Botany

Permanent URI for this collection

https://hdl.handle.net/10530/421

Browse

Now showing 1 - 19 of 19

A comparative study of certain cultivars of manihot esculenta crantz with special reference to certain morphological characteristics, photosynthesis and water relations.
(1992) Zobolo, Alpheus Mpilo; Boshoff, D.N.
Cassava {Manihot esculenta Crantz) is cultivated for its tuberous roots. In this study four cultivars MSAF 2, CMC 40, M 170 and M 5 were compared for their yield and morphological and physiological characteristics. The cultivars were planted in the field and in pots. Photosynthesis and transpiration were measured using a portable Infra - red C02 analyser. The leaf chamber had an area of 1120 mm2. Measurements were made between 9:30 and 15:30. The leaf area was determined using a AT area meter. The leaf water potential was measured with a pressure bomb. The chlorophyll a was extracted with 90 % acetone and determined spectrophotometrically. The drying of the plant material was done at 105 °C in an oven. The photosynthetic rate decreased from top to bottom within the plant's canopy. The maximum photosynthetic rate obtained ranged from 8,4 to 10,97 umol CO* m~a s"1. CMC 40 had the lowest leaf photosynthetic rate. The winter retention of LAI and photosynthesis were the lowest in CMC 40. The photosynthetic rate was high in the morning and declined in the afternoon. In MSAF 2 the photosynthetic rate decreased when the leaf water potential was below -0,5 MPa. in CMC 40, M 170 and M 5 the photosynthetic rate decreased when the leaf water potential was below -0,6 MPa. A decrease in the photosynthetic rate with a decreasing leaf water potential was followed by a decrease in the relative transpiration rate in MSAF 2. CMC 40 had the lowest transpiration rate. The chlorophyll a content was lowest in CMC 40- The maximum chlorophyll a content ranged from 0,96 to 1,19 |ig mm-2 in field plants and from 0,32 to 0,40 \iq mm_a in potted plants. The chlorophyll a content was high during the first growth season and declined in post winter regrowth in all the cultivars. Plant height, leaf numbers, LAI and the partitioning of dry matter followed a seasonal pattern in all the cultivars. The total dry mass increased as LAI increased up to 1/31 in potted plants and up to LAI 2,42 - 6,14 in field plants. In the first year of growth in field plants, the tuber dry mass increased with LAI up to levels of 2,29 - 3,61, then declined. In the potted plants, the tuber dry mass increased with LAI up to 1,2 and continued to increase in spite of the decline in LAI, which was still close to 0,8. At 707 DAP, MSAF 2 had the highest root dry mass while CMC 40 had the lowest. The maximum tuber dry mass obtained was 110-353 g m"a in potted plants and 2505-3577 g m~a in field plants. The number of tubers per plant was highest in M 170 (7,5¬ 9,4) and lowest in CMC 40 (3,2 - 4,25). MSAF 2 was intermediate (6,25 - 6,6). CMC 40 and M 5 had a higher stem dry mass than M 170 and MSAF 2. Except for a few exceptions, a significantly higher LAI resulted in a significantly higher root yield only if it coincided with a significantly higher HI. The maximum HI ranged from 0,7 - 0,8 in field plants and from 0,39 - 0,82 in potted plants.
Morphology and selection of high yielding cashew (Anacardium occidentale L.) Strains for Maputaland, South Africa
(2001) Vololoniana, Ramiakato; Ferreira, D.P.; de Wet, H.
The Industrial Development Corporation (IDC) and Ithala Development Finance Corporation Limited (ITHALA) are in the process of establishing a cashew industry in South Africa at Coastal Cashews, Maputaland. This study concentrated on the morphology and yield characteristics of most of the strains already planted at Coastal Cashew farm. One hundred and thirty different strains, originating from various countries such as Zambia and Brazil, have been studied. Morphological and yield characteristics were considered for suggestions about strains for inclusion in a propagation program. Most morphological characteristics such as apple size and colour, leaf surface area and others, varied between strains, reflecting the diverse origin of plant material. Similarly, most of the yield characteristics such as nut production, nut size and others, varied between strains and within strains between seasons. Based on the morphological (number of panicles per tree, number of perfect flowers per panicle, and others) and the yield characteristics (nut per panicle, nut size, and others), a model has been proposed where the number of panicles per tree and the number of perfect flowers per panicle are used to predict the yield of a tree (strain).
Genetic improvement of selected indigenous Cucurbitaceae species important for food and medicinal purposes in KwaZulu-Natal, South Africa
(2007) Ntuli, Nontuthuko Rosemary; Ferreira, D.P.; Hannweg, K.; Zobolo, A.M.
Coccinia palmata (Cogn.) and Lagenaha sphaerica (Sond.) Naud. are indigenous Cucurbitaceae species widely distributed in pantropical to tropical regions of Southern Africa. They are widely used for food and medicinal purposes, in nature these species exist as diploids, with their basic haploid (n) chromosome numbers being 12 and 11 for C. palmata and L sphaerica respectively. However, in higher plants nuclear DNA endoreduplication often occurs during their growth and differentiation which causes polysomaty in their tissues. For both C. palmata and L sphaerica, the optimum germination conditions were 25°C under light. Growth was either in the nursery (in pots/bags) or in the field (with and without bags). Colchicine treatment of seeds before and after incubation for germination was used to induce polyploidy in both of these Cucurbitaceae species. The effectiveness of colchicine in inducing polyploidy (genetic improvement) in the roots and shoots of both species was established. In both species treated roots had higher tetraploid and octoploid ratios than leaves. Colchicine treatment lowered the germinability (germination percentage), induced dwarfism, enhanced stem branching, reduced leaf area and number of stomata, and increased guard cell length and leaf chlorophyll content in both species. In C. palmata, colchicine treatment increased root fresh and dry weight but reduced shoot fresh and dry weight. However, colchicine treatment inhibited female plants' flowering and therefore fruiting in both species.
The screening of medicinal plants traditionally used to treat diarrhoea, in Ongoye area, KwaZulu Natal.
(2008) Mlambo, Nandi Precious; de Wet, H.; Basson, A.K.; Ntuli, N.R.
This study focused on the investigation of plants used for the treatment of diarrhoea around Ongoye forest, KwaZulu-Natal, South Africa. The study revealed that 35 plant species in this area are used to treat diarrhoea. Acetone, methanol, cold and hot distilled water extracts from the different plant parts (bark, leaves, stems and the whole plant) were done. These plants are: Acacia karoo, Acacia robusta, Acanthospermum australe, Aloe arborescens, Baccharoides adoensis, Calfilepis laureola, Catharanthus roseus, Chenopodium ambrosioids, Chromolaena odarata, Dichrostachys cinerca, Faurea macnaughton, Hewittia mafambaricaa, Hypoxis hemerocalfidea, Ihlaza, Lippia javanica, Maytenus heterophylla, Melia azedarach, Psidium guajava, Schotia brachypetala, Sclerocarya birrea, Syzygium cordatum, Tetradenia riparia, Thchilia dregeana, Ungazini, Vernonia oligocephala and Vernonia tigna. Above mentioned plants were screened for antibacterial activity against the following ATCC bacteria strains: Bacillus subtilis, Escherichia colt, Klebsiella pneumoniae and Staphylococcus aureus. Escherichia coli, Salmonella spp, Shigella flexneri and Shigella sonnei. The antibacterial activities were determined by disk-diffusion, agar-well diffusion, minimum inhibitory concentrations (MIC) and bio-autographic methods. The plant extracts were screened for the following phytochemrcals: alkaloids, flavonoids, soponins, anthraquinones, cardiac glycosides and tannins. Most of the plant extracts showed high antibacterial activity against most of the tested micro-organisms with the diameter of inhibition zones ranging between 10 and 30 mm. Of the plants studied, the most active extracts were those obtained from the following plants: Acacia robusta, Aloe arborescens, Baccharoides adoensis, Chromolaena odarata, Ihlaza, Lippia javanica, Psidium guajava, Syzygium cordatum, Schotia brachypetala, Tetradenia hparia, and Vemonia tigna. Staphylococcus aureus was the bacterium that was mostly inhibited by almost a!f the plant extracts, followed by Klebsiella pneumoniae, Escherichia coli and Bacillus subtilis. the least inhibited bacteria strains were Shigella sonnei, Shigella flexneri and Salmonella typhii. The MIC values for active extracts ranged between 1 mg/ml and 0.4 mg/ml. The results obtained appeared to confirm the antibacterial potential of the plants investigated, and their potential in the treatment of diarrhoea in the Ongoye area.
The effects of browsing on growth, structure and physiological aspects of Acacia grandicornuta and Combretum apiculatum
(2010) Mamashela, Charlotte Thandeka; Scogings, P.F.; Zobolo, A.M.
Very little is known about plants growing in savannas, especially how woody plants respond to browsing and variations in resources. It is assumed that growth rate and concentrations of defenses are inversely related, but will be affected by resource availability. It can be postulated further that increased growth and photosynthesis would be observed concomitant with reduced tannin concentration when water and nutrients are abundant at the beginning of the wet season. Growth in terms of shoots length, thorn length and plant height would increase in terms of increasing photosynthetic rate on browsed plants compared to unbrowsed plants. Therefore, research was conducted to investigate the effects of browsing on Acacia grandicornuta and Combretum apiculatum. Research was conducted at the Nkuhlu experimental exclosures (Kruger National Park) on these two tree species. The exclosures were designed so that there were three broad levels of browsing pressure: no mammal herbivores excluded, elephants and giraffes excluded and all mammal herbivores bigger than hares excluded, all of which incorporate the catena from sodic footslope to sandy crests. The focus was on heavily browsed plants between the heights of 0.7-1.7 m. Ten trees per species per treatment (full, partial and no exclosure) were sampled and height and stem circumference were measured in the early and late wet season. Five new shoots per tree were marked; these shoots were re-measured at intervals to monitor their growth. Leaves were harvested from other short trees of both species in all the exclosures. Leaves were dried, milled and analysed for phosphorus (P), nitrogen (N) and condensed tannins (CT). Photosynthetic measurements were also recorded at the same time from short individual trees of C. apiculatum from the full and non exclosure. The results showed that there were no significant effects of the treatments and no significant growth on shoot and thorn length of A. grandicornuta in all the treatments from October to December 2007. There was significant growth in the shoot lengths of C. apiculatum from October to December 2007 in all the treatments (full exclosure t = -4.65, df = 10.20 and P = 0.001, non exclosure t = - 4.67, df = 7.90 and P = 0.002 and partial exclosure t = - 8.86, df = 7.30 and P < 0.001). There was a significant effect of the treatments on the shoot lengths of C. apiculatum during December 2007. There was no significant growth in heights and stem circumference of A. grandicornuta from September 2007 and March 2008 (P> 0.05). There was significant growth in the height of C. apiculatum in the full exclosure (t =2.33, df = 17.10 and P = 0.032) and the stem circumference of C. apiculatum was significantly smaller in the partial exclosure (t =3.71, df =8.00 and P = 0.006) in September 2007 compared to March 2008. The pattern for both A. grandicornuta and C. apiculatum in all the treatments was a decreasing P concentration from October 2007 to March 2008. Nitrogen decreased in A. grandicornuta where mammals were excluded and also decreased in the non exclosure. In the partial exclosure there was no change in N concentration from October 2007 to March 2008. For C. apiculatum, N concentration decreased in all the treatments from October 2007 to March 2008. The CT concentration remained the same for A. grandicornuta in all the treatments and in all the months. The CT concentration of C. apiculatum in the full exclosure significantly increased (t = -7.08, df = 10.60 and P < 0.001), in the non exclosure the CT concentration also increased (t = -5.34, df = 8.00 and P = 0.001). In the partial exclosure, the CT concentration remained the same for C. apiculatum from October 2007 to March 2008. The leaf removal of A. grandicornuta was not correlated with CT concentration and was not correlated for C. apiculatum. The results from the photosynthesis data showed a steadily decrease in Jmax and Vcmax from November 2007 to March 2008 where the herbivores were excluded. The plants in the non exclosure responded differently compared with the plants in the full exclosure. Jmax and Vcmax decreased form November 2007 to February 2008 but increased again during March 2008 where herbivores were not excluded. A nursery experiment was conducted to see the effects of browsing as affected by water availability. The interests were in finding out the responses of plants after browsing at different water levels. Potted seedlings of C. apiculatum were allowed to grow in the nursery and watered once after 3 days. The heights, basal circumferences, shoot lengths were measured and plants were given to goats to achieve a range of browsing intensities in September 2007 (0, 30, 60 and 90% intensity). Plants were weighed before and after browsing to estimate the amount removed, and were separated into three groups that were watered after 3, 7 and 10 days for four months. After four months of growth, the plants were re-measured (heights, basal circumferences, shoot lengths), harvested, separated into morphological parts (roots, shoots and leaves), oven dried and each part weighed. Leaves were then analysed for P, N and CT. Increased water availability resulted in increased leaf, shoot and root mass. The results from the combined data showed that water treatment had a significant effect on leaf mass (t = -9.39, df = 20.60 and P < 0.001) shoot mass( t = -6.18, df = 34.40 and P < 0.001) and root mass (t = -2.19, df = 31.20 and P = 0.036). Defoliation did not have an effect on leaf and root mass within each water treatment but defoliation had a significant effect on shoot mass. The data was combined and the results show that water treatment had a significant effects on heights (t = -4.28, df = 38.00 and P < 0.001) shoot length (t = -8.02, df = 29.10 and P < 0.001) and basal circumference of the seedlings after defoliation (t = -7.02, df = 29.00 and P < 0.001). Defoliation had a significant effect on height, shoot length and basal circumference of seedlings after defoliation (P< 0.001). Water had a significant effect on P, N and CT concentration in the seedlings where P, N and CT concentrations increased with increasing water availability. The chemical concentrations between seedlings which were watered every 10 and 3 days, were significant for phosphorus (t = -2.07, df = 28.20 and P = 0.047) N concentration (t = 2.74, df = 35.90 and P = 0.009) and CT concentration (t = -2.23, df = 20.50 and P = 0.037). There was no effect of defoliation on P and N concentrations on the seedlings which were defoliated at different intensities. Defoliation had an effect on CT concentration on seedlings which were watered after 7 and 3 days. It was concluded that A. grandicornuta was not affected by treatments or season in terms of growth. The C. apiculatum trees which were exposed to browsing increase their growth rate in the form of shoots length and stem circumference. No growth in terms of height was detected in C. apiculatum trees in browsed plants because the plants were suppressed by browsing. No growth in A. grandicornuta was recorded in all the treatments. The CT concentration for A. grandicornuta remained constant in all the treatments for all the seasons. The CT concentration in C. apiculatum increased under browsing, which was unexpected. Increased shoot length occurred when browsing occurred during the growth season when resources were abundant and browsing was inevitable. When growth increases, photosynthesis was expected to increase in C. apiculatum trees exposed to browsing. The photosynthetic rate in C. apiculatum exposed to browsing was higher than in unbrowsed C. apiculatum trees. Heavily defoliated seedlings increased their growth in the form of height, stem diameter and shoot length as a defence strategy as expected. Seedlings with more resources produced more CT in their leaves as a form of defence mechanism which was expected. Seedling parts which allocated more biomass had more water access than seedlings which had less water. Since very little is known about tree responses to browsing, this research will help improve knowledge and understanding of browse browser interactions in savannas. The knowledge gained from this research is useful for building models of browse-browser interactions in seasonal subtropical zones where browsers are abundant and have the potential to deplete vegetation resources and how to prevent this from happening.
An ethnopharmacological study of plants used for treating respiratory infections in rural Maputaland
(University of Zululand, 2012) York, Talita; de Wet, H.; Van Vuuren, S.F.
This study aimed, firstly, to perform an ethnobotanical survey, focusing on lay people’s knowledge on plants used for treating respiratory infections in northern Maputaland, KwaZulu- Natal, South Africa. Eighty homesteads were visited purposively and ethnobotanical information was gathered using structured questionnaires. The study documented 30 plant species, with Acanthospermum glabratum, Aloe marlothii, Krauseola mosambicina, Ozoroa obovata, Parinari capensis subsp. incohata and Plectranthus neochilus recorded for the first time, globally, as medicinal plants used for treating respiratory ailments and related symptoms. The two most frequently used plant species were the indigenous Lippia javanica, followed by the exotic Eucalyptus grandis. Both these plant species are highly aromatic. For eight of the 30 plant species used, new vernacular names, not recorded before, were given by the interviewees. Although six of the 80 interviewees were healers, the current study focused on lay knowledge, which makes the information recorded during the current survey invaluable.
An ethnobotanical and antidiarrhoeal investigation of plants used traditionally in the Maputaland area homesteads
(University of Zululand, 2013) Nkwanyana, Mduduzi Nkosinathi; de Wet, H.; Van Vuuren, S.F.
Zulu people living in the rural area of Maputaland (KwaZulu-Natal, South Africa) rely heavily on medicinal plants, particularly for the treatment of diarrhoea. The main aim of this study was to determine which plants are used in this area to treat diarrhoea and to validate their antidiarrhoeal efficacy against diarrhoeal-related pathogens. An ethnobotanical survey was conducted in four different localities in northern Maputaland (Mabibi, Mseleni, Mbazwana/ Olakeni and Tshongwe) on plants that are used to treat diarrhoeal infections. Twenty three plant species were documented and collected in the survey. A muthi market survey was also performed where three more plant species namely Sarcophyte sanguinea, Ximenia caffra and Strychnos henningsii were identified to treat diarrhoea. Acacia burkei, Brachylaena transvaalensis, Cissampelos hirta and Sarcostemma viminale were recorded for the first time globally as antidiarrhoeal remedies. Psidium guajava was the most mentioned (43%) plant to be used traditionally to treat diarrhoea followed by Catharanthus roseus and Melia azedarach. Most of the interviewees mentioned the use of plants individually but some mentioned the use of plants in combinations. The following plants were said to be used in combination; Brachylaena transvaalensis with Psidium guajava; Sclerocarya birrea, Acanthospermum glabratum in combination with Krauseola mosambicina; Psidium guajava and Mangifera indica in combination with Sarcophyte sanguinea. Most plants were used as leaf decoctions. The study also revealed that the choice of plants used was based on the availability of the plant in and around the interviewees’ homestead. One new vernacular name was recorded which demonstrates the importance of recording this information. Antidiarrhoeal studies were performed with the crude extracts against diarrhoeal pathogens. Organic extracts of Terminalia sericea showed noteworthy antibacterial activity (mean MIC value of 0.04 mg/ml against Shigella flexneri). Many other plant species showed noteworthy activities against different pathogens. More than 80% of plant species screened were active against at least one out of seven of the diarrhoeal pathogens. Proteus vulgaris showed overall the least susceptibility, while Shigella flexneri proved to be the most susceptible pathogen. Aqueous extracts generally showed poorer antimicrobial activity with some exceptions i.e. Acacia burkei, Garcinia livingstonei, Sclerocarya birrea and Terminalia sericea. The antibacterial activity of plant species collected from the homesteads demonstrated better activity compared to those collected from the muthi markets. In the combination studies, synergy (ƩFIC < 0.50) was observed against at least four or more pathogens. Combinations of Acanthospermum glabratum with Psidium guajava and Brachylaena transvaalensis with Psidium guajava, proved to be the most favourable combinations. Some aqueous extracts in combination showed synergistic interactions. The combination of Acanthospermum glabratum with Krauseola mosambicina showed (76%) synergistic interactions when investigated in various ratios. The results from this study correlates to a certain extent with the use of particular plant species to treat diarrhoea infections. Furthermore there is some correlation between the best antimicrobial activities and the most frequently used plant species and plant combinations used by the lay people in the Maputaland area.
A survey of traditional leafy vegetables and studies of genetic diversity of Cucurbita landraces in northern KwaZulu-Natal, South Africa
(University of Zululand, 2013) Ntuli, Nontuthuko Rosemary; Zobolo, A.M.; Madakadze, R.M.; Tongoona, P.B.
Traditional leafy vegetables (TLVs) are commonly herbaceous plants with relatively high nutrition and health significance. They have formed part of food security in rural-based communities for generations. The utilization of TLVs; the diversity in morphology, yield and genetics of highly preferred vegetable species was investigated. The objectives were to identify the known and preferred TLVs, and determine morphology, yield and genetic diversity of most preferred Cucurbita landraces in northern KwaZulu-Natal. In a total of 72 recorded species, the following were recorded for the first time as TLVs: Commelina erecta, Deinbollia oblongifolia, Erythroxylum delagoense, Galinsoga ciliata, Ipomoea wightii, Limeum sulcatum, Priva meyeri var. meyeri, Trachyandra asperata var. asperata and Trachyandra cf. saltii var. saltii. High species diversity was recorded at Umkhanyakude district when compared with others. Most vegetables were collected from the wild, during rainy seasons, and were consumed daily to every two days. Cucurbita species were predominantly grown in spring and summer, from the seeds that were saved from the previous harvest. Leafy shoots were harvested in less than two months from seeding. Diversity in morphology and yield was evident in landraces within the same and among different Cucurbita species. Cucurbita pepo landraces had the highest shoot, fruit and seed yields. In all Cucurbita landraces, harvest-pruning initiated at six weeks from planting resulted in longer vines and higher numbers of: lateral branches; leaves; pistillate and staminate flowers. Dendrogram from molecular analysis using random amplified polymorphic DNA (RAPD) markers primarily grouped C. pepo landraces according to the fruit colour change at maturity, while both RAPD and simple sequence repeat (SSR) markers also grouped them according to their agro-ecological origin. Some unique RAPD and SSR bands discriminated the self-pollinated C. pepo landraces from the unselfed ones. The newly documented TLVs have formed the basis for future research of their growth, yield as well as improved palatability. Also the results of diversity in morphology and genetics of Cucurbita landraces can be used to improve these vegetable species.
Antibacterial activities of selected medicinal plants used to treat sexually transmitted infections in Blouberg area, Limpopo Province
(University of Zululand, 2013) Mongalo, Nkoana Ishmael; Zobolo, A.M.; Opoku, A.R.
This work validates the use of these medicinal plants in treatment of sexually transmitted vi infections (STIs). Phytochemicals detected may well explain the biological activity reported. Thirteen traditional healers were interviewed using a structured questionnaire on the use of medicinal plants in the treatment of sexually transmitted infections within Blouberg area, Limpopo Province- South Africa. Eleven medicinal plants from eight families have been documented and sixty-two plant extracts were prepared and tested for antibacterial activity against 23 human pathogenic bacterial strains using disc diffusion method.
Toxicology and herb-drug interaction of selected anti-hypertension plants used by lay persons in Northern KwaZulu-Natal (South Africa)
(University of Zululand, 2017) Ramulondi, Mmbulaheni; De Wet, H.; Van Vuuren, S.F
A recent (2015) ethnobotanical study which was conducted in northern Maputaland showed that the lay people use medicinal plants singularly, in plant combinations, as well as concurrently with conventional drugs to treat hypertension. Because of the lack of studies validating the safety of South African medicinal plants and the limited interactive studies done between medicinal plants and conventional drugs this study was undertaken. The study was designed to validate the safety of 26 medicinal plants used singularly, in 19 plant combinations as well as when combined with conventional hypertension drugs (13 plants). Five medicinal plants (Citrullus lanatus, Cladostemon kirkii, Hyphaene coriacea and Pyrenacantha kaurabassana and Strychnos madagascariensis) investigated in the current study were evaluated for the first time for any toxicology. Apart from the combination between Aloe marlothii and Hypoxis hemerocallidea, none of the combinations investigated in the current study have been previously tested for any toxicity. Aqueous and organic (1:1 dichloromethane-methanol) extracts were prepared. The toxicity was evaluated using three assays [the brine shrimp lethality assay (BSLA), Ames test and MTT assay (human hepatocarcinoma cell line HepG2/C3A)]. The toxicity interaction of the plant combination was evaluated using the sum of fractional inhibitory concentration (ΣFIC). Herb-drug interaction was performed on the aqueous extracts of the 13 medicinal plants which were recorded to be used concurrently with conventional drugs (adcon napamol, aluminum hydroxide, amlodipine, aspirin, enalapril, pharmapress and ridaq). The three assays applied were the CYP3A4 inhibition assay, the beta-glucuronidase inhibition assay as well as the carboxylesterase inhibition assay. These assays were chosen according to the enzymes involved in the metabolism of the hypertension conventional drugs. The overall toxicity profile of the plant extracts tested in BSLA showed that 17 of the organic extracts were toxic while only two of the aqueous extracts were toxic. The aqueous extracts which were toxic were Catharanthus roseus and Citrus limon and these two extracts were further tested at varied concentrations to determine dosage. The results showed that as the concentration increases, the mortality percent also increased. For the extracts tested for mutagenicity, four of the organic extracts were mutagenic while two of the aqueous extracts (Catharanthus roseus and Ozoroa engleri) were mutagenic toward Salmonella typhimurium bacterial strain TA98 and TA100. For the 13 medicinal plants which were tested in MTT, the results showed that Sarcophyte sanguinea was hepatotoxic at the concentration of 100 μg/ml. Apart from Hypoxis hemerocallidea which had moderate hepatotoxicity, the aqueous extracts of the most frequently used medicinal plants were non-toxic thus considered safe to use as a traditional medicine. However, in vivo tests (at preclinical level) are necessary to confirm this assumption. For the plant combinations, the mortality percentage of the two concentrations tested in BSLA showed a significant correlation between dosage and toxicity i.e. toxicity was dosage dependant. The overall toxicity profile of the two concentrations tested indicated that organic extracts were more toxic than the aqueous extracts. The results of plant combinations when tested in the Ames test also showed that the organic extracts had more mutagenic effect than the aqueous extracts. The aqueous extract combination (Catharanthus roseus and Momordica balsamina) was the only combination to be toxic in both assays but also the most regularly use combination by the people. In the BSLA, six plant combinations showed antagonistic interactions (aqueous and organic extracts). In the Ames test five combinations from organic extracts had antagonistic interaction with only two aqueous combinations showing antagonistic response. For the herb-drug interaction studies, all the extracts tested had an inhibitory effect on either of the three enzymes. A high inhibition percentage (97%) was observed on the enzyme CYP3A4, with Sarcophyte sanguinea and Psidium guajava. The lowest overall inhibitory effect was observed on beta-glucuronidase. The inhibition of the enzymes by the plant extracts was dosage dependent. The outcome of this study established that low toxicity of the aqueous extracts was observed in most of the assays. Even though all the plant extracts tested for herb-drug interaction showed to inhibit beta-glucuronidase enzyme resulting in improved hypertensive drug efficacy, these medicinal plants cannot be recommended to be used concurrently with hypertensive drugs since they also inhibit the two enzymes which are responsible for the metabolism of hypertension drugs. It is thus best practice not to take any herbals concurrently with any allopathic medicine.
Phytosociology and vegetation ecology of uMlalazi Nature Reserve
(University of Zululand, 2017) Zungu, Nqobile S'phesihle; Mostert, T.H.C
The need to conduct research on vegetation is important for identifying ecologically sensitive areas and understanding the major ecological processes driving these unique ecosystems in order to conserve and manage them effectively. The aim of this study was to identify, classify, map, describe and name the vegetation clusters in uMlalazi Nature Reserve. A total of 149 relevés were sampled. The sampling was carried out according to the Braun-Blanquet method with the plant data entered in TURBOVEG and exported into Juice. Classification was completed using the modified TWINSPAN algorithm, resulting in thirteen plant communities. These communities are described in terms of their structure, composition and distribution. These communities can be divided into those that occur on clay soils and those that occur on sandy soils. Ordination was carried out using the Non-metric Multidimensional Scaling to investigate the relationship between species and their underlying environmental factors. Ordination revealed that the presence or absence of some environmental factors such as, exposure to salt spray, salt content, moisture availability and clay content are important in shaping most of the communities in the study area. Differences in species richness, salt content, distance from the sea and human induced fire and grazing between plant communities are clearly articulated. Towards the end, the structure, distribution and ecology of the dune communities from pioneer to dune forest is given. The proposed classification, ordination clusters, vegetation map and description of communities can be used for the uMlalazi Nature Reserve management, land-use planning and even further research. The study showed that uMlalazi Nature Reserve serves as an important refuge for plant species and communities of biological and economic significance.
Effect of NPK basal fertilizer, nitrogen top dressing and season on growth and yield of Cucurbita argyrosperma
(University of Zululand, 2017) Mbhele, Zoliswa
Cucurbita argyrosperma is grown for its edible shoots, flowers, immature and mature fruits as well as seeds, which provide proteins, vitamins, edible oils and minerals. The objective of this study was to investigate the effect of NPK basal fertilizer, nitrogen top dressing and seasonal variation on the agronomic traits of C. argyrosperma. Plants were grown at 0; 150; 300 and 450 kg ha-1 NPK basal fertilizer and 0; 150 and 300 kg ha-1 nitrogen top dressing during warm and cold seasons. The application of 300 kg ha-1 NPK and 300 kg ha-1 N resulted in longer vines and larger fruit size. Thicker stems, heavier fresh shoots and roots, vigorously growing first, second and third leaves from the apex, were recorded after an application of 450 kg ha-1 NPK and 300 kg ha-1 N. In the presence of NPK, any addition of nitrogen resulted in numerous leaves with more chlorophyll content. The application of 150 NPK and 300 N resulted in higher root moisture content and more staminate flowers. Numerous pistillate flowers were recorded at a combination of 450 kg ha-1 NPK and 150 kg ha-1 N fertilizers. However, 100 seed mass was not affected by the application of either NPK or nitrogen top dressing. In the warm season plants had thicker stems; numerous leaves; fast-growing first and second leaves from the apex; higher total chlorophyll content as well as heavier fresh and dry shoots and roots. Plants in the warm season (23° – 33°) also produced numerous staminate flowers; many fruits per plant with larger sizes; numerous and heavier seeds per fruit; and heavier hundred seed mass. Plants grown during cold season (16° – 25°) had their third leaf from the apex growing faster, as well as higher shoot and root moisture content. Season did not affect shoot growth as well as the number of pistillate flowers. A positive definition with PCA and significant positive correlation of all measured agronomic traits except shoot and root moisture content show them as proper traits to measure growth and yield in C. argyrosperma. Cluster analysis showed that the application of 300 and 450 kg ha-1 NPK fertilizer at varying nitrogen top dressing concentrations during warm and cold seasons, respectively, can promote growth and yield of C. argyrosperma.
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.
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.
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.
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.
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.
Indigenous knowledge, variation in morphology, nutritional composition and genetics of Strychnos spinosa morphotypes
(2023) Mbhele, Zoliswa; Ntuli, NR and Zharare, GE
Strychnos spinosa Lam., commonly known as green monkey orange (English) and umHlala (isiZulu), belongs to the Loganiaceae family. It is of African origin, and in South Africa it grows predominantly in the Eastern Cape, Limpopo, KwaZulu-Natal, and Mpumalanga provinces. It is used for food, medicine and to improve the socio-economic status of rural communities. However, studies on indigenous knowledge, variation in morphology, nutritional composition, and genetics among S. spinosa morphotypes are limited. Thus, this study aimed to determine the indigenous knowledge, variation in morphology, nutrition, and genetics among S. spinosa morphotypes. Local indigenous knowledge on S. spinosa was documented from Oyemeni community in KwaZulu Natal, whereas variation in morphology, nutritional and genetic analysis were assesed from morphotypes at Bonamanzi Game Reserve in Northern KwaZulu-Natal. Indigenous uses of S. spinosa included direct fruit consumption; development of local and nutrient dense food products and drinks, such as fermented maize meal (umBhantshi), fermented porridge (amaHewu), alcohol, juice, and jam; various medicines; as well as for homestead protection, livestock increase and firewood. Oyemeni community gave the first report on umBhantshi preparation from S. spinosa, and indigenous knowledge on the morphological and organoleptic variations that exist within S. spinosa. Apparently, the whole study was the first evidence of variation among S. spinosa morphotypes based on morphological, nutritional, and genetic traits. This also included the first report on the existence of purple, pyriform, and rough fruits, as well as a purple tint on the juvenile leaves. Fruit and seed traits, as well as calcium, phosphorus, magnesium, copper, iron, manganese, fat, acid detergent fibre, neutral detergent fibre, sodium and crude protein nutrient, were the important traits used to determine variation among S. spinosa morphotypes, based on principal component analysis. In cluster analyses, morphotypes GRR-dGEO, GRxCP-GEF, GvRxCR-GEF, GRxCP-dGEF, PRR-dGRF, PRxCP-GEO, GvRR-dGEO, GvRR-GRO, GRxCR-dGEF, and GRxCR-dGEO were associated based on their rough pericarp texture, small-sized fruits, high nutrient content in fruits, and related genetic attributes. These morphotypes can be recommended for future breeding, domestication, use in various food products and commercialisation practices. This study also reported the first development and successful use of simple sequence repeat markers for genetic diversity and population structure of S. spinosa. Results on diversity in morphology and genetics of S. spinosa morphotypes can be used to improve these fruit species for commercialisation and enhanced food security, as they have a nutritional profile that is above well-known commericial fruits.
Variation in growth, nutrition and phytochemicals of sequentially harvested shoots and fruits, and genetic studies of Lagenaria siceraria landraces in South Africa
(University of Zululand, 2024) Buthelezi, Lungelo Given; Ntuli, N.R. Mavengahama, S. and Sibiya, J.
Lagenaria siceraria (Molina) Standley, a member of the Cucurbitaceae family, is valued for its many uses, serving as a crucial food source with edible plant parts such as leaves, shoots, fruit pulp, and seeds. However, studies on L. siceraria regarding the relationship between shoot, peduncle and fruit traits during growth; nutritional and phytochemical composition of sequentially harvested shoots and fruits; as well as genetic diversity among landraces using single nucleotide polymorphism (SNP) markers, are limited. These studies are crucial for enhancing plant physiological understanding, optimizing crop yields, improving nutritional value, and preserving genetic diversity in L. siceraria. Therefore, the objectives of this study were to correlate shoot, peduncle, and fruits’ traits during growth; compare the nutritional composition of shoots and fruits, and phytochemical profile of fruits harvested at different maturity stages; and assess the genetic variability using SNP markers in L. siceraria landraces sourced from northern KwaZulu-Natal and Limpopo, South Africa. Multivariate analyses were conducted along with the estimations of heritability. Harvested shoot, peduncle, and fruit traits showed significant variation (p < 0.05) within each growth period and at different growth stages. Peduncles of all landraces became shorter and thicker when fruits were elongating and widening, from 0–5 days after anthesis (DAA). Positive correlations were notable among all shoot traits (shoot length, shoot width, shoot fresh mass, shoot dry mass, and shoot moisture content), and peduncle width correlating with fruit length and width. The first three principal components explained 85% of the total variability. Clustering identified three main groups, with singlets for landraces KRI and NSRC. Landraces were clustered according to peduncle and fruit sizes, as well as availability of harvestable shoots. High heritability estimates were recorded for peduncle length (55.2%) and shoot width (60.2%). Differences in nutrient attributes were significant within and among landraces where shoots and fruits were harvested at various growth stages. Nutritional traits correlated either positively or negatively with each other based on their translocation modes and similar chemical properties. The first five principal components explained 90.218% and 89.918% total variability in shoots and fruits, respectively. Micronutrients Ca, Mg, K, P, and N in shoots and macronutrients Fe, Zn, Cu, and Al in fruits, were the primary contributors of variability. Shoot nutrient content associated landraces into three major clusters, based on landraces with superior and inferior levels of specific nutrients at different growth stages, as well as those with distinctive nutrient profiles. Fruit nutrient status also grouped landraces into two major clusters, reflecting variations in nutrient content at different growth stages. Phytochemical analysis identified five isoprenoids in fruits harvested at 7 DAA across all landraces, namely 1-Dodecene, 2,3-Dimethyldodecane, E-15-Heptadecenal, Eicosane, and Tridecane, 6-propyl. Lighter metabolites in molecular mass displayed shorter retention rates (9.08-16.29 min) with lower relative peak areas (1.09-6.97%), while heavier compounds exhibited longer retention rates (13.42-18.00 mins) with higher relative peak areas (2.25-11.41%). Landraces were grouped into five clusters based on fruit and seed attributes and significant isoprenoid units. Terpenoids were the predominant phytochemicals commonly identified among landraces’ fruits at different stages of growth, where 1-Dodecene; Decane,3,7-dimethyl-; 1-Octadecane; 1-Pentadecene; E-14-Hexadecenal; E-15-Heptadecenal; Eicosane; Tetradecane, 4-methyl; and Tridecane, 6-propyl-, were the highest contributors to variation. Correlation in phytochemicals was predominantly based on their availability at different fruit growth stages. Three distinct clusters grouped landraces according to the unique presence of phytochemicals at different stages of growth, as well as landraces with similar fruit traits and phytochemical availability at different growth stages. Genetic variation at a single nucleotide base was identified among studied landraces, where the sequencing of 16 landraces revealed variations in the target genes ACS27 and CmFIS8. Molecular variance analysis and phylogenetic tree construction indicated variations among landraces. Sequenced landraces showed an average of 1.75 alleles, effective alleles at 0.419, Shannon’s information index at 0.403, expected heterozygosity at 0.265, gene flow at 6.80, and genetic differentiation at 0.082. Sequence variations were observed, and landraces were clustered based on genetic differences. Analysis of Molecular Variance (AMOVA) indicated 100% variation among landraces of different origins.

Browse

Browsing Botany by Issue Date

Results Per Page

Sort Options