Botany

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    Comparative assessment of agro-morphological traits and nutrient content of Sesamum alatum in response to poultry and goat manures
    (2021) Mbatha, Khulekani Cyprian
    Sesamum alatum Thonn. is one of the scarcely known and highly nutritious leafy vegetables that is still collected from the wild or as weeds among crops in South Africa. The plant is also used for medicinal and cosmetic purposes in Africa and elsewhere. Despite its importance and agronomic potential, the cultivation of S. alatum under different agronomic systems for improved harvestable yield and nutrient content is still lacking. The study aimed to determine the response of S. alatum agro-morphological traits and nutrient content to the application of poultry and goat manures. This study was conducted under rain-fed shade cloth conditions during the summer months of 2018 and 2019. Pots (20L) were filled with 60 kg of soil mixed with poultry and goat manures at 0, 1, 2, and 3 t ha–1 each. The layout was a completely randomized design (CRD) of 2 × 4 factorial combinations. Taller plants with numerous branches that produced many and bigger leaves and heavier shoots were recorded in season two. The application of manure resulted in taller plants with profuse branching, many, and broader leaves as well as heavier dried shoots. However, goat manure was more effective than poultry manure. The recommended rates for optimum plant agro morphological productivity were ≥ 2 t ha–1 for both manures except for the seed mass. Application rates ≥ 2 t ha–1 of goat manure gave the best vegetative and reproductive growth in S. alatum. Poultry and goat manure application led to an increase in moisture content, Ca, Mg, K, P, and micronutrients in Sesamum alatum. Goat manure produced the highest nutrient content of S. alatum than poultry manure, although differences were not substantial. Therefore, both manures could be equally used to improve agro morphological traits and nutrient content of S. alatum.
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    Morpho-agronomic and genetic variation and segregation patterns of phaseolus vulgaris landraces from selected provinces of South Africa
    (University of Zululand, 2021) Ndlangamandla, Valencia Vuyisile
    Phaseolus vulgaris L. (dry beans) of Central American origin is a self-pollinating crop with a low frequency of crossing. It is planted for its edible leaves, immature pods, and dried seeds throughout the world. In South Africa, local communities grow a variety of P. vulgaris landraces. Landraces are significant for breeding purposes because they contain important germplasm. However, studies on variation in morphology and genetics among P. vulgaris landraces are limited in South Africa. Thus, this study aimed to determine the morpho-agronomic and genetic variations among P. vulgaris landraces. P. vulgaris landraces collected from the various rural communities of four selected provinces in South Africa were grown in a randomized complete block design with three replications over two seasons. Significant variations were recorded in germination percentages, vegetative and reproductive traits. The vegetative and reproductive traits correlated positively with each other, and with both traits. The first five informative principal components explained 88.749% and 91.678% of the total variation in the morpho-agronomic and segregation patterns, respectively. The landraces were clustered in a biplot and dendrogram based on their seed coats, shape, similar morpho-agronomic traits, and their area of origin. The 12 parents of P. vulgaris produced offspring that are different from their parents in seed colour, shape, and size. The genetic diversity analysis with simple sequence repeat (SSR) markers revealed the range of genetic diversity, observed heterozygosity, and polymorphic information content as 0.00–0.65, 0.00–0.05, and 0.00–0.58, respectively. The population structure divided the 40 landraces into two subpopulations namely Mesoamerican and Andean gene pools. Although there was considerable overlap among the landraces, numerous Mesoamerican landraces carried certain seed features or genes from the Andean gene pool, indicating a significant amount of mixing. Although, the populations showed an overlap among the landraces as several from the Mesoamerican group carried some seed traits or genes from the Andean gene pool, as they showed a high level of admixture. The grouping of landraces in a principal coordinate analysis (PCoA) and dendrogram had a similar clustering to the population structure. The landraces demonstrating admixture were also grouped in the same cluster (dendrogram) and similar quadrants (PCoA). The findings of the variance in morpho-agronomic and genetics of P. vulgaris landraces can be used to improve, conserve them, and increase their productivity.
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    A Toxicological Evaluation and Anti-Candidal Activity of Plants used by Women in Northern Maputaland (South Africa) for the Treatment of Gynaecology and Obstretrics Ailments
    (University of Zululand, 2021) Ngubane, Samukelisiwe Clerance
    Medicinal plants still play an important role in the primary healthcare of lay people in northern Maputaland in spite of the availability of hospitals and clinics. According to an ethnobotanical survey conducted in 2014, the lay people in northern Maputaland use plant species independently and in combination to treat gynaecology and obstetrics medical conditions. These plant species were generally regarded as safe by the lay people except for one plant species, Trichilia dregeana. Consequently, this study’s aim was to investigate the safety of medicinal plant species used by the lay people in northern Maputaland. Furthermore, as these plant species were used to treat medical conditions specifically related to woman, the inclusion of the efficacy of these plant species against Candida stains was included due to the prevalence of vaginal thrush. The aqueous and organic (1:1 methanol-dichloromethane) extracts were prepared from 51 plant samples (including leaf samples collected for potential substitution for the roots). Toxicology of these plants was assessed using the brine shrimp lethality assay (BSLA) and the Ames assay (using Salmonella typhimurium TA98 and TA100 strains) for mutagenicity. The anti-Candidal activity was assessed using the antimicrobial micro-dilution assay to determine the minimum inhibitory concentration of of the plant samples aginst Candida albicans ATCC 10231, C. tropicalis ATCC 750 and C. glabrata ATCC 900300. There were three plant spescies (Acalypha villicaulis root, Grewia occidentalis root and Gymnosporia senegalensis leaves) that indicated neither toxicity nor mutagenicity in this study. All the toxic plants samples (in BSLA) were further subjected to two-fold dilution and demonstrated acceptable toxic concentrations, which were found to range from 0.98 to 0.10 mg/ml. However, Hermannia boraginiflora, Sapium integerrimum, Scadoxus puniceus and Tabernaemontana elegans remained toxic even after diluted to the lowest concentration of 0.031 mg/ml. Plant species combinations that were found to be non-toxic in BSLA in both aqueous and organic extract were Euphobia tirucalli (root) + Ozoroa engleri (bark) + Scadoxus puniceus (bulb) + Senecio serratuloides (whole plant), Bridelia cathartica (root) + iii Opuntia stricta (stem) + Searsia nebulosa (bark) and B. cathartica (root) + Erythrina humeana (root). In the Ames test, plant samples that appeared to be non-mutagenic against both S. typhimurium TA98 and TA100 strains were A. villicaulis root, Cyperus natalensis root, Euclea natalensis leaves, G. occidentalis root, Ochna natalitia leaves, S. integerrimum leaves and S. puniceus bulb. However, Hypoxis hemerocallidea and O. stricta appeared to be the most mutagenic against both the S. typhimurium TA98 and TA100 strains with both aqueous and organic extracts showing mutagenicity. The antimicrobial microdilution assay indicated a small number of plant species that were active against Candida strains and were in most cases these were the methanoldichloromethane extracts. A moderate activity against C. albicans was observed with the aqueous extract of Euclea natalensis root and Rhoicissus digitata leaves. The methanol-dichloromethane extracs of O. stricta stem, P. africanum root and S. birrea stem were also active (moderately) against C. albicans. Against the C. tropicalis, a moderate activity was observed against A. villicaulis leaves, Acanthospermum glabratum whole plants, B. cathartica leaves, Cassytha filiformis whole plant, Euphorbia tirucalli stem and Garcinia livingstonei root. A noteworthy anti-Candidal activity was observed with Commiphora neglecta root and leaves both with the minimum inhibitory concentration (MIC) of 0.13 mg/ml against Candida tropicalis. There was no activity observed against C. glabrata. This study has indicated that medicinal plant species may have toxic and/ or mutagenic effects, even without any noteworthy signs after consumption. However, it was determined that toxicity can be reduced by carefully managing the dose. The reduction of concentration is not known whether it may affect the efficacy, therefore further studies on the efficacy are recommended.
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    Accumulation and distribution pattern of lead and cadmium and their effect on vegetative and reproductive traits of Corchorus olitorius
    (University of Zululand, 2020) Ndlovu, Sibongokuhle
    Lead and cadmium heavy metal toxicity are some of the major concerns on agriculture because they can enter the food chain through the consumption of contaminated vegetables and cause serious health issues to humans. Corchorus olitorius L. is a wild leafy vegetable that can be harvested from areas such as roadsides and mining areas, which are prone to contamination by these heavy metals. However, limited studies focus on determining the effect of toxic Pb and Cd accumulation on morphological features of wild edible plants. C. olitorius seeds were sown in potted soil treated with 0, 5, 10, 15, 20 and 25 mg kg‒1 Cd(NO3)2 and 0, 150, 300, 600, 900, and 1000 mg kg‒ 1 Pb(NO3)2. The experiment was arranged in a randomized complete block design and each concentration had five replications. Differences in germination percentage, seedling mortality, vegetative and reproductive traits were recorded among treatments. Harvested immature and mature plants were separated into leaves, stems, and roots; dried and grounded into powder; and analyzed for heavy metal accumulation using Atomic Absorption Spectroscopy (AAS) and Scanning iv Electron Microscopy (SEM) in combination with Energy Dispersive X-ray (EDX) techniques. Concentrations up to the maximum of 600 mg kg–1 Pb and 10 mg kg–1 Cd soil treatments resulted in toxic accumulation of these heavy metals in different plant parts, but either promoted or did not affect germination percentage, seedling growth, as well as vegetative and reproductive traits, when compared with the control. Pb was relatively restricted to and highly accumulated in the roots, whereas Cd was easily translocated and was concentrated in the aerial parts. In three and two informative principal components of morphological and accumulation analyses, respectively, almost all investigated traits were associated with principal component one which had the highest variability. The biplots and dendrograms in both analyses mainly grouped Pb and Cd treatments into separate clusters. Results of metal accumulation analysis using both AAS and SEM coupled with EDX techniques were complementary to each other. C. olitorius is a potential plant for the use in the phytoremediation of Pb and Cd contaminated soils but is toxic for harvest and consumption from such areas.
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    Agro-morphological, nutritional variability and heritability studies of Lagenaria siceraria landraces in northern KwaZulu-Natal, South Africa
    (University of Zululand, 2019) Buthelezi, Lungelo Given; Ntuli, N.R.
    Lagenaria siceraria (Molina) Standley of the Cucurbitaceae family is one of many underutilised ancient cultigens with great economic potential. Its nutritious tender shoots, flowers, fruits, and seeds are of culinary use and widely consumed in rural communities as a vegetable relish. It has abundant nutrients and minerals essential for human health. However, research on morphological and nutritional variation among L. siceraria landraces from South Africa is very marginal. Therefore, the objective of this study was to characterise variability in growth, yield and nutritional composition among L. siceraria landraces from northern KwaZulu-Natal. L. siceraria landraces with various fruit and seed morphology, collected from different agro-ecological areas of northern KwaZulu-Natal were grown in a randomised complete block design with three replications over two summer seasons. Seedling, vegetative and reproductive traits were compared among landraces, while pulp of the mature fruit was analysed for nutrient composition. Analysis of variance, correlation, principal component analysis, cluster analysis and heritability estimates were conducted on morphological traits and nutrient content. Landraces with different fruit and seed morphology, from different areas varied significantly in seedling, vegetative and reproductive traits as well as nutrient content. Significant positive correlations were mainly recorded among reproductive traits and also among the majority of nutrients. The first five and three informative principal components were responsible for 74.393% and 80.270% of the total variability in morphological traits and nutrient composition, respectively. First components (PC1) with 26.635% and 42.076% variability were positively associated with most of morphological traits and nutrients, respectively. In morphological trait and nutrient analyses, biplot and dendrogram grouped landraces mainly according to fruit and seed morphology and then their origin. High heritability estimates were recorded among fruit and seed traits as well as among various nutrients. Therefore, this study can be the foundation for strategic improvement, direct production or conservation of the Lagenaria siceraria using these landraces.
University of Zululand