27 research outputs found
Floral biology and the effects of plant-pollinator interaction on pollination intensity, fruit and seed set in Solanum
Reproductive biology and patterns of plant-pollinator interaction are fundamental to gene flow, diversity and evolutionary success of plants. Consequently, we examined the magnitude of insect-plant interaction based on the dynamics of breeding systems and floral biology and their effects on pollination intensity, fruit and seed set. Field and laboratory experiments covering stigma receptivity, anthesis, pollen shed, load and viability, pollinator watch vis-à-vis controlled self, cross and pollinator-exclusion experiments were performed on nine taxa of Solanum: Solanum aethiopicum L., Solanum anguivi Lam., Solanum gilo Raddi, Solanum erianthum Don, Solanum torvum SW, Solanum melongena L. (‘Melongena’ and ‘Golden’) and Solanum scabrum Mill. (‘Scabrum’ and ‘Erectum’). Pollen shed commenced 30 min before flower opening attaining peak at 20 to 30 min and continued until closure. Stigma was receptive 15 to 30 min before pollen release, making most species primary inbreeders (100% selfed) but facultatively outbreeding (12.5 to 75%) through insect pollinators such as Megachile latimanus, Diplolepis rosae and Bombus pennsylvanicus. S. scabrum ‘Scabrum’ was an obligate inbreeder, while S. scabrum ‘Erectum’ was facultatively outbreeding (12.5%). S. melongena ‘Melongena’ was strongly outcrossing (75%) than its relative ‘Golden’ (25%). Small pollen and anther assured high pollen load and pollination efficiency and vice versa, except S. torvum. Diploid species (2n = 24) received crossed pollen (25 to 53.9%) from related species than the tetraploid S. scabrum (2n = 48; 0 to 11%). We concluded that insect-pollinators complement self pollination in Solanum. They provide cross-pollen, which enhanced gene exchange and hybrids in natural population and lower inbreeding depression.Key words: Breeding system, hybridization, insect pollinator, outcrossing, pollination, Solanum
The Causes of the Fluctuation in the Exchange Rate in South Africa
ABSTRACT This study uses the OLS estimation method to analyse the factors that determine exchange rate variation in South Africa. Two groups of explanatory variables are used: the first group comes from extant empirical studies and the other group consists of new variables. The analysis of existing variables reveals that the variables are individually and jointly insignificant. The explanatory variables used in the regression include Gross Domestic Product, Consumer Price Index and Inflation Rate. Quarterly data for these variables are used in the estimation. The second regression uses the following explanatory variables: South Africa’s Foreign Reserves, South Africa’s Total Money Stock, South Africa’s Prime Overdraft Rate and the USA Interest rate. According to the results, all the variables but one (South Africa’s Foreign Reserves) are found to be statistically significant. The coefficient of determination was remarkably higher than the one obtained from the first regression. The study calls for the South African policymakers to increase the interest rate in order to reverse the adverse effects of steady depreciation that has been experienced in the exchange rate recently
Phytochemical constituents and antioxidant activities of aqueous and methanol stem extracts of Costus afer Ker Gawl. (Costaceae)
Medicinal plants contain bioactive compounds capable of preventing and fighting oxidative related diseases. These compounds must be screened and assayed before effective drugs are developed. Thus, phytochemical constituents and antioxidant activities of aqueous and methanol stem extracts of Costus afer Ker-Gawl were evaluated. C. afer contained flavonoids, phenols, anthraquinones, cardiac glycosides, terpenoids, alkaloids and tannins. Preliminary screening of free radical scavenging activity of extracts with 2,2-Diphenyl-1-picrylhydrazyl (DPPH) using thin layer chromatography tested positive. The aqueous extract had a higher free radical scavenging activity with IC50 (concentration of samples required for 50% inhibition of DPPH radical activity) value of 64.42 g/ml than methanol extract (92.33 g/ml). Furthermore, total phenolic content in aqueous extract (0.66 ± 0.02 mg gallic acid equivalent/g) was significantly higher (p < 0.05) than methanol extract (0.52 ± 0.01 mg gallic acid equivalent/g). In addition, inhibition of lipid peroxidation by aqueous extract (80.60 ± 0.28%) was significantly higher (p < 0.05) than methanol extract (77.00 ± 0.84%). Nevertheless, methanol and aqueous extracts of C. afer possess anti-oxidative properties as well as bioactive metabolites. Thus, stem extracts of C. afer could serve as sources of antioxidants and bioactive compounds for nutrition and therapeutic purposes.Key words: Costus afer, phytochemicals, antioxidant, phenol, nutrition, therapeutic
Cultivars of Codiaeum variegatum (L.) Blume (Euphorbiaceae) show variability in phytochemical and cytological characteristics
In the course of their evolution, plant developed chemical defences when attacked. These phytochemicals inadvertently protect humans against pathogens as antimicrobial medicines. Thus, six clone cultivars of Codiaeum variegatum (Spirale, Royal, Broad Spotted Guinea, Punctatum, Sunray and Royal-like) were chemically and cytologically investigated to evaluate their therapeutic potentials, values and variability. The shoots were relatively rich in alkaloids, cardiac glycosides, saponins, tannins, cardenolides, steroids, and phyllates. Flavonoids, phlobatannins, phenols and anthraquinoneswere sparingly present. Anthraquinones and cardenolides were absent in ‘Spirale’ while ‘Sunray’ lacked tannins, phlobatannins and phenols. Terpenes were found only in ‘Sunray’. Overall, alkaloids were themost abundant with the highest mean value of 1.46% in ‘Royal’ while flavonoids and anthraquinones were trace, 0.002 and 0.003%, in ‘Sunray’ and ‘Royal-like’. Five pigments, carotene (yellow-orange),phaeophytin (grey), chlorophyll a (blue-green) and b (green), and xanthophyll (yellow) were determined. ‘Spirale’, ‘Royal’, ‘Broad Spotted Guinea’ and ‘Punctatum’ had diploid chromosme number of 2n = 60while ‘Sunray’ and ‘Royal-like’ possessed 2n = 30 and 24 respectively. ‘Spirale’ and ‘Sunray’ appeared to have reasonably diverged from the rest. Genetic mutation and chromosomes variability couldaccount for the wide morphological variation and morphotypes in this plant species
Socioeconomic Analysis and Technical Efficiency among Smallholder Sorghum Farmers in GaMasemola Township of Limpopo Province, South Africa
Sorghum farming group in South Africa is divided into the smallholder and business ranchers attributable to the distinctions in cultivar sizes, utility creation and production strategies. Sorghum is utilized primarily for sustenance and refreshments in Ga-Masemola (GM) town. Smallholder sorghum farmers in the town utilize some portion of their wage for recreation, goat and cows' compost are utilized as manures to enhance soil fruitfulness and increment sorghum yield, they rely upon precipitation water for the water system and they have no entrance to expansion administrations. The study distinguish and depict the socioeconomic characteristics of smallholder sorghum farmers in Ga-Masemola town; it looks at the causes of technical efficiency among smallholder sorghum ranchers in the town, and it recognizes and portrays difficulties confronted by smallholder sorghum farmers in the town. Essential information was gathered utilizing organized surveys and an example size of 48 smallholder sorghum farmers in the town was chosen. Cobb Douglas model was utilized to analyze the information or data gotten.The socioeconomic characteristics of smallholder sorghum farmers were:farming experience, age, sexual orientation, instructive level and family unit measure. The study indicates that the determinants of technical efficiency among smallholder sorghum farmers in Ga-Masemola town that were observed to be huge are the measure of land dedicated and the amount of seeds utilized. Farmers are confronting difficulties, for example, sicknesses, low capital, pests, separation to the homestead, absence of water and atmosphere (i.e. climate) changes.The study suggested and recommended that smallholder sorghum farmers in Ga-Masemola (GM) town require arable land to expand their production; they additionally require agriculture extension officers for training and spreading or disseminating information about inputs allocation. Besides, the smallholder farmers should be encouraged to utilize enhanced seeds varieties in order to expand their technical efficiency. 
An assessment of the role of information and communication technology (ICT) in enhancing employee performance: a case-study of Nkonkobe local municipality
The operations and utilisation of Information and Communication Technology (ICT) are not well understood and have rarely been addressed both nationally and internationally. The aim of this study is therefore to establish a base level of understanding of the operational core values of ICT in Nkonkobe Local Municipality in the Eastern Cape Province of South Africa. The study used a qualitative research design that involved a desktop review methodology. Data was collected through the review of available published or existing documents. Data analysis included using document analysis which consist of the existing information reviewed from the literature or document containing information about various municipalities issues, journals and books as well as reviewed of various data analysis done in relation to the assessment of the role of ICT in enhancing employees performance with the aim of analyzing the organization structure of the municipality. Findings from previous literature revealed that there are constraints faced in the operations and utilisation of ICT. The study confirmed some of the operational hurdles to include lack of IT skills, and lack of clear understanding of ICT as well as training. The findings also identified the search for solutions to the challenges faced by the employees in Nkonkobe Local Municipality by providing an insight for further research regarding the institutional weaknesses and policy issues in this part of the world. The implications of the findings are that unless the limitations named above are resolved, ICT in Nkonkobe Local Municipality will continue to experience poor service delivery, poor economic growth and development. Recommendations to overcome these challenges are suggested.Thesis (MPA) -- Faculty of Management and Commerce, 201
An assessment of the role of information and communication technology (ICT) in enhancing employee performance: a case-study of Nkonkobe local municipality
The operations and utilisation of Information and Communication Technology (ICT) are not well understood and have rarely been addressed both nationally and internationally. The aim of this study is therefore to establish a base level of understanding of the operational core values of ICT in Nkonkobe Local Municipality in the Eastern Cape Province of South Africa. The study used a qualitative research design that involved a desktop review methodology. Data was collected through the review of available published or existing documents. Data analysis included using document analysis which consist of the existing information reviewed from the literature or document containing information about various municipalities issues, journals and books as well as reviewed of various data analysis done in relation to the assessment of the role of ICT in enhancing employees performance with the aim of analyzing the organization structure of the municipality. Findings from previous literature revealed that there are constraints faced in the operations and utilisation of ICT. The study confirmed some of the operational hurdles to include lack of IT skills, and lack of clear understanding of ICT as well as training. The findings also identified the search for solutions to the challenges faced by the employees in Nkonkobe Local Municipality by providing an insight for further research regarding the institutional weaknesses and policy issues in this part of the world. The implications of the findings are that unless the limitations named above are resolved, ICT in Nkonkobe Local Municipality will continue to experience poor service delivery, poor economic growth and development. Recommendations to overcome these challenges are suggested.Thesis (MPA) -- Faculty of Management and Commerce, 201
Diversity in composition of scarlet (S. aethiopicum) and gboma (S. macrocarpon) eggplants and of interspecific hybrids between S. aethiopicum and common eggplant (S. melongena)
[EN] Scarlet (Solanum aethiopicum) and gboma (S. macrocarpon) eggplants are cultivated vegetable crops native to Africa, for which no comprehensive reports exist on composition and diversity. We have evaluated diversity in composition of three varieties of scarlet eggplant and four varieties of gboma eggplant, as well as of four interspecific hybrids between scarlet and common eggplant (S. melongena) and their respective parents. With the exception of moisture (between 85.8 and 88.3 g/100 g) and pH (between 5.32 and 5.89), there was a wide diversity among varieties within each of the species for the composition traits evaluated, revealing ample possibilities for selection of varieties with improved fruit composition. Scarlet eggplant varieties evaluated presented, on average, lower content than gboma eggplant varieties for carbohydrates (3.60 vs 6.48 g/100 g), starch (3.18 vs 6.15 g/100 g), vitamin C (11.6 vs 18.9 mg/100 g), and total phenolics (24.4 vs 144 mg/100 g) and higher values for soluble sugars content and for the ascorbic/dehydroascorbic acid ratio. Interspecific hybrids between scarlet and gboma eggplants presented moisture content (79.0 g/100 g) and pH (5.15) values below those of any of the parents. For the rest of traits, values were intermediate between both parents, although much more similar to the scarlet eggplant parent. (C) 2015 Elsevier Inc. All rights reserved.This work was partially financed by the Ministerio de Ciencia y
Tecnologı´a and FEDER (AGL2012-34213) and project OTRI-UCMFundacio´n
Sabor y Salud (323-2012).San José, R.; Plazas Ávila, MDLO.; Sánchez-Mata, MC.; Cámara Hurtado, MM.; Prohens Tomás, J. (2016). Diversity in composition of scarlet (S. aethiopicum) and gboma (S. macrocarpon) eggplants and of interspecific hybrids between S. aethiopicum and common eggplant (S. melongena). Journal of Food Composition and Analysis. 45:130-140. https://doi.org/10.1016/j.jfca.2015.10.009S1301404