challenges
- Authors: Obers, Nöelle Marie Thérèse
- Date: 2014
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61346 , vital:28017 , http://0-journals.co.za.wam.seals.ac.za/content/high/28/3/EJC159132
- Description: The aim of the research reported on in this article was to contribute to an understanding of how women academics experience career success; how their choices and challenges impact on their career advancement; and how the playing fields in academia can be levelled. Understanding the constraints and identifying enabling aspects may help women academics to overcome obstacles in their career development and be more represented in academia and ultimately in society. This research was a case study undertaken at one higher education institution (HEI), Rhodes University (RU). The data was collected from institutional documents; questionnaire data from women academics at the HEI; and in-depth interviews with six women academics. The data indicate that mentoring is a strategy to enhance levels of self-esteem and research productivity and ultimately improve the representation of women in leadership and senior positions.
- Full Text:
- Date Issued: 2014
- Authors: Obers, Nöelle Marie Thérèse
- Date: 2014
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61346 , vital:28017 , http://0-journals.co.za.wam.seals.ac.za/content/high/28/3/EJC159132
- Description: The aim of the research reported on in this article was to contribute to an understanding of how women academics experience career success; how their choices and challenges impact on their career advancement; and how the playing fields in academia can be levelled. Understanding the constraints and identifying enabling aspects may help women academics to overcome obstacles in their career development and be more represented in academia and ultimately in society. This research was a case study undertaken at one higher education institution (HEI), Rhodes University (RU). The data was collected from institutional documents; questionnaire data from women academics at the HEI; and in-depth interviews with six women academics. The data indicate that mentoring is a strategy to enhance levels of self-esteem and research productivity and ultimately improve the representation of women in leadership and senior positions.
- Full Text:
- Date Issued: 2014
Resource nationalism: a threat or a panacea to economic development
- Authors: Ocran, Matthew
- Subjects: Natural resources , Nationalism , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20901 , vital:29412
- Description: I seek to achieve three objectives in my lecture: first I attempt an outline of the evolution of economic thought regarding progress from the medieval period to contemporary times. Following the discussion of the mainstream theories of economic growth I then review the associated empirical literature. I also consider a brief case study on two successful countries before addressing the question whether resource nationalism matter in determining economic development. Lastly, I provide some policy recommendations for economic development in South Africa and other resource rich countries on the continent.
- Full Text:
- Authors: Ocran, Matthew
- Subjects: Natural resources , Nationalism , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20901 , vital:29412
- Description: I seek to achieve three objectives in my lecture: first I attempt an outline of the evolution of economic thought regarding progress from the medieval period to contemporary times. Following the discussion of the mainstream theories of economic growth I then review the associated empirical literature. I also consider a brief case study on two successful countries before addressing the question whether resource nationalism matter in determining economic development. Lastly, I provide some policy recommendations for economic development in South Africa and other resource rich countries on the continent.
- Full Text:
Effects of number of ring substituents on the physicochemical properties of zinc aminophenoxy phthalocyanine-single walled carbon nanotube conjugate
- Ogbodu, Rachael O, Nyokong, Tebello
- Authors: Ogbodu, Rachael O , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190356 , vital:44987 , xlink:href="https://doi.org/10.1016/j.jphotochem.2013.09.015"
- Description: This work reports on the linking of zinc monoaminophenoxy (ZnMAPPc) or zinc tetraaminophenoxy phthalocyanine (ZnTAPPc) complexes to single walled carbon nanotubes (SWCNTs) through either covalent or non-covalent (adsorption) bonding. The functionalized complexes showed better thermal stability when compared to the SWCNT-COOH, ZnMAPPc and ZnTAPPc alone as confirmed by thermogravimetric analyses. The covalently linked ZnMAPc-SWCNT showed higher electron transfer rate constant and photoinduced electron efficiency when compared to adsorbed complexes. ZnMAPPc-SWCNT complexes (linked and adsorbed) showed better photophysical and photochemical properties when compared to ZnTAPPc-SWCNT complexes. The triplet, singlet oxygen and florescence quantum yields of ZnMAPPc (or ZnTAPPc) decrease upon linking or adsorption onto SWCNTs.
- Full Text:
- Date Issued: 2014
- Authors: Ogbodu, Rachael O , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190356 , vital:44987 , xlink:href="https://doi.org/10.1016/j.jphotochem.2013.09.015"
- Description: This work reports on the linking of zinc monoaminophenoxy (ZnMAPPc) or zinc tetraaminophenoxy phthalocyanine (ZnTAPPc) complexes to single walled carbon nanotubes (SWCNTs) through either covalent or non-covalent (adsorption) bonding. The functionalized complexes showed better thermal stability when compared to the SWCNT-COOH, ZnMAPPc and ZnTAPPc alone as confirmed by thermogravimetric analyses. The covalently linked ZnMAPc-SWCNT showed higher electron transfer rate constant and photoinduced electron efficiency when compared to adsorbed complexes. ZnMAPPc-SWCNT complexes (linked and adsorbed) showed better photophysical and photochemical properties when compared to ZnTAPPc-SWCNT complexes. The triplet, singlet oxygen and florescence quantum yields of ZnMAPPc (or ZnTAPPc) decrease upon linking or adsorption onto SWCNTs.
- Full Text:
- Date Issued: 2014
Effect of bovine serum albumin and single walled carbon nanotube on the photophysical properties of zinc octacarboxy phthalocyanine
- Ogbodu, Racheal O, Nyokong, Tebello
- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189806 , vital:44933 , xlink:href="https://doi.org/10.1016/j.saa.2013.10.064"
- Description: This work reports on the photophysical parameters of the conjugate between zinc octacarboxy phthalocyanine (ZnOCPc) and bovine serum albumin (BSA) represented as ZnOCPc–BSA (1) which was further adsorbed onto single walled carbon nanotubes (SWCNT) represented as (ZnOCPc–BSA–SWCNT 2). ZnOCPc (without BSA) was also adsorbed on SWCNT represented as ZnOCPc–SWCNT (3). The presence of BSA resulted in the increase in singlet oxygen quantum yield (ΦΔ) for 1 (at ΦΔ = 0.44) and 2 (at ΦΔ = 0.41) compared to ΦΔ = 0.21 for ZnOCPc alone. For complex 3 which did not contain BSA singlet oxygen quantum yield decreased.
- Full Text:
- Date Issued: 2014
- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189806 , vital:44933 , xlink:href="https://doi.org/10.1016/j.saa.2013.10.064"
- Description: This work reports on the photophysical parameters of the conjugate between zinc octacarboxy phthalocyanine (ZnOCPc) and bovine serum albumin (BSA) represented as ZnOCPc–BSA (1) which was further adsorbed onto single walled carbon nanotubes (SWCNT) represented as (ZnOCPc–BSA–SWCNT 2). ZnOCPc (without BSA) was also adsorbed on SWCNT represented as ZnOCPc–SWCNT (3). The presence of BSA resulted in the increase in singlet oxygen quantum yield (ΦΔ) for 1 (at ΦΔ = 0.44) and 2 (at ΦΔ = 0.41) compared to ΦΔ = 0.21 for ZnOCPc alone. For complex 3 which did not contain BSA singlet oxygen quantum yield decreased.
- Full Text:
- Date Issued: 2014
Apprehension of bias and the spectacle of the fair-minded observer: a survey of recent commonwealth and South African decisions on pre-judgment
- Okpaluba, Chuks, Juma, Laurence
- Authors: Okpaluba, Chuks , Juma, Laurence
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126107 , vital:35850 , http://specjuris.ufh.ac.za/apprehension-bias-and-spectacle-fair-minded-observer-survey-recent-commonwealth-and-south-african
- Description: A perusal of contemporary Commonwealth case law reveals that allegations of bias or apprehension of bias tend to revolve around the pecuniary or other interests of the Judge arising from kinship, previous relationship, or association with party or counsel.1Apparent bias could also be inferred from the judge‘s conduct or utterances, especially, his/her criticisms or cumulative criticisms of a party during proceedings or in adjudication.2In other instances, a judge‘s previous knowledge or association with the case in court, or of an important witness, may disqualify him/her from sitting or passing judgment in the case.3
- Full Text:
- Date Issued: 2014
- Authors: Okpaluba, Chuks , Juma, Laurence
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126107 , vital:35850 , http://specjuris.ufh.ac.za/apprehension-bias-and-spectacle-fair-minded-observer-survey-recent-commonwealth-and-south-african
- Description: A perusal of contemporary Commonwealth case law reveals that allegations of bias or apprehension of bias tend to revolve around the pecuniary or other interests of the Judge arising from kinship, previous relationship, or association with party or counsel.1Apparent bias could also be inferred from the judge‘s conduct or utterances, especially, his/her criticisms or cumulative criticisms of a party during proceedings or in adjudication.2In other instances, a judge‘s previous knowledge or association with the case in court, or of an important witness, may disqualify him/her from sitting or passing judgment in the case.3
- Full Text:
- Date Issued: 2014
Incorporating surrogate species and seascape connectivity to improve marine conservation outcomes
- Olds, Andrew D, Connolly, Rod M, Pitt, Kylie A, Maxwell, Paul S, Aswani, Shankar, Albert, Simon
- Authors: Olds, Andrew D , Connolly, Rod M , Pitt, Kylie A , Maxwell, Paul S , Aswani, Shankar , Albert, Simon
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124722 , vital:35655 , https://doi.10.1111/cobi.12242
- Description: Conservation focuses on maintaining biodiversity and ecosystem functioning, but gaps in our knowledge of species biology and ecological processes often impede progress. For this reason, focal species and habitats are used as surrogates for multispecies conservation, but species-based approaches are not widely adopted in marine ecosystems. Reserves in the Solomon Islands were designed on the basis of local ecological knowledge to conserve bumphead parrotfish (Bolbometopon muricatum) and to protect food security and ecosystem functioning. Bumphead parrotfish are an iconic threatened species and may be a useful surrogate for multispecies conservation. They move across tropical seascapes throughout their life history, in a pattern of habitat use that is shared with many other species. We examined their value as a conservation surrogate and assessed the importance of seascape connectivity (i.e., the physical connectedness of patches in the seascape) among reefs, mangroves, and seagrass to marine reserve performance. Reserves were designed for bumphead parrotfish, but also enhanced the abundance of other species. Integration of local ecological knowledge and seascape connectivity enhanced the abundance of 17 other harvested fish species in local reserves. This result has important implications for ecosystem functioning and local villagers because many of these species perform important ecological processes and provide the foundation for extensive subsistence fisheries. Our findings suggest greater success in maintaining and restoring marine ecosystems may be achieved when they are managed to conserve surrogate species and preserve functional seascape connections.
- Full Text:
- Date Issued: 2014
- Authors: Olds, Andrew D , Connolly, Rod M , Pitt, Kylie A , Maxwell, Paul S , Aswani, Shankar , Albert, Simon
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124722 , vital:35655 , https://doi.10.1111/cobi.12242
- Description: Conservation focuses on maintaining biodiversity and ecosystem functioning, but gaps in our knowledge of species biology and ecological processes often impede progress. For this reason, focal species and habitats are used as surrogates for multispecies conservation, but species-based approaches are not widely adopted in marine ecosystems. Reserves in the Solomon Islands were designed on the basis of local ecological knowledge to conserve bumphead parrotfish (Bolbometopon muricatum) and to protect food security and ecosystem functioning. Bumphead parrotfish are an iconic threatened species and may be a useful surrogate for multispecies conservation. They move across tropical seascapes throughout their life history, in a pattern of habitat use that is shared with many other species. We examined their value as a conservation surrogate and assessed the importance of seascape connectivity (i.e., the physical connectedness of patches in the seascape) among reefs, mangroves, and seagrass to marine reserve performance. Reserves were designed for bumphead parrotfish, but also enhanced the abundance of other species. Integration of local ecological knowledge and seascape connectivity enhanced the abundance of 17 other harvested fish species in local reserves. This result has important implications for ecosystem functioning and local villagers because many of these species perform important ecological processes and provide the foundation for extensive subsistence fisheries. Our findings suggest greater success in maintaining and restoring marine ecosystems may be achieved when they are managed to conserve surrogate species and preserve functional seascape connections.
- Full Text:
- Date Issued: 2014
Steam activation, characterisation and adsorption studies of activated carbon from maize tassels.
- Olorundare, O F, Msagati, Titus A, Krause, Rui W M, Okonkwo, J O, Mamba, Bhekie B
- Authors: Olorundare, O F , Msagati, Titus A , Krause, Rui W M , Okonkwo, J O , Mamba, Bhekie B
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123847 , vital:35507 , https://doi.org/10.1080/02757540.2013.877001
- Description: In this paper, steam-produced activated carbon (STAC) from maize tassel (MT) was evaluated for its ability to remove basic dye (methylene blue MB) from aqueous solution in a batch adsorption process. The equilibrium experiments were conducted in the range of 50–300 mg/L initial MB concentrations at 30°C, for effect of pH, adsorbent dosage and contact time. The experimental data were analysed by Langmuir, Freundlich and Temkin isotherm models of adsorption. Freundlich adsorption isotherm was found to have highest value of R2(R2=0.97) compared to other models of Langmuir and Temkin having (0.96 and 0.95 respectively). STAC has a high adsorptive capacity for MB dye (200 mg/g) and also showed favourable adsorption for the dye with the separation factor for the dye-activated carbon system. The kinetic data obtained were analysed using pseudo first-order kinetic equation and pseudo second-order kinetic equation. The experimental data fitted well into pseudo second-order kinetic equation, as demonstrated by the high value of R2.
- Full Text:
- Date Issued: 2014
- Authors: Olorundare, O F , Msagati, Titus A , Krause, Rui W M , Okonkwo, J O , Mamba, Bhekie B
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123847 , vital:35507 , https://doi.org/10.1080/02757540.2013.877001
- Description: In this paper, steam-produced activated carbon (STAC) from maize tassel (MT) was evaluated for its ability to remove basic dye (methylene blue MB) from aqueous solution in a batch adsorption process. The equilibrium experiments were conducted in the range of 50–300 mg/L initial MB concentrations at 30°C, for effect of pH, adsorbent dosage and contact time. The experimental data were analysed by Langmuir, Freundlich and Temkin isotherm models of adsorption. Freundlich adsorption isotherm was found to have highest value of R2(R2=0.97) compared to other models of Langmuir and Temkin having (0.96 and 0.95 respectively). STAC has a high adsorptive capacity for MB dye (200 mg/g) and also showed favourable adsorption for the dye with the separation factor for the dye-activated carbon system. The kinetic data obtained were analysed using pseudo first-order kinetic equation and pseudo second-order kinetic equation. The experimental data fitted well into pseudo second-order kinetic equation, as demonstrated by the high value of R2.
- Full Text:
- Date Issued: 2014
Activated carbon from lignocellulosic waste residues: effect of activating agent on porosity characteristics and use as adsorbents for organic species
- Olorundare, O F, Okonkwo, J O, Msagati, T A M, Mamba, Bhekie B, Krause, Rui W M
- Authors: Olorundare, O F , Okonkwo, J O , Msagati, T A M , Mamba, Bhekie B , Krause, Rui W M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125233 , vital:35748 , https://doi.org/10.1007/s11270-014-1876-2
- Description: This paper reports on the effect of activating agents such as the impregnation ratio of phosphoric acid (1:1–1:5) at constant activation temperature on the performance of porous activated carbon from waste residues (maize tassel). The variation in the impregnation ratio of the produced activated carbon (AC) from 1:1 to 1:5 enabled the preparation of a high surface area (1,263 m2/g) and a large pore volume (1.592 cm3/g) of AC produced from maize tassel (MT) using a convectional chemical activating agent (phosphoric acid). Impregnation ratios (IR) of the precursors were varied between 1:1 and 1:5 in which it was found that the ratio of 1:4 was optimal based on the high surface area, while 1:5 has the optimal pore volume value for the produced activated carbon.
- Full Text:
- Date Issued: 2014
- Authors: Olorundare, O F , Okonkwo, J O , Msagati, T A M , Mamba, Bhekie B , Krause, Rui W M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125233 , vital:35748 , https://doi.org/10.1007/s11270-014-1876-2
- Description: This paper reports on the effect of activating agents such as the impregnation ratio of phosphoric acid (1:1–1:5) at constant activation temperature on the performance of porous activated carbon from waste residues (maize tassel). The variation in the impregnation ratio of the produced activated carbon (AC) from 1:1 to 1:5 enabled the preparation of a high surface area (1,263 m2/g) and a large pore volume (1.592 cm3/g) of AC produced from maize tassel (MT) using a convectional chemical activating agent (phosphoric acid). Impregnation ratios (IR) of the precursors were varied between 1:1 and 1:5 in which it was found that the ratio of 1:4 was optimal based on the high surface area, while 1:5 has the optimal pore volume value for the produced activated carbon.
- Full Text:
- Date Issued: 2014
Editorial
- Authors: Olvitt, Lausanne L
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391156 , vital:68625 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/121960"
- Description: This year marks the end of the United Nations Decade of Education for Sustainable Development which was first proposed at the World Summit on Sustainable Development in 2002 in Johannesburg. At the end of 2014 UNESCO hosted the World Conference on Education for Sustainable Development in Nagoya, Japan. To mark this occasion Professor Rob O’Donoghue produced a reflective Think Piece that traces the emergence of education for sustainable development (ESD) from its educational roots in the Modernist project, to the diversity of practices that currently frame ESD as a transgressive process of cultural change. O’Donoghue interrogates tensions around knowledge and participation in the ESD terrain and proposes that knowledge-led and ethics-led learning in relation to valued purposes might create educational possibilities for expansive, transgressive and reflexive learning processes towards a more sustainable future. This Think Piece opens the Journal; many of the strengths, tensions and generative opportunities in environment and sustainability education referred to by O’Donoghue are reflected in this edition of the journal.
- Full Text:
- Date Issued: 2014
- Authors: Olvitt, Lausanne L
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391156 , vital:68625 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/121960"
- Description: This year marks the end of the United Nations Decade of Education for Sustainable Development which was first proposed at the World Summit on Sustainable Development in 2002 in Johannesburg. At the end of 2014 UNESCO hosted the World Conference on Education for Sustainable Development in Nagoya, Japan. To mark this occasion Professor Rob O’Donoghue produced a reflective Think Piece that traces the emergence of education for sustainable development (ESD) from its educational roots in the Modernist project, to the diversity of practices that currently frame ESD as a transgressive process of cultural change. O’Donoghue interrogates tensions around knowledge and participation in the ESD terrain and proposes that knowledge-led and ethics-led learning in relation to valued purposes might create educational possibilities for expansive, transgressive and reflexive learning processes towards a more sustainable future. This Think Piece opens the Journal; many of the strengths, tensions and generative opportunities in environment and sustainability education referred to by O’Donoghue are reflected in this edition of the journal.
- Full Text:
- Date Issued: 2014
Comparison of the biology of geographically distinct populations of the citrus pest, Thaumatotibia leucotreta (Meyrick)(Lepidoptera: Tortricidae)
- Opoku-Debrah, John K, Hill, Martin P, Knox, Caroline M, Moore, Sean D
- Authors: Opoku-Debrah, John K , Hill, Martin P , Knox, Caroline M , Moore, Sean D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405769 , vital:70204 , xlink:href="https://hdl.handle.net/10520/EJC160246"
- Description: Baculovirus biopesticides are an important component of integrated pest management programmes worldwide. One such example is the Cryptophlebia leucotreta granulovirus (CrleGV) which is used for the control of false codling moth, Thaumatotibia (= Cryptophlebia) leucotreta (Meyrick) (Lepidoptera: Tortricidae), a pest of citrus and other crops in South Africa. A potential problem associated with constant application of viral biopesticides is the differing susceptibility to the virus observed between different geographic populations of the insect host. This could be related to a number of factors, including biological performance and fitness of the target insect population. This study compared a variety of phenotypic traits between geographically distinct T. leucotreta populations collected from the Addo, Marble Hall, Citrusdal and Nelspruit regions of South Africa, and reared under laboratory conditions for several generations. Traits including pupal mass, female fecundity, egg hatch, pupal survival, adult eclosion and developmental time were used as parameters to measure biological performance and fitness. Insects from the Citrusdal region of the Western Cape exhibited significantly lower pupal mass, female fecundity, egg hatch, pupal survival, adult eclosion and the longest duration in larval and pupal development compared to the other colonies investigated. This is the first study to report differences in the performance of laboratory reared T. leucotreta from different geographic locations, and the findings may have important implications for the application of viral biopesticides for the control of this pest in South Africa.
- Full Text:
- Date Issued: 2014
- Authors: Opoku-Debrah, John K , Hill, Martin P , Knox, Caroline M , Moore, Sean D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405769 , vital:70204 , xlink:href="https://hdl.handle.net/10520/EJC160246"
- Description: Baculovirus biopesticides are an important component of integrated pest management programmes worldwide. One such example is the Cryptophlebia leucotreta granulovirus (CrleGV) which is used for the control of false codling moth, Thaumatotibia (= Cryptophlebia) leucotreta (Meyrick) (Lepidoptera: Tortricidae), a pest of citrus and other crops in South Africa. A potential problem associated with constant application of viral biopesticides is the differing susceptibility to the virus observed between different geographic populations of the insect host. This could be related to a number of factors, including biological performance and fitness of the target insect population. This study compared a variety of phenotypic traits between geographically distinct T. leucotreta populations collected from the Addo, Marble Hall, Citrusdal and Nelspruit regions of South Africa, and reared under laboratory conditions for several generations. Traits including pupal mass, female fecundity, egg hatch, pupal survival, adult eclosion and developmental time were used as parameters to measure biological performance and fitness. Insects from the Citrusdal region of the Western Cape exhibited significantly lower pupal mass, female fecundity, egg hatch, pupal survival, adult eclosion and the longest duration in larval and pupal development compared to the other colonies investigated. This is the first study to report differences in the performance of laboratory reared T. leucotreta from different geographic locations, and the findings may have important implications for the application of viral biopesticides for the control of this pest in South Africa.
- Full Text:
- Date Issued: 2014
Applications of lead phthalocyanines embedded in electrospun fibers for the photoinactivation of Escherichia coli in water
- Osifeko, Olawale L, Nyokong, Tebello
- Authors: Osifeko, Olawale L , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189898 , vital:44945 , xlink:href="https://doi.org/10.1016/j.dyepig.2014.05.010"
- Description: Lead (II) pyridyloxyphthalocyanine (PbTpyPc) and its quaternized form (PbTepyPc) were synthesized and the photophysical behavior examined. Low fluorescence quantum yields (ΦF) of 0.01 and 0.02 were observed for PbTepyPc and PbTpyPc, respectively. The singlet oxygen quantum yields (ΦΔ) were 0.60 and 0.68, for PbTepyPc and PbTpyPc, respectively using DPBF as a quencher in DMF. Singlet oxygen production of the embedded sensitizers in electrospun fiber were quantified using ADMA and were found to be ΦΔ = 0.41 and ΦΔ = 0.21 for PbTepyPc and PbTpyPc, respectively. Photodynamic inactivation of Escherichia coli (E. coli) with the quaternized photosensitizer at 5 μM, totally inactivated the E. coli (with log CFU = 10 decrease). Only 0.4 log CFU decrease was obtained with PbTpyPc. The embedded non-quaternized photosensitizer (PbTpyPc) was less active on the gram negative bacteria but the quaternized photosensitizer (PbTepyPc) was effective towards inactivation of E. coli.
- Full Text:
- Date Issued: 2014
- Authors: Osifeko, Olawale L , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189898 , vital:44945 , xlink:href="https://doi.org/10.1016/j.dyepig.2014.05.010"
- Description: Lead (II) pyridyloxyphthalocyanine (PbTpyPc) and its quaternized form (PbTepyPc) were synthesized and the photophysical behavior examined. Low fluorescence quantum yields (ΦF) of 0.01 and 0.02 were observed for PbTepyPc and PbTpyPc, respectively. The singlet oxygen quantum yields (ΦΔ) were 0.60 and 0.68, for PbTepyPc and PbTpyPc, respectively using DPBF as a quencher in DMF. Singlet oxygen production of the embedded sensitizers in electrospun fiber were quantified using ADMA and were found to be ΦΔ = 0.41 and ΦΔ = 0.21 for PbTepyPc and PbTpyPc, respectively. Photodynamic inactivation of Escherichia coli (E. coli) with the quaternized photosensitizer at 5 μM, totally inactivated the E. coli (with log CFU = 10 decrease). Only 0.4 log CFU decrease was obtained with PbTpyPc. The embedded non-quaternized photosensitizer (PbTpyPc) was less active on the gram negative bacteria but the quaternized photosensitizer (PbTepyPc) was effective towards inactivation of E. coli.
- Full Text:
- Date Issued: 2014
Tapping into the World of Terpenoids
- Authors: Oyedeji, A O
- Date: 2014
- Subjects: Terpenoids , Terpenes , Medicinal plants -- Analysis
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/11260/1111 , vital:30607
- Description: Terpenes are a class of secondary metabolites found in plants and insects (such as termites or swallowtail butterflies). Terpenes are strong-smelling aromatic hydrocarbon which are used by plants/ insects to protect themselves by deterring parasites. They are secondary metabolites synthesized in plants. When a hydrogen or atoms of hydrogen, are replaced by other atoms such as oxygen, in a terpene compound, the terpene becomes a terpenoid (also known as isoprenoids). Terpenoids are a large and diverse class of naturally occurring organic chemicals, derived from five-carbon isoprene units assembled and modified in thousands of ways. They are multicyclic structures that differ from one another not only in functional group but also in their basic carbon skeletons. Terpenoids are found in all classes of living things, and are the largest group of natural products.
- Full Text:
- Date Issued: 2014
- Authors: Oyedeji, A O
- Date: 2014
- Subjects: Terpenoids , Terpenes , Medicinal plants -- Analysis
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/11260/1111 , vital:30607
- Description: Terpenes are a class of secondary metabolites found in plants and insects (such as termites or swallowtail butterflies). Terpenes are strong-smelling aromatic hydrocarbon which are used by plants/ insects to protect themselves by deterring parasites. They are secondary metabolites synthesized in plants. When a hydrogen or atoms of hydrogen, are replaced by other atoms such as oxygen, in a terpene compound, the terpene becomes a terpenoid (also known as isoprenoids). Terpenoids are a large and diverse class of naturally occurring organic chemicals, derived from five-carbon isoprene units assembled and modified in thousands of ways. They are multicyclic structures that differ from one another not only in functional group but also in their basic carbon skeletons. Terpenoids are found in all classes of living things, and are the largest group of natural products.
- Full Text:
- Date Issued: 2014
Modelling annual evapotranspiration in a semi-arid, African savanna: functional convergence theory, MODIS LAI and the Penman–Monteith equation
- Palmer, Anthony R, Weideman, Craig I, Finca, Andiswa, Everson, Colin S, Hanan, Niall P, Ellery, William F N
- Authors: Palmer, Anthony R , Weideman, Craig I , Finca, Andiswa , Everson, Colin S , Hanan, Niall P , Ellery, William F N
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144387 , vital:38341 , DOI: 10.2989/10220119.2014.931305
- Description: Accurately measuring evapotranspiration (ET) is essential if we are to derive reasonable estimates of production and water use for semi-arid savannas. Estimates of ET are also important in defining the health of an ecosystem and the quantity of water used by the vegetation when preparing a catchment-scale water balance. We derived ET0 from an automatic weather station 30 km west of Skukuza, Kruger National Park, South Africa using the Penman– Monteith equation, and then used the MODIS LAI to inform the model of canopy phenological dynamics. This result was compared with 173 days of ET measurements from the eddy covariance (ETec) system near Skukuza in 2007 as well as from the ET recorded by a large-aperture scintillometer at the same site in 2005. The model compared favourably with both sets of measured data and, when used independently of the eddy covariance data, ETMODIS predicted an annual ET of 378 mm in 2007 for the semi-arid savanna around the Skukuza flux site.
- Full Text:
- Date Issued: 2014
- Authors: Palmer, Anthony R , Weideman, Craig I , Finca, Andiswa , Everson, Colin S , Hanan, Niall P , Ellery, William F N
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144387 , vital:38341 , DOI: 10.2989/10220119.2014.931305
- Description: Accurately measuring evapotranspiration (ET) is essential if we are to derive reasonable estimates of production and water use for semi-arid savannas. Estimates of ET are also important in defining the health of an ecosystem and the quantity of water used by the vegetation when preparing a catchment-scale water balance. We derived ET0 from an automatic weather station 30 km west of Skukuza, Kruger National Park, South Africa using the Penman– Monteith equation, and then used the MODIS LAI to inform the model of canopy phenological dynamics. This result was compared with 173 days of ET measurements from the eddy covariance (ETec) system near Skukuza in 2007 as well as from the ET recorded by a large-aperture scintillometer at the same site in 2005. The model compared favourably with both sets of measured data and, when used independently of the eddy covariance data, ETMODIS predicted an annual ET of 378 mm in 2007 for the semi-arid savanna around the Skukuza flux site.
- Full Text:
- Date Issued: 2014
Aspects of the biology and life history of largespot pompano, Trachinotus botla, in South Africa
- Parker, Daniel, Booth, Anthony J
- Authors: Parker, Daniel , Booth, Anthony J
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123798 , vital:35499 , https://doi.10.1071/MF14029
- Description: Trachinotus botla is an important recreational surf zone-dependent fish species distributed in the Indo-west Pacific from South Africa to Australia. In South Africa it is restricted to the northern KwaZulu-Natal coast. Biological investigations revealed that it is a fast growing species that attains a maximum age of, 7 years. Males and females sexually matured in their third year. It has a protracted summer spawning season with evidence of serial spawning behaviour. T. botla is an opportunistic predator with a generalist diet, with fish feeding on a wide variety of prey items particularly those that are temporally ‘superabundant’. Small fish fed predominantly on copepods and terrestrial insects, whereas larger fish consumed bivalves and crabs. Teleosts, primarily engraulids, were important components to the diet of fish of all sizes. An ontogenetic dietary shift was observed just after sexual maturity (300-mm fork length) that is possibly linked to a change in habitat preference with larger fish foraging on deeper reefs.
- Full Text:
- Date Issued: 2015
- Authors: Parker, Daniel , Booth, Anthony J
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123798 , vital:35499 , https://doi.10.1071/MF14029
- Description: Trachinotus botla is an important recreational surf zone-dependent fish species distributed in the Indo-west Pacific from South Africa to Australia. In South Africa it is restricted to the northern KwaZulu-Natal coast. Biological investigations revealed that it is a fast growing species that attains a maximum age of, 7 years. Males and females sexually matured in their third year. It has a protracted summer spawning season with evidence of serial spawning behaviour. T. botla is an opportunistic predator with a generalist diet, with fish feeding on a wide variety of prey items particularly those that are temporally ‘superabundant’. Small fish fed predominantly on copepods and terrestrial insects, whereas larger fish consumed bivalves and crabs. Teleosts, primarily engraulids, were important components to the diet of fish of all sizes. An ontogenetic dietary shift was observed just after sexual maturity (300-mm fork length) that is possibly linked to a change in habitat preference with larger fish foraging on deeper reefs.
- Full Text:
- Date Issued: 2015
Prioritisation of potential agents for the biological control of the invasive alien weed, Pereskia aculeata (Cactaceae), in South Africa
- Paterson, Iain D, Vitorino, Marcello D, de Cristo, S C, Martin, Grant D, Hill, Martin P
- Authors: Paterson, Iain D , Vitorino, Marcello D , de Cristo, S C , Martin, Grant D , Hill, Martin P
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76946 , vital:30644 , https://doi.org/10.1080/09583157.2013.864382
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien species in South Africa that is native in Central and South America. In South Africa, P. aculeata outcompetes native plant species leading to a reduction in biodiversity at infested sites. Herbicidal and mechanical control of the plant is ineffective and unsustainable, so biological control is considered the only potential solution. Climatic matching and genotype matching indicated that the most appropriate regions in which to collect biological control agents were Santa Catarina and Rio de Janeiro provinces in Southern Brazil. Surveys throughout the native distribution resulted in 15 natural enemy species that were associated with the plant. Field host range data, as well as previous host plant records, were used to prioritise which of the species were most likely to be suitably host specific for release in South Africa. The mode of damage was used to determine which species were most likely to be damaging and effective if released. The most promising species prioritised for further study, including host specificity and impact studies, were the stem-wilter Catorhintha schaffneri Brailovsky and Garcia (Coreidae); the stem boring species Acanthodoxus machacalis Martins and Monné (Cerambycidae), Cryptorhynchus sp. (Curculionidae) and Maracayia chlorisalis (Walker) (Crambidae) and the fruit galler Asphondylia sp. (Cecidomyiidae). By prioritising the potential biological control agents that are most likely to be host-specific and damaging, the risk of conducting host specificity testing on unsuitable or ineffective biological control agents is reduced.
- Full Text:
- Date Issued: 2014
- Authors: Paterson, Iain D , Vitorino, Marcello D , de Cristo, S C , Martin, Grant D , Hill, Martin P
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76946 , vital:30644 , https://doi.org/10.1080/09583157.2013.864382
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien species in South Africa that is native in Central and South America. In South Africa, P. aculeata outcompetes native plant species leading to a reduction in biodiversity at infested sites. Herbicidal and mechanical control of the plant is ineffective and unsustainable, so biological control is considered the only potential solution. Climatic matching and genotype matching indicated that the most appropriate regions in which to collect biological control agents were Santa Catarina and Rio de Janeiro provinces in Southern Brazil. Surveys throughout the native distribution resulted in 15 natural enemy species that were associated with the plant. Field host range data, as well as previous host plant records, were used to prioritise which of the species were most likely to be suitably host specific for release in South Africa. The mode of damage was used to determine which species were most likely to be damaging and effective if released. The most promising species prioritised for further study, including host specificity and impact studies, were the stem-wilter Catorhintha schaffneri Brailovsky and Garcia (Coreidae); the stem boring species Acanthodoxus machacalis Martins and Monné (Cerambycidae), Cryptorhynchus sp. (Curculionidae) and Maracayia chlorisalis (Walker) (Crambidae) and the fruit galler Asphondylia sp. (Cecidomyiidae). By prioritising the potential biological control agents that are most likely to be host-specific and damaging, the risk of conducting host specificity testing on unsuitable or ineffective biological control agents is reduced.
- Full Text:
- Date Issued: 2014
A promising biological control agent for the invasive alien plant, Pereskia aculeata Miller (Cactaceae), in South Africa
- Paterson, Iain D, Mdodana, Lumka A, Mpekula, Ongezwa, Mabunda, Bheki D, Hill, Martin P
- Authors: Paterson, Iain D , Mdodana, Lumka A , Mpekula, Ongezwa , Mabunda, Bheki D , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416806 , vital:71387 , xlink:href="https://doi.org/10.1080/09583157.2014.919439"
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien plant from Central and South America that has become a problematic environmental weed in South Africa. A potential biological control agent, the stem-wilter, Catorhintha schaffneri Brailovsky and Garcia (Coreidae), was collected in southern Brazil and imported into quarantine in South Africa. Field host range data suggested that C. schaffneri has a host range restricted to P. aculeata. No-choice nymph survival tests were then conducted on 27 test plant species in 9 families. Survival to the adult stage was only recorded on P. aculeata and the closely related Pereskia grandifolia Haw. (Cactaceae). Mortality was significantly higher on P. grandifolia with only 3% of the nymphs reaching the adult stage compared with 74% on P. aculeata indicating that P. aculeata is the primary host plant. P. grandifolia is native in South America and is of no agricultural importance in South Africa so any feeding on P. grandifolia in South Africa would have no negative environmental or economic consequences. In other tests, adult survival on P. aculeata [25.8 days (SE ± 3.74)] was significantly longer than on other test plant species [4.3 days (SE ± 0.36)] further confirming the host specificity of the species. Impact studies conducted in quarantine indicated that C. schaffneri is damaging to P. aculeata, significantly reducing the number of leaves and the shoot lengths of plants, even at relatively low insect densities. C. schaffneri is safe for release in South Africa and is likely to be a damaging and effective agent.
- Full Text:
- Date Issued: 2014
- Authors: Paterson, Iain D , Mdodana, Lumka A , Mpekula, Ongezwa , Mabunda, Bheki D , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416806 , vital:71387 , xlink:href="https://doi.org/10.1080/09583157.2014.919439"
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien plant from Central and South America that has become a problematic environmental weed in South Africa. A potential biological control agent, the stem-wilter, Catorhintha schaffneri Brailovsky and Garcia (Coreidae), was collected in southern Brazil and imported into quarantine in South Africa. Field host range data suggested that C. schaffneri has a host range restricted to P. aculeata. No-choice nymph survival tests were then conducted on 27 test plant species in 9 families. Survival to the adult stage was only recorded on P. aculeata and the closely related Pereskia grandifolia Haw. (Cactaceae). Mortality was significantly higher on P. grandifolia with only 3% of the nymphs reaching the adult stage compared with 74% on P. aculeata indicating that P. aculeata is the primary host plant. P. grandifolia is native in South America and is of no agricultural importance in South Africa so any feeding on P. grandifolia in South Africa would have no negative environmental or economic consequences. In other tests, adult survival on P. aculeata [25.8 days (SE ± 3.74)] was significantly longer than on other test plant species [4.3 days (SE ± 0.36)] further confirming the host specificity of the species. Impact studies conducted in quarantine indicated that C. schaffneri is damaging to P. aculeata, significantly reducing the number of leaves and the shoot lengths of plants, even at relatively low insect densities. C. schaffneri is safe for release in South Africa and is likely to be a damaging and effective agent.
- Full Text:
- Date Issued: 2014
ISSRs indicate that Chromolaena odorata invading southern Africa originates in Jamaica or Cuba
- Paterson, Iain D, Zachariades, Coastas
- Authors: Paterson, Iain D , Zachariades, Coastas
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406105 , vital:70239 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.04.005"
- Description: Two biotypes of the invasive alien plant, Chromolaena odorata (L.) R.M. King and Rob. (Asteraceae: Eupatorieae), are recognized in the plant’s introduced distribution. The Asian/West African (A/WA) biotype is present in West and Central Africa, India, Southeast Asia and Oceania, while the southern African (SA) biotype is only present in southern Africa. Biological control using insect natural enemies has been significantly more successful against the A/WA biotype than the SA biotype, suggesting that host plant incompatibility may have resulted in reduced efficacy of biological control agents in southern Africa. Inter-Simple Sequence Repeats (ISSR) were used to identify the origin of the SA biotype as Jamaica or Cuba. The data also confirm that the SA biotype is genetically distinct from the A/WA biotype and that the SA biotype is the result of a separate introduction. Biological control agents for C. odorata in southern Africa should be sourced from Jamaica and Cuba in order to avoid host plant incompatibility problems.
- Full Text:
- Date Issued: 2014
- Authors: Paterson, Iain D , Zachariades, Coastas
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406105 , vital:70239 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.04.005"
- Description: Two biotypes of the invasive alien plant, Chromolaena odorata (L.) R.M. King and Rob. (Asteraceae: Eupatorieae), are recognized in the plant’s introduced distribution. The Asian/West African (A/WA) biotype is present in West and Central Africa, India, Southeast Asia and Oceania, while the southern African (SA) biotype is only present in southern Africa. Biological control using insect natural enemies has been significantly more successful against the A/WA biotype than the SA biotype, suggesting that host plant incompatibility may have resulted in reduced efficacy of biological control agents in southern Africa. Inter-Simple Sequence Repeats (ISSR) were used to identify the origin of the SA biotype as Jamaica or Cuba. The data also confirm that the SA biotype is genetically distinct from the A/WA biotype and that the SA biotype is the result of a separate introduction. Biological control agents for C. odorata in southern Africa should be sourced from Jamaica and Cuba in order to avoid host plant incompatibility problems.
- Full Text:
- Date Issued: 2014