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Elizabeth Joubert - One of the best experts on this subject based on the ideXlab platform.
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Bitter profiling of phenolic fractions of green Cyclopia genistoides herbal tea.
Food chemistry, 2018Co-Authors: Lara Alexander, Magdalena Muller, Dalene De Beer, Marieta Van Der Rijst, Elizabeth JoubertAbstract:Abstract The bitter taste of Cyclopia genistoides infusions is unacceptable to consumers, who are used to the slightly sweet taste of the herbal teas produced from other Cyclopia species. Bitter taste intensities of crude phenolic fractions of a bitter hot water extract of C. genistoides were determined by a trained panel to identify the fraction contributing most to the bitter taste. Fractions, enriched in benzophenones (B), xanthones (X) and flavanones (F), and each tested at their infusion equivalent concentration (IEC) scored 5, 31 and 13 (on a 100-point scale), respectively. Fraction B, containing mostly iriflophenone glucosides, was perceived as not bitter. The major xanthone in fraction X, mangiferin, was significantly (p
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Cyclopia extracts enhance th1 th2 and th17 type t cell responses and induce foxp3 cells in murine cell culture
Planta Medica, 2017Co-Authors: Shiho Murakami, Elizabeth Joubert, Yutaka Miura, Makoto Hattori, Hiroshi Matsuda, Christiaan J Malherbe, Christo J F Muller, Tadashi YoshidaAbstract:Cyclopia genistoides, one of the traditional South African medicinal plants, and other species of the same genus offer noteworthy phenolic profiles, in particular high levels of the anti-allergic xanthone mangiferin. Hot water and 40% ethanol-water (v/v) extracts, prepared from C. genistoides, Cyclopia subternata, and Cyclopia maculata, were tested for immune-regulating activity in vitro using murine splenocytes and mesenteric lymph node cells. The 40% ethanol-water extracts of C. genistoides and C. subternata significantly enhanced production of several types of cytokines, including IL-4, IL-17, and IFN-γ, by antigen-stimulated splenocytes. A concentration-dependent response was observed, noticeably for IFN-γ production. The activity of the extracts did not correlate with the content of any of the major phenolic compounds, indicative that other extract constituents also play a role in immunomodulation. Additionally, the increased ratio of CD4+CD25+Foxp3+ Treg cells to total CD4+ cells indicated induction of Foxp3+ cells when mesenteric lymph node cells were cultured in the presence of these two extracts. This study is the first reporting immunostimulatory activity for Cyclopia, which are widely consumed as the herbal tea known as honeybush, underpinning further investigations into the potential use of its extracts as adjuvants for mucosal immunotherapy.
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dietary exposure to honeybush Cyclopia polyphenol enriched extracts altered redox status and expression of oxidative stress and antioxidant defense related genes in rat liver
South African Journal of Botany, 2017Co-Authors: J D Van Der Merwe, Elizabeth Joubert, Dalene De Beer, Sonja Swanevelder, W C A GelderblomAbstract:Abstract Interest in Cyclopia spp. (honeybush) as a source material for production of polyphenol-enriched extracts (PEEs) for the food ingredient and nutraceutical markets requires investigation of their safety. PEEs of Cyclopia subternata (PECsub) and Cyclopia genistoides (PECgen) were fed (2.5 g/kg feed) to male Fischer rats for 28 days, while PECsub, having the highest total polyphenol content and antioxidant activity, was also fed for 90 days. Their dietary intake did not significantly (P ≥ 0.05) affect body weight gain or relative liver and kidney weight. PECsub resulted in a significant (P
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Effect of harvest date on growth, production and quality of honeybush (Cyclopia genistoides and C. subternata)
South African Journal of Botany, 2017Co-Authors: M.s. North, Elizabeth Joubert, Dalene De Beer, K. De Kock, M.e. JoubertAbstract:Abstract Cyclopia spp., used for production of honeybush herbal tea, is endemic to specific climatic zones in the Western and Eastern Cape of South Africa. Most of the plant material is harvested from wild plants in mountainous areas. Production and market development of this popular herbal tea is unsustainable without increased commercial production. Information on cultivation requirements, growth habit and production potential is essential to ensure a sustainable industry. The effect of harvest date on growth, production and tea quality was evaluated in non-irrigated commercial plantations of Cyclopia genistoides and Cyclopia subternata. Cyclopia genistoides bushes, harvested annually, did not recover the height of un-harvested bushes. Fastest C. genistoides bush regrowth and highest dry mass yield occurred after February harvests, with September harvests resulting in the highest sieve quality and mangiferin content (only the second annual harvest). For the “fermented” product, its hot water soluble solids (as indication of cup strength) and total polyphenol content, tended to increase with years of harvest. The mangiferin content of “unfermented” (green) C. genistoides plant material increased with years of harvest. Cyclopia subternata bushes harvested during August and September recovered the fastest in height. The August and May harvests delivered the highest fresh mass yield, while harvesting during August delivered significantly more of the finer processed tea ( 2800 μm) than a September, February or May harvest. Annual harvesting is encouraged, but harvesting should not take place during flowering (August to September), because the flowers add very little to the final product yield. Based on 10,000 bushes/ha, an estimated annual production of 8.5 or 10.4 tons/ha of C. genistoides and C. subternata (fresh plant material), respectively, can be achieved.
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Analysis of honeybush tea (Cyclopia spp.) volatiles by comprehensive two-dimensional gas chromatography using a single-stage thermal modulator.
Analytical and Bioanalytical Chemistry, 2017Co-Authors: Gaalebalwe Ntlhokwe, Magdalena Muller, Elizabeth Joubert, Andreas G. J. Tredoux, Tadeusz Górecki, Matthew Edwards, Jochen Vestner, Lené Erasmus, J. Christel Cronje, Andre De VilliersAbstract:The applicability of comprehensive two-dimensional gas chromatography (GC×GC) using a single-stage thermal modulator was explored for the analysis of honeybush tea (Cyclopia spp.) volatile compounds. Headspace solid phase micro-extraction (HS-SPME) was used in combination with GC×GC separation on a non-polar × polar column set with flame ionisation (FID) detection for the analysis of fermented Cyclopia maculata, Cyclopia subternata and Cyclopia genistoides tea infusions of a single harvest season. Method optimisation entailed evaluation of the effects of several experimental parameters on the performance of the modulator, the choice of columns in both dimensions, as well as the HS-SPME extraction fibre. Eighty-four volatile compounds were identified by co-injection of reference standards. Principal component analysis (PCA) showed clear differentiation between the species based on their volatile profiles. Due to the highly reproducible separations obtained using the single-stage thermal modulator, multivariate data analysis was simplified. The results demonstrate both the complexity of honeybush volatile profiles and the potential of GC×GC separation in combination with suitable data analysis techniques for the investigation of the relationship between sensory properties and volatile composition of these products. The developed method therefore offers a fast and inexpensive methodology for the profiling of honeybush tea volatiles. Graphical abstract Surface plot obtained for the GC×GC-FID analysis of honeybush tea volatiles.
Bryan L. Stegelmeier - One of the best experts on this subject based on the ideXlab platform.
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Development of an Enzyme-Linked Immunosorbent Assay for the Veratrum Plant Teratogens: Cyclopamine and Jervine
Journal of agricultural and food chemistry, 2003Co-Authors: Stephen T. Lee, Kip E. Panter, William Gaffield, Bryan L. StegelmeierAbstract:Veratrum californicum was responsible for large losses of sheep grazing high mountain ranges in central Idaho in the 1950s. Veratrum induces various birth defects including the cyclopic-type craniofacial defect (monkey-faced lambs) that is specifically induced in lambs after pregnant ewes grazed the plant on the 14th day of gestation. The steroidal alkaloids cyclopamine (1) and jervine (2) were isolated from Veratrum and shown to be primarily responsible for the malformations. Cyclopamine (1) and jervine (2) are potent teratogens that inhibit Sonic hedgehog (Shh) signaling during gastrulation-stage embryonic development, producing Cyclopia and holoprosencephaly. Although losses to the sheep industry from Veratrum are now relatively infrequent, occasional incidents of toxicoses and craniofacial malformations are still reported in sheep and other species. However, the benefits to biomedical research using cyclopamine (1) as a tool to study human diseases have greatly expanded. A competitive inhibition enzyme-linked immunosorbent assay (ELISA) to detect and measure cyclopamine (1) and jervine (2) was developed using polyclonal antibodies produced in ewes. The limits of detection of the assay were 90.0 and 22.7 pg for cyclopamine (1) and jervine (2), respectively. This assay was used for the detection and measurement of cyclopamine (1) spiked into sheep blood. The simple extraction-ELISA methods developed in this study demonstrate the potential of using these techniques for the rapid screening of biological samples to detect the presence and concentration of cyclopamine (1) and jervine (2) and will be beneficial to pharmacological studies and livestock diagnostics.
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development of an enzyme linked immunosorbent assay for the veratrum plant teratogens cyclopamine and jervine
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Kip E. Panter, William Gaffield, Bryan L. StegelmeierAbstract:Veratrum californicum was responsible for large losses of sheep grazing high mountain ranges in central Idaho in the 1950s. Veratrum induces various birth defects including the cyclopic-type craniofacial defect (monkey-faced lambs) that is specifically induced in lambs after pregnant ewes grazed the plant on the 14th day of gestation. The steroidal alkaloids cyclopamine (1) and jervine (2) were isolated from Veratrum and shown to be primarily responsible for the malformations. Cyclopamine (1) and jervine (2) are potent teratogens that inhibit Sonic hedgehog (Shh) signaling during gastrulation-stage embryonic development, producing Cyclopia and holoprosencephaly. Although losses to the sheep industry from Veratrum are now relatively infrequent, occasional incidents of toxicoses and craniofacial malformations are still reported in sheep and other species. However, the benefits to biomedical research using cyclopamine (1) as a tool to study human diseases have greatly expanded. A competitive inhibition enzym...
Maria Luczkiewicz - One of the best experts on this subject based on the ideXlab platform.
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Honeybush Tea ( Cyclopia sp.): A Traditional South-African Tisane
Tea in Health and Disease Prevention, 2013Co-Authors: Adam Kokotkiewicz, Maria LuczkiewiczAbstract:Honeybush tea is a well-recognized South-African beverage manufactured from the aerial parts of several Cyclopia spp., which are characteristic of the fynbos shrublands of the Cape Floristic Region. The harvested material is traditionally fermented in order to develop the characteristic sweet aroma of the final product, or dried in unfermented state to give the so called ‘green honeybush’. Honeybush infusions are characterized by distinctive honey-like aroma, lack of caffeine and the presence of numerous phenolic compounds, including xanthones, flavanones and flavones. Cyclopi a extracts exhibit substantial antioxidant, antimutagenic and phytoestrogenic effects, which were demonstrated with in vitro and animal models. The growing popularity of honeybush makes it an important export commodity, but has also forced the need to refine the tea production process and standardize procedures in order to obtain a high-quality product. The current review covers botanical issues, tea manufacture, chemical composition and biological activity of Cyclopia extracts.
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isolation and structure elucidation of phenolic compounds from Cyclopia subternata vogel honeybush intact plant and in vitro cultures
Food Chemistry, 2012Co-Authors: Adam Kokotkiewicz, Maria Luczkiewicz, Pawel Sowinski, Daniel Glod, Krzysztof Gorynski, Adam BucińskiAbstract:Abstract In the presented work, an insight was made into the polyphenolic composition of intact plant material and in vitro cultures of indigenous South African plant Cyclopia subternata Vogel (honeybush). Ethyl acetate fractions of methanol extracts were separated by means of gravity column chromatography and/or semipreparative HPLC on two serially connected monolithic RP-18 columns. The structures of the isolated compounds were determined by means of 1D and 2D NMR techniques and additionally confirmed by LC-DAD-ESI-MS. Apart from the previously described honeybush components, that is mangiferin ( 1 ), scolymoside ( 2 ), hesperidin ( 3 ) and narirutin ( 4 ), three additional compounds: iriflophenone 3- C - β -glucoside (benzophenone) ( 5 ), phloretin 3′,5′-di- C - β -glucoside (dihydrochalcone) ( 6 ), and isorhoifolin (flavone) ( 7 ) were identified for the first time in the herb of C. subternata . Additionally, three isoflavone glucosides, namely calycosin 7- O - β -glucoside ( 8 ), rothindin ( 9 ) and ononin ( 10 ), which had not been previously reported in Cyclopia plants, were identified in the callus of the above species. As far as the authors are concerned, this is the first report on the presence of benzophenone and dihydrochalcone derivatives in Cyclopia genus.
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In vitro cultures of Cyclopia plants (honeybush) as a source of bioactive xanthones and flavanones.
Zeitschrift fur Naturforschung. C Journal of biosciences, 2009Co-Authors: Adam Kokotkiewicz, Małgorzata Wnuk, Adam Buciński, Maria LuczkiewiczAbstract:In vitro shoot and callus cultures of the endemic South-African shrubs: Cyclopia intermedia E. Mey., Cyclopia subternata Vogel, and Cyclopia genistoides (L.) Vent. (Fabaceae) were established and examined for the presence of polyphenolic compounds. The xanthones mangiferin and isomangiferin, as well as the flavanones hesperidin and eriocitrin were identified by LC-ESI-MS and LC-DAD, and analyzed quantitatively by HPLC. The respective intact plants were analyzed for comparison. From all in vitro cultures, the highest levels of mangiferin (1.55%) and isomangiferin (0.56%) were recorded in C. subternata microshoots, compared to 1.31% and 0.49% found in the intact plant. Callus cultures of all species synthesized only trace amounts of mangiferin and isomangiferin. Hesperidin and eriocitrin contents were significanly lower in all in vitro cultures, in comparison to the respective intact plants. Among the obtained in vitro biomasses, the highest hesperidin content was recorded in C. intermedia (0.9%) and C. subternata (0.87%) microshoots, whereas C. subternata callus was characterized by the best growth parameters and highest hesperidin content (0.69%) from all examined Cyclopia calli.
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Honeybush (Cyclopia sp.) - a rich source of compounds with high antimutagenic properties.
Fitoterapia, 2008Co-Authors: Adam Kokotkiewicz, Maria LuczkiewiczAbstract:The genus Cyclopia (Fabaceae family) includes a number of shrubs endemic to Cape Fynbos region of South Africa. The most common of these plants is Cyclopia intermedia E. Mey., used together with other Cyclopia species (mainly C. subternata and C. sessiliflora) to manufacture the honeybush herbal tea which has been produced in South Africa roughly since the beginning of the 19th century. Honeybush infusions are gaining popularity due to their characteristic honey-like flavour, low tannin content, absence of caffeine and potential health effects related to their antimutagenic and antioxidant properties. The presented review summarizes information concerning botany, chemistry, biological activity and application of Cyclopia plants.
Adam Kokotkiewicz - One of the best experts on this subject based on the ideXlab platform.
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Honeybush Tea ( Cyclopia sp.): A Traditional South-African Tisane
Tea in Health and Disease Prevention, 2013Co-Authors: Adam Kokotkiewicz, Maria LuczkiewiczAbstract:Honeybush tea is a well-recognized South-African beverage manufactured from the aerial parts of several Cyclopia spp., which are characteristic of the fynbos shrublands of the Cape Floristic Region. The harvested material is traditionally fermented in order to develop the characteristic sweet aroma of the final product, or dried in unfermented state to give the so called ‘green honeybush’. Honeybush infusions are characterized by distinctive honey-like aroma, lack of caffeine and the presence of numerous phenolic compounds, including xanthones, flavanones and flavones. Cyclopi a extracts exhibit substantial antioxidant, antimutagenic and phytoestrogenic effects, which were demonstrated with in vitro and animal models. The growing popularity of honeybush makes it an important export commodity, but has also forced the need to refine the tea production process and standardize procedures in order to obtain a high-quality product. The current review covers botanical issues, tea manufacture, chemical composition and biological activity of Cyclopia extracts.
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isolation and structure elucidation of phenolic compounds from Cyclopia subternata vogel honeybush intact plant and in vitro cultures
Food Chemistry, 2012Co-Authors: Adam Kokotkiewicz, Maria Luczkiewicz, Pawel Sowinski, Daniel Glod, Krzysztof Gorynski, Adam BucińskiAbstract:Abstract In the presented work, an insight was made into the polyphenolic composition of intact plant material and in vitro cultures of indigenous South African plant Cyclopia subternata Vogel (honeybush). Ethyl acetate fractions of methanol extracts were separated by means of gravity column chromatography and/or semipreparative HPLC on two serially connected monolithic RP-18 columns. The structures of the isolated compounds were determined by means of 1D and 2D NMR techniques and additionally confirmed by LC-DAD-ESI-MS. Apart from the previously described honeybush components, that is mangiferin ( 1 ), scolymoside ( 2 ), hesperidin ( 3 ) and narirutin ( 4 ), three additional compounds: iriflophenone 3- C - β -glucoside (benzophenone) ( 5 ), phloretin 3′,5′-di- C - β -glucoside (dihydrochalcone) ( 6 ), and isorhoifolin (flavone) ( 7 ) were identified for the first time in the herb of C. subternata . Additionally, three isoflavone glucosides, namely calycosin 7- O - β -glucoside ( 8 ), rothindin ( 9 ) and ononin ( 10 ), which had not been previously reported in Cyclopia plants, were identified in the callus of the above species. As far as the authors are concerned, this is the first report on the presence of benzophenone and dihydrochalcone derivatives in Cyclopia genus.
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In vitro cultures of Cyclopia plants (honeybush) as a source of bioactive xanthones and flavanones.
Zeitschrift fur Naturforschung. C Journal of biosciences, 2009Co-Authors: Adam Kokotkiewicz, Małgorzata Wnuk, Adam Buciński, Maria LuczkiewiczAbstract:In vitro shoot and callus cultures of the endemic South-African shrubs: Cyclopia intermedia E. Mey., Cyclopia subternata Vogel, and Cyclopia genistoides (L.) Vent. (Fabaceae) were established and examined for the presence of polyphenolic compounds. The xanthones mangiferin and isomangiferin, as well as the flavanones hesperidin and eriocitrin were identified by LC-ESI-MS and LC-DAD, and analyzed quantitatively by HPLC. The respective intact plants were analyzed for comparison. From all in vitro cultures, the highest levels of mangiferin (1.55%) and isomangiferin (0.56%) were recorded in C. subternata microshoots, compared to 1.31% and 0.49% found in the intact plant. Callus cultures of all species synthesized only trace amounts of mangiferin and isomangiferin. Hesperidin and eriocitrin contents were significanly lower in all in vitro cultures, in comparison to the respective intact plants. Among the obtained in vitro biomasses, the highest hesperidin content was recorded in C. intermedia (0.9%) and C. subternata (0.87%) microshoots, whereas C. subternata callus was characterized by the best growth parameters and highest hesperidin content (0.69%) from all examined Cyclopia calli.
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Honeybush (Cyclopia sp.) - a rich source of compounds with high antimutagenic properties.
Fitoterapia, 2008Co-Authors: Adam Kokotkiewicz, Maria LuczkiewiczAbstract:The genus Cyclopia (Fabaceae family) includes a number of shrubs endemic to Cape Fynbos region of South Africa. The most common of these plants is Cyclopia intermedia E. Mey., used together with other Cyclopia species (mainly C. subternata and C. sessiliflora) to manufacture the honeybush herbal tea which has been produced in South Africa roughly since the beginning of the 19th century. Honeybush infusions are gaining popularity due to their characteristic honey-like flavour, low tannin content, absence of caffeine and potential health effects related to their antimutagenic and antioxidant properties. The presented review summarizes information concerning botany, chemistry, biological activity and application of Cyclopia plants.
Felix D. Dakora - One of the best experts on this subject based on the ideXlab platform.
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Relationship between acid phosphatase activity and P concentration in organs of Cyclopia and Aspalathus species, and a non-legume of the Cape Floristic Region
Journal of Plant Ecology, 2018Co-Authors: S.t. Maseko, Felix D. DakoraAbstract:The role of tissue acid phosphatase (APase) activity of legumes and non-legumes in their P nutrition and adaptation to low-P soils is not well understood. To better understand this, a relationship between APase activity and P concentration in leaves, stems, roots and nodules of legumes, Cyclopia and Aspalathus and a non-legume, Leucadendron strictum, all native to the P-poor soils of the Cape fynbos biome, was assessed. Plants were collected and each separated into leaves, stems and roots. Phosphatase enzyme activity was assayed in soil using the p-nitrophenol method, while soil P and shoot P were measured using ICP-MS. To measure tissue APase activity, an acetate buffer was added into ground plant material and contents filtered. An acetate buffer and a p-nitrophenyl solution were added to the supernatant and contents incubated. After incubation, NaOH (0.5 M) was added and absorbance read at 405 nm. At Koksrivier, Cyclopia genistoides exhibited the highest leaf enzyme activity whilst Aspalathus aspalathoides showed the highest enzyme activity in the stems. At both Kleinberg and Kanetberg, Cyclopia subternata and Cyclopia longifolia showed the highest APase activity in leaves, followed by stems and lowest in roots. P concentration closely mirrored enzyme activity in organs of all test species from each site. APase activity positively correlated with P concentration in organs of all the test Cyclopia and Leucadendron species, indicating that intracellular APase activity is directly linked to P mobilization and translocation in these species. Percentage of N derived from fixation was positively correlated with tissue APase activity in C. genistoides (r = 0.911*), A. aspalathoides (r = 0.868*) and Aspalathus caledonensis (r = 0.957*), suggesting that APase activity could be directly or indirectly linked to symbiotic functioning in these fynbos legumes, possibly via increased P supply to sites of N₂ fixation.
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Nitrogen nutrition, carbon accumulation and δ13C of Cyclopia and Aspalathus species in different settings of the Cape fynbos, South Africa
Journal of Plant Ecology, 2015Co-Authors: S.t. Maseko, Felix D. DakoraAbstract:Aims Cyclopia and Aspalathus are legumes harvested for production of Honeybush and Rooibos tea, respectively. Farmers grow these species from either seeds or cuttings over several years with continuous annual harvesting. The aims of this study were to assess the effect of plant age, plant species, toposequence, planting material and farmer practice on nitrogen (N) nutrition and water-use efficiency of two Cyclopia and Aspalathus species in the Cape fynbos. Methods The study was conducted using plants from Koksrivier farm located near Gansbaai (33° S 18° E, 39 m.a.s.l), and at Kanetberg farm near Barrydale (33° S 21° E, 830 m.a.s.l). The 15N natural abundance technique was used to determine N2 fixation, carbon (C) assimilation and δ13C in shoot of Cyclopia and Aspalathus species. Important Findings Older tea plantations of C. genistoides and C. subternata derived more N from fixation and exhibited greater water-use efficiency than younger plants. At Koksrivier, Aspalathus caledonensis and A. aspalathoides showed greater water-use efficiency and derived more N from fixation than Cyclopia genistoides. Annual harvesting of C. genistoides decreased N2 fixation. At Kanetberg, C. subternata plants on the upper and middle slopes derived more N from atmospheric fixation than those on the lower slope. C. subternata plants grown from seedlings recorded greater %Ndfa than cuttings. N2 fixation and water-use efficiency of Cyclopia was affected by age, slope and planting material. Further, symbiotic N nutrition and water-use efficiency of Cyclopia and Aspalathus were related.
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Cyclopia and Aspalathus species in different settings of the Cape fynbos, South Africa
2015Co-Authors: S.t. Maseko, Felix D. DakoraAbstract:Aims Cyclopia and Aspalathus are legumes harvested for production of Honeybush and Rooibos tea, respectively. Farmers grow these species from either seeds or cuttings over several years with continuous annual harvesting. The aims of this study were to assess the effect of plant age, plant species, toposequence, planting material and farmer practice on nitrogen (N) nutrition and water-use efficiency of two Cyclopia and Aspalathus species in the Cape fynbos.
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Rhizosphere acid and alkaline phosphatase activity as a marker of P nutrition in nodulated Cyclopia and Aspalathus species in the Cape fynbos of South Africa
South African Journal of Botany, 2013Co-Authors: S.t. Maseko, Felix D. DakoraAbstract:Cyclopia and Aspalathus species are important economic legumes in the Cape fynbos of South Africa, as they are used for making Honeybush and Rooibos tea, and for trade in the cut wild flower industry. The aim of this study was to assess acid and alkaline phosphatase activity in the rhizosphere of Cyclopia genistoides, Cyclopia subternata, Aspalathus caledonensis and Aspalathus aspalathoides as an indicator of P supply and P nutrition in the nutrient-poor soils of the Cape fynbos. Whether at Kokrivier or Kanetberg, the P enzyme activities were much higher in the rhizospheres of the legumes C. genistoides, C. subternata, A. caledonensis, and A. aspalathoides compared to those of the non-legumes Leucadendron strictum, Elegia thyrsoidea and Mimetes cucullatus, or bulk soil. As a result, plant-available P concentration in the rhizosphere, as well as shoot P levels closely mirrored acid and alkaline phosphatase activity in the rhizosphere of each plant species. Relative to younger plants, older Cyclopia species exhibited, much greater acid and alkaline phosphatase activity in the rhizosphere and this again resulted in much higher plant-available rhizosphere P. C. subternata plants developed from cuttings at Kanetberg showed greater rhizosphere acid and alkaline phosphatase activity than seedlings and bulk soil. As a result, the concentration of plant available-P and organic P were much higher in the rhizosphere of cuttings than seedlings, leading to greater shoot P in cuttings than seedlings. Taken together, these data suggest that rhizosphere P enzyme activity can be used as a good indicator of P supply and P nutrition in Cyclopia cuttings and seedlings, but less so in Aspalathus species in the Cape fynbos. The enhanced P nutrition in plants from cuttings probably accounts for the higher tea yields obtained by farmers when they use cuttings instead of seedlings in their plantations.
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Field assessment of symbiotic N2 fixation in wild and cultivated Cyclopia species in the South African fynbos by 15N natural abundance
Tree physiology, 2008Co-Authors: Amy C. Spriggs, Felix D. DakoraAbstract:Summary Nitrogen (N) derived from symbiotic fixation of atmospheric N2 in wild and cultivated populations of Cyclopia, a woody endemic genus used to make honeybush tea in the Western Cape of South Africa, was quantified by the 15 N natural abundance method. Because Cyclopia species are naturally mycorrhizal, non-N2-fixing arbuscular mycorrhizal shrubs of similar phenology to Cyclopia were chosen as reference plants to provide thed 15 N value of soil-derived N. Isotopic analysis showed that wild populations of Cyclopia were highly dependent on N2 fixation for their N nutrition, ranging from 70 ± 4% to 100 ± 7% (mean ± SE) at all sites, except for one. Further evidence of the high dependency of wild Cyclopia populations on symbiotic N was provided by their significantly higher foliar N concentrations compared with the non-legume reference plants. However, cultivated Cyclopia exhibited variable amounts of N2 fixation, with Cyclopia genistoides (L.) R. Br., for example, showing low amounts of N2 fixation at Sites P2 and P3 (0 ± 51% and 8 ± 46%, respectively) as a result of low D values (D is defined as the difference between the mean d 15 N value of the reference plants and the B value of the test Cyclopia species, where B is the d 15 N of an inoculated test legume grown in an N-free growth medium), whereas at Sites P1, P2, P5 and P6, up to 89 ± 2%, 94 ± 13%, 85 ± 13% and 100 ± 18%, respectively, plant N was derived from atmospheric fixation. The high symbiotic N nutrition observed for wild populations of Cyclopia suggests that these populations are major contributors to the N economy of the nutrientpoor soils of the South African fynbos. These data indicate that by breeding for high N2 fixation rates in Cyclopia cultivars and selecting more efficient rhizobial strains, this legume has the potential to achieve higher N2 fixation rates under cultivation. The low variability in Cyclopia d 15 N values within sites, however, suggests that genetic variability is not a major factor influencing N2 fixation rates in cultivated Cyclopia, and that more benefit may be gained from soil amelioration and the selection of improved rhizobial strains.
