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Item Germination characteristics of dimorphic honeybush (Cyclopia spp.) seed.(Elsevier B.V., 2016-04-09) Koen, J.; Slabbert, M.M.; Bester, C.; Bierman, F.Cyclopia is a genus of leguminous shrubs endemic to the fynbos biome of South Africa. Cyclopia spp. are used to make honeybush tea for which a high market demand has led to the overharvesting of Cyclopia species in the wild. Consequently, it has become important to study the cultivation requirements of honeybush in order to support farmers with the cultivation of this crop. Honeybush seeds are known to have either physical or combinational dormancy upon maturity, depending on the species. The plants also produce colour-dimorphic (green and brown), mature seeds in the same pod. A study of honeybush (Cyclopia maculata, Cyclopia genistoides and Cyclopia subternata) seed anatomy was carried out using light and dissection microscopy. It is hypothesized that seed physical dormancy is attributable to a relatively thick (3.5 μm) cuticular layer of the integument, a layer of macrosclereid cells, and the presence of a hygroscopically activated hilar valve. There is an absence of other structural openings by which moisture may enter the seed. No consistent structural differences were found amongst the three species or their colour-dimorphic seed. Seeds of the same three honeybush species were divided by colour and their germination response to selected variables (scarification, stratification, seed age and germination temperature) was evaluated. Three dormancy-breaking treatments (wet heat, dry heat and microwave energy) were identified as potential alternatives to conventional sulphuric acid scarification. Highest germination percentage of scarified seed for the three species tested was obtained after 3 weeks of cold stratification at 2 °C and incubated at 15 °C. Brown C. subternata seeds stored for three years gave a significantly higher germination percentage than seed stored for one year only. In non-treated seed, brown seeds had a higher germination percentage than green seeds. In treated seed (i.e. scarified and/or stratified), green seeds had a better germination percentage than brown seeds.Item Antioxidant enzyme activity, proline accumulation, leaf area and cell membrane stability in water stressed Amaranthus leaves.(Elsevier B.V., 2014-08-27) Slabbert, M.M.; Krüger, G.H.J.Traditional crops are extremely important for food production in low income, food-deficit countries (LIFDCs) where they continue to bemaintained by socio-cultural preferences and traditional uses. Significant potential exists to improve these crops, one of which is to select for improved productivity during moisture stress conditions. Germplasm of Amaranthus tricolor, Amaranthus hypochondriacus and Amaranthus hybridus were subjected to various screening methods to measure metabolic and physiological changes during water stress. The activities of enzymes involved in the oxygen-scavenging system during abiotic stress conditions (superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR)), free proline production, leaf area (LA), cell membrane stability (CMS), leaf water potential (LWP) and relative water content (RWC) were measured in these three amaranth species during induced water stress. This study showed significant differences in metabolic responses during water deficit of the three species tested. Moisture stress and a decrease in RWC and LWP were first experienced in A. hybridus and A. hypochondriacus, followed by A. tricolor. There was an indirect correlation between leaf water status (RWC and LWP), enzyme activity, proline production and leaf area. The combined effect of GR, APX and SOD could ensure higher levels of regulation of the toxic effect of H2O2 which could be associated with drought tolerance in Amaranthus. Distinct differences in onset of proline accumulation and the amount of accumulated in leaves upon induced water stress was noticed for the three amaranth species tested. Proline accumulation during water stress conditions in amaranth seems to be indirect and could possibly have a protective role apart from osmoregulation during stress conditions. This contention is supported by the decrease in leaf area and high cell membrane stability for two of the species tested. This study forms part of a project aimed at the development of improved traditional crops to contribute to food production and quality for subsistence farmers in areas with low precipitation or variable rainfall patterns.Item Antioxidant activities of co-encapsulated Natal plum (Carissa macrocarpa) juice inoculated with Ltp. plantarum 75 in different biopolymeric matrices after In vitro digestion.(MDPI, 2022-07-16) Seke, Faith; Manhivi, Vimbainashe E.; Guerin, Marie; Shoko, Tinotenda; Akinola, Stephen A.; Garcia, Cyrielle; Remize, Fabienne; Slabbert, Retha M.; Sivakumar, DhariniBiopolymeric systems that co-encapsulate probiotics, and bioactive compounds ensure timely delivery in the gastrointestinal tract. Cyanidin 3-sambubioside is the dominant anthocyanin in Natal plum (Carissa macrocarpa). This study aims at the co-encapsulation of Natal plum (Carissa macrocarpa) juice inoculated with Lactiplantibacillus plantarum 75 (Ltp. plantarum 75) by freeze-drying using pea protein isolate, maltodextrin, and psyllium mucilage and evaluating their release in vitro. An encapsulation efficiency of >85% was noted in lactic acid bacteria (LAB) survival and anthocyanin content. Freeze-drying produced pinkish-red powder, rich in polyphenols and LAB (>6 Log CFU mL1) after 14 days of storage. Natal plum juice +maltodextrin + pea protein isolate + psyllium mucilage + Ltp. plantarum 75 (NMPeaPsyB) showed the highest LAB population (6.74 Log CFU mL1) with a survival rate of 81.9%. After digestion, NMPeaPsyB and NMPeaPsy had the highest LAB survival (>50%) at 67.5% and 67.5 0.75%, respectively, and the highest bio accessibility of cyanidin 3-sambubioside in Natal plum juice than the other co-encapsulation with other biopolymers. NMPeaPsy and NMPeaPsyB showed phenolic stability in the gastric phase and controlled release in the intestinal simulated phase. The antioxidant activities had strong correlations with cyanidin 3-sambubioside. The results confirmed that microencapsulation is important for improving stability and allowing for the development of functional foods.Item A comparison of bioactive metabolites, antinutrients, and bioactivities of African pumpkin leaves (Momordica balsamina L.) cooked by different culinary techniques.(MDPI, 2022-03-15) Mashiane, Petunia; Shoko, Tinotenda; Manhivi, Vimbainashe; Slabbert, Retha; Sultanbawa, Yasmina; Sivakumar, DhariniPrior to consumption, African pumpkin leaves (Momordica balsamina L.) are generally cooked. In this study, the effects of common household cooking methods (boiling, steaming, microwaving, stir-frying) on bioactive metabolites, carotenoids, antioxidant activity, antinutrients and inhibitory effects on -glucosidase and -amylase activities were examined. A set of 14 bioactive metabolites were identified in raw and cooked African leaves using UPLC-QTOF/MS. The results showed that the four different types of household cooking methods had different effects on the bioactive metabolomics profile of African pumpkin leaves. In comparison to raw leaves and leaves cooked in other methods, the concentrations of six phenolic compounds, rutin, crypto chlorogenic acid (4-caffeoylquinic acid), pseudolaroside A, isorhamnetin 3-O-robinoside, quercetin 3-galactoside, and trans-4-feruloylquinic acid, were highest in stir-fried leaves. Of all household cooking methods tested, stir-frying increased the content of lutein, -carotene, and zeaxanthin by 60.00%, 146.15%, and 123.51%, respectively. Moreover, stir-frying African pumpkin leaves increased the antioxidant activity (DPPH and ABTS) and the inhibition of -glucosidase and -amylase. Compared to all four methods of household cooking, stir-frying reduced the antinutritive compounds compared to raw leaves. This work provides useful information to the consumers on the selection of suitable cooking methods for African pumpkin leaves.Item Changes in antinutrients, phenolics, antioxidant activities and in vitro a-glucosidase inhibitory activity in pumpkin leaves (Cucurbita moschata) during different domestic cooking methods.(Springer, 2021-06-07) Mashitoa, Florence M.; Manhivi, Vimbainashe; Slabber, Retha M.; Shai, Jerry L.; Sivakumar, DhariniPumpkin leaves (Cucurbita moschata) were subjected to different household cooking methods (boiling, microwaving, steaming, and stir-frying) to evaluate their effect on antinutrients, phenolic compounds, antioxidant properties (ABTS, and DPPH) and in vitro a-glucosidase activity. All cooking methods studied significantly reduced the antinutrients and antioxidant activities, whilst phenolic compounds p-coumaric and ferulic acids significantly increased. The cooking methods reduced the oxalates by more than 50%, tannins by 47% and phytates by 79.22%. Steaming and boiling resulted in highest concentrations of p-coumaric (195.40 mg kg-1) and ferulic acids (103.90 mg kg-1) compared to other methods. Overall, boiled leaves retained the highest total phenolic compounds, whilst steamed leaves retained the highest antioxidant capacity. Raw pumpkin leaf extracts showed higher in vitro a-glucosidase inhibitory effects than the cooked leaves. Thus, cooking affected the inhibitory effect of in vitro a-glucosidase activity.Item Seed germination and vegetative propagation of Helichrysumod oratissimum(Elsevier B.V., 2023-08-23) Makena, Ivy Masefako; Matsiliza-Mlathi, Babalwa; Kleynhans, RianaHelichrysum odoratissimum is a popular indigenous herb of South Africa, well known for its aromaticity. It offers potential as a source of extracts for the development of cosmeceutical products as it has been reported to be a natural antibiotic, and has antifungal, antimicrobial, antioxidant and antiviral properties. In order to be commercialized, a sustainable production system is required to ensure a consistent supply of good quality material. Therefore, the production of H. odoratissimum by seed and stem cutting was evaluated. The interactive effect of different seed priming methods and temperature levels were investigated on germination indices of H. odoratissimum seeds. A randomized complete block design with three replicates was used to evaluate the effect of season, cutting position, rooting hormone and growth media on survival percentage, number of buds, number of leaves, rooting percentage, number of roots per cutting and root length of H.odoratissimum stem cuttings. Data for both aspects was analysed using ANOVA and means with significant differences were separated with a t-test at 5% level of significance. Smoke treated seeds incubated at 20 °Chad a significantly higher germination percentage (91,7%), mean germination rate (0.59) and coefficient velocity of germination (59.5) compared to most other treatments. Almost all factors tested in vegetative propagation significantly affected parameters measured. Apical cuttings taken during autumn resulted in significantly higher survival (78.5) and rooting percentages (71.1%) compared to other seasons. Cuttings planted in a perlite, vermiculite and sand mixture during autumn significantly outperformed all other season/media combinations with regards to rooting percentage (75%). PGR application improved the number of roots obtained significantly in autumn and winter, but not in summer and spring, compared to the control. It was therefore concluded that, for higher seed germination H. odoratissimum seeds must be primed with smoke water and incubated at 1520 °C and cuttings may be taken autumn for higher rooting and survival rates as well as improved root length. A PGR application can be beneficial depending on the type of medium used.Item Rooting and survival of Lobostemon fruticosus (L) H. Buek stemcuttings as affected by season, media and cutting position.(Elsevier B.V., 2018-09-07) Swarts, A.; Matsiliza-Mlathi, B.; Kleynhans, R.The eight-day healing bush (Lobostemon fruticosus) belongs to the Boraginaceae family and is one of the oldest medicinal plants used in the Cape by Khoisan and early settlers. The natural populations of L. fruticosus are being destroyed by veld fires and overharvesting, leading to a need for propagation of plant material especially for commercial use. The objective of the study was to investigate the effect of season, plant growth regulator, growth media and cutting position on survival and rooting of L. fruticosus. A randomised complete block design was used with 2 block replications per season and 10 cuttings as an experimental unit. Treatments included four media, three plant growth regulator treatments and two cutting positions. Improved survival and better root quality was observed in cuttings planted in autumn (survival percentage 85.6% and root score 4.3) compared to spring (survival percentage 50.1% and root score 2.3). In autumn, cuttings planted in peat (91.25%) had the best survival percentage, however, only differed significantly from those planted in bark (77.5%), while in spring, cuttings planted in bark (68.33%) had significantly higher survival percentage compared to all other media {peat (52.92%); peat Pol (51.67%) and sand Pol (27.5%). Survival percentage was significantly higher in heel cutting planted in both bark (85.83%) and peat (78.33%) as compared to apical cuttings planted in the same growth media (bark 60% and peat 65.83%). While cuttings planted in peat consistently outperformed most other season- media treatment combinations in autumn an increase in rooting percentage, root length and root quality recorded in cuttings planted in bark during spring. Increased budding was recorded in cuttings planted in spring, except for cuttings planted in the sand Pol media. Survival percentage, rooting percentage, root quality and budding leaves significantly increased in heel cuttings {survival percentage (61.46%); rooting percentage (41.88%); root score (3.25) and budding leaves (58.96%)} planted in spring as compared to apical cuttings {survival percentage (38.75%); rooting percentage (17.08%); root score (1.34) and budding leaves (38.54%)} of the same season. Rooting percentage (66.25%), root length (57.76mm), root score (4.99) and budding leaf percentage were significantly higher in heel cuttings planted in bark as compared to apical cuttings. Application of PGR's produced a significantly better rooting percentage {Dip 'N Grow® (52.66%) and Seradix B® No. 2 (47.81%), significantly longer roots {Seradix B® No. 2 (36.23 mm) and Dip 'N Grow® (35.34 mm)} and a significantly better root quality score {Seradix B® No. 2 (3.64); Dip 'N Grow® (3.62)} compared to the control. Based on the current findings it is therefore recommended that, L. fruticosus stem cuttings can be propagated successfully using heel cutting type, Seradix B® No. 2 or Dip ‘N Grow® as growth regulator application and, coco-peat as growth media if propagating during autumn or bark if propagating during spring.