Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Two genera of ophiostomatoid fungi occur in the seed-bearing structures of serotinous Protea species in the Cape Floristic Region. These fungi are dispersed by arthropods, including mites and beetles that visit the Protea host plants. Although the vectors of Proteaassociated ophiostomatoid fungi are known, their dispersal patterns remain unknown – especially the manner in which recently burnt fynbos vegetation is recolonized. Additionally, their reproduction strategy has not previously been investigated. The focus of this study was, therefore, to determine the extent of within- and between-plant dispersal of Proteaassociated ophiostomatoid fungi at the population level and to investigate their reproductive strategy. One Protea-associated ophiostomatoid fungus, Knoxdaviesia proteae, is found exclusively in the fruiting structures of P. repens and was the focus of this study. In order to interrogate natural populations of this fungus, 12 polymorphic microsatellite markers specific to K. proteae were developed with an ISSR-PCR enrichment strategy and pyrosequencing. These markers were amplified in two distantly separated populations of K. proteae. The genetic and genotypic diversities of both populations were exceptionally high and neither showed significant population differentiation. The lack of population structure in both populations implies that K. proteae individuals within a P. repens stand are in panmixia. As one of the sampling sites had burnt recently, the process whereby young fynbos is recolonized could be investigated. Compared to the adjacent, unburnt area, K. proteae individuals in the burnt area of this population had significantly less private alleles, suggestive of a young population that had experienced a genetic bottleneck. Knoxdaviesia proteae individuals that did not originate from the adjacent unburnt area were encountered within the burnt site and, additionally, isolation-by-distance could not be detected. The parsimony-based haplotype networks and the tests for linkage disequilibrium indicated that recombination is taking place within as well as between the two distantly separated populations. The observed panmixia in P. repens stands, widespread recolonization and the high genetic similarity and number of migrants between the two populations emphasizes long-distance dispersal and therefore the role of beetles in the movement of K. proteae. This cohesive genetic structure and connection across large distances is likely a result of multiple migration events facilitated by beetles carrying numerous phoretic mites. / AFRIKAANSE OPSOMMING: Twee genera ophiostomatoid swamme kom in die saad-draende strukture van bloeiende Protea spesies in the Kaapse Floristiese Streek voor. Hierdie Protea-verwante ophiostomatoid swamme word gekenmerk deur hul assosiasie met geleedpotige vektore – spesifiek die myt en kewer besoekers van die Protea gasheer plante. Alhoewel die geleedpotige vektore van Protea-verwante ophiostomatoid swamme bekend is, is die wyse waarop hierdie swamme versprei onbekend; veral die manier waarop onlangse gebrande fynbos geherkoloniseer word. Verder is die voortplantings-strategie van hierdie swamme nog nie voorheen ondersoek nie. Die fokus van hierdie studie was dus om die omvang van binne- en tussen-plant verspreiding van Protea-verwante ophiostomatoid swamme te bepaal op die populasie vlak en om hul voorplantings-strategie te ondersoek. Een Protea-verwante ophiostomatoid swam, Knoxdaviesia proteae, word uitsluitlik in die vrugdraende strukture van P. repens aangetref en was die fokus van hierdie studie. Om natuurlike populasies van hierdie swam te ondersoek is 12 mikrosatelliet-merkers spesifiek vir K. proteae ontwerp deur ‘n ISSR-PCR strategie en “pyro”-basisvolgorde bepaling te gebruik. Hierdie merkers is geamplifiseer in twee K. proteae populasies wat ver van mekaar geskei is. Die genetiese en genotipiese diversiteit van beide populasies was uitsonderlik hoog en nie een het beduidende populasie-differensiasie getoon nie. Die gebrek aan populasie struktuur in beide populasies veronderstel dat K. proteae individue binne ‘n P. repens stand in panmiksia is. Aangesien een van die steekproef terreine onlangs gebrand het, kon die herkolonisasie proses van jong fynbos ondersoek word. In vergelyking met die aangrensende, ongebrande area, het K. proteae individue in die gebrande area beduidend minder private allele gehad. Dit dui op ‘n jong populasie wat ‘n genetiese bottelnek beleef het. Knoxdaviesia proteae individue wat nie van die aangrensende, ongebrande area afkomstig is nie is ook binne die gebrande terrein aangetref. Verder is afsondering-deur-afstand nie aangetref nie. Die parsimonie-gebaseerde haplotiepe-netwerke en die toetse vir koppeling-onewewigtigheid het aangedui dat rekombinasie binne sowel as tussen die twee populasies plaasvind. Die panmiksia wat waargeneem is in P. repens populasies, wydverspreide herkolonisasie en die hoë genetiese ooreenkoms en hoeveelheid immigrante tussen die twee populasies beklemtoon lang afstand verspreiding en dus die rol van kewers in die beweging van K. proteae. Hierdie samehangende genetiese struktuur en die verband oor groot afstande is waarskynlik ‘n gevolg van verskeie migrasies gefasiliteer deur kewers wat talle foretiese myte dra.

Thesis (PhD (Botany and Zoology))--University of Stellenbosch, 2010.

Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Worldwide, invasive alien plants (IAPs) alter aspects of invaded ecosystems including geomorphology, above-ground vegetation, soil seed banks and soil nutrient regimes, thereby affecting the long-term stability of ecosystems. In many cases these invasions call for various management interventions, including restoration. Effects of alien plant invaders on native ecosystems are widely acknowledged, but compared to terrestrial ecosystems, riparian habitats are poorly studied. Riparian habitats are inherently rich in biodiversity, but are particularly prone to invasion by IAPs because of their dynamic nature and because these ecosystems are affected by many anthropogenic activities. This enhances the proliferation of IAPs, especially trees such as Tamarix spp. (e.g. in the southwestern United States), Salix spp. (e.g. in Australia), and Australian Acacia spp. and Eucalyptus camaldulensis (in South Africa). Initiatives such as the Working for Water (WfW) programme in South Africa that are focusing on clearing IAPs, particularly in riparian zones, have reported much success in the short term, but ecosystem recovery remains limited. There is a poor understanding of the nature of the impacts of invasive trees, and of the opportunities that exist for ecosystem restoration. The objective of my thesis was to investigate the effects of the widespread invasions of Eucalyptus camaldulensis in riparian zones. Methodological constraints have been identified as one reason for limited success of restoration projects. Many studies examining the effects of IAPs used a comparative approach of uninvaded (reference) and invaded sites. However, this approach often fails to separate cause from effect. An experimental removal approach has been suggested as an alternative, but it is often inappropriate for large invasive trees owing to time and cost constraints. I used a comparative gradient approach, involving sampling along a continuum from uninvaded sites, and varying E. camaldulensis invasion densities categorised as “lightly”, “moderately” and “heavily” invaded (hereafter the gradient of invasion), each with four replicates (n = 16). This approach enabled me to detect trends that could be reliably attributed to invasion. Furthermore, my study attempted to provide a comprehensive understanding of the effects of IAPs in invaded ecosystems by considering various components of the ecosystem and integrating their feedback relationships to establish the net effects on ecosystem processes. The riparian zone is a unique ecosystem which provides an opportunity for such a multifaceted study examining and integrating the effects of invasive trees on riparian geomorphology, above-ground vegetation, soil seed banks, and soil properties. I studied the effects of E. camaldulensis invasion in riparian zones along the Berg River in the Mediterranean-type climate zone of the Western Cape, South Africa. I asked the questions 1) Are environmental conditions (i.e. the riparian environment created by geomorphological processes) altered by Eucalyptus invasion and if so, are these conditions less suitable for recruitment of indigenous species? 2. Has Eucalyptus invasion altered the composition of indigenous species (potentially limiting post-clearing propagule supply)? 3: How does Eucalyptus invasion change the composition of the riparian soil seed bank; and its potential to re-initiate ecosystem recovery? 4: Do soil properties (physical and chemical) change with Eucalyptus invasion? Data for all four questions were collected in the same sites to enable cross comparisons. For the first question, I employed photogrammetry techniques in a GIS and remote sensing environment to analyse repeated aerial photographs (1938 -2010) to reconstruct the invasion history and riparian geomorphology evolutionary dynamics. For the second and third questions, I compared richness, diversity, evenness and composition of resident above-ground and seed bank vegetation between uninvaded sites and the gradient of invaded sites. For the fourth question, I compared a set of variables describing physico-chemical properties in uninvaded sites to the gradient of invaded sites seasonally. Results of the geomorphology study showed that the riparian zone has been very dynamic over the 70 years, with a 13.5% net decrease in area. There was evidence of channel narrowing, riverbank steepening and river bed incision in areas that were densely invaded. No significant trends were detected in hydrometeorological data. The above-ground vegetation study revealed that species richness, diversity and structural attributes (e.g. height, relative cover and mean basal diameter) of native species decreased consistently along the invasion gradient. Invasion also altered native and alien plant species composition, both of which showed a high preference for lightly invaded sites. The seed bank study revealed that E. camaldulensis invasion had no significant effect on total and native species richness, diversity and evenness, however the effects were bigger on native than alien species. Alien species density was significantly higher than native species density. Invasion also influenced the composition of the native seed bank. However, native seed banks were more diverse than above-ground plant assemblages with some native fynbos species occurring only in the seed bank. In the soil study, I found that soil pH levels were significantly lower in invaded sites than in uninvaded sites in all seasons. Litter cover and thickness increased significantly with invasion intensity. Soil moisture decreased consistently with invasion intensity while temperature increased in winter and spring. Total macro, micro and available nutrients did not vary significantly along the invasion gradient (p > 0.05), but exchangeable cation content was significantly higher in uninvaded than in invaded sites, especially in winter and spring. Narrowing of river channel and steepening of river banks reduces the suitability of the riparian zone to perform certain ecological functions such as soil seed storage and providing space for vegetation to grow. This reduces opportunities for seedling recruitment and consequently reduces species diversity. Conversely, the reduction of species diversity in above-ground vegetation reduces seed input into the soil leading to depauperate soil-stored seed banks. The abundance of seeds of Acacia mearnsii in the soil-stored seed bank poses a threat of secondary invasions post clearing of E. camaldulensis if this is adopted as a management action. The study was successful in addressing the stated objectives. The transition from a native-dominated riparian plant community to a monoculture of E. camaldulensis over c. 50 years has resulted in marked changes to riparian geomorphology and above-ground vegetation, but has yet to radically change the total soil seed bank and soil nutrient concentrations. The findings offer support to the WfW clearing initiatives and show that potential for recovery of native species after removal of the invasive eucalypts still exists. This knowledge not only enhances effectiveness of restoration and long term management of riparian ecosystems, but also advances the field of riparian ecology and restoration. Further experimental work is needed to establish the mechanisms responsible for the changes associated with Eucalyptus invasion. The contribution of agriculture in shaping channel morphology also needs to be investigated. / AFRIKAANSE OPSOMMING: Die langtermyn stabiliteit van ekosisteme wêreldwyd word bedreig deur uitheemse indringer plante (UIPs) wat, onder andere, die geomorfologie, bo-grondse plantegroei, onder-grondse saadbanke en voedingstofstatus van ekosisteme kan verander. In baie gevalle word bestuursoperasies vir indringer plante vereis, en sluit onder andere herstel (restorasie) in. Die invloed van UIPs op inheemse ekosisteme word wyd erken, maar kennis oor oewerbank-habitatte, in vergeleke met ander terrestriële ekosisteme, skiet steeds tekort. Oewerbank-habitatte is inherent ryk aan biodiversiteit maar uiters sensitief vir indringing deur UIPs. Dit is weens die dinamiese aard van hierdie ekosisteme asook vele menslike aktiwiteite in hierdie tipe habitat. Dit dra by tot die vermeerdering van UIPs, veral bome wat byvoorbeeld insluit Tamarix (tamariske) (bv. in die suid-wes van die Verenigde State van Amerika), Salix (wilger) (in bv. Australië) en die Australiese Acacia (wattel) en Eucalyptus spesies (bloekom) in Suid Afrika. Inisiatiewe soos die Werk vir Water (WvW) program in Suid Afrika fokus juis daarop om UIPs vanuit oewerbank areas te verwyder, en alhoewel groot sukses in die kort termyn behaal is, is die herstel van ekosisteme steeds beperk. Daar is dus min inligting beskikbaar oor die impak van indringer bome en gevolglik ook oor geleenthede vir die herstel van hierdie ekosisteme. My tesis ondersoek die impak van die wydverspreide voorkoms van die indringer, Eucalyptus camaldulensis, in oewerbank-omgewings. Beperkte metodes is tans beskikbaar om die impak van indringer plante te ondersoek, en dit is geïdentifiseer as een van die oorsake vir die beperkte sukses van herstelprojekte. Baie studies ondersoek die effekte van UIPs deur natuurlike areas sonder enige indringer plante te vergelyk met areas waar UIPs voorkom. Hierdie tipe benadering kan ongelukkig, in meeste gevalle, nie onderskei tussen die oorsaak en die impak nie. ʼn Alternatiewe voorstel is om UIPs eksperimenteel te verwyder, maar is ongelukkig nie van toepassing op groot bome nie weens die tyd en kostes verbonde hieraan. Ek het gebruik gemaak van ʼn vergelykende-gradiënt benadering wat steekproefnemings langs ʼn geleidelike kontinuum van natuurlike areas sonder enige indringer plante na areas wat effens gematig, en erg ingedring is (hiernaas bekend as die indringer-gradiënt) deur die indringer, E. camaldulensis. Die steekproefnemings van elke kategorie van indringing (geen, effens, gematig en erg) is vier keer herhaal (n = 16). Hierdie benadering het my toegelaat om neigings te identifiseer wat met sekerheid toegeskryf kan word aan die teenwoordigheid van indringers. My studie het ook verder gemik om ʼn omvattende beskrywing van die impak van UIPs in ekosisteme met indringers te verskaf deur verskeie komponente van die ekosisteem, sowel as hul terugvoer-verhoudinge, in ag te neem, en sodoende die totale effek op ekosisteem prosesse te bepaal. ʼn Oewerbank is ʼn unieke ekosisteem wat ʼn geleentheid bied vir ʼn veelsydige studie wat die impakte van indringer bome op oewerbank-geomorfologie, bo-grond plantegroei, grond saadbanke en grondeienskappe, kan bestudeer en integreer. Ek het die impak van die teenwoordigheid van die indringer, E. camaldulensis in oewerbank areas langs die Bergrivier, wat ʼn Meditereense-tipe klimaat het, in die Wes Kaap, Suid Afrika, bestudeer. My studie het die volgende vrae gevra: 1) Is omgewings-omstandighede (bv. die oewerbank-omgewing geskep deur geomorfologiese prosesse) verander deur die teenwoordigheid van die Eucalyptus indringing, en indien wel, is hierdie omstandighede minder geskik vir inheemse spesies?; 2) Het die indringing van Eucalyptus gelei tot ʼn verandering in die samestelling van inheemse spesie gemeenskappe (moontlik beperkte plant voorplantings materiaal nadat die indringer verwyder is)?; 3) Hoe verander die indringing van Eucalyptus die samestelling van saad teenwoordig in die grond (saad bank) van die oewerbank en het dit die potensiaal om ekosisteem-herstel weer aan die gang te sit?; 4) Verander indringer Eucalyptus grond eienskappe (fisies en chemies)? Data vir al vier vrae is by dieselfde plek versamel om vergelykings te kan tref. Vir die eerste vraag het ek fotogrammetrie-tegnieke in ʼn Geografiese Inligting Stelsel (GIS) en afstandwaarnemings-omgewing toegepas om herhaalde lugfotos (1938-2010) te analiseer om die indringings geskiedenis sowel as die oewerbank se geomorfologiese evolusionêre dinamika saam te stel. Vir die tweede en derde vraag, het ek die aantal, diversiteit, gelykheid en samestelling van die bo-grond en saad bank plantegroei tussen natuurlike (geen indringers) en die gradiënt met indringers vergelyk. Vir die vierde en laaste vraag, het ek ʼn stel veranderlikes wat die fisies-chemiese eienskappe van die natuurlike omgewing sonder indringers beskryf, vergelyk met die eienskappe van die indringers gradiënt op ʼn seisoenale basis. Die resultate van die geomorfologiese studie wys dat die oewerbank omgewing baie dinamies was oor die afgelope 70 jaar met ʼn totale afname van 13.5% in rivieroewer-area in die gebied wat bestudeer is. Daar is ook bewyse vir ʼn vernouing van die kanaal, toename in die steilte van die rivierbank sowel as insnyding in die rivierbedding in areas wat ernstige indringing ervaar. Daar was geen beduidende neigings in die hidro-meteorologiese data nie. Die studie van die bo-grondse plantegroei het gewys dat die aantal plantspesies, diversiteit en strukturele kenmerke (bv. hoogte, dekking en gemiddelde basale diameter) van inheemse spesies afneem soos wat die indringings gradiënt toeneem. Indringing verander ook die inheemse sowel as uitheemse plant spesies samestelling. Beide inheemse en uitheemse spesies het areas wat slegs effense indringing wys, verkies. ʼn Studie van die saad bank (aantal sade in die grond) het gewys dat die indringer, E. camaldulensis geen merkwaardige invloed op die aantal, diversiteit en gelykheid van die totale en inheemse spesies teenwoordig gehad het nie. Die aantal uitheemse spesies was merkwaardig meer as die aantal inheemse spesies. Alhoewel indringing ook die samestelling van die inheemse saadbank beïnvloed het, was die inheemse saad bank, waarvan sommige spesies slegs daar voorgekom het, meer divers as die bo-grond plant samestellings. ʼn Studie van die grond het gewys dat die pH vlakke, afgesien van die seisoen, aansienlik laer is in die areas met indringers in vergeleke met areas sonder die indringers. Die hoeveelheid en dikte van plantmateriaal op die grond neem ook toe met ʼn toename in indringers. Die waterinhoud van die grond het afgeneem met ʼn toename in indringers en temperatuur het verhoog in beide winter en lente. Die totale makro- en mikrovoedingstowwe het nie merkwaardig gewissel saam met die indringingsgradiënt nie (p > 0.05), maar die uitruilbare katioon inhoud was aansienlik hoër, veral in die winter en lente-maande, in die areas sonder indringers in vergelyking met die areas met indringers. Vernouing van rivierkanaal en versteiling van rivieroewers verminder die geskiktheid van die oewersone om sekere ekologiese funksies te verrig soos grond-saadstoring en die verskaffing van ruimte vir plante om te groei. Dit verminder geleenthede vir werwing van saailinge en verminder gevolglik spesiediversiteit. Aan die ander kant, die vermindering van die spesiediversiteit in die bogrondse plantegroei verminder saadinsette in die grond en dit lei tot verarming van grondgestoorde saadbanke. Die oorvloed van sade van Acacia mearnsii in die grondgestoorde saadbank hou die bedreiging van sekondêre indringing in na die skoonmaak van E. camaldulensis indien dit wel as 'n bestuursaksie aangeneem word. Hierdie studie het die uiteengesette doelwitte suksesvol aangespreek. Die oorgang van ʼn oewerbank-gemeenskap wat hoofsaaklik uit inheemse plante bestaan na ʼn gemeenskap wat slegs uit E. camaldulensis bestaan, oor ʼn periode van ongeveer 50 jaar, het duidelike veranderinge tot gevolg gehad. Hierdie veranderinge is veral opmerklik in die oewerbank-geomorfologie en bo-grondse plantegroei, maar tot op hede is dit nog nie so opmerklik in die saadbank en grond-voedingstowwe konsentrasies nie. Hierdie bevindinge bied ondersteuning aan die WvW verwyderings-ondernemings en wys dat daar wel moontlike herstel van inheemse spesies kan wees na die verwydering van die indringer Eucalyptus. Hierdie kennis dra nie net by tot verhoogde effektiwiteit van herstelwerk en langtermyn-bestuursplanne nie, maar ook tot die navorsingsveld van oewerbankekologie en-herstel. Verdere eksperimentele navorsing word benodig om die moontlike meganismes wat verantwoordelik is vir die waargeneemde veranderinge, geassosieerd met Eucalyptus indringing, te verduidelik. Die bydrae van landbou tot die vorming van kanaal morfologie moet ook verder bestudeer word.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Plant secondary compounds have been exploited as medicines, flavourants, incense and are widely used for different culinary purposes. Efficacy of herbal remedies is determined by the phytochemical profile which is dependent on the species, locality and growth conditions. Salvia stenophylla (Burch. ex Benth.) is a local aromatic sage growing in almost all South African biomes, with the volatile compound accumulation varying depending on season, locality and genotype. Salvia stenophylla extracts have proven anti-inflammatory, anti-plasmodial, anti-oxidant and anti-anxiety properties due to the presence of essential oils, flavonoids and caffeic acid derived phytochemicals. As a result, S. stenophylla extracts are increasingly being used for the formulation of pharmaceutical and cosmeceutical products. However, these industries largely depend on the wild populations for raw materials, and increased commercialization of sage-based natural products and medicine exerts harvesting pressure. This might reduce the sustainability of herbal medicines since there is no formal cultivation of S. stenophylla in South Africa. Medicinal plant biotechnology provides options for propagation and manipulation of herbal plant to increase synthesis of secondary compounds. The aims of this study were to develop tissue culture propagation system so as to provide an alternative to wild-harvesting, to improve essential oil quality and accumulation in S. stenophylla by applying third generation biotechnological tools to alter terpene biosynthesis via heterologous gene expression aided by Agrobacterium-gene transfer and to charaterize the resultant metabolite profiles using thin layer chromatography, gas chromatography mass spectrometry and liquid chromatography mass spectrometry. Initially, seeds were germinated in-vitro on one-tenth Murashige and Skoog medium (MS) (1962). Seeds were decontaminated by washing them in 3.5% (w/v) hypochloride and were either scarified using 70% (v/v) sulphuric acid, placed on media with smoke solution or both. Both scarification and smoke supplementation induced germination, but seeds subjected to both treatments, as a combination, showed very poor germination. Seedlings produced were used to establish an efficient tissue culture system for S. stenophylla. Shoot tips, nodal and basal explants were placed on MS media with different plant growth regulator (PGR) combinations and concentrations. The best plantlet regeneration and shoot elongation were observed on plants on medium supplemented with 5.7 μM indole acetic acid (IAA) and 8.9 μM N-6-benzyladenine (BA), producing 4-6 shoots per explant with 6.67 cm mean length. Treatment with 4.5 μM 2,4 dichlorophenoxyacetic acid (2,4 D) did not produce shoots but had the highest biomass production, which was all in the form of callus. The resultant shoots from the micropropation system had similar metabolites as wild type plant and also they had some compounds that were not detected in their wild type counterparts. The effects of nitrogen, potassium, water stress, and phytohormones on metabolite accumulation were also studied in a S. stenophylla microplant system. Plant growth regulator free half strength MS medium encouraged the most prolific growth. Increasing potassium and nitrogen concentrations correlated to the accumulation of (-)-α-bisabolol whilst changes in other major compounds like ß-bisabolene, α-muurolene, α-patchoulene, and D-limonene were insignificant. To investigate the effects of water stress on metabolite accumulation and profile, water stress was induced using sorbitol and polyethyl glycol. Reduced water availability only negatively affected rooting in-vitro whilst the chemical profile was not affected. The study also focused on terpene production in S. stenophylla by over-expressing the heterologous geranyl diphosphate synthase gene (AgGPPS2) from Abies grandis, using Agrobacterium tumefaciens (EHA105). The AgGPPS2 gene was ligated to a pCAMBIA1301 vector which was cloned in EHA105 and this in turn was used to transform S. stenophylla. Resultant transgenic plantlets exhibited normal growth characteristics but showed variation in the metabolite accumulation. GC-MS analysis showed a 6% increase in (-)-α-bisabolol accumulation whilst 3-δ-carene, α-pinene and camphor were lowered. Solvent extracts were analysed using LC-MS and these had rosmarinic acid in greater abundance in transgenic than in the wild type plants. However, the chemical profiles of the wild type and transgenic plants showed some similarities suggesting AgGPPS2 expression only alters the abundance of some secondary compounds, whilst the overall integrity of the metabolome is maintained. Unlike most metabolite engineering studies elsewhere, this is the first attempt a local South African sage has been genetically engineered to enhance terpene biosynthesis. This is crucial in an economy that is increasing becoming plant based for pharmaceutical, industrial and food needs. Further studies are required to elucidate the efficacy of transgenic and in-vitro plant-derived extracts. / AFRIKAANSE OPSOMMING: Plant sekondêre produkte word gebruik as medisinale-, geur-en reukmiddels en word ook as algemene bestandeel gebruik in kookkuns. Die doeltreffendheid van kruie middels word bepaal deur die fitochemiese profiel. Hierdie profiel is afhanklik van die spesie, ligging en groei kondisies. Salvia stenophylla (Burch. ex Benth.) is ‘n plaaslike aromatiese salie wat voorkom in byna al die biome van Suid-Afrika , waar die versameling van vlugtige verbindings varieer op grond van die seisoen, ligging en genotipe. Salvia stenophylla ekstraksies is bewys om anti-inflamatories, antiplasmodiaal, anti-oksidant en anti-angs eienskappe te besit as gevolg van die noodsaaklike olies, flavonoïede en afgeleide kaffieksuur fitochemikalieë wat die plant besit. As gevolg word S. stenophylla ekstraksies meer en meer aangewend in die ontwikkeling van farmaseutiese en kosmetiese produkte. Hierdie industrieë benodig rou plant material vanuit die natuurlike populasies wat druk op die biome sit as gevolg van die verhoogde kommersialisering van salie-gebaseerde natuurlike produkte en medisyne. Gevolglik is die volhoubaarheid van medisyne afkomstig vanaf kruie soos salie in bedwang omdat geen formele kultivasie van S. stenophylla in Suid-Afrika al in plek gestel is nie. Medisinale plant biotegnologie bied moontlikhede vir kultiveering, voortplanting en manipuleering van kruie om sodoende die produksie van sekondêre verbindings in kruie te verhoog. Die doel van hierdie studie was om ‘n weefselkultuur voortplantingssisteem te ontwikkel om sodoende ‘n alternatief te bied vir wild oesting. Die studie het gefokus op die verbetering van noodsaaklike olie kwaliteit en akkumulasie in S. stenophylla deur die gebruik van derde generasie biotegnologiese gereedskap om terpeen biosintese te modifiseer. Hierdie is bereik deur weefselkultuur en heterologiese geen uitdrukking wat aangehelp is deur Agrobacterium geen oordrag. Die gevolglike metaboliet profiele was gekarakteriseer deur gebruik te maak van dun laag chromatogragie, gas chromatografie massa spektrometrie en vloeistof chromatografie massa spektrometrie. Aanvanklik is die sade ontkiem in-vitro op een-tiende Murashige en Skoog medium (MS) (1962). Dekontaminasie van die sade is gedoen deur die sade te was in 3.5% (w/v) hipochloried waarna die sade óf geskarifideer is deur te was met 70% (v/v) swawelsuur óf op medium geplaas is wat ‘n rook oplossing bevat óf albei. Beide skarifikasie en rook aanvulling het ontkieming aangehelp, maar sade wat aan albei behandelings blootgestel is, het baie swak ontkieming getoon. Saailinge was gebruik om ‘n effektiewe weefselkultuursisteem vir S. stenophylla te produseer. Stingel punte, nodale en basale eksplante was op MS medium geplaas met verskillende kombinasies en konsentrasies van verskeie plant groei reguleerders (PGR). Die beste plant regenerasie en stingel verlenging was geobserveer met plante op medium aangevul met 5.7 μM indool asynsuur (IAS) en 8.9 μM N-6-bensieladenien (BA), waar dit 4 tot 6 stingels per plant met ‘n gemiddelde lengte van 6.67 cm gegroei het. Behandeling met 2,4 Dichlorophenoksiasynsuur (2,4 D) het nie stingels produseer nie, maar het die hoogste biomassa produksie getoon in die vorm van kallus. Die gevolglike stingels van die mikrovoortplantingsisteem het soortgelyke metaboliete as die wilde tipe plante, maar verbindings wat nie in die wilde tipe plante voorkom nie was ook ontdek. Die effek van stikstof, kalium, water stres en fitohormone op metaboliet akkumulasie was ook bestudeer in S. stenophylla mikroplantsisteem. Plant groei reguleerder vrye half sterkte MS medium het die produktiefste groei aangemoedig. Verhoging van kalium en stikstof konsentrasies het gekorreleer met die versameling van (-)-α-bisabolol en terwyl veranderinge in ander belangrike verbindings soos ß-bisaboleen, α-muuroleen, α -patchouleen en D-limoneen onbeduidend was. Om die effek van water stres op metaboliet- akkumulasie en -profiel te ondersoek was water stres geinduseer deur sorbitol en poli-etielglikol te gebruik. Die verlaging van water beskikbaarheid het slegs ‘n negatiewe invloed op in-vitro wortelvorming gehad terwyl die chemiese profiel onveranderd gebly het. Die studie het ook gefokus op die terpeen produksie in S. stenophylla deur die ooruitdrukking van die heterologiese geranieldifosfaatsintase geen (AgGPPS2) vanaf Abies grandis met behulp van Agrobacterium tumefaciens (EHA105). Die AgGPPS2 geen was geligeer in ‘n pCAMVIA1301 vektor wat geklooneer was in EHA105 en dit op sy beurt was getransformeer in S. stenophylla. Die gevolglike transgeniese plante het normale groei ten toongestel, maar het variase in metaboliet akkumulasie getoon. GC-MS analises het gewys dat ‘n 6% toename in (-)-α-bisabolol versameling terwyl 3-δ-kareen, α-pineen en kamfor verlaag het. Opgelosde ekstraksies was geanaliseer deur VC-MS en het gewys dat roosmariensuur in groter hoeveelhede in transgeniese plante as wilde tipe plante akkumuleer. Nogtans het die chemiese profiele van die twee genotipes sommige ooreenkomste getoon, wat voorstel dat AgGPPS2 uitdrukking slegs sekere sekondêre verbindings menigte male vermeerder terwyl die algehele integriteit van die metaboloom gehoue bly. In teenstelling met die meederheid studies oor metaboliet ingenieuring wat elders plaasvind, is hierdie die eerste poging om ‘n plaalike Suid-Afrikaanse salie genieties te ingenieur met die oog om die terpeen biosintese te verbeter. Hiedie is krities in ‘n ekonomie wat voortdurend vorder om plant gebaseerde produkte te maak vir farmaseuties, industrieël en voedsel behoeftes. Verdere studies is nodig om helderheid te gee oor die effektiewiteit van transgeniese en in-vitro plant afkomstige ekstraksies.

Thesis (PhD)--Stellenbosch University, 2013. / Pollinators play a fundamental role in floral evolution. They can exert selection on the flowers they visit in a plethora of different ways, ranging from innate floral preferences to differences in body size and shape and behavioural elements such as flower constancy and learning capacity. Since different pollinators exhibit differences in these characters, shifts between pollinating species are often considered the most likely drivers of floral diversification. While many lines of evidence support this claim, numerous angiosperms pollinated by a single species also exhibit floral variation. Throughout my thesis, I explore and investigate floral diversification in such species in the absence of pollinator shifts. In Chapter 2, I investigate variation in the preference of conspecific male and female pollinators for the floral traits of a sexually deceptive daisy that comprises distinct floral forms. I show that its pollinator exhibits gender-specific variation in floral preferences, and that some floral forms have specialized on the male pollinator. This chapter thus illustrates the importance of intraspecific variation in pollinator preference for floral diversification, an underappreciated mechanism in this field of research. The innate preferences of pollinators are likely to have a genetic basis, especially innate preferences that govern mate choice. Genetic structure within the pollinators of sexually deceptive plants, which mimic female insects to achieve pollination, may thus provide an important source of selection on the plants they pollinate. This depends on an association between genetic divergence and divergent mate preferences, and I explore this intriguing idea in Chapter 3. While pollinators associated with sexually deceptive floral forms did exhibit significant genetic structuring, male pollinators from different phylogeographic clades all exhibited preference for the same sexually deceptive floral form, thus rejecting this hypothesis. Another behavioural attribute of pollinators that may affect floral evolution, particularly in deceptive plant species, is learning ability. Studies on sexually deceptive orchids often report that male pollinators tend to avoid sexually deceptive flowers with experience. In Chapter 4, I systematically investigate learning abilities within male pollinators and the costs they suffer on sexually deceptive floral forms that vary in deceptiveness. Results reveal a positive relationship between the level of floral deceptiveness and the 4 associated mating costs that deceived males suffer. Pollinator learning, however, appears to occur only on the most deceptive floral forms, suggesting a link between the costs suffered to the occurrence of learning. In Chapter 4, I systematically investigate learning abilities within male pollinators and the costs they suffer on sexually deceptive floral forms that vary in deceptiveness. Results reveal a positive relationship between the level of floral deceptiveness and the associated mating costs that deceived males suffer. Pollinator learning, however, appears to occur only on the most deceptive floral forms, suggesting a link between the costs suffered to the occurrence of learning. In Chapter 5, I explore the importance of florivory damage in a polymorphic daisy. Studies on floral evolution often overlook the significance of florivorous visits and focus only on pollinator-mediated selection. I show that floral polymorphism is maintained by antagonistic selection exerted by pollinators and florivores on the same floral traits. Lastly, I focus on evolutionary history to explore similarity in the patterns of South African angiosperm evolution and the pollinator species used throughout my thesis. Molecular dating shows this pollinator exhibits broadly congruent evolutionary patterns to these angiosperms, indicative of a shared biogeography. Taken together, my thesis demonstrates the vast impact of floral visitors, in particular pollinating insects, on the evolution of floral form. / My research was funded by the National Research Foundation of South Africa (NRF) and personal funding was provided by a NRF Innovation scholarship and merit bursaries from the Botany and Zoology department at Stellenbosch University. A WhiteSci Travel Grant and financial support from Prof. Erik Svensson at Lund University also allowed me to present parts of my research at international conference.

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Very little is known about the diversity of fungi associated with Afromontane forests of the Cape Floristic Region (CFR) of South Africa. The ophiostomatoid fungi include many species, some known as pathogens in the CFR, while others are well-known saprophytes important in wood degradation. This study focused on the biodiversity and ecology of tree-associated ophiostomatoid fungi (Ophiostomatales) in the CFR. In addition to this, mites and subcortical beetles associated with the CFR trees were collected, regardless of whether they were associated with ophiostomatoid fungi or not. A relatively high diversity of ophiostomatoid fungi were collected from native trees, ten of which were newly described here. Three further fungal species, two of which are probably new to science, were also collected from exotic Pinus species growing in these forests. Four Ophiostomatales species (including three newly described species) were associated with subcortical beetles on Rapanea melanophloeos and Olea capensis ssp. macrocarpa. These were Sporothrix pallida, Sporothrix aemuluphilus, Raffaelea scabbardiae and Raffaelea rapaneae, associated with the beetles Lanurgus sp. 1, Ctonoxylon sp. 1, Xyleborinus aemuluphilus and a Platypodinae species. This represents a first study to explore the associations between subcortical beetles and ophiostomatoid fungi on native trees in the CFR. In addition to fungi associated with subcortical beetles, several members of the Ophiostomatales associated with wounds on Rapanea melanophloes trees were also collected. These included Ophiostoma stenoceras, Sporothrix reniformis, S. rapaneae, S. lunateae and S. noisomeae. All but O. stenoceras were new to science, and were formally described here. All of these wound-associated species from R. melanophloeos belong to the Sporothrix schenckii – O. stenoceras complex, except for S. noisomeae that was provisionally placed in the S. lignivora complex. Besides fungal taxa collected from wounds on Rapanea melanophloeos, other fungi were also collected from wounds on other host trees species. Three more previously undescribed ophiostomatoid fungal species were collected from this niche. They included Sporothix capensis collected from O. capensis ssp. macrocarpa, Graphilbum roseus collected from many different, unrelated host trees and Graphium ilexiense (Microascales), isolated from wounds on Ilex mitis. The latter represented the first isolation of an ophiostomatoid fungus from this host tree species. Two possibly new fungal species (Sporothrix sp. 1, Ceratocystiopsis sp. 1) and Ophiostoma ips, associated with three bark beetles (Orthotomicus erosus, Hylurgus ligniperda and Hylastes angustatus), were collected from Pinus. Several fungal species were collected from both native trees and non-native trees. These included Sporothrix fusiforme from Brabejum stellatifolium and Acacia mearnsii, O. quercus and O. pluriannulatum-like fungus from several native trees and from A. mearnsii. This suggests a possibility for host shifting of some of these fungi between native and non-native hosts or even between different native hosts. Eight non-ophiostomatoid fungi associated subcortical beetles taxa were found also to infest native trees in the Afromontane forests and in total more than 4500 beetle individuals were collected. Some species of ophiostomatoid fungi collected in this study were found to be associated with other arthropods such as mites. Four phoretic mites species associated with ophiostomatoid fungi (Dendrolaelaps quadrisetus, Histiogaster sp. 3, Elattoma sp. 1 & 2) were collected. In addition, sixteen species of tree wound-associated mites were collected from 12 native trees. Of these, nine were associated with several ophiostomatoid fungi (Graphilbum roseus, O. pluriannulatum-like, O. quercus) that were isolated from several different host trees. This suggests that they may aid in the transport of these fungi from one host species to another. The possible consequences of transfers of Ophiostomatales species between hosts were tested using pathogenicity tests, which highlighted that some fungi are pathogenic on several different trees. Transfers seemed most likely in fungal species isolated from wounds, especially those associated with mites, because the mites may aid in the vectoring of these. When phoretic mites were tested for their specificity to their vector beetles, they proved to be highly specific. Although some of the fungi associated with these mites and their sub-cortical beetles were also pathogenic, it is less likely for these fungi to be transferred to other host tree species due to the high specificity of their arthropod associates. This study represents one of a few studies that focused on ophiostomatoid fungi, subcortical beetles and mites associated with trees in the Afromontane forests of South Africa. Although we collected a high diversity of Ophiostomatales members, many more still await discovery. It is recommended that future studies focus on the complex inter-organismal interactions in many of the systems uncovered in this study. / AFRIKAANSE OPSOMMING: Baie min is bekend oor die diversiteit van fungi wat met die Afromontane woude van die Kaapse Floristiese Streek (KFS) van Suid Afrika geassosieer is. Die ophiostomatoïde fungi sluit baie spesies in, sommiges bekend as patogene in die KFS, terwyl ander bekende en belangrike saprofiete in houtdegradasie is. Hierdie studie het op die biodiversiteit en ekologie van die boom-geassosieerde ophiostomatoïde fungi (Ophiostomatales) in die KFS gefokus. Daarbenewens is myte en subkortikale kewers wat met die KFS bome geassosieer word ook versamel, ongeag of hulle geassosieerd was met ophiostomatoïde fungi of nie. „n Relatief hoë diversiteit van ophiostomatoïde fungi is van inheemse bome versamel, tien waarvan hier nuut beskryf is. Drie verdere fungi spesies, twee waarvan ook waarskynlik nuut is tot die wetenskap, is ook vanaf Pinus spesies versamel wat in hierdie woude gegroei het. Vier Ophiostomatales spesies (insluitend drie nuut beskryfde spesies) wat met subkortikale kewers op Rapanea melanophloeos en Olea capensis L. ssp. macrocarpa geassosieer is, is ook versamel. Hulle was Sporothrix pallida, Sporothrix aemuluphilus, Raffaelea scabbardiae en Raffaelea rapaneae, geassosieer met die kewers Lanurgus sp. 1, Ctonoxylon sp. 1, Xyleborinus aemuluphilus en „n Platypodinae spesie. Hierdie verteenwoordig die eerste studie wat die assosiasies tussen subkortikale kewers en ophiostomatoïde fungi op inheemse bome in die KFS ondersoek. Addisioneel tot fungi geassosieer met die subkortikale kewers, is verskeie lede van die Ophiostomatales vanaf wonde op Rapanea melanophloes bome versamel. Hulle sluit in Ophiostoma stenoceras, Sporothrix reniformis, S. rapaneae, S. lunateae en S. noisomeae. Almal behalwe O. stenoceras was nuut tot die wetenskap, en is hier formeel beskryf. Al hierdie wond-geassosieerde spesies vanaf R. melanophloeos behoort aan die Sporothrix schenckii – O. stenoceras kompleks, behalwe vir S. noisomeae wat voorlopig in die S. lignivora kompleks geplaas is. Benewens fungi taxa wat van die wonde op Rapanea melanophloes versamel is, is ander fungi ook vanaf die wonde op ander gasheer boom spesies versamel. Drie verdere ophiostomatoïde fungus spesies is in hierdie nis versamel. Hulle sluit in Sporothix capensis wat vanaf O. capensis ssp. macrocarpa versamel is, Graphilbum roseus wat vanaf baie verskillende, onverwante gasheer bome versamel is en Graphium ilexiense (Microascales), wat vanaf wonde op Ilex mitis versamel is. Laasgenoemde verteenwoordig die eerste isolasie van „n ophiostomatoïde fungus vanaf hierdie gasheer boom spesie. Twee moontlik nuwe fungus spesies (Sporothrix sp. 1, Ceratocystiopsis sp. 1) en Ophiostoma ips, geassosieer met drie baskewers (Orthotomicus erosus, Hylurgus ligniperda en Hylastes angustatus) is vanaf Pinus versamel. Verskeie fungi spesies is van beide inheemse en nie-inheemse bome versamel. Hulle het Sporothrix fusiforme vanaf Brabejum stellatifolium en Acacia mearnsii, O. quercus en O. pluriannulatum-like fungus vanaf verskeie inheemse bome en vanaf A. mearnsii ingesluit. Dit suggereer die moontlikheid van gasheer-skuiwing van sommige van hierdie fungi tussen inheemse en uitheemse gashere of selfs tussen verskillende inheemse gashere. Agt nie- ophiostomatoïde geassosieerde subkortikale kewers was ook versamel en in totaal is meer as 4500 kewer indiwidue versamel. Sommige ophiostomatoïde fungus spesies wat in hierdie studie versamel is, was met ander geleedpotiges soos myte geassosieer. Vier foretiese myt spesies wat met ophiostomatoïde fungi geassosieer is (Dendrolaelaps quadrisetus, Histiogaster sp. 3, Elattoma sp. 1 & 2), is versamel. Nege addisioneële myt spesies was met verskeie ophiostomatoïde spesies vanaf verskeie boomspesies geassosieer (Graphilbum roseus, O. pluriannulatum-like, O. quercus). Dit suggereer dat myte die vervoer van hierdie fungi van een gasheer spesie na die ander mag bewerkstellig. Die moontlike gevolge van die oordrag van Ophiostomatales spesies tussen gashere is getoets deur patogeniteitstoetse. Dit het beklemtoon dat sommige fungi patogenies is op verskeie onverwante boomspesies. Oordraag van spesies is mees waarskynlik in fungi spesies wat vanaf wonde geisoleer is, veral dié wat met myte geassosieer is, want die myte mag hierdie fungi help vervoer. Toe foretiese myte getoets is vir hulle spesifisiteit tot hulle vektore, is hulle hoogs spesifiek bevind. Alhoewel sommige fungi wat met hierdie myte en hulle geassosieerde kewers geassosieer word wel patogenies is, is dit minder waarskylik dat hulle na ander gasheer bome sal verskuif as gevolg van die hoë spesifisiteit van hulle geleedpotige assosiate. Hierdie studie verteenwoordig een van net enkele studies gefokus op ophiostomatoïde fungi, subkortikale kewers en myte wat met bome van die Afromontane woude van Suid-Afrika geassosieer is. Alhoewel ons „n hoë diversiteit van Ophiotomatale lede versamel het, wag baie meer fungi spesies waarskynlik nog op ontdekking. Daar word voorgestel dat toekomstige studies fokus op die komplekse inter-organismiese interaksies in baie van die sisteme wat in hierdie studie blootgelê is.

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Salvia africana lutea is one of 26 Sage species indigenous to Southern Africa from a total of 900 worldwide. The genus Salvia belongs to the Lamiaceae family. Labeled a ‘broad spectrum remedy’ S. africana lutea amongst other sage species is medicinally important. Reports are many highlighting its benefits, which include from alleviating coughs and colds to gynaecological complaints. Studies have revealed in vitro antimicrobial, anti-cancer and antioxidant activity. Plant secondary metabolites fundamentally have a strong bearing on the phytochemical activities a plant may possess. Consequently the environment indirectly affects the phytochemical properties as it influences the variation in the plant metabolome via plant-environment interactions. Five S. africana lutea plant populations, within the Western Cape province of South Africa were sampled and chemotypes and bioactivity tested. Four populations were wild growing in protected areas namely; Brackenfell, Koeberg, Silwerstroomstrand and Yzerfontein, while the fifth was a garden growing population from Stellenbosch. Using gas chromatography hyphenated with mass spectrometry (GC-MS), compounds such as monosaccharides, carboxylic acids and fatty acids were detected. Variation of compounds identified with 80% certainty was compared across all populations. Stellenbosch population showed some compounds that were not present in the other four sites. These compounds were namely; propanoic acid, rythronic acid, 2-keto-1-gluconic acid and 1,3-dibromobicyclon, while this population also did not have xylitol that was detected in all the other four populations. To consolidate the GC-MS findings, analysis on the metabolite profiles (utilizing liquid chromatography linked with mass spectrometry (LC-MS) and nuclear magnetic resonance (1H NMR)) was done. Principal component analysis (PCA) was applied to the NMR data. The partial least squaresdiscriminant analysis (PLS-DA) was used to integrate LC-MS and NMR data sets. All statistics were performed with the SIMCA-P+ 12.0 software. By integrating LC-MS and 1H NMR analyses, large chemotype differences leading to samples grouping by site, suggested strong plant-environment interactions as factors influencing metabolite composition. Signals distinguishing the Stellenbosch profile were in the aromatic part of the 1H NMR spectra. Antimicrobial activity was tested against two Fusarium species. Fusarium is a plant pathogenic species that causes large agricultural losses particularly in the maize crop, one of the staple foods in the African continent. Some species also produce mycotoxins in infected crop and lead to a significant increase in the risk factor of cancers when contaminated foods are consumed. Four high-mycotoxin producing strains from two species F. verticillioides (MRC 826 and MRC 8267); F. proliferatum (MRC 7140 and MRC 6809) were utilized in all in vitro antifungal assays in this study. A preliminary assay using dichloromethane: methanol (1:1 v/v) crude plant extracts of the five populations; Stellenbosch, Brackenfell, Koeberg, Silwerstoomstrand and Yzerfontein, from 2009 and 2011. All test samples exhibited good activity as the minimum inhibitory concentrations (MIC) values ranged from 0.031 mg ml-1 to 0.5 mg ml-1, values below the latter are regarded as strong inhibitors. The Stellenbosch extracts were the most active for both 2009 and 2011 collections, with the best activity against F. verticillioides MRC 8267 and MRC 826 at 0.031 mg ml-1. While the least activity, albeit still a strong inhibitor, was observed from the Yzerfontein extracts with an MIC value of 0.5 mg ml-1. Generally comparison between the two years revealed that samples collected in 2011 were more potent than those in 2009, possibly due to prolonged storage that may have resulted in chemical decomposition. As the Stellenbosch population had shown the best activity as well as a relatively different chemical profile, leaves from these plants were then introduced into tissue culture conditions. Leaf explants were placed on solid plant growth regulator (PGR)-free Murashige and Skoog media and that supplemented with hormones in various combinations. (two concentrations of benzyl adenine (BA) utilized individually and in combination with naphthalene acetic acid (NAA) 4.4 and 8.8, while for NAA 0.27, 2.7 and 5.4.) Namely: 4.4 BA, 8.8 BA, 0.27 NAA: 4.4 BA, 2.7 NAA: 4.4 BA, 5.4 NAA: 4.4 BA, 2.7 NAA: 8.8 BA and 5.4 NAA: 8.8 BA. The PGR combinations did not induce shooting nor rooting, only callus on PGR-free MS media. Antifungal activity of the callus extract was in the same range as the whole plant extracts from which the leaf explants were harvested from, showing no ‘loss’ of activity after introduction to tissue culture conditions. Metabolite profiles using LC-MS, however, did reveal qualitative and quantitative differences, though they appear to not have any bearing on the activity. A bioassay-guided fractionation was then conducted on samples collected from Stellenbosch. This led to the identification of carnosol and carnosic acid being involved in the anti-Fusarium activity of S africana-lutea. A combinational study revealed no synergistic activity of the two compounds against four Fusarium test strains, with fractional inhibitory concentration (FIC) values of 1.5 and 3.0. Antifungal activity of carnosol and carnosic acid was observed to be in the same range (strong inhibitor) as was the callus and whole plant extracts. The study showed variation in population chemotypes and identified two compounds that are involved in S. africana-lutea activity against Fusarium species. It also provided a tissue culture system onto which mass production of the two bioactives may be achieved from, in the development of new fungicides. / AFRIKAANSE OPSOMMING: Salvia Africana lutea is een van die 26 Salie spesies wat inheems aan Suid-Afrika is uit ‘n totaal van 900 spesies wêreldwyd. Die genus Salvia hoort tot die Lamiaceae familie. S. africana lutea word geklassifiseer as ‘n “breë spektrum geneesmiddel”, en medisinaal as belangrik geag tussen die ander salie spesies, want volgens verslag word dit gebruik vir die verligting van hoes en verkoues tot selfs ginekologiese ongesteldhede. Definitiewe biologiese aktiwiteit eksperimente het anti-mikrobiese, antikanker en anti-oksidant aktiwiteite aan die lig gebring. Plant sekondêre metaboliete het fundamenteel ‘n baie sterk verband met die fitochemiese aktiwiteite van ‘n plant. Gevolglik affekteer die omgewing indirek die fitochemiese eienskappe, want dit beïnvloed die variasie in die plant metaboloom deur die interaksies van die plant met die omgewing. In vyf streke binne die Wes-Kaap van Suid-Afrika waar S. africana lutea bevolkings voorkom, is steekproewe gedoen en chemotipes en bioaktiwiteit getoets. Vier bevolkings was wild-groeiende bevolkings in beskermde areas, naamlik; Brackenfell, Koeberg, Silwerstroomstrand en Yzerfontein, terwyl die vyfde uit ‘n tuingroeiende bevolking in Stellenbosch geneem is. Deur gas chromatografie gekoppel met massa spektrometrie te gebruik, is primêre samestellings soos monosakkariede, karboksielsure en vetsure gevind. Variasies van samestellings wat met 80% sekerheid geïdentifiseer is, is oorkruis met al die bevolkings vergelyk. Die Stellenbosch bevolking het ‘n paar samestellings geopenbaar wat nie aanwesig was in die ander vier terreine nie. Hierdie samestellings was: propanoësuur, erythroniese suur, 2-keto-1-glukoniese suur en 1,3-dibromobicyclon. Verder het hierdie bevolking geen xylitol gehad nie en dit is in al vier die ander bevolkings gevind. Verdere studies was gedoen met die gebruik van vloeibare chromatografie gekoppel met massa spektrometrie (LC-MS) sowel as kern magnetiese resonansie (1H NMR). Chemiese profiele het hoë variasies getoon, en dus deur te fokus op die aromatiese samestelling streke, het die Stellenbosch terrein duidelik merkbare verskille en punte op die PLS-DA aangetoon. Met die koppeling van NMR data met LC-MS data, is daar gevind dat onderskeidende punte van die NMR PLS-DA wat gegroepeer is met retensie tye die skeiding van die Stellenbosch terrein van ander terreine gedryf het. Dit het onweerlegbaar bewys dat daar variasie binne die vyf bevolkings voorkom en dat Stellenbosch die mees noemenswaardige chemotipe variasie het. Dit blyk uit die anti-mikrobiese eksperimente dat aktiwiteit teen Fusarium heel nuwe belangstelling wek. Fusarium is ‘n plant-patogeniese spesie wat groot landbou verliese veroorsaak veral in die mielie gewasse, een van die stapelvoedsels van die Afrika kontinent. Dit produseer ook mikotoksiene in aangetaste gewasse en hierdie kan lei tot die ontstaan van kankers wanneer besmette voedsel op groot skaal verbruik word. Vier hoë-mikotoksien produserende swamlyne van twee spesies, naamlik F. verticillioides (MRC 826 en MRC 8267) en F. proliferatum (MRC 7140 en MRC 6809) is gebruik in alle in vitro anti-swam ondersoeke in hierdie studie. Die eerste analise het dichloromethan: methanol (1:1 v/v) ongesuiwerde plant ekstrakte bevat van die vyf bevolkings: Stellenbosch, Brackenfell, Koeberg, Silwerstroomstrand en Yzerfontein, geneem gedurende 2009 en 2011. Al hierdie toets monsters het goeie aktiwiteit getoon waar die minimum beperkende konsentrasie (MIC) waardes van 0.031 mg ml-1 tot 0.5 mg ml-1 gevarieer het. Waardes laer as laasgenoemde word beskou as sterk inhibeerders. Die Stellenbosch ekstrakte was die mees aktief vir albei jare hierbo genoem, met die beste aktiwiteit teen F. verticillioides MRC 8267 en MCR 826 by 0.031 mg ml-1. Die minste aktiwiteit (hoewel nog ‘n sterk inhibeerder) waargeneem was van die Yzerfontein ekstrakte, met ‘n MIC waarde van 0.5 mg ml-1. Oor die algemeen het ‘n vergelyking tussen die twee jare aangetoon dat die monsters wat in 2011 versamel is veel sterker was dan dié van 2009, moontlik te wyte aan ‘n verlengde bewaringstyd wat moontlik ‘n chemiese dekomposisie ten gevolge gehad het. Omdat die Stellenbosch bevolking die beste aktiwiteit getoon het sowel as ‘n relatief afwykende chemiese profiel, is blare van hierdie plante toe bekendgestel aan weefselkultuur kondisies. Blaar eksplante is op soliede hormoonvrye Murashige en Skoog media geplaas en dit is aangevul met sintetiese auksien Naftaleen asynsuur (NAA) en sitokien Bensiel adenien (BA) individueel en in verskillende kombinasies. Geen wortels of uitloopsels is waargeneem in al die hormoon kombinasies nie maar in die hormoonvrye media het daar egter Kallus in twintig persent van die eksplante voorgekom. Kallus is toe as subkultuur van hormoonvrye MS media gekweek en saamgevoeg en dichloromethan: methanol (1:1v/v) ekstrakte is getoets teen die volgende Fusarium swamlyne MRC 826; MRC 8267; MRC 7140 en MRC 6809. MIC waardes het sterk inhiberende eienskappe getoon met die laagste waarde as 0.025 mg ml-1 teen drie swamlyne: MRC 1740, MRC 8267 en MRC 826, en die hoogste was 0.25 mg ml-1 na 48 uur. Die minimum inhiberende konsentrasie waardes het gestyg na 0.5mg ml-1 na 60 uur, wat ‘n fungistatiese aksie getoon het. Maar van 60 tot 92 uu het waardes egter ‘n swamdodende aksie aangetoon met geen verandering van 0.5mg ml-1 nie. In die identifisering van die bioaktiewe komponente, is die ekstraksie van Stellenbosch se bevolking in dichloromethan: methanol (1:1 v/v) uitgevoer, en met gebruik van vyftig gram van die ekstrak is bioanalise-geleide fraksionering gedoen deur gebruik van ‘n VersaFlash®. Die mees aktiewe fraksie is verder gefraksioneer deur die gebruik van ‘n konvensionele silikajel kolom. Aktiewe fraksies is getoets deur LC-MS te gebruik, en twee verbindings, carnosol en carnosic suur, is geïdentifiseer. Voorbereidende TLC is gebruik om identiteit te bevestig, want fraksies was naas die kommersiele standaarde van die twee verbindings getoets. Sinergistiese aktiwiteit van die twee samestellings is ondersoek deur ‘n antiswam ontleding teen die vier swamlyne uit te voer. Hierdie studie het dus die veronderstelde bestaan van verskillende chemotipes tussen die bevolkings waarvan voorbeelde geneem is, bekend gestel. Veral die Stellenbosch se bevolking het die meeste verskil, heel moontlik omrede die verlengde en hoër versteurings deur die nabyheid van mense. Plant– omgewing interaksies speel ‘n belangrike rol in die metaboloom van plante, wat dan indirek hul eienskappe verander, en in hierdie geval die antiswam aktiwiteit. Die tuingroeiende bevolking was die mees aktief, heel moontlik omrede hierdie aspek. Nietemin was geen bioaktiwiteit verloor waar die mees kragtige bevolking met weefsel kultuur kondisies in aanraking gebring is nie. Dus is dit ideaal vir kommersialisering. Een nuwe belangrike bevinding was die carnosol en carnosic suur wat twee welbekende samestellings is wat meesal geassosieer is met Rosmarinus officinalis en gedokumenteer is vir antioksidant aktiwiteit. Hier dui laasgenoemde samestellings ‘n antiswam aktiwiteit aan teen die getoetste Fusarium swamlyne. Met ‘n gevestigde weefsel kultuur sisteem alreeds in plek, voorsien dit ‘n beginpunt vir die bestudering van hoe hierdie bioaktiewe komponente in massa geproduseer kan word in die ontwikkeling van nuwe swamdodende produkte.

Thesis (PhD (Botany and Zoology))—University of Stellenbosch, 2009. / Natural ecosystems provide many services that are crucial for sustainability and health of human society. Ecosystem services are the benefits people obtain from ecosystems (i.e. goods and services) and can be classified into provisioning (e.g. fibre, fuel wood); regulating (e.g. water and climate regulation); supporting (e.g. soil retention) and cultural (e.g. aesthetic value). The growing global human population and other threats place enormous stress on the natural environment reducing its capability to provide services. According to the Millennium Ecosystem Assessment, more than 60% of ecosystem services worldwide are being degraded or used unsustainably. The need to safeguard ecosystem services is therefore urgent. Biodiversity underpins most ecosystem services, but the functional relationship between biodiversity and services is not well known. A wide range of strategies exist for safeguarding biodiversity, but no such approaches have been developed for ecosystem services. A key conservation strategy is the use of systematic conservation planning to identify priority areas where effort should be focused. There are calls for the inclusion of ecosystem services into conservation planning geared towards biodiversity. Ecosystem services have been used for many years as an additional rationale to justify biodiversity conservation and it is often assumed that conserving biodiversity will also conserve services. However, it is unclear how different facets of biodiversity relate to different services and to what extent conserving biodiversity will safeguard services. This thesis addresses a range of issues relating to the integration of ecosystem services into conservation planning in South Africa. I first investigated the status of ecosystem services in conservation planning worldwide by reviewing the conservation planning literature from 1998 to 2005. Ecosystem services are clearly not adequately addressed in conservation assessments. A critical barrier preventing the inclusion of ecosystem services in conservation plans is the lack of spatially-explicit data. I developed a methodology for mapping ecosystem services in South Africa and mapped the distribution of five important ecosystem services (surface water supply, water flow regulation, carbon storage, soil retention and accumulation). Using the five services to examine relationships within services and between biodiversity revealed a lack of congruence between services and different levels of congruence with biodiversity features. However, including ecosystem services in a biodiversity assessment captured at least thirty percent of each of three services selected for the study. Nevertheless, a biodiversity plan may not necessarily capture adequate amounts of ecosystem services. Ecosystem services should be planned for explicitly instead of relying on biodiversity data. I identified priorities that met targets for five services in the grasslands of South Africa. This thesis provides new insights on planning for biodiversity and ecosystem services. The results have immediate applicability for conservation planning in South Africa. Keywords: Conservation planning, conservation assessments, ecosystem functions, ecosystem processes, ecosystem services, natural capital, biodiversity, soil, water, carbon.

Thesis (PhD (Botany and Zoology))--University of Stellenbosch, 1988. / Thesis (PhD (Botany and Zoology))--University of Stellenbosch, 1988. / Microfiche format 470 leaves single sided printed, preliminary pages i-vi and numbered pages 1-466. Includes bibliography and a list of figures. Copied with a Kodak 2400 DSV-E microfiche reader and digitized at 300 dpi (OCR), used Bizhub 250. / Please refer to full text to view abstract.

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: My master’s research combines aspects of pollination biology and invasion biology to explore the invasive predictors and impacts of a globally invasive group of plants – Australian acacias. Specifically, I investigate the role of reproductive biology in their invasion success (Chapter 2), the impacts of a specific species, Acacia saligna, on native plant-pollinator communities in South Africa (Chapter 3), and if the impact of A. saligna on native plant species can be predicted, based on floral trait similarity (Chapter 4). Australian acacias possess many floral traits implicated in plant invasion success, including extensive, dense floral displays, prolific seed production, long-lived seed banks, and propensity for vegetative reproduction. In Chapter 2 of my thesis, co-authors and I investigate if such reproductive traits influence whether or not a species becomes invasive once it is introduced by qualitatively and quantitatively analyzing literature and data collected from published and unpublished data. We found that invasive species reach reproductive maturity earlier and are more commonly able to resprout. Our findings have important implications for management of existing Acacia invasions as well as the assessment and prevention of further introductions of Acacia species leading to invasion. Impacts of invasive plant species on native plant visitation and consequent reproduction are often negative and have important implications for future ecosystem health. Acacia saligna is a problematic woody invasive shrub in many Mediterranean regions, and in South Africa, it invades fynbos vegetation, which boasts one of the highest plant diversities per area in the world as well as many specialized pollination mutualisms. It blooms during the flowering peak of most native species and forms dense, showy floral displays, thus the possibility of pollinator-mediated interactions with co-flowering native species is high. In Chapter 3, I assess the impact of flowering A. saligna on insect visitation to co-flowering native species by conducting flower observations at both an invaded and uninvaded (control) site. One of the native species most-visited by native honeybees, Roepera fulva, had high flower visitor overlap with A. saligna and suffered significantly lower visitation from all insects and from bees when A. saligna was present than at the control site. The native honeybee appears to be the most important visitor to A. saligna as it was the most frequent and mobile. Due to its foraging efficiency and dominance in pollinator communities, Apis mellifera subsp. capensis could be an important mediator of the negative effect of A. saligna on co-flowering natives, especially those frequently visited by honeybees. The use of floral traits as predictors of a species’ effect on co-flowering plants via pollination is commonly used in pollination biology. In the fourth chapter of my thesis, I apply the predictive principle of floral traits on flower visitation to see if floral traits can predict the impact of an invasive plant species on co-flowering native species, and if so, which floral traits are the most important. Following the same flower observation protocol as Chapter 3, I assess two measures of invasion impact on native flowers – change in visitation rate to native plant species between invaded and uninvaded sites and flower visitor overlap between A. saligna and native species – and test for a correlation with floral trait similarity of native species to and A. saligna. Similarity of categorical traits and all traits combined (categorical and continuous) were significantly positively correlated with flower visitor overlap, indicating that native species with categorical traits similar to A. saligna were more likely to share flower visitors with A. saligna. Floral symmetry and shape similarity were the most important categorical traits in driving flower visitor overlap. Findings suggest an important link between categorical floral traits and ability to predict invasive plant impact on native flower-insect interactions; however, more comprehensive studies are required for conclusive results. / AFRIKAANSE OPSOMMING: My Meestersgraad se navorsing kombineer aspekte van bestuiwingsbiologie en indringerbiologie om ondersoek in te stel na die indringing-voorspelbaarheid en die impak van Australiese Akasias, 'n wêreldwye indringende groep van plante. Ek het spesifiek gekyk na die rol van voortplantingsbiologie in hul indringing sukses (Hoofstuk 2), die impak van 'n spesifieke spesie, Acacia saligna, op die inheemse plant-bestuiwer gemeenskappe in Suid-Afrika (Hoofstuk 3), en of die impak van Acacia saligna op inheemse plantspesies voorspel kan word, gebaseer is op die ooreenkomste in blomeienskappe (Hoofstuk 4). Australiese Akasias het baie voortplantingseienskappe wat geassisioeer word met plantindringing sukses, insluitend ‘n uitgebreide, digte blommedrag, uitermatige hoë saadproduksie, langlewende saadbank, en die geneigdheid vir vegetatiewe voortplanting. In hoofstuk 2 van my tesis, ondersoek ek en my medeskrywers of sulke voortplantingseienskappe beïnvloed of 'n spesie ‘n indringer raak, deur 'n ontleding van die literatuur en data wat versamel is uit gepubliseerde en ongepubliseerde data. Ons het gevind dat indringerspesies geslagsrypheid vroeër bereik en meer algemeen in staat is om weer uit te loop. Ons bevindinge het belangrike implikasies vir die bestuur van die bestaande Akasiastande sowel as die evaluering en die voorkoming van verdere vestiging van Akasia spesies wat lei tot indringers. Impakte van uitheemse plantspesies op inheemse plant-besoeke deur bestuiwers, en gevolglike voortplanting is dikwels negatief en het belangrike implikasies vir die toekomstige ekosisteem gesondheid. Acacia saligna is 'n problematiese houtagtige indringende struik in baie Mediterreense streke, en in Suid-Afrika. Dit dring in die Fynbos in, wat spog met een van die wêreld se hoogste plant diversiteit per oppervlak, sowel as baie gespesialiseerde bestuiwing-mutualismes. Dit blom gedurende die bloeiseisoen van die meeste inheemse spesies en vorm digte, pronkerige blomuitstallings, dus is die moontlikheid hoog vir bestuiwer-gemedieerde interaksies met inheemse spesies wat saam blom. In Hoofstuk 3, het ek die impak van Acacia saligna, op insek besoeke aan saamblommende inheemse spesies bepaal, deur waarnemings op beide ingedringde en natuurlike studie gebiede. Een van die inheemse spesies, Roepera fulva, wat die meeste besoek is deur inheemse heuningbye, het 'n hoë blom besoeker oorvleueling met Acacia saligna en het aansienlik minder besoeke van alle insekte en van bye gekry toe Acacia saligna teenwoordig was as by die natuurlike studie gebied. Die inheemse heuningby, Apis mellifera subsp. capensis, blyk die mees belangrikste besoeker aan Acacia saligna te wees aangesien dit die mees gereeldste en beweeglikste was. As gevolg van sy oorheersing in bestuiwer gemeenskappe, is die by 'n belangrike faktor van die negatiewe uitwerking van Acacia saligna op die inheemse plante wat dieselfde tyd blom, veral dié wat gereeld besoek word deur heuningbye. Die gebruik van blomeienskappe as voorspellers van 'n spesie se effek op saamblommende plante deur middel van bestuiwing, word algemeen gebruik in bestuiwingsbiologie. In die vierde hoofstuk van my tesis, het ek die voorspellende beginsel van die blomeienskappe op blombesoeking toegepas, om te sien of blomeienskappe die impak van 'n uitheemse plantspesie kan voorspel op saamblommende inheemse spesies, en indien wel, watter blomeienskappe die belangrikste is. Deur dieselfde blom waarneming protokol as in Hoofstuk 3 te gebruik, het ek twee maatstawwe van indringings impakte op inheemse blomme vergelyk - verandering in besoek gereeldheid aan inheemse plante tussen ingedringde en natuurlike studie gebiede en blom besoeker oorvleueling tussen die Acacia saligna en inheemse spesies – en die toets vir 'n korrelasie van blomeienskap ooreenkomste in inheemse spesies en Acacia saligna. Soortgelykheid van kategoriese eienskappe en al die eienskappe gekombineer (kategoriese en deurlopende) is beduidend positief gekorreleerd met blombesoeker oorvleueling, wat aandui dat inheemse spesies met kategoriese eienskappe soortgelyk aan Acacia saligna meer geneig was om blom besoekers te deel met Acacia saligna. Blom simmetrie en vorm ooreenkoms was die belangrikste kategoriese eienskappe wat ly tot blombesoeker oorvleueling. Bevindinge dui op 'n belangrike skakel tussen die die kategoriese blomeienskappe en die vermoë om indringerplant impakte op inheemse blom-insek interaksies te voorspel, alhoewel, meer omvattende studies nog nodig is. / DST-NRF Centre of Excellence for Invasion Biology and the Department of Botany and Zoology at Stellenbosch University for research funding