A review of therapeutic potentials of sweet potato: Pharmacological activities and influence of the cultivar

Sweet potato (Ipomoea batatas) is a global food crop, now being recognized as a functional food due to several of its nutraceutical components. Several experimental studies have reported that sweet potato can generally be beneficial in the prevention or treatment of chronic diseases through its antioxidant, anti-inflammatory, immunomodulatory, anticancer/antitumour, antimicrobial and antiulcer activities. Studies on the haematinic effect of potato leaves and their ability to enhance some haemotological parameters are reviewed in this paper. Furthermore, the review provides an overview of the significance and influence of cultivar on the composition and pharmacological activities of sweet potato. Sweet potato contains a lot of beneficial phytochemicals, some of which are peculiar to certain varieties. There is, therefore, a need for the continuous evaluation and selection of cultivars with the appropriate phytochemical composition and bioactivities to be able to fully explore the medicinal value of sweet potato. Studies aimed at the isolation, characterization and toxicological evaluation of its bioactive compounds may help to strengthen and confirm the possible role of sweet potato as a health promoting food and an alternative remedy for chronic diseases. This review highlights the pharmacological reports on different forms of sweet potato and their potential medicinal values.Keywords: Sweet potato, Cultivar influence, Chronic diseases, Ipomoea batatas, Diabetes, Anticancer, Haematological effec

Conflicts Around Forest Reserves in Zimbabwe: What Prospects for Community Management?

Summary Due to the failure of the post?independent state to address the land inequities of the colonial era, conflicts over land resources are prevalent in Zimbabwe. This is particularly the case in and around state forest reserves. Recognising these conflicts, the Zimbabwe Forestry Commission has been exploring possibilities of co?management arrangements for forest reserves. This article examines one such pilot programme, exploring its historical origins in both national and local debates about forest policy The way historical experiences of forest management impinge on current thinking are highlighted, including how these feed into the contrasting perceptions of the ecological, economic and social values of forest resources of officials and local people. Major social differences among communities surrounding forest areas mean that local perceptions are highly varied. Given this context, the prospects for co?management arrangements where forest resources are shared are discussed

Studies on the mycorrhizosphere and nutrient dynamics in the establishment and growth of Uapaca kirkiana in Zimbabwe

Thesis (PhD (Forest and Wood Science))—University of Stellenbosch, 2006.Experiments carried out in this study sought to contribute to the understanding of the ecological interactions involved in Uapaca kirkiana seedling establishment and growth in a natural woodland ecosystem. These include soil pH reactions, plant root surface pH change, root exudates that affect the chemical behaviour of the soil in the vicinity of the root, and microbial effects. Although it was difficult to determine which of these factors play a dominant role in the soil-plant relationship, the study contributed to the understanding of the mycorrhizal fungi-host plant association. It revealed the diversity of mycorrhizal fungal species occurring in the different ecological sites, and also analysed the relationship between soil factors. Soil pH and K had significant influences on the fungi population diversity. K was considered important in its role in the translocation of auxins to the root sites where they enhance root susceptibility to mycorrhizal fungal infection. More work needs to be undertaken to establish the role of soil pH

The business of the Expanded Public Works Programme (EPWP) in the social sector

SeptemberAn increasing number of people are becoming conversant with the aims and goals of the Expanded Public Works Programme (EPWP). These numbers, however, constitute a far cry from the desired critical mass of the target people whom the EPWP is intended to benefit. Beyond the promise and expectation of a million jobs, the quality of this awareness remains nascent and emerging. What is required is an accompanying effort aimed at enhancing a deeper understanding, knowledge and practice based on the nature of the EPWP in general, and its extension to the Social Sector in particular. Contributing to this understanding is the now familiar definition that the EPWP is one part of an overall government strategy to reduce poverty through the alleviation and reduction of unemployment. It is a deliberate approach so that participants gain the necessary skills, increase their capacity to earn an income and increase their chances of getting gainful employment or embarking on sustainable entrepreneurial activities at a community level. Furthermore, it is also one of the key interventions in the second economy to address the social and economic inequities. This meaning of the EPWP is as true for the infrastructure sector as it is for the economic, the environmental and cultural sector. Extended to the social sector, the meaning has, unwittingly, yet to manifest the far salient and profound role of the EPWP in this sector

SEEDLING EMERGENCE AND GROWTH RESPONSE OF SPINACH TO SOIL AMENDED WITH DIFFERENT SPENT OYSTER MUSHROOM SUBSTRATES

Soil health is one of the most important factors that influence plant productivity. Incorporation of soil into plant residues that are high in organic matter has been reported to improve soil’s physical and chemical properties which enhance plant growth and development. Therefore, the objective of this study was to investigate the effect of soils amended with different spent oyster mushroom substrates on seedling emergence and growth of spinach (Spinacia oleracea). The respective soil samples were amended with different Spent Mushroom Substrates (SMS) at ratio 60:40 (soil/substrate). Treatments were: T1= U. panicoides + soil, T2= Z. mays + soil, T3= D. stramonium + soil, T4= Substrate mix [60% soil: U. panicoides (13.33%), Z. mays (13.33%) and D. stramonium (13.33%)] and T5= un-amended soil (100%). The respective treatments were filled into 25cm diameter pots and arranged in a Complete Randomized Design (CRD) in a temperature-controlled glasshouse. In each respective pot, three S. oleracea seeds were planted at a depth of 2cm and watered 3 times a week. S. oleracea growth response was determined by assessing the following variables: emergence rate, plant height, number of leaves/plant and chlorophyll content over a period of 12 weeks. Total dry biomass was assessed at harvest by oven drying the plants at 60ºC for 72 hrs. On the first assessment, seedlings raised in Z. mays SMS had significantly higher emergence percentage than seedlings raised in D. stramonium, Substrate mix, U. panicoides SMS (p<0.05). Seedlings raised in Z. mays SMS attained 100% emergence 7 days after planting (DAP), and un-amended soils had 91.75% 9 DAP. Seedlings raised in Z. mays and D. stramonium SMS had significantly higher plant height than seedlings raised in U. panicoides SMS and un-amended soils (p<0.05). Seedlings raised in Z. mays SMS attained 26.27cm height compared to U. panicoides SMS and un-amended soils which attained 12.67cm and 14cm height, respectively. Findings of this study revealed that Z. mays and D. stramonium SMS amended soils have inherent properties that positively influenced the seedling emergence, establishment, and growth of S. oleracea. This would, therefore, have influence on the leaves which are the main agronomic yield of the crop

SEEDLING EMERGENCE AND GROWTH RESPONSE OF SPINACH TO SOIL AMENDED WITH DIFFERENT SPENT OYSTER MUSHROOM SUBSTRATES

Soil health is one of the most important factors that influence plant productivity. Incorporation of soil into plant residues that are high in organic matter has been reported to improve soil’s physical and chemical properties which enhance plant growth and development. Therefore, the objective of this study was to investigate the effect of soils amended with different spent oyster mushroom substrates on seedling emergence and growth of spinach (Spinacia oleracea). The respective soil samples were amended with different Spent Mushroom Substrates (SMS) at ratio 60:40 (soil/substrate). Treatments were: T1= U. panicoides + soil, T2= Z. mays + soil, T3= D. stramonium + soil, T4= Substrate mix [60% soil: U. panicoides (13.33%), Z. mays (13.33%) and D. stramonium (13.33%)] and T5= un-amended soil (100%). The respective treatments were filled into 25cm diameter pots and arranged in a Complete Randomized Design (CRD) in a temperature-controlled glasshouse. In each respective pot, three S. oleracea seeds were planted at a depth of 2cm and watered 3 times a week. S. oleracea growth response was determined by assessing the following variables: emergence rate, plant height, number of leaves/plant and chlorophyll content over a period of 12 weeks. Total dry biomass was assessed at harvest by oven drying the plants at 60ºC for 72 hrs. On the first assessment, seedlings raised in Z. mays SMS had significantly higher emergence percentage than seedlings raised in D. stramonium, Substrate mix, U. panicoides SMS (p<0.05). Seedlings raised in Z. mays SMS attained 100% emergence 7 days after planting (DAP), and un-amended soils had 91.75% 9 DAP. Seedlings raised in Z. mays and D. stramonium SMS had significantly higher plant height than seedlings raised in U. panicoides SMS and un-amended soils (p<0.05). Seedlings raised in Z. mays SMS attained 26.27cm height compared to U. panicoides SMS and un-amended soils which attained 12.67cm and 14cm height, respectively. Findings of this study revealed that Z. mays and D. stramonium SMS amended soils have inherent properties that positively influenced the seedling emergence, establishment, and growth of S. oleracea. This would, therefore, have influence on the leaves which are the main agronomic yield of the crop

Effect of ectomycorrhizal fungi in the protection of Uapaca kirkiana seedlings against root pathogens in Zimbabwe

Investigations carried out on the use of ectomycorhhizal fungi in the management of Uapaca kirkiana root diseases caused by three pathogens (Rhizoctonia solani, Phytophthora parasitica and Pseudomonas solani) revealed that different mycorrhizal fungi vary in their ability to protect roots against these respective pathogens. Difference in the disease severity in various treatments was noted to have been due to the combined effect of the intrinsic biological differences of the pathogens resulting in them having different pathogenicity and the biological differences of mycorrhizal fungi. The study also highlighted that ability of mycorrhizal fungi to protect roots against these pathogens was dependent on the colonisation efficiency, which is influenced by factors such as spore germination and hyphal growth through the soil. Certain macro- and microelements were shown to inhibit growth of pathogenic fungi such as R. solani and P. parasitica. In vitro studies indicated both Zn and Cu to be significantly effective against R. solani. These elements suppressed growth of R. solani probably through their antifungal properties. Copper was also significantly effective against P. parasitica. Effect of Ca was, on the other hand, not significantly different from the control (state) on both R. solani and P. parasitica. Findings of this work may be used to explain differences in the ability of different ectomycorrhizal fungi to protect roots against different root pathogens, particularly if the mycorrhizal fungi species differ in their nutrient sequestration.Keywords: ectomycorrhizae; fungi; inoculum; pathogens; Uapaca kirkianaSouthern Forests 2010, 72(1): 37–4

Histological characterization of wild cucumber resistance to Meloidogyne species

Using nematode resistant varieties is one of efective and environmental sound strategies being adopted in the management of economically important Meloidogyne species. Wild cucumber (Cucumis africanus) has been reported to possess resistance to Meloidogyne species. Two mechanism of nematode resistance, pre- and post-penetration resistance, had been identifed, with post-penetration mechanism being used in plant breeding programs and crop rotation systems. The objective of this study was to determine the mechanism of nematode resistance in C. africanus to M. incognita and M. javanica. 6 weeks old C. africanus seedlings were separately inoculated with 100 s-stage juveniles (J2) of M. incognita and M. javanica. For 30 days, fve seedlings were harvested from both M. incognita and M. javanica experiments every other day. Seedlings’ roots were examined for necrotic spots, rootlet interferences, giant cells and root gall numbers as indicators of successful or unsuccessful nematode penetration. Harvesting times were highly signifcant (P≤0.01) on necrotic spot, rootlet interference and root gall numbers in both C. africanus—M. incognita and—M. javanica relations, but were not signifcant for giant cell number in C. africanus—M. incognita. The results suggested that C. africanus have post-penetration nematode resistance to both Meloidogyne species

Effects of various hormonal treated plant substrates on development and yield of Pleurotus ostreatus

Effects of various hormonally treated substrates on mycelial development, pinning and biomass of Pleurotus ostreatus were investigated. A 3 × 4 experimental layout was used i.e. three substrates: Urochloa panicoides, Zea mays and Datura stramonium and four hormonal treatments: cytokinins; auxins; gibberellins and control. Treatments were replicated three times and arranged in a Completely Randomize Block Design. The results indicated significant differences on mycelial, pinning, fruit caps and biomass (p ≤ 0.05). Mycelial development in respective substrates was as follows: U. panicoides (100%), Z. mays (84.78%) and D. stramonium (36.31%) and pinning rate was 65.48, 32.99, and 12.23% respectively. Hormones also had significant effect on cap size and style length (p ≤ 0.05). Cap sizes were: auxins: 13.42 cm, cytokinins: 9.9 cm and gibberellins: 7.13 cm and style lengths were: 6.93, 8.83 and 11.03 cm respectively. Mushroom biomasses from different substrates were: U. panicoides (7,609.56 g), Z. mays (7,296.42 g) and D. stramonium (4,368.15 g) indicating significant influence of substrate on mushroom biomass

Aqueous-Methanol Extracts of Orange-Fleshed Sweet Potato (Ipomoea batatas) Ameliorate Oxidative Stress and Modulate Type 2 Diabetes Associated Genes in Insulin Resistant C2C12 Cells

Edible plants such as sweet potato are sources of natural antioxidants that can be exploited in the management and treatment of insulin resistance. This present study investigated the effects of the extracts of an orange-fleshed sweet potato on oxidative stress biomarkers (glutathione status and lipid peroxidation) and activities of antioxidant enzymes (catalase, CAT and glutathione peroxidase, GPx) in palmitate-induced insulin resistant C2C12 cells. The intracellular antioxidant status of the cells was also measured using Ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays. Furthermore, this study determined the effect of the extracts on the regulation of some type 2 diabetes associated genes; glucose transporter 4 (glut4), Nuclear respiratory factor 1 (nrf1), Myocyte enhanced factor 2A (mef2a), Carnitine palmitoyltransferase 1 (cpt1) and Acetyl-CoA carboxylase 2 (acc2). The results showed a significant (p &lt; 0.05) increase in intracellular GSH level, a significant reduction in the level of malonaldehyde and a significant improvement in the intracellular antioxidant status upon treatment of the insulin resistant cells with the extracts. The extracts were also able to positively modulate the expression levels of the type 2 diabetes associated genes. On the other hand, HPLC-MS analysis of the extracts showed the presence of polyphenols which could have contributed to the bioactivity of the extracts through their antioxidant effects