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  • PublicationJournal Article
    The majority of rural communities in South Africa are characterised by insufficient nutrition and food insecurity at the household level. Due to a lack of information about indigenous fruit trees and their use, food-insecure households are missing out on the nutrition that these fruits provide. Strychnos spinosa Lam. (monkey orange; umHlala) has been identified as one of southern Africa’s top priority fruit species for domestication. However, indigenous information on S. spinosa usage and morphological diversity is still lacking. Indigenous knowledge of species characteristics might be a good place to start when attempting to understand variations in key phenotypic traits. Information on the use and morphological variation of S. spinosa was collected from participants of 100 randomly selected homesteads. Participants were interviewed using a structured questionnaire. The results indicate that S. spinosa is a multi-purpose tree with numerous uses. Most respondents (97%) mentioned that they use it for fermented maize meal (umBhantshi); and others mentioned fermented porridge (amaHewu); alcohol; fruit; juice; jam; homestead protection; snakebite; firewood; food allergy; livestock increase; and only 7% mentioned for stomachache. Morphological variation was observed in leaf colour and shape, fruit rind colour, size, rind texture, pulp colour, pulp texture, and taste. However, the most mentioned variety featured green (78%), rounded leaves (78%) and green (39%), large (46%), smooth-textured rind (73%) fruits that had brown pulp (54%) and tasted sweet (58%). Understanding local knowledge systems and preferences can thus inform the selection of ethno-varieties that hold importance to local people and the potential to improve livelihoods in externally led domestication and development programs.
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  • PublicationJournal Article
    Indigenous fruit tree species (IFTs) can play a crucial role in poverty alleviation and as a source of food in South Africa. Although these species contain nutrient-rich edible fruits that are also locally processed to food products such as jams and jellies, they are still underutilized and also harvested from the wild. This study aimed to prioritize in northern KwaZulu-Natal, IFTs with domestication and commercialization potential. A literature survey and focus groups were used to list tree species that produce edible fruits with this potential. Plant experts, through focus groups and reference group meetings, further ranked fruit trees using a scorecard method based on various attributes. A total of 29 prioritized IFTs was obtained, of which the Sapotaceae was the most represented family with a maximum of four species. Based on scorecard assessment, the most preferred species in descending order were Strychnos spinosa Lam., Garcinia livingstonei T.Anderson, Englerophytum magalismontanum (Sond.) T.D.Penn, Sclerocarya birrea (A.Rich) Hochst., Dovyalis caffra (Hook.f. & Harv) Hook.f., Vangueria infaustia Burch. and Berchemia zeyheri (Sond.) Grubov. Strychnos spinosa was ranked as the first most important IFTs with a final score of 151, whereas Berchemia zeyheri was ranked the least with the final score of 146.1. However, the final scores of all most preferred species were relatively similar to one another. The top seven species identified in this study should be considered as a baseline for future IFTs development programmes such as domestication, whereby these species are introduced to small-holder farmers and food processing industries.
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  • PublicationJournal Article
    Strychnos spinosa Lam. of the Loganiaceae family is associated with versatility, poverty eradication, and rural economic development. However, the morphological diversity of S. spinosa is not well documented. This limits efforts toward its improvement and commercial exploitation. This study aimed to characterize the variability, vegetative and reproductive traits, and heritability of S. spinosa morphotypes at Bonamanzi Game Reserve. The majority of the morphotypes had green, rough, round immature fruits with dark green, elongated, open fully developed leaves. Fruits varied between roundish and pyriform shape as well as green and purple colour. Positive correlation was mainly seen between fruit and seed traits. Principal component analysis indicated fruit and seed traits as major discriminating factors for morphotypes, followed by leaf size and seed thickness. A dendrogram primarily grouped morphotypes according to fruit texture. Genotypic variance and genotypic coefficient of variation were higher than environmental variance and environmental coefficient variation in reproductive traits of S. spinosa. A rough pericarp texture and purple tinge on the immature leaves of some morphotypes was recorded for the first time. Differences in morphological features across S. spinosa morphotypes indicate a high level of diversity that could be utilized by breeders to generate new cultivars. This first report on variability and heritability among S. spinosa morphotypes forms the basis of available germplasm essential for future breeding programs.
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  • PublicationJournal Article
    Natural forests are an important source of livelihood for various communities. Yet economically important fruit tree species endemic to sub Saharan Africa e.g. Sclerocaryea birrea (Marula) are critically endangered due to over-exploitation and climate change. Effective conservation, management and utilization of native fruit trees require accurate quantitative information on how the trees interact with their environment. In this study we investigated the water use patterns and fruit yield dynamics of S. birrea, and another widely used species Strychnos spinosa (Monkey orange) growing on nutrient poor sandy soils in northern KwaZulu-Natal Province, South Africa. The study aimed to understand how the water use and yield of these species are influenced by climate and soils. These data are essential to support biodiversity conservation and management, and agroforestry programs. Transpiration was measured on co-occurring trees of each species over two years using the heat ratio sap flow method. The sap flow and environmental data were used to develop and test a simple Penman-Monteith transpiration model. The model provided insights on how environmental factors affected water use and yield in the trees’ natural habitats. The two species had similar diurnal transpiration trends characterized by midday stomatal closure. Peak transpiration per unit leaf area was higher for S. spinosa (∼2.3 L/m2/d) than S. birrea (∼1.4 L/m2/d). S. birrea transpiration responded strongly to rainfall pulses with the soil water deficit explaining ∼ 65% of the variation in tree water use. S. spinosa transpiration, on the other hand, was largely driven by the atmospheric evaporative demand rather than by soil water availability (R2 < 0.10), suggesting that the two species had different mechanisms to cope with drought stress. Despite the contrasting water relations, transpiration could be determined accurately using the combination model. The model has potential applications in agroforestry and species-specific conservation programs by providing accurate information on their water requirements.
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  • PublicationJournal Article
    2020
     | Society for Biology ...
    Sugarcane production in South Africa is limited by drought stress and its impact is expected to increase due to climate change. However, limited research is conducted to develop cultivars that are suitable for cultivation under water-stressed conditions. This study aimed to select, through morphological and physiological traits, the ethyl methanesulfonate treatment (s) that can produce calli and plantlets that are resistant to mannitol-induced osmotic stress. Sugarcane calli were exposed to ethyl methanesulfonate for 0.5, 1, 2, and 3 hours. To determine optimal selection lethal doses, calli were cultured on media containing 0, 150, 225 and 300 mM mannitol for further eight weeks under dark and light conditions. Incubation periods of half an hour and one hour induced genomic mutations without inhibiting callus growth and plant regeneration abilities. EMS-treated calli retained whiter, compact and with yellowish friable texture when compared with the control after the two-weeks recovery period post exposure to osmotic stress. Callus that was exposed for one hour was able to recover and regenerate plantlets at 225 and 407 mM mannitol stress. However, the two-hour incubation period and above resulted in stunted and albino plantlets. The LD50 and LD90 for selection were calculated as 225 and 407 mM mannitol. The EMS mutagenesis and in vitro selection for osmotic stress using mannitol can be used successfully to select sugarcane plantlets with better morphological and physiological responses to water stress in a very short time.
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  • PublicationJournal Article
    Lead (Pb) can enter the food chain through the consumption of contaminated plants and can cause serious health issues. However, research on how Pb accumulation affects morphology of leafy vegetables in South Africa is minimal. This study tested the effect of lead accumulation on vegetative and reproductive traits of Corchorus olitorius. Plants were grown under varying Pb concentrations, and studied for their variation in vegetative and reproductive traits as well as Pb accumulation in leaves, stems and roots. Plants grown within allowable soil concentrations of 150 mg kg–1 Pb accumulated toxic (≥ 10 mg kg–1) Pb in all plant parts without causing any morphological defect, except for a decrease in chlorophyll content. Minor reductions in growth and yield were evident only at 900-1000 mg kg–1 concentration. Pb accumulation increased as its concentration increased in the soil, with a higher accumulation in roots in comparison to aerial parts. In conclusion, C. olitorius can grow and reproduce under toxic Pb levels (≥ 300 mg kg–1) and accumulate toxic amounts of Pb (≥ 10 mg kg–1) without visible morphological defects. Therefore, it is suitable for phytoremediation but unsafe for consumption when it is collected from sites prone to Pb contamination.
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  • PublicationJournal Article
    Mncwango NC, Mavengahama S, Ntuli NR, van Jaarsveld CM. 2020. Diversity, consumption dynamics and ethnomedical claims of traditional leafy vegetables consumed by a rural community in the KwaMbonambi area, northern KwaZulu-Natal, South Africa. Biodiversitas 21: 1201-1207. Traditional leafy vegetables (TLVs) are mostly wild and informally-domesticated edible plant species. Their nutritious leaves, shoot tips, flowers and fruits are consumed as vegetables, particularly by rural communities in Africa. However, their consumption and cultivation are still marginal. This study aimed to identify the most preferred TLVs, as well as factors that affect the consumption and cultivation of these species. A questionnaire was administered among 100 respondents to record the preferred TLVs; the reason (s) for preference; consumption frequency; and constraints towards consumption of these vegetable species. This study recorded a total of 18 TLVs that belong to 14 genera and 11 families. Among these, Amaranthus hybridus, A. spinosus, A. thunbergii, Bidens biternata and Corchorus olitorius were the most preferred species. Vegetables were preferred primarily based on the taste; where most people ate them once a week when they are available. The major TLV consumption constraints were seasonal availability and low shelf life. A decline in the availability of TLVs was primarily caused by drought. Regardless of the observed decline, only 23% of respondents practiced informal cultivation of Amaranthus species. Bidens pilosa, Momordica balsamina, and Corchorus olitorius vegetable species were also known to possess some medicinal values. Future research on improving taste, increasing edible plant parts and elongating shelf life for preferred TLVs, is a necessity.
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  • PublicationJournal Article
    In Africa, some women are still heavily depending on traditional medicine during childbearing to maintain healthy pregnancy, postpartum recovery and for infant care. This study was designed to assess the prevalence of traditional medicine use and associated factors of its use during childbearing. Data were collected using structured questionnaires and individual interviews were conducted with 140 women. The results indicated that majority of women (79%) were still using traditional medicine during childbearing for different purposes even with the availability of free health care services. The most commonly used traditional medicine used during pregnancy was isihlambezo. Umhlabelo herbal mixture was the most cited remedy used for post-partum recovery. For infant care, imbiza was the only used traditional remedy. The results of this study highlight the need for health care workers to be aware of this practice and be able to provide mediation during ante-natal care classes.
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  • PublicationJournal Article
    Sesamum alatum Thonn., of the Pedaliaceae family is rich in nutrients and is also used for medicinal purposes, but it is still collected from the wild. It thrives well in sandy soils which are known for low fertility and moisture content. Rural communities in KwaZulu-Natal usually keep cows, goats, poultry and sheep as their livestock, where they also source organic manure for subsistence farming. Animal manure improves both plant and soil properties. Application of animal manure also results in an increase in growth, yield and nutrient content of leafy vegetables such as Amaranthus, Abelmoschus, and Corchorus species. In India, Sesamum indicum, a domesticated relative of S. alatum, also had its vegetative, reproductive and nutrient properties improved with the application of poultry manure. A selection of organic manure(s) for S. alatum domestication is possible by reviewing the use of various domesticated animal manures to improve morpho-agronomic traits and nutrient content of leafy vegetables. Therefore, determining an agronomic protocol for this species in South Africa is a priority for future research.
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  • PublicationJournal Article
    The exploring of biostimulant sources is important for sustainable agriculture. Although all parts of the moringa plant (Moringa oleifera Lam.) are rich in phytohormones and phytochemicals which may be utilised as a potential plant growth enhancer, most attention has been placed on its leaves as a possible biostimulant for enhancing productivity of plants. Little has been reported on moringa seed extract (MSE) as a growth enhancer on medicinal plants. Thus, this study investigated the efficacy of MSE doses (water spray as control, MSE at 2, 4, 6 and 8%) on growth attributes, mineral content and phytochemical compositions of cancer bush plants (Lessertia frutescens L.) grown during the winter–spring and spring–summer seasons of 2021. A gradual increase in growth characteristics, chlorophyll content, phenols and flavonoid contents was recorded in all concentrations of MSE-treated plants compared with controls. Furthermore, all levels of MSE effectively enhanced the concentrations of macronutrients such as calcium, magnesium, phosphorus, nitrogen and potassium as well as micronutrients comprising copper, zinc, iron, manganese and sodium of cancer bush plants relative to untreated plants. Both 6 and 8% MSE concentrations showed high productivity, minerals and phytochemical constituents in cancer bush plants in comparison with 2 and 4% MSE treatments. Overall, the findings of this study demonstrated that, even at low concentrations, MSE can be successfully applied as a biostimulant to improve the growth and biochemical attributes of cancer bush plants.
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