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  • ItemOpen Access
    An analysis of municipality management key performance indicator (KPI) and its relation to municipal manager (MM) turnover: comparison between municipalities in Gauteng and Limpopo provinces
    (University of the Free State, 2022) Mashashane, Ndangano Banyana; Cloete, Pringle
    Effective public administration and municipal management are vital for developmental states' functioning, such as South Africa. Without efficient and effective municipal managers committed to clearly outlined and systematically implemented development plans, South Africa may struggle to live up to its developmental objectives. As such, good governance of municipal managers needs to be regularly checked through project management appraisal systems. However, it is due to the goal of good governance, which is consistently checked through regular project management appraisals, that we observe a high staff turnover in local municipalities. Staff turnover can be costly if it results in the loss of human capital investment and intellectual capital, exacerbated by costs to replacing management and a loss of productivity (Mzezewa and Raushai, 2019:5). Hattingh (2020:3) notes that the South African local government invests in the human capital and intellectual development of their senior managers through offering training and other capacity building initiatives while also providing financial assistance to further qualifications while under contract. However, a recent financial audit claims that more than half of the local municipalities are currently labelled as financially distressed, which adds to the high employee turnover rate in municipal management positions. According to the Department of Cooperative Governance, of those employees suspended, 21 were municipal managers (Hattingh, 2020:33). As a response to the current problem, the government has allocated R6.6-billion to support municipalities through building capacity and strengthening municipal administrations (Hattingh, 2020:4; Polity, 2021). Based on the implications of managerialism, this dissertation hopes to add a body of knowledge on any trends of accomplishments, or any entry requirements met, which may predict the capability of good governance of municipal managers and to increase staff retention to prevent further loss of capital. The problem, however, is that a shortage of research exists on trends of which municipal manager KPI's (competencies), skills and experiences lead to completion of their contractual term and not suspension. This study therefore aimed to identify which Key Performance Indicators (KPIs) and core managerial competencies (CMCs) are present amongst municipal managers who complete their contractual terms while also performing well within the human resource management retention theory of job fit. In other words, the objective of this study is to explore and compare descriptively the municipal management turnover and any trends in the managers (MM's) KPI's and experiences that promote completion of managerial contract with the local government. The study is a cross-sectional descriptive quantitative exploration of municipality managers' performance challenges, preventing them from completing their full contractual term as a municipal manager. Information came from multiple sources, including Curriculum Vitae (CVs), KPI, CMCs, audits and exit reviews of managers. Secondary data was thematically categorised into the core competencies and KPI categories required by local government, and lastly, data was analysed and interpreted. This analysis will ultimately assist in the development of guidelines towards determining minimum requirements of managerial positions in municipalities to facilitate greater staff retention.
  • ItemOpen Access
    Perceived self-efficacy as a factor realising choice satisfaction regarding post-compulsory Physical Sciences
    (University of the Free State, 2019) Venter, Elizabeth Petronella; Stott, A. E.; Le Roux, A.
    Societies are dependent on learners studying Science, Technology, Engineering and Mathematics in order to address, for example, issues related to health, sustainability and poverty. There is a global decline in the uptake of STEM-related studies by learners at post-compulsory level, which has prompted a worldwide research focus on factors that can influence renewed learner interest in the uptake of studies related to this field. Researchers have identified four groups of factors which influence post-compulsory uptake of Science: Systemic, School, External and Individual. Self-efficacy, a concept from Social Cognitive Theory, forms part of the group of individual factors, and is under-researched in science education on post-compulsory level. Self-efficacy can also be incorporated into the Capability Approach as a conversion factor. Conversion factors transform available opportunities into realised opportunities. In this study I argue that perceived self-efficacy can possibly be seen as ‘perceived power’, in other words a personal conversion factor towards post-compulsory choice satisfaction in the context of Physical Sciences. Given the firmly established role of perceived self-efficacy in affecting a variety of aspects of people’s lives, it is conceivable for the level of perceived self-efficacy employed to affect the extent to which learners realise post-compulsory choice satisfaction regarding Physical Sciences. In 2017, I surveyed 541 Grade 10 learners from the Lejweleputswa district in the Free State, South-Africa. These Grade 10 learners were surveyed, from a capabilities perspective, on their perceived self-efficacy, satisfaction with choice regarding Physical Sciences, and some basic opportunities identified in education. Biographical data were also collected with the aim of including an account regarding the structural constraints and human diversity of learners. From a capabilities perspective, structural constraints relate to policies and institutions influencing learner opportunities, while an account of human diversity includes elements like gender and ethnicity. A simple linear regression was done to determine the relationship between perceived self-efficacy and satisfaction with choice. Multiple regression was done to adjust for biographical factors and basic opportunities identified in education. The findings show a statistically significant positive relationship between perceived self-efficacy and choice satisfaction regarding Physical Sciences. A relationship independent of biographical factors and mediated by basic opportunities in education was found. Statistically the influence of perceived self-efficacy on choice satisfaction, although small, is independent of biographical factors and basic realised opportunities in education. It is therefore conceivable that perceived self-efficacy can be seen as a personal conversion factor. This could have numerous implications regarding further research, teaching practise and policy-making.
  • ItemOpen Access
    Communities facing disruption: A pastoral approach to issues of trauma and restoration
    (University of the Free State, 2022) Mouton, Dawid Petrus; Van den Berg, J.
    Trauma and disruption can turn life upside-down for individuals and communities, shaking all stability and bringing into question the core tenets of meaningful existence. As positive and transformative science, Practical Theology finds its scope and object in the lived realities of people in the concrete, local context, where it aims to bring about change and transformation, and restoration of hope and meaningful life. In contexts where life in communities has become permeated with persistent violence, disruption and trauma, the need for a collective response to issues of trauma and disruption becomes even more acute. Making use of qualitative research and a broadly narrative approach, this study on the one hand explored the potential of resistance, agency and hope in the narratives of people facing disruption, while on the other hand, it seeks to propose a framework for a congregational pastoral care ministry response to trauma and disruption. The argument presented in this thesis is that such an approach is first and foremost grounded in the confessional identity and calling of the church. Through the metaphor of “facing” the study sought to describe some of the impacts of trauma and disruption, while the metaphor also provided a guiding narrative for a conceptual response framework. Using principles from autoethnography, the study also dealt with issues of identity, positionality and the worldview of the practical theologian and minister as a significant member of the culture being studied, highlighting the need for personal transformation and ongoing professional re-orientation in service of the ministry of care to and with her/his community. The study is valuable in at least two ways. It firstly emphasises the call for the local church to an embodied and collective ministry of care in response to issues of trauma and disruption and suggests a framework for it. It also creates the space for reflection about the subjective presence of the minister/pastor in ministry and research, and how this subjective presence, through an autoethnographic and reflexive stance, can open up new possibilities for both the spiritual leader and the community. The thesis is presented as a set of five (5) interrelated articles, enfolded by an introductory and a concluding chapter. The cohesive introduction serves to clarify the broader scope and framework of the study as well as the structure of the thesis, while the conclusion summarizes the main findings of the study and reflects on the research process in the context of the research questions and aims, and my personal journey with this project.
  • ItemOpen Access
    An investigation of the iron-cyanide mineralization in gold mine dumps
    (University of the Free State, 2022) Welman-Purchase, M. D.; Hansen, R. N.
    Cyanide, in the form of NaCN/KCN, is still widely used world-wide in the gold extraction process. Success of this extraction is owed to the high affinity that cyanide has for gold. Post extraction, waste material is added to tailings dam facilities in the form of a slurry. This slurry is likely to contain cyanide, which is hazardous if it is not managed. Another element that cyanide has a high affinity for, is iron. Iron-cyanide compounds (such as Prussian and Turnbull’s blue) are CNSAD (strong acid dissociable cyanide), meaning that they are stable compounds that only dissociate at pH conditions that are very low (<1). UV-radiation also dissociates these compounds. The potential determination of iron-cyanide compounds to form in the environment and their subsequent dissociation, is an area that requires more investigation. The main aims of the study include the modelling of Prussian/Turnbull’s blue in the goldmine tailings environment. To determine in a lab investigation whether or not iron-cyanide are able to form in different samples associated with such environments. Different analysis of the different samples and the analysis of a blue sample found on a tailings dam close to Welkom. Further modelling the affects that pH and the presence of other complexes has on the production of Prussian blue. The last aim was to determine if there are bacteria present that are able to degrade cyanide. The research approach consisted of two branches, namely modelling and the analysis of samples. Modelling was preformed using PHREEQC. The samples mentioned in this research consist of two branches, namely the laboratory study of adding cyanide to different samples and analysing them, and analysing tailings samples. Methods used in the laborarory study include XRD, FT-IR, XPS and total cyanide analysis. 9 samples were collected from a tailings dam close to Welkom, which forms apart of the Free State goldfields. XRF, ICP-OES, total cyanide, CNS analyzer (LECO) and metagenome analysis were performed on these samples. The main findings show that Prussian and Turnbull’s blue are able to form in such tailings environments. Prussian blue forms in an oxic environment and Turnbull’s blue forms in both an oxic and anoxic environment. The main variables that affect the formation of these iron-cyanide compounds is oxygen, the pH and concentrations of cyanide and iron available in solution. A NaCN solution was added to a pyrite sample, a Witwatersrand reference material and a tailings sample, where pyrite and the Witwatersrand reference material produced a blue substance. The analysis of these two samples and a blue sample from a tailings dam were analysed with FT-IR, revealing the presence of an iron-cyanide bond. The cyanide concentrations of the 9 tailings samples ranged from 0.6 – 10 ppm, where the highest concentration was found in a sample containing a blue substance (2.1) and the lowest is deeper into the tailings below the blue sample (2.3), suggesting that iron-cyanide compounds/complexes immobilize cyanide. The metagenome analysis revealed that the naturally occurring bacteria in the tailings are able to degrade or assimilate cyanide in the oligotrophic tailings environment. Cyanide is a source of carbon for the bacteria and an energy source. In conclusion, iron-cyanide compounds/complexes are able to form in the goldmine tailings environment, where a blue sample from a tailings dam was analysed and determined to be an iron-cyanide compound. It was also determined that these compounds/complexes immobilize cyanide, which are naturally degraded by the bacteria on the tailings dam. Ultimately, geochemical risk assessments for mining projects may benefit from including a microbiological aspect, which has not previously been considered. It is recommended that the following options be followed for remediation of cyanide: 1) The addition of an iron-source for iron-cyanide formation, immobilizing the cyanide 2) Burial of the material, possible burial in a mine void (anoxic environments result in higher pH conditions and zero UV radiation) or the addition of a pH buffer e.g., dolomite 3) Determine which microbes are present in the environment 4) Nurture the bacteria colonies, if found to be necessary
  • ItemOpen Access
    Investigating the role of viroplasm formation and calcium levels on the production of prostaglandin E₂ during rotavirus infection
    (University of the Free State, 2022) Sander, Willem Jacobus; O'Neill, H. G.; Pohl-Albertyn, C. H.
    Both in vitro and in vivo studies have shown that levels of prostaglandin E₂ (PGE₂), an immunomodulatory eicosanoid, are increased during rotavirus (RV) infection. Although it has been shown that inhibition of cyclooxygenase (COX) (PGE₂ biomes) has adverse effects on viral yield, the mechanism of PGE₂ induction during replication remains unknown. Viroplasms are viral factories that consist of several viral proteins, in particular NSP2 and NSP5, and cellular lipid droplets. Lipid droplets (LDs), with their high content of neutral lipids and the proximity of PGE₂ biosynthetic enzymes, are well known sites for PGE₂ biosynthesis. In addition, during replication, RV has been shown to increase the total lipid content of infected cells, while modulating specific lipid classes during infection. Inhibitors that prevent the formations of LDs severely limit the amount of viroplasms formed and subsequently decrease viral progeny production. Another viral protein critical for viral replication is the enterotoxin, NSP4. NSP4, contains a viroporin domain that selectively conducts calcium (Ca²⁺) from the endoplasmic reticulum to the cytosol, increasing free intracellular Ca²⁺. Intracellular Ca²⁺ levels are crucial for the activation and function of cytoplasmic phospholipase A₂, the rate-limiting enzyme in PGE₂ biosynthesis. Both LDs and phospholipase A₂ are also essential for PGE₂ biosynthesis. Therefore, the main objective of the study was to determine when and by which mechanism(s) RV induces/amplifies the production of prostaglandin E₂. During early infection, RV attaches to several cellular receptors and enters the cells by either clathrin-dependent or -independent endocytosis. Other viruses such as bovine ephemeral fever virus haven been shown to require the activation COX-2-mediated PGE₂/EP receptor signalling for enhanced clathrin-mediated endocytosis. To determine if PGE₂ exerts its proviral effects during internalisation we supplemented MA104 cells with γ-linolenic acid (GLA), a precursor of arachidonic acid. Infection of supplemented cells with RV SA11 led to increased production of PGE₂ as monitored by ELISA. Confocal microscopy demonstrated that PGE₂ co-localises with the viroplasm-forming proteins, NSP5 and NSP2. Due to the known association of viroplasms as well as PGE₂ with lipid droplets, our results indicate a possible role for viroplasms in the production of RV-induced PGE₂. Replication kinetics showed that inhibitors, targeting the biosynthesis of PGE₂, had negative effects on RV yield, especially during the early stages of infection. Using flow cytometry and PGE₂ addback experiments, we show that PGE₂ enhances the attachment and internalisation of rotavirus in MA104 cells, indicating a possible role for PGE₂ during clathrin-mediated RV entry. Due to the well-known association between viroplasms and LDs, and the fact that LDs are production centres for the PGE₂, we next explored the possible role if any, of viroplasm components in the induction of PGE₂ production during RV infection. Transfection of HEK293 cells with plasmids, encoding the ORFs for NSP2 and NSP5 or both NSP2 and NSP5, showed that neither protein on their own, nor the formation of viroplasm-like structures was able to induce PGE₂ production. A MA104 cell line, stably expressing NSP5, was used to generate and characterize several SA11-based rescued rotaviruses (rSA11_aNSP5 and rSA11_aNSP5) with mutations in the α-helix within the C-terminal of NSP5. We demonstrate that a rSA11 with replaced hydrophobic amino acids in the C-terminal appeared to from less viroplasms compared to rSA11. This led to reduced replication of both rSA11_aNSP5 and rSA11_pNSP5, confirming the pivotal role of the α-helix within the C-terminal during RV replication. These mutations also affected the production of PGE₂ in HEK293 infected cells, although this is more likely due to decreased viral replication. Furthermore, we investigated how the introduced mutations affect NSP5 co-sedimentation with LD-associated protein, perilipin 2, and showed that the NSP5 mutations decreasing the hydrophobicity or abolishment of the α-helix changed the sedimentation profile. Our results indicate that individual viroplasm components or the formation of VLS do not induce PGE₂ in transfected cells, but that mutations in the C-terminal of NSP5 decrease PGE₂, most probably due to decreased replication. After showing that viroplasms mainly indirectly induce the production of PGE₂, we switched our focus to the role of Calcium (Ca²⁺) as it is essential for several cellular signalling and physiological processes, including the activation of cytoplasmic phospholipase A₂ (cPLA₂). This enzyme plays a role in lipid droplet (LD) biogenesis and is the rate-limiting enzyme in prostaglandin E₂ (PGE₂) biosynthesis. During rotavirus (RV) replication, NSP4 modulates the levels of cytoplasmic Ca²⁺ (cyto[Ca²⁺]) by a viroporin domain, which selectively conducts Ca²⁺ from endoplasmic reticulum (ER) stores to the cytoplasm. This modulation of cyto[Ca²⁺] is crucial for several viral process, including entry and assembly. We, therefore, investigated the role of the viroporin domain of NSP4 in the induction of PGE₂ production during RV infection. We show that RV infection of HEK293 cells increases the activity of cPLA₂, and that the chelation of cyto[Ca²⁺] decreases the activity of cPLA₂, leading to decreases in viral progeny and RNA yield. Mutations within the viroporin domain, which decreases the conductively of Ca²⁺, decreased the activity of cPLA₂ and subsequently affected PGE₂ levels as well as viral progeny and RNA yield. Our results indicate that the viroporin domain of NSP4 plays a role in the induction of PGE₂ production by increasing the activity of cPLA₂ in a Ca²⁺-dependent manner. Taken together, the data shows that PGE₂ is most likely induced in a NSP4-cyto[Ca²⁺]-cPLA₂-dependent manner enhancing RV internalisation. This enhanced internalisation increases viral yield, which could contribute indirectly to PGE₂ production by increasing the numbers of LDs and thus sites of PGE₂ production.
  • ItemOpen Access
    Geophysical investigations in the Khakhea-Bray Transboundary Aquifer
    (University of the Free State, 2022) Ngobe, Thandeka Fortunate; Gomo, M.
    A limited number of transboundary aquifers (TBAs) in the Southern African Development Community (SADC) region have been subjected to investigations that will improve the hydrogeological understanding of the shared groundwater resource. The Khakhea-Bray transboundary aquifer, shared between Botswana and South Africa, is one of the TBAs that lacks a conceptual understanding of the groundwater systems. Therefore, this study aims to contribute to filling this research gap by conducting a geophysical investigation in the Khakhea-Bray TBA. The study applied the magnetotelluric approach to understanding the factors influencing groundwater occurrence in the dolomite of the Khakhea-Bray TBA. An ADMT-300S groundwater detectors of the ADMT series products was used to conduct the geophysical survey. This equipment measures the electric potential difference of the subsurface geology for 300 m below the surface measured at a 5 m depth interval. The magnetotelluric geophysical survey was carried out by targeting existing boreholes with accessible drilling data within the TBA. The survey stations were spaced at 3 to 5 Km intervals in areas with no boreholes. The integrated analysis approach used lithology data and water strike information from seven boreholes. The lithology data provided insight into the subsurface geology of the study area. The water strikes information of boreholes was used to calibrate the geophysical data of the dolomite aquifer system. This was done to identify the electrical properties of the water strike zones within the aquifer system, establishing the factors influencing groundwater occurrence. The geophysical data from survey stations on the same transverse line was processed into electric potential difference cross section models using RockWorks 2021 software. The distance weighting anisotropic method was applied to interpolate the data between the survey stations. The results show that the weathered-fractured zone is the main factor influencing the groundwater occurrence in the dolomite rock. The weathered-fractured zone was characterized by electric potential difference values varying between 0.02 mV to 0.065 mV. The weathered fractured zones in the dolomite were observed at shallow depths ranging between 7.5 m and 90 m. These dolomite aquifers were confirmed by the water strikes of the existing boreholes that were drilled targeting the dolomite aquifer zones. Another zone exhibiting the electric potential difference values ranging between 0.02 mV and 0.065 mV was observed at depths between 165 m and 300 m. The zone below 165 m showing the electric potential difference values between 0.02 mV and 0.065 mV was regarded as an unconfirmed potential weathered-fractured zone that needs to be validated with lithology and water strike data. Since the weathered-fractured zone was identified as the factor for groundwater occurrence in the dolomite of the study area, this suggests that during groundwater exploration for borehole drilling in the study area, the zones showing electric properties of a weathered-fractured aquifer zone must be targeted to increase the success rate of the borehole. The developed models showed the subsurface stratigraphy and the potential zones for groundwater occurrence within the transboundary dolomitic aquifer system of Khakhea-Bray TBA. This implies that the MT has the ability to map the aquifers and delineate the subsurface stratigraphic layers in dolomite settings. The models also revealed that the dolomite aquifers are confined, suggesting that these aquifers are less vulnerable to pollution from surface sources. The confined aquifer also suggests that the aquifer is not recharged directly from the top but through preferential flow paths on the dolomite rock surface.
  • ItemOpen Access
    Priming effect of leaf rust and salicylic acid in Russian wheat aphid resistance
    (University of the Free State, 2022) Bilal, Huzaifa; Mohase, L.; Boshoff, W. H. P.
    Wheat (Triticum aestivum L.) is one of the primary sources of carbohydrates for humans and livestock (Karakas et al., 2021). It is an essential cereal for the human diet and contributes to global food security. Almost 50% of calories for human consumption come from grains; out of this, about a quarter comes from wheat (González-Esteban, 2017). Wheat grain is a rich source of carbohydrates, dietary fibre, vitamins (B-vitamins) and phytochemicals (Shewry and Hey, 2015). In addition to this, it has 13-17% bran, 2-3% germ and 80-85% mealy endosperm (Šramková et al., 2009). Wheat is a significant source of globulin, albumin, and amphiphilic protein content (Dubreil et al., 1998). Furthermore, wheat provides lipids and essential minerals like calcium, copper, iron, phosphorus, potassium, manganese, magnesium, and zinc (Rachon et al., 2015). The current global wheat production is 642 million tons, and the future (2050) demand is about 840 million tons. This demand may be attained on limited resources (water, land) if new agronomic, physiological and genetic research strategies and practices are introduced (Sharma et al., 2015). Domestication of wheat occurred 10,000 years ago, and wheat spread worldwide as a major cereal crop. Its diverse adaptability to different environments makes it easy to domesticate. Genetic miscellany (ploidy level) of wheat and its progenitors reward novel diversity quickly in different climatic zones (Dubcovsky and Dvorak, 2007). Commercial wheat cultivation started in South Africa in the early 1910s in Cape Town, with seeds introduced earlier by the Dutch traders (Nhemachena and Kirsten, 2017), and has become the second most crucial grain crop cultivated in South Africa after maize (Anonymous, 2021; Bester, 2014). Both tetraploid and hexaploid wheat cultivars are produced in approximately 90% of the available agro-climatic regions of South Africa (Lantican et al., 2005). The dominant wheat-producing areas are the Western Cape (winter rainfall, mainly dryland), Free State (summer rainfall, both dryland and irrigated), Northern Cape (irrigated) and North West (mainly irrigated) provinces. Even though cultivation occurs in winter and summer rainfall regions, between 1983 and 2008, wheat was cultivated predominantly under dryland conditions where annual production averaged 1.5 to 3 million tonnes (2-2.5 tons/ha) (Nhemachena and Kirsten, 2017). However, about 30% of harvested wheat is produced under irrigation, where the yield potential varies between 6 to 12 tons/ha, with higher winter temperatures being the main limitation in the lower-yielding areas (Anonymous, 2021). The major companies or institutions supplying improved wheat cultivars in South Africa are Sensako (now part of Syngenta), Pannar Seed (Corteva AgrisciencesTM) and the Agricultural Research Council-Small Grains (ARC-SG) (Nhemachena and Kirsten, 2017). The wheat varieties are constantly improved for high yield and tolerance or resistance to prevailing drought, salinity, heat, pests and diseases. In South Africa, the wheat industry contributes about USD 40 billion to the gross value of agricultural production (Jankielsohn, 2016) and 28 000 jobs (Bester, 2014). Some pathogens (causing diseases like rust and powdery mildew) and pests similar to the Russian wheat aphid (RWA) significantly reduce yield and flour quality (Kazi et al., 2013). Russian wheat aphid infestations significantly challenge successful wheat production (Njom et al., 2017) because they reduce wheat yield and deteriorate flour quality (Girma et al., 1993). The emergence of RWA biotypes with increased virulence threatens wheat production and reduces the desired targets to meet the South African demand for high-quality wheat grain.
  • ItemOpen Access
    Investigation of the food security situation and food consumption patterns in Grassland Phase 4 informal settlement in Mangaung, South Africa
    (University of the Free State, 2022) Louw, Malessa; Du Toit, A.; Cronjé, N.; Van Niekerk, J. A.
    The current food system must provide adequate access to nutritious food for people in poor communities. An inadequate food system can contribute to food insecurity and malnutrition affecting low-income households. Poverty in informal settlements (townships) is the main cause of the lack of physical and economic access to nutritious food. Challenges such as long distances to grocery shops, transport problems, increased inflation rates, low incomes, unemployment, and inadequate information about nutritious food mean that the food system needs to become more effective in distributing adequate food. Many low-income households rely on cheap and nutrientpoor cereals such as bread, maize flour, and rice without adding many other nutrientrich food groups to their meals. The objective of this study was to investigate the food security and consumption habits of households in Grassland Phase 4 informal settlement in Mangaung. The study looked at preparation and consumption patterns, coping strategies, access to water sources, location of food purchases, total household income, and household transport. Challenges in the food system prevent adequate access to food, making households in informal settlements such as Grassland Phase 4 vulnerable to food insecurity and poor consumption patterns. The research design is quantitative, with a descriptive and exploratory approach. The sample size was 300, with compensation for incomplete questionnaires. In this study, a structured questionnaire with closed and open-ended questions was used to collect the required data. In this study, the software program EvaSys© was used to compile and construct the questionnaire. The HFIAS score, HFIAP indicator, and CSI score were used to determine the level of food insecurity. In this study, the FCS method was used to determine dietary diversity and frequency of food groups consumed. SPSS version 25 was used for basic descriptive statistics. The data collected were presented as frequencies and percentages in tables and graphs for each categorical question. Pearson and Spearman correlation coefficients were calculated in this study using the scaled data. The results of the study show that 54% of the respondent population was female, and 78.5% of the household heads were in a productive and economically active age group of 21 to 59 years. Only 27.9% of the respondents had tertiary education. Most (73.8%) of the respondents occupied a shack or informal dwelling. The main income of the household came from social benefits (51.4%) and old age pensions (45.5%). The results showed that 4.7% of the households had an income of less than R1000 per month. In addition, 19.4% of the households had no electricity and used a paraffin cooker to prepare meals. Many (66.8%) of the respondents used a minibus taxi for grocery shopping. The study found that 54.1% of households needed access to a water source for cooking. The HFIAS score of 3.32 showed that households had a medium level of food insecurity. The HFIAP category showed that 49.9% of households were food insecure, of which 17.8% were severely food insecure. These households went to bed hungry and sometimes had nothing to eat for a whole day. The CSI score of 41.8 indicates a moderate level of food insecurity. The FCS value of 31 indicates that the status of food security in Grassland Phase 4 is borderline (acceptable). This study thus shows that households are experiencing moderate to severe food insecurity and are consuming only certain major food groups. This study shows that the most consumed cereal was maize flour and the least consumed was whole grains. A process such as nixtamalization, which increases the nutritional value of maize, is essential for households where maize is consumed as a staple food, as maize contains little fibre and other nutritional components.
  • ItemOpen Access
    Molecular changes of sorghum cell suspension Cultures in response to exogenous abscisic acid
    (University of the Free State, 2022) Muthego, Dakalo; Ngara, R.
    Abiotic stresses reduce the growth and productivity of crops, thus threatening food security. It is therefore, important to develop crops that can withstand harsh environmental conditions in order to ensure availability of food. In general, plants have developed a wide range of mechanisms in response to these abiotic stresses. For example, under stress conditions, plants undergo molecular changes which include alterations in gene, protein and metabolite expression patterns that are mostly regulated by the plant hormone abscisic acid (ABA). ABAregulated stress responsive pathways are well studied in the model plant Arabidopsis (Arabidopsis thaliana), yet similar processes in sorghum (Sorghum bicolor), a drought tolerant crop, are not yet fully understood. The aim of the study was to investigate the biochemical properties and protein expression patterns of sorghum cell suspension cultures in response to exogenous ABA. White sorghum cell suspension cultures were used, and at eight days postsubculture, the cultures were treated with 100 μM ABA prepared in 70% (v/v) methanol. For control cells, an equal volume of 70% (v/v) methanol was added, and both treatment groups were incubated with shaking at 27℃ for 72 hours. Analysis of cell viability using the 3-(4,5- dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that ABA does not affect the viability of the cells at 0, 24, 48 and 72 hours. However, exogenous application of ABA for 72 hours resulted in increased accumulation of proline in the sorghum cells relative to the controls. Furthermore, proteins were extracted from the cells, as total soluble proteins (TSP), and from the culture medium, as culture filtrate proteins (CF) 72 hours after the exogenous ABA treatment. The protein profiles of the two proteomes were visually analysed on Coomassie brilliant blue-stained one-dimensional sodium dodecyl sulfate polyacrylamide gels. The gels showed that the two proteomes were of good quality even under control conditions. Furthermore, following the 72-hour ABA treatment, proteins were differentially expressed in both the TSP and CF proteomes. Moreover, isobaric tags for relative and absolute quantitation (iTRAQ) method and mass spectrometry were used to identify and quantify the differentially expressed proteins. A total of 725 and 256 proteins were identified in the TSP and CF proteomes, respectively. Of all these, 46 and 82 were ABA-responsive in the TSP and CF, respectively, and 8 proteins were common to both proteomes. Signal peptide analysis revealed that the majority of TSP found in the intracellular matrix did not have a predicted signal peptide (72%), while the majority of CF proteins found in the extracellular matrix contained signal-peptides (82%). Amongst these differentially expressed proteins in both the TSP and CF proteomes, the majority of them proteins were involved in metabolism with 37% and 35%, followed by defence with 24% and 24%, respectively. However, the metabolic processes in the CF were mainly related to carbohydrate metabolism. The signal transduction functional group was only unique to the TSP fraction, while transporters, and cell structure functional groups were unique to the CF protein fraction. The differentially expressed proteins are well-known stress proteins such as peroxidases and superoxide dismutases whose levels change under abiotic stresses. Together with causing an increase in proline content, a known osmoprotectant, exogenous ABA does indeed act as a stress phytohormone. Furthermore, these results showed that ABA influences the differential expression of both intracellular and extracellular matrix proteins, possibly suggesting the importance of both cell compartments in stress response. Furthermore, these two compartments have different roles in stress responses as suggested by the results. Therefore, the application of exogenous ABA could be the way forward to further understand plant stress response networks, and possibly to develop crops that can survive under any abiotic stress.
  • ItemOpen Access
    Abiotic stress tolerance and nutritional traits of newly developed quality protein maize hybrids in sub-Saharan Africa
    (University of the Free State, 2022) Engida, Bitew Tilahun; Labuschagne, M. T.; Terekegn, A.; Van Biljon, A.; Wegary, D.
    Drought and poor soil fertility are some of the most serious maize production challenges in sub-Saharan Africa (SSA). Identification and development of quality protein maize (QPM) cultivars that have high yield potential and tolerance to these stresses is a reliable and affordable option to improve food security and malnutrition problems in the region, especially for small scale farming communities. Although several stress tolerant maize varieties have been released and disseminated for commercial production in SSA so far, limited development and release of stress tolerant and high yielding QPM varieties compared to normal maize varieties is evident. Limited attention has also been given to the development of nutritionally enriched varieties compared to grain yield improvement. Therefore, the main goal of this study was to study 40 newly developed QPM hybrids obtained from the International Maize and Wheat Improvement Center (CIMMYT) – Zimbabwe, under stressed and non-stressed environments to allow selection of QPM hybrids that could outperform the existing commercial QPM and normal maize cultivars with respect to grain yield and concentrations of tryptophan, iron (Fe), zinc (Zn) and molar ratios of Fe and Zn to phytic acid. The specific objectives were: (1) to determine variability and performance of QPM hybrids for grain yield and agronomic traits under stressed and non-stressed environments, (2) to determine tryptophan, Zn and Fe concentrations, and molar ratios of Zn and Fe to phytic acid in QPM hybrids grown under stressed and non-stressed environments, (3) to analyse genotype by environment interaction and grain yield stability of QPM hybrids and (4) to determine correlations among grain yield, agronomic and nutritional traits in QPM hybrids evaluated under stressed and non-stressed environments. Significant variation was seen for grain yield, and almost all studied agronomic and nutritional traits under stressed and non-stressed environments. Phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) for grain yield and all other agronomic and nutritional traits under all conditions, indicating that environment effect was higher than genotype effect on the expression of the traits under stressed and non-stressed environments. Broad sense heritability of grain yield was higher than 0.6 across all environments, with the exception of managed drought conditions. Anthesis silking interval (ASI) had relatively high GCV estimates and genetic advance, as a percentage of the mean, across all conditions. This indicated that the presence of sufficient genetic variability among genotypes can improve synchronization under different management conditions through selection. Grain yield was reduced by 47% under random stress, 68% under managed drought and 71% under low N conditions. Protein and tryptophan concentrations in the grain were decreased by 36.0% and 21% respectively under low N conditions and Fe and Zn concentration also decreased by 48% and 36% under low N stress and 63% and 9% under random stress, respectively. Some QPM hybrids showed better or comparable performance in terms of grain yield potential and nutritional quality traits compared with the best QPM and normal maize checks under different management conditions, indicating the genetic gain that has been made in the QPM breeding programme. Based on Additive Main effect and Multiplicative Interaction (AMMI) analysis and Genotype and Genotype by Environment interaction (GGE) biplot analysis entries 10 (CZH142238Q) and 14 (CZH15142Q) under optimum; 23 (CZH17192Q) under random stress; 19 (CZH17188Q) and 40 (CZH17209Q) under managed drought and 14 (CZH15142Q) under low N were the most stable and the highest yielding hybrids. Environments Kwekwe (KW), Bindura (BIN), Chokwe (CHO) and Bako (BK2) were identified as discriminating and representative sites for optimum conditions, random stress, managed drought and low N stress conditions, respectively, therefore these environments are promising for selecting well adapted genotypes in the respective management conditions. Grain yield was significant and positive correlated with number of ears per plant and negatively with days to anthesis and silking under low N stress. This confirmed the importance of these secondary traits in developing high yielding and early maturing genotypes. Grain yield was not significantly correlated with most of the nutritional quality traits under all management conditions, indicating a lack of common genes for simultaneous improvement of grain yield and these nutritional traits. Significant and positive correlations were observed between Fe and Zn under low N and random stress conditions.
  • ItemOpen Access
    Delineation of groundwater protection zones: Towards a groundwater management plan in the Sutherland area, South Africa
    (University of the Free State, 2022) Mulder, Daniél; Fourie, F. D.
    The water resources of the largely groundwater-dependent Central Karoo region have been put under much strain as a result of continuous drought over the past seven years (DWS, 2021a). Rainfall patterns have been erratic, with the lowest recorded rainfall in decades. Hence, there has been limited recharge to the respective aquifers, resulting in declining groundwater levels and a decrease in borehole yields. The town of Sutherland relies solely on groundwater for its water supply. It was reported by the DWS (2021a) that in the long term, continuous water level monitoring of the production boreholes has indicated a general drop in water levels and a correlating decline in yields. In addition to dropping water levels, there has been a large increase in the number of privately owned boreholes drilled within the town area. Previously, these boreholes mostly targeted shallow water strikes within the fractured aquifer. However, with the declining water levels noted above, these boreholes have become increasingly low yielding and, in some cases, even dry. The response to this has been private drilling continuing past the shallow fractures to deeper water strikes in the aquifer, likely contributing towards a general drop in water levels within production boreholes close to town. The existing water supply boreholes are located within a 1-km radius of the town where the significant increase in groundwater use is occurring. Furthermore, historically, other than wellhead protection, the supply boreholes have been unprotected against contamination and the impact of other groundwater users. Figure 1 depicts one of the existing production boreholes and wellhead protection with a residential area in the background. In 2021, the expansion of the existing town supply with newly developed boreholes and wellfields targeted relatively undeveloped and undisturbed areas. This presented the opportunity to delineate protection zones and to develop standard operating procedures for sustainable aquifer management that will prevent the deterioration of groundwater quality and the aquifer itself through contamination and over-abstraction.
  • ItemOpen Access
    Synthesis of aromatic monopyrrolo-tetrathiafulvalene derivatives with variable degree of π‐conjugation
    (University of the Free State, 2021) Mncwangi, Sibusiso Nicko; Azov, V. A.
    Tetrathiafulvalene (TTF, 1) and its derivatives have attracted much interest and found widespread applications in molecular, supramolecular and materials chemistry.⁽¹⁾ Monopyrrolo‐tetrathiafulvalenes (MPTTF, 59) possess more extended π–system in comparison to the parent TTF 1, better π–stacking capability and, therefore, they are capable of forming stronger charge‐transfer complexes with molecular acceptors.⁽²⁾
  • ItemOpen Access
    Amphiphile-coated magnetic iron oxide nanoparticles for the extraction of contaminants from the aqueous media
    (University of the Free State, 2023) Mzinjani, Viwe; Azov, V. A; Langner, E. H. G.
    The availability of clean water to the community/ society is becoming a huge problem for its ecosystem. These toxic contaminants come from surface and subsurface water systems such as dams, rivers, and oceans that are eluted from industrial, domestic, agricultural, and recreational activities. Both organic and inorganic contaminants are found in these water systems in high concentrations, which put aquatic life at tremendous risk and the environment in general. Thus, the need for synthetic materials that can be used to solve this ongoing problem of water contamination is becoming an obvious research goal that needs urgent attention. Nanomaterials such as nanoparticles are currently being investigated as a tool to remove various contaminants in wastewater. Nanoparticles are very small particles with sizes ranging from 1 to 100 nm. Depending on their type, these nanomaterials may demonstrate various unique properties, such as strong catalytic activity, superparamagnetism, quantum confinement, and extremely high surface-to-volume ratios. In this project, the high surface-to-volume property was explored during the adsorption of methylene blue dye in spiked water samples. Magnetic iron oxide nanoparticles were chosen because of their magnetic susceptibility and most availability of iron metal on earth, making them cheaper materials since they can be prepared from cheap iron precursors. Magnetite NPs were prepared using the co-precipitation method, where iron precursors of Fe²⁺ and Fe³‏⁺ were dissolved in de-ionized water and ammonium hydroxide was used as the precipitating agent under an inert atmosphere. Better adsorption capacities of these nanoparticles can be achieved by functionalizing them with different organic and inorganic molecules. In this study, mono-alkyl phosphate esters of varying alkyl chain lengths were synthesized and used to functionalize the as-synthesized magnetite NPs to render better affinity towards organic dyes (Figure 1). The as-prepared magnetite NPs were characterized using techniques such as TEM, SEM, FTIR, EDS, and PXRD, and the organic functionalization molecules were characterized using NMR (¹H, ¹³C, and ³¹P), FTIR, and mass spectrometry. These characterization techniques confirmed the successful synthesis of the nanoparticles and mono-alkyl phosphate esters of varying alkyl chain lengths. TEM and SEM micrographs showed close to spherical shapes of the prepared nanoparticles with particle diameters ranging from 12 – 16 nm for bare Fe₃O₄ NPs and 17 – 22 nm for functionalized NPs. Comparable particle size was also obtained from the PXRD results using the Scherrer equation (eq. 3.1) where a particle size of 13 nm was obtained. PXRD characteristic peaks confirmed the inverse spinel structure of the Fe₃O₄ NPs. The presence of iron (Fe) and oxygen (O) in the EDS results confirmed the formation of the magnetite nanoparticles and the presence of carbon (C) and phosphorus (P) on the coated nanoparticles confirmed the successful coating of the Fe₃O₄ NPs. FTIR, NMR, and MS results showed comparable results to those found in the literature.
  • ItemOpen Access
    Pathogen variation and genetic control of Puccinia triticina in Zimbabwe
    (University of the Free State, 2022) Chiuraise, Nyashadzashe; Boshoff, W. H. P.; Visser, B.; Maré, A.
    Genetic resistance is the most cost-effective approach to manage wheat leaf rust caused by Puccinia triticina Eriks. (Pt). However, the continuous emergence of more virulent races can deplete monogenic sources of resistance. The aim of this study was to determine the distribution, race and genetic diversity of Pt isolates in Zimbabwe and to characterise the sources of resistance in selected wheat accessions. In total, 104 single pustule isolates of Pt were established from infected wheat samples that were collected from the main wheat production regions of Zimbabwe during surveys from 2019 to 2021. Results from phenotyping a set of 46 differential and additional wheat lines revealed Pt race MCDS as dominant in Zimbabwe. Genotyping of 48 Pt isolates with 19 microsatellite markers, followed by DARwin and STRUCTURE analyses, confirmed a high genetic similarity between the Zimbabwean isolates and representative isolates of the South African Pt races MCDS, MCPS and MFPS. However, five isolates (19_1_2019, 24_3_2019, 5_1_2020, 20_1_2020, 23_2_2020) with genetic similarity to South African races SDDN and SCDS were detected. The detection of the five genetically distinct Pt isolates among the Zimbabwean isolates indicates genetic variation that could have arisen from foreign introductions. The infection type (IT) data from screening the 39 differential lines and 72 Zimbabwean wheat accessions with nine Pt races were not informative in postulating the presence of any all-stage resistance genes (ASR). Forty-nine Zimbabwean varieties showed low (resistant) seedling ITs to all nine Pt races tested in the greenhouse and at least 53 varieties were strongly resistant with immune responses to races CFPS+Lr20 and MFPS in the field. From these, 25 wheat lines with ASR to all Pt race isolates were crossed with an MCDS susceptible variety. Twenty-three varieties displayed an F2 segregation ratio of 3:1, indicating the inheritance of a single dominant leaf rust (Lr) resistance gene. Molecular markers detected Lr19 in 20 of these varieties. Five adult plant resistance genes (APR) namely Lr27, Lr34, Lr37, Lr46 and Lr68 were detected in the Zimbabwean germplasm, with Lr46 being the most common and Lr34 the least common. A multi-environmental trial (MET) conducted over two seasons in Zimbabwe identified wheat varieties SC001, SC002, SC004, SC027 and SC W9101 as widely adapted with stable yields, acceptable leaf rust resistance while meeting the quality traits required in the wheat value chain. Overall, the outcomes of this study make a valuable contribution to shaping longer term strategies to control wheat leaf rust in Zimbabwe.
  • ItemOpen Access
    Purification strategies for equine Chorionic Gonadotropin
    (University of the Free State, 2022) Boneschans, Martie; O'Neill, F. H.; Opperman, D. J.
    Equine Chorionic Gonadotropin (eCG) is a glycoprotein hormone secreted by the endometrial cups of pregnant mares during days 37 to 120 of gestation. In equids it exhibits luteinizing hormone (LH) activity, while in non-equine species eCG exhibits both LH - and follicle stimulating hormone (FSH) like activity. Due to the high sialic acid content of eCG the 60 kD protein possess a long half-life in mammalian plasma. This, together with its dual hormonal activity (LH and FSH) makes eCG an extremely effective hormone for use in animal reproduction. Recombinant production of the hormone is still in its initial phases, therefore eCG, for commercial use, is still primarily purified from the serum of pregnant mares. Equine serum albumin remains the biggest challenge in the purification of eCG due to its relative abundance in the serum and similar molecular weight (70 kDa). This study investigated some of the strategies involved in the isolation of eCG in order to identify possible areas for improvement. We compared three different acid precipitation steps as an initial phase in the isolation of eCG from eCG-spiked equine serum. Precipitation with metaphosphoric acid (MPA) showed the highest purification factor compared to precipitation with 15% (v/v) –and 25% (v/v) trichloroacetic acid (TCA) but resulted in high eCG losses. We also investigated the use of albumin affinity chromatography in the purification process but found that both albumin and eCG bound to the albumin affinity resin, raising our suspicions about possible interaction between the proteins. Ultrafiltration, using filtration units with a MWCO of 30 kDa, proved an ineffective method in the isolation of eCG as we found that eCG exhibits an affinity for the porous membrane of the filtration unit. During cation exchange chromatography we found that when eCG was mixed with BSA, the proteins exhibited changes in their column binding properties. This was confirmed with anion exchange where neither a continuous salt – nor pH gradient could separate eCG and albumin. This further supports our notion of a possible interaction between the two proteins as albumin is widely known as a carrier protein for thyroid hormones and other molecules. We found that Lectin affinity (LAC) - and hydrophobic interaction chromatography (HIC) did succeed in separating eCG and albumin but we could not elute most of the eCG from the LAC column, therefore future work should include further optimization of the method. HIC was performed on small scale and future work should look in to using higher concentrations of protein.
  • ItemOpen Access
    Genotype and environmental effects on maize grain yield, nutritional value and milling quality
    (University of the Free State, 2022) Khajoane, Tsietso Jeanett; Mbuma, N. W.; Labuschagne, M. T.; Ramburan, S.
    In sub-Saharan Africa and other regions in the world, many people rely on maize as their primary food. To guarantee food security, high yielding and nutritious maize hybrids must be bred. Breeding for increased maize grain yield, nutritional quality traits and milling quality allows diversification and an increase in maize production. It also helps in the alleviation of malnutrition in countries that rely on maize as their dietary source. This research was conducted in order to: 1) determine the genotype and environmental effects on maize grain yield, nutritional quality traits, and milling quality, 2) determine the interrelationship among grain yield, nutritional quality traits and milling quality in maize genotypes and 3) to evaluate genotype by environment interaction for grain yield and to determine the grain yield stability of maize hybrids. Eighteen maize genotypes (nine commercial and nine experimental hybrids) were planted using a randomized complete block design (RCBD), replicated six times at seven sites representing the diverse agro-ecologies where maize is predominantly grown in South Africa. Genotype and genotype by environment interaction effects were highly significant (P ≤ 0.001) for all traits, indicating the existence of variability in the maize breeding populations. On average, broad sense heritability (H²) of nutritional quality traits, milling quality and defective grain (DEFG) ranged from 30.86 to 82.50%, which indicated that the phenotypic differences were mostly attributed to genotypic effects. Low H² (17.63%) for grain yield was observed, which indicated that phenotypic differences observed were mostly attributed to environmental factors. High performing genotypes were identified, such as G15-Ex (grain yield, fat and milling quality), G16-Ex (protein and low moisture), G11-Ex (starch) and G14-Ex (fibre). Genotype G2-C and G4-Ex had low mean values for DEFG. The findings in this study provided variation that can be exploited in breeding programmes to improve maize. Significant and positive correlation was found for protein content with grain yield, indicating that these traits could be selected and improved simultaneously. Milling quality was positively correlated with grain yield, protein, fat and low moisture, indicating that multiple trait selection would be possible. Starch was negatively associated with protein content and grain yield, suggesting that the improvement of starch will have a negative effect on maize grain yield and protein content. The clustered heat map identified three clusters of maize hybrids, which were 1) G1-C, G7-C, G9-C, G13-Ex, G14-Ex, G16-Ex and G17-Ex, associated with high protein and fibre content, 2) G4-Ex, G5-C, G6-C, G8-C and G11-Ex, associated with high grain yield, fat, moisture and fibre content and 3) G3-C, G10-C, G12-Ex, G15-Ex and G18-Ex, associated with high milling quality and fat content. Additive main effects and multiplicative interaction analysis (AMMI) identified experimental genotypes G4-Ex, G15-Ex and G17-Ex as high yielding and the most stable genotypes, which suggested that these genotypes have broad adaptation. Genotypes G8-C and G11-Ex were high yielding but unstable. The GGE scatter plot identified high yielding genotypes that showed specific (G2-C, G7-C, G8-C, G16-Ex and G17-Ex) and broad (G1-C, G4-Ex, G13-Ex and G15-Ex) adaptation in test environments and revealed two mega environments. Therefore, testing maize genotypes in different environments is important to determine their adaptability and stability before cultivar release and recommendation for commercial production. Maize hybrids with improved grain yield and nutritional quality may be used to alleviate challenges associated with malnutrition.
  • ItemOpen Access
    Enzootic geophagy by elephants (Loxodonta Africana) in relation to geochemical composition of mineral licks in Addo Elephant National Park, South Africa
    (University of the Free State, 2022) Darker, Kristen Nadine; Butler, H. J. B.
    Geophagy, the deliberate ingestion of soil, is a common occurrence amongst various animal species including mammalian herbivores such as elephants. Despite the documented instances of soil-eating, and several nonexclusive hypotheses, the real motivation behind the phenomenon remains controversial. In this study, six camera traps were set up throughout Addo Elephant National Park, South Africa at selected geophagy sites which captured visitation frequency as well as the demographic trend of elephant groups during site visits from April 2019 to May 2020. The geochemical and mineralogical composition of soils at these selected geophagy sites were analysed using X-ray diffractometry (XRD) and X-ray fluorescence spectrometry (XRF). Furthermore, the spatial distribution of five collared elephants (three matriarchs and two males) in relation to the six geophagy sites were investigated using kernel density estimations (KDE). Females had larger home ranges that incorporated more geophagy sites than males. Visitation frequency to geophagy sites were estimated using 500 m buffer zones from the centre of each site. Individuals visited at least three or more geophagy sites throughout the study period. Overall, essential elements Na, Ca and Mn were identified as main drivers for geophagic behaviour in the elephants of AENP. These essential elements (Na, Ca and Mn) are important for certain physiological demands such as bone and tusk growth in elephants and reproductive (pregnancy and lactation) demands in females. Geophagy is considered to be a contributing factor of movement patterns and area utilisation and may have important implications for conservation and management.
  • ItemOpen Access
    Influence of different selenium application methods on the physiology and morphology of drought-stressed edamame
    (University of the Free State, 2022) Sekhurwane, Masego; Moloi, M. J.
    Drought is one of the common stress factors accelerated by anthropogenic climate change contributing to crop losses across the globe. Since South Africa is classified as semi-arid, production of drought sensitive crops such as edamame (Glycine max L. Merrill) is a challenge. Over the recent years, selenium application gained attention of biologists due to its ability to reduce the adverse impacts of drought stress on crops. However, the effective method of selenium application for inducing tolerance to drought stress in edamame is not recorded. Therefore, the aim of this research was to determine the influence of different selenium application methods (seed dressing, foliar spray and soil drench) on the physiological, biochemical and morphological responses of two edamame cultivars (tolerant UVE14 and susceptible UVE17) under drought stress. The study also established relationships between the physiological, biochemical, and morphological characteristics under drought stress in edamame. The research was conducted under controlled conditions in a greenhouse. Before drought stress induction (30% water holding capacity, WHC) at the third trifoliate leaf stage (vegetative stage 4, V4), selenium was applied using different application methods [i.e., seed dressing (before sowing), foliar spray and soil drench (at first trifoliate stage)]. Optimally watered (100% WHC) plants treated with different selenium application methods served as positive controls. Physiological and biochemical data collection took place at flowering stage (reproductive stage 2, R2) and pod filling stage (R4), whereas morphological data was collected at maturity (R8) stage. The physiological responses included different chlorophyll a fluorescence parameters, stomatal conductance (gs), chloroplast pigments, electrolyte leakage (EL) and relative water content RWC). The biochemical parameters included superoxide dismutase (SOD), hydrogen peroxide (H₂O₂), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) and protein content. Results showed that the physiological and biochemical parameters were significantly different for selenium application methods at flowering and pod filling stages under drought stress. Water levels in the soil affected the physio-biochemical responses of edamame cultivars under different selenium application methods. Also, cultivars responded differently under different selenium application methods. The soil drench method was more efficient because it increased total performance index (PItotal),total chlorophyll content, stomatal conductance, RWC, H₂O₂, carotenoid, APX, GPX and SOD. Morphological data further agreed with the physio-biochemical data, showing that selenium application through soil drenching and seed dressing increased the number of seeds per plant (SPP) for drought-stressed UVE17 cultivar. The soil drenching treatment on drought-stressed edamame resulted in a high significant mean difference in the number of pods per plant (PPP), SPP and seed mass per plant (SMP), compared to the foliar and seed application methods. Correlation analysis provided evidence that increased PPP under selenium soil drench application was positively associated with high RWC, PIabs, PItotal. In addition, SOD and GPX were positively correlated to plant height (PH) and PPP for drought-stressed edamame under selenium soil drench application. Furthermore, carotenoid content positively correlated with PPP, SMPP and SPP for drought-stressed edamame under selenium seed dressing application. This study shows that under drought stress, application of selenium as a soil drench treatment is the most effective method for improving tolerance of edamame to drought stress, followed by the seed dressing method. Therefore, this work provides essential information for combating the negative effects of drought stress, which can positively contribute to food security in South Africa.
  • ItemOpen Access
    Sustainable wood harvesting principles with the aim to restore rangeland in the Thornbush Savanna of Namibia
    (University of the Free State, 2022) Boys, Jerome Marcelino; Smit, G.N.; Malan, P. J.
    The savannas of northern Namibia are prone to woody plant thickening, and land owners, therefore, attempt to restore rangelands through the removal of some or all of the woody plants with a view to reduce the negative competition interactions with the herbaceous layer, allowing an increase in the grazing capacity for livestock. The utilization of the bush resource made available through these bush control programs has led to the development of a lucrative bush value-chain industry which often leads to the over-exploitation of the resource for short-term financial gains. The effect of the most common harvesting practices such as non-selective and selective woody biomass harvesting was investigated over a three-year period in an area northwest of Otjiwarongo, described as the North-central plateau of Namibia and with vegetation classified as Thornbush Savanna. The dominant woody plant species were Senegalia mellifera and Vachellia reficiens. They are also the most sought-after species for charcoal production for their high wood yield potential, and for this reason they are also the species of interest in this study. The coppicing ability, survival, change in woody species composition, woody plant recruitment through coppice and/or sapling establishment, rate of biomass production, effect of annual total coppice defoliation on coppice regrowth survival of selected species, and growth rates and mortalities of woody plants were studied. The trail layout consisted of plots of 50 x 30 m (1 500m²) with at least two replications of each treatment. The non-selective (bush-roller and chainsaw) harvesting showed no significant differences (P>0.05) in coppice regrowth of Senegalia mellifera and Vachellia reficiens. However, although not significant (P>0.05), the chainsaw harvested plots had higher coppice rates when considering all other woody species whereas, bush-roller harvested plots had a higher sapling establishment as compared to the chainsaw harvested plots. Dichrostachys cinerea was the only species that had a highly significant (P=0.002) increase in sapling establishment. There was a change in dominance from high wood-potential (mostly S. mellifera, V. reficiens, Vachellia tortilis, V. hebeclada) to low wood-potential (mostly all Grewia species, D. cinerea, Catophractes alexandrii) species. The ETTE ha⁻¹ is projected to return to its original pre-harvest state in less than 12 years, whereas the wood biomass did not show any signs of returning to its original pre-harvest state. Annual total defoliation of coppice proved to be effective for the control of coppicing woody plants without the need for any chemical treatment (arboricide). There was a highly significant difference (P<0.01) in the rate of coppice between the two seasons (hot wet summer and cold dry winter) as treatments. Plants initially harvested in summer had a higher coppice and survival rate than plants harvested in winter. The summer harvested S. mellifera stumps coppiced more vigorously compared to V. reficiens. The winter harvested V. reficiens coppiced more vigorously compared to S. mellifera. There were highly significant differences (P<0.001) in coppice amongst the selectively versus non-selectively harvested plots. Plants harvested selectively, while retaining 4 500 ETTE ha⁻¹, had lower coppicing rates than those where the whole area was harvested non-selectively. The high ETTE ha⁻¹ before harvesting could not be matched three years after harvesting, whereas plants ha⁻¹ in the selectively thinned plots significantly (P<0.05) exceeded the original plant density (plants ha⁻¹) before initial harvesting within three years. Mature S. mellifera woody plants had a significantly higher (P<0.001) mortality rate in the bush-thickened control plots. The mortality of V. reficiens was not as high as that of S. mellifera. Regarding shoot growth, the growth in shoot length was more pronounced than that of shoot diameter. Vachellia reficiens had a significantly higher (P=0.001) growth rate in shoot length compared to S. mellifera. Allometric regression equations were also developed from harvested undamaged Senegalia mellifera and Vachellia reficiens plants for inclusion into the BECVOL-3 model. Highly significant relationships (P<0.01) were found between the spatial canopy volume and the dependent biomass variables predicted. There were negligible differences in percentage species composition of herbaceous plants amongst the different bush control treatment plots. Although surveys in all plots confirmed a state of bush thickening as per the general rule of thumb and thus the need for some form of bush thinning, the grass dry matter production did not improve, as generally assumed, with reduced woody plant competition. The herbaceous dry matter production showed a more pronounced positive response to increased rainfall rather than bush thinning during the study period. The first year of the study had a below-average annual rainfall and the rest of the years followed with above average annual rainfall.
  • ItemOpen Access
    Physio-morphological and biochemical traits of dibutyldithiophosphate treated drought-stressed edamame
    (University of the Free State, 2022) Khoza, Minah Bongiwe; Moloi, M. J.; Bowden, N.
    Edamame (Glycine max L. Merrill) has recently received attention in South Africa due to its high nutritional value. Production of edamame in South Africa is limited since the country consists of arid and semi-arid regions, with insufficient water available for irrigation. Dibutyldithiophosphate, a biodegradable chemical that slowly releases hydrogen sulfide, could be a solution based on recent studies that indicate H₂S acts as a signaling molecule for tolerance induction during various environmental stresses. This study investigated the impact of dibutyldithiophosphate on the physiological, biochemical and morphological characteristics of drought-stressed edamame cultivars (UVE14 and UVE17). Furthermore, the study established the relationships between the physiological, biochemical and the morphological characteristics [plant height, branches per plant, total seeds per plant, total seed mass per plant, and pods per plant] of drought-stressed edamame under different dibutyldithiophosphate concentrations. Dibutyldithiophosphate was directly applied around the seed during sowing before drought stress (30% water holding capacity) introduction at the third trifoliate leaf stage. Drought stress adversely affected the physiological, biochemical and morphological responses of the edamame cultivars. The efficacy of dibutyldithiophosphate differed according to the cultivars, growth stages (flowering and pod-filling), concentrations of dibutyldithiophosphate (0, 0.1, 1, and 2 mg/mL), as well as the water level (drought or optimal watering). The concentrations required to activate the physiological and biochemical responses were generally higher in drought-stressed UVE17 than UVE14 cultvar. To improve drought tolerance in edamame, dibutyldithiophosphate application upregulated the photosynthetic capacity (increased total chlorophyll content, chlorophyll-a, chlorophyll-b, and photochemical reflective index), which resulted in increased accumulation of sugars (total soluble sugars) and proline. The increase in total soluble sugars and proline indicate that dibutyldithiophosphate application increases the osmotic and antioxidative potential of drought-stressed edamame. Additionally, results of this study showed that dibutyldithiophosphate application decreased membrane damage by increasing the antioxidative capacity [superoxide dismutase, ascorbate peroxidase, flavonoid reflective index, and carotenoid reflective index] in drought-stressed edamame. Application of dibutyldithiophosphate also improved drought tolerance in a susceptible cultivar (UVE17) by increasing pods per plant (0.1 mg/mL), branches per plant (1 mg/mL), and total seed per plant (2 mg/mL). For drought-stressed UVE14, application of dibutyldithiophosphate increased branches per plant (all concentrations), pods per plant (0.1 and 1 mg/mL) and total seed per plant (2 mg/mL). Since there were more positive correlations between the physiological, biochemical and morphological characteristics under 0.1 and 1 mg/mL, these dibutyldithiophosphate concentrations could be recommended for drought tolerance stimulation in edamame. As a result, the hypothesis that application of dibutyldithiophosphate enhances the physiological, biochemical and morphological responses of drought-stressed edamame is accepted. In addition, it is acknowledged that application of dibutyldithiophosphate on drought-stressed edamame increases the relationships between physiological, biochemical and morphological responses.