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10 result(s) for "Mashela, Phatu W."
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Morphometric and total protein responses in Meloidogyne incognita second-stage juveniles to Nemafric-BL phytonematicide
After hatch, second-stage juveniles (J2) of root-knot ( Meloidogyne species) nematodes could spend at least 12 weeks in soil solutions searching for penetration sites of suitable host plants. The external covering of nematodes, the cuticle, consists of various layers that contain glycoproteins, lipids, soluble proteins (collagens) and insoluble proteins (cuticulins). Generally, cucurbitacins are lipophilic, but there is scant information on how cuticular proteins relate to these complex terpenoids. A study was conducted to investigate the nature and extent of damage post-exposure of J2 to a wide range of Nemafric-BL phytonematicide concentrations. Post-72 h exposure to Nemafric-BL phytonematicide, nematode morphometrics versus phytonematicides exhibited either negative quadratic, positive quadratic, or negative linear relations, with the models explained by significant ( P  < 0.05) associations (R-squared). Similarly, total proteins versus phytonematicide exhibited significant negative quadratic relations. The principal component analysis indicated that concentration level of 2–4% of Nemafric-BL phytonematicide have the highest impact on the morphometric changes of J2. In conclusion, the nature and extent of damage suggested that Nemafric-BL phytonematicide was highly nematicidal as opposed to being nematostatic, thereby explaining its potent suppressive effects on nematode population densities.
Morphological adjustment in free-living Steinernema feltiae infective juveniles to increasing concentration of Nemafric-BL phytonematicide
Third-stage larvae (L3) of Steinernema feltiae exist as free-living infective juveniles (IJ), with suspended development activities. In contrast, parasitic stages (L1, L2, L4, adult) have mutualistic relations with Xenorhabdus species bacteria, along with unique morphological changes and development inside the cadaver of host insects and/or plant-parasitic nematodes. Commercial IJ strains are tolerant to cucurbitacin-containing phytonematicides, but we have scant information on how morphological adjustments in IJ are achieved. In this study, we investigated the nature of morphological adjustments in commercial S. feltiae IJ strains to Nemafric-BL phytonematicide, which contains cucurbitacin B as active ingredient. Post-72 h exposure to phytonematicide concentration, IJ specimens were fixed on mounting slides. Length (body, excretory pore to anterior end, pharynx, rectum, stoma, tail), diameter (head width, neck base, mid-body, anal body), cuticle thickness and De Man ratios were measured with a computer software programme attached to Omax light microscope. Morphometric data against increasing phytonematicide concentration exhibited either density-dependent quadratic, linear or neutral relations. Increase in body length at low phytonematicide concentration was accompanied by decrease in tail length and pharynx length during muscle contraction when IJ were still alive. After death at high phytonematicide concentration, the opposite morphometric effects ensued due to muscle relaxation. The observed changes in morphometric structures were explained on the basis of morphological adjustments that modulated volumes of pseudocoelom cavity in IJ. The modulation is intended to maintain hydrostatic pressure within permissible upper limits in order to avoid structural damage to internal organs embedded in the pseudocoelom fluids.
Shelf-life in cucurbitacin-containing phytonematicides: Non-conformity to Arrhenius model
Shelf-life information provides end-users with the assurance that the product is still in compliance with label claims. Behavioral reaction orders of the Arrhenius model had been consistently used under fixed conditions to provide shelf-life in food products. Due to non-conformity of the cucurbitacin-containing phytonematicides to the Arrhenius behavioral reaction orders, an alternative quadratic model consistent with the behavioral reaction orders of cucurbitacins was developed under chilled (5°C at 95-98% RH) and fixed tropical (38°C at 90% RH) conditions, while room temperature constituted unfixed conditions. Sampling for cucurbitacins was done at time-frames compliant with geometric series, with cucurbitacin analysis regularly performed using high-performance liquid chromatography techniques. Under chilled conditions, neither the Arrhenius nor the quadratic model could predict the shelf-life for Nemarioc-AL phytonematicide, whereas Nemafric-BL phytonematicide had shelf-life of 35 weeks. In contrast, under tropical conditions, the positive quadratic models showed that Nemarioc-AL and Nemafric-BL phytonematicides had shelf-life of 35 and 825 weeks, respectively. In conclusion, the two phytonematicides could be stored under fixed tropical conditions to enhance the shelf-life of their active ingredients.
Medicinal plant cultivation for sustainable use and commercialisation of high-value crops
Many traditional healing systems are based on natural biological resources, and there is a general shift in most par ts of the world towards natural medicine, with direct implications on the demand and supply of medicinal plants. This review highlights the economic impor tance of medicinal plants, their contribution to healthcare systems, and potential oppor tunities for rural economic development through cultivation. A systematic literature review with specific search terms related to medicinal plants was used to collect scientific and non-scientific information from peer-reviewed literature and grey literature databases. The findings indicate that trade in medicinal plants is increasing, and although they are considered minor crops compared to major food crops, their value is among the highest in the list of traded plants globally. The trade also serves as a revenue source for many rural livelihoods, with women playing a significant role. Medicinal plants contribute to primary health care in many developing countries, and they are also an essential source of modern drug discovery. Cultivation of medicinal plants offers emerging rural farmers an oppor tunity to grow these plants as new and alternative crops, thus reducing unsustainable wild harvesting and competition with established commercial farmers who mostly focus on food crops. Fur thermore, medicinal plant cultivation should be promoted as one of the options for local economic development and sustainability through job creation, the revival of the rural economy, and income generation for small businesses, such as the transpor t businesses, involved in the value chain. Land accessibility, financial resources, and direct market access for rural communities can elevate their contribution to the industry. Formalisation of the lower levels of the medicinal plant trade is also recommended.
Suitability of treated wastewater with respect to pH, electrical conductivity, selected cations and sodium adsorption ratio for irrigation in a semi-arid region
Increasing incidents of drought spells in most Sub-Saharan African countries call for exploration of innovative alternative sources of water for irrigation. A study was conducted to investigate the cation concentrations for different disposal points of treated wastewater and for borehole water. A 4 × 5 factorial experiment included a borehole as a reference sampling site plus three other sampling sites along the wastewater disposal system over 5 months. Monthly collected water samples were analysed for pH, EC, Ca, Mg, Na and K, with sodium adsorption ratio (SAR) computed and compared with those of water from the borehole, the FAO-desired ranges and the South African (SA) quality standards for irrigation water. Except at two sampling sites during one month, pH values were within the FAO-desired range. Relative to the FAO desired ranges and SA water quality standards, most variables in treated wastewater were much lower, suggesting that the test treated wastewater was suitable for irrigation.
Diversity and Conservation through Cultivation of Hypoxis in Africa—A Case Study of Hypoxis hemerocallidea
Africa has the largest diversity of the genus Hypoxis, accounting for 61% of the current globally accepted taxa within the genus, including some endemic species. Using Hypoxis hemerocallidea as a case study, this review addresses the conservation concerns arising from the unsustainable, wild harvesting of a number of Hypoxis species. Hypoxis hemerocallidea is one of the wild-harvested, economically important, indigenous medicinal plants of southern Africa, with potential in natural product and drug development. There are several products made from the species, including capsules, tinctures, tonics and creams that are available in the market. The use of H. hemerocallidea as a “cure-all” medicine puts an important harvesting pressure on the species. Unsustainable harvesting causes a continuing decline of its populations and it is therefore of high priority for conservation, including a strong case to cultivate the species. Reviewing the current knowledge and gaps on cultivation of H. hemerocallidea, we suggest the creation of a platform for linking all the stakeholders in the industry.
NADES Compounds Identified in Hypoxis hemerocallidea Corms during Dormancy
Soaking Hypoxis hemerocallidea corms in distilled water improved the propagation and development of cormlets, suggesting the potential leaching-out of inhibitory chemical compounds. To investigate the presence of inhibitory compounds, nuclear magnetic resonance (NMR) spectral data of the leachate from dormant H. hemerocallidea corms were obtained using a 600 MHz 1H-NMR spectrometer. The 1H-NMR analysis led to the identification of choline, succinate, propylene glycol, and lactose, as inhibitory compounds. These four chemical compounds are part of the “Natural Deep Eutectic Solvents” (NADES) that protect plant cells during stress periods, each of which has the potential to inhibit bud growth and development. These compounds are supposedly leached out of the corms during the first rain under natural conditions, possibly accompanied by changes in the ratios of dormancy-breaking phytohormones and inhibitory compounds, to release bud dormancy. The identified chemical compounds heralded a novel frontier in the vegetative propagation of H. hemerocallidea as a medicinal plant, and for its enhanced sustainable uses.
The Interaction Between Accessions and Fruit Maturity Stages in Mimusops zeyheri and Its Impact on Postharvest Quality and Nutritional Composition
Mimusops zeyheri Sond is an undervalued indigenous fruit tree with fruits that are consumed as a health snack in rural communities aross Sub‐Saharan Africa. This study aimed to assess the interaction effect of five accessions of M. zeyheri and four fruit maturity stages on some quality and nutritional compositions. Fruits of five M. zeyheri accessions were grouped into four maturity stages for analysis of fruit size, fruit firmness, total soluble solids, titratable acidity, proximate analysis, and amino acids. Accession 6E consistently had the highest size (27.62 mm), while accession 3L (6.40 kg) had the highest fruit firmness. Accession M7 displayed the highest TA (3.20%) at dark green unripe stage (T1). Highest moisture content and protein percentage were recorded in accession HY at T1. This changes were in concomitant to an increase in moisture content and a decrease in ash and protein content. Accessions M7 at T1 to T4 maturity stage exhibited the highest essential amino acids including histidine and threonine, as well as Ca, Mg, and Na. Accessions 3E and 6E at T2 and T3 maturity stage exhibited the highest P, Fe, Zn, and Mn. These findings highlight the variability of physicochemical and nutritional compositions among different M. zeyheri accessions at varying stages of fruit maturity. The study examines the variation in quality and physicochemical properties of five Mimusops zeyheri accessions at four maturity stages. Significant findings include an increase in total soluble solids and moisture content alongside decreased firmness and acidity. Variations in proximate compositions across accessions highlight M. zeyheri accessions potential as a nutritious fruit source, suitable for fresh consumption or food supplementation, promoting food security and supporting rural development.
NADES Compounds Identified in IHypoxis hemerocallidea/I Corms during Dormancy
Soaking Hypoxis hemerocallidea corms in distilled water improved the propagation and development of cormlets, suggesting the potential leaching-out of inhibitory chemical compounds. To investigate the presence of inhibitory compounds, nuclear magnetic resonance (NMR) spectral data of the leachate from dormant H. hemerocallidea corms were obtained using a 600 MHz [sup.1] H-NMR spectrometer. The [sup.1] H-NMR analysis led to the identification of choline, succinate, propylene glycol, and lactose, as inhibitory compounds. These four chemical compounds are part of the “Natural Deep Eutectic Solvents” (NADES) that protect plant cells during stress periods, each of which has the potential to inhibit bud growth and development. These compounds are supposedly leached out of the corms during the first rain under natural conditions, possibly accompanied by changes in the ratios of dormancy-breaking phytohormones and inhibitory compounds, to release bud dormancy. The identified chemical compounds heralded a novel frontier in the vegetative propagation of H. hemerocallidea as a medicinal plant, and for its enhanced sustainable uses.
Performance of Vernonia as an Alternative Industrial Oil Crop in Limpopo Province of South Africa
Vernonia (Vernonia galamensis) is an industrial oil seed crop with potential as a source of natural epoxy fatty acids. Diverse accessions of V. galamensis var. ethiopica were studied at the Limpopo Province in South Africa to determine agronomic performance and to identify suitable germplasm with quantity and quality seed oil content. Thirty-six accessions were subjected to field evaluations using a partially balanced lattice design in 2005 and 2006. Significant differences were observed for days to flowering (88-143 d), plant height (131.6-167.85 cm), number of productive primary head (23-72 head plant-1), number of productive secondary head (12-35 head plant-1), thousand seed weight (1.68-3.63 g), and seed yield (1594.89- 3126.09 kg ha-1) between different accessions. Results from oil analysis show significant differences in the contents of seed oil (20.36-35.86%), vernolic acid (70.15-77.92%), linoleic acid (12.05-14.73%), oleic acid (3.72-5.52%), palmitic acid (2.49-3.24%), and stearic acid (1.73-3.28%). Of the five accessions identified as potentially useful, three (Vge-17, Vge-18, and Vge-19) had better seed yield and agronomic performances and two (Vge-4 and Vge-31) increased contents of seed oil and vernolic acid. Accessions Vge-4 and Vge-18 also displayed relatively high oil yield, 966.58 and 801.28 kg ha-1, respectively. The accessions will be used in the stra tegic improvement of vernonia to maximize seed yield and oil content as an alternative crop in the province and similar environments.