Bibliography: leaves 173-184. This study aimed to broaden understanding of breeding systems in Australian Proteaceae and to study the optimum requirements for promotion of seed germination in two lesser researched genera with horticultural potential, Dryandra quercifolia and Dryandra formosa. The timing and pattern of stigma receptivity was determined using a combination of techniques. Findings can be used to breed and improve these species for further commercialisation in cut flower and garden industries. The study of pistil structure further identified the potential of this structure to affect the capacity of a proteaceous flower to be fertilised. Aspects such as the morphology and size of the stigmatic cavity and the quantity of transmitting tissue in the style were highlighted as filters to pollen tube passage. Comparative studies with other angiosperm species confirmed the unusual structure of the pistil of the proteaceous flower. Seed germination was found to be promoted by exposure of seeds to controlled temperatures of 15°C.

Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Trials were conducted to follow colour development during the growth season of the commercial Leucadendron cultivar 'Siivan' Red', as well as the Protea cultivars 'Ivy', 'Carnival' and 'Sylvia'. HPLC analysis showed that pigments responsible for red colour in Leucadendron and Protea cultivars are anthocyanins. Initial extraction of anthocyan ins from freeze-dried and finely ground Leucadendron leaves, using 5% formic acid in methanol, resulted in the precipitation of gel-like compounds, making the extracts impossible to filter for HPLC. Trials were conducted to determine the optimum extraction solvent and extraction time for anthocyanin quantification in Leucadendron, using 'Safari Sunset' (Leucadendron sa/ignurn x L. /aureo/urn) as reference material. Acetone, 80% acetone, 5% formic acid in water and 5% formic acid in methanol were added to freeze dried leaf samples and allowed to extract for one hour. Extracts were analysed by reverse-phase HPLC. Extractions with methanol and water yielded extracts with a high content of pectin-like compounds, making them difficult to purify for HPLC. 80% acetone proved to be the most efficient extraction solvent, yielding the highest anthocyanin concentration, and showing the least amount of insoluble compounds. Optimal extraction time was determined for 80% acetone by testing 1, 6 and 24-hour extractions respectively. Although 6 hour extraction showed a slightly higher yield, a 1-hour extraction should suffice for quantification of anthocyanin changes over time, as trends will clearly be evident. 'Siivan Red' shoots meeting export quality can generally be harvested from mid February to mid April (late summer to autumn). The harvesting period ends as the colour of the distal leaves forming the flower head change from red to green. Anthocyanin, chlorophyll and carotenoid fluctuations were investigated in 'Siivan Red' during the 2000 growth season. The observed red colour loss is the result of the net degradation of anthocyanins and appeared to be correlated to the phenological development of the shoot. Although a positive correlation was noted between anthocyanin content and average daily temperature and mean daily sunlight hours, it appears unlikely that they are the causal factors for the observed colour change. Anthocyanin degradation started during conditions of long exposure to high light intensities and continued during a period of low temperature (autumn), both which are known to favour anthocyanin synthesis rather than its degradation. Therefore it appears that colour development in 'Silvan Red' is developmentally regulated. The Leucadendron cultivar 'Safari Sunset' with the same parentage as 'Siivan Red', is noted for its more intense red-purple colouration, which it does not lose during its development. The more intense colouration of 'Safari Sunset' has been ascribed to the higher total anthocyanin concentration, which was almost double that encountered in 'Siivan Red'. 'Safari Sunset' was shown to contain the same major types of anthocyanins, and hence the purple colouration (not seen in 'Siivan Red') can not be explained in terms of different types of anthocyanins being present. However, the ratio between the two major anthocyanins present in both 'Safari Sunset' and 'Siivan Red' were significantly different in that 'Safari Sunset' showed a considerably higher concentration of peak 1, which is most likely responsible for the observed purple colouration. High anthocyanin concentrations have been noted to buffer against visual changes in colour, which is the most probable reason that a colour loss is not observed in 'Safari Sunset'. Colour development of the innermost involucral bracts of three Protea cultivars was followed from an initially selected inflorescence size to commercial harvest (when flowers have opened slightly). 'Ivy', 'Carnival' and 'Sylvia' show a light pink, dark pink and red colouration respectively, which has been ascribed to differences in total anthocyanin concentration. Colour development in 'Carnival' showed a quadratic trend with time, with the highest rate of anthocyanin synthesis occurring a week prior to harvest. Colour development in 'Ivy' and 'Sylvia' were shown to be linear with time. As inflorescences are closed during their development and anthocyanin synthesis in the innermost involucral bracts occurred in darkness, light does not appear to have a major influence on colour development. Temperature did not appear to have a significant effect on flower colour, as flowers developing later in the season, when ambient temperatures were lower, showed no significant differences in anthocyanin concentration to those harvested earlier. Hence, it appears that colour development in all three cultivars is developmentally regulated. / AFRIKAANSE OPSOMMING: Hierdie studie is onderneem om kleurontwikkeling van die Leucadendron kultivar 'Silvan Red' en die Protea kultivars 'Ivy', 'Carnival' en 'Sylvia' te ondersoek. Die rooi kleur van distale 'Siivan Red' blare en Protea omwindselblare is te wyte aan antosianiene. Eerstens is gepoog om die ektraksie van antosianiene vir kwantifisering deur hoë druk vloeistof chromatografie (HPLC) te verfyn. Aanvanklik is 5% mieresuur in metanol gebruik om antosianien vanuit gefriesdroogde en fyngemaalde Leucadendron blare te ekstraheer. 'n Gelagtige neerslag het dit egter onmoontlik gemaak om die ekstrak te filtreer. Vervolgens is eksperimente uitgevoer om die geskiktheid van asetoon, 80% asetoon, 5% mieresuur in water en 5% mieresuur in metanol as alternatiewe vir 5% mieresuur in metanol te bepaal. Antosianiene is deur middel van HPLC gekwantifiseer na 'n uurlange ekstraksie vanuit 'Safari Sunset' (Leucadendron sa/ignurn x L. /aureo/urn) blaarmonsters. 'n Onoplosbare neerslag van onsuiwerhede na ekstraksie met metanol en water het filtrasie bemoeilik. 80% asetoon was die doeltreffendste ekstraheermiddel deurdat dit beide die hoogste opbrengs van antosianiene en die minste onsuiwerhede gelewer het. Vervolgens is die optimale duur van antosianienekstraksie met 80% asetoon bepaal deur vir een, ses en 24 uur te ekstraheer. Resultate het getoon dat, alhoewel ses uur ekstraksie 'n effense hoër antosianienkonsentrasie lewer, 'n uur voldoende behoort te wees vir kwantifisering van antosianien. Uitvoergehalte 'Siivan Red' lote word gewoonlik vanaf middel Februarie tot middel April (Iaat somer tot herfs) geoes. Die oestyd eindig met 'n verandering in die kleur van distale blare van rooi na groen wat die bemarkbaarheid van lote verlaag. Ten einde hierdie kleurverandering te kwantifiseer is veranderinge in die konsentrasies van antosianien, chlorofiel en karotenoide in distale 'Siivan Red' blare gedurende die 2000 groeiseisoen gemeet en in verband gebring met omgewingstoestande en ontwikkelingstadiums. Rooi kleurverlies van distale 'Silvan Red' blare hou klaarblyklik verband met 'n geleidelike afname in hul antosianienkonsentrasies vanweë netto degradasie. Veranderinge in die kleur en antosianienkonsentrasie van blare het saamgeval met spesifieke ontwikkelingsperiodes. Kleurveranderinge in 'Siivan Red' kon nie met omgewingstoestande verbind word nie. Kleuronwikkeling word klaarblyklik intern gereguleer om saam te val met spesifieke ontwikkelingstadia. Die Leucadendron kultivars 'Safari Sunset' en 'Siivan Red' het dieselfde ouers. Eersgenoemde kultivar het egter In intenser rooi-pers kleur wat ook stabiel blyoor die hele groeiseisoen. Die intenser kleur kan toegeskryf word aan die bykans twee keer hoër antosianienkonsentrasies wat 'Safari Sunset' blare oor die groeisoen handhaaf. Hierdie hoër antosianienkonsentrasie is moontlik ook die rede vir die oëskynlik groter kleurstabiliteit van 'Safari Sunset' aangesien hoë pigmentvlakke kleur buffer teen veranderinge in pigmentkonsentrasie. 'Safari Sunset' se pers skynsel is moontlik te wyte aan die relatief groter bydrae van piek 1 op die chromatogram tot die totale antosianienkonsentrasie. Andersins het die twee kultivars 'n soortgelyke antosianienprofiel. Ten einde die regulering van kleurontwikkeling in Protea te ondersoek, is antosianienkonsentrasies in die binneste bloeiwyse-omwindelsblare van die Protea kultivars 'Ivy', 'Carnival' en 'Sylvia' gemeet vanaf 'n pre-geselekteerde blomgrootte tot en met kommersiële oestyd wanneer die blomme begin oopgaan. Die drie kultivars wisselonderskeidelik in kleur van lig pienk en donker pienk tot rooi. Hierdie kleurverskille was te wyte aan verskille in antosianienkonsentrasie. Antosianienkonsentrasies in 'Ivy' en 'Sylvia' het lineêr toegeneem oor tyd, terwyl in die geval van 'Carnival', maksimum antosianienvlakke reeds 'n week voor oes bereik is. Blomme wat by laer temperature later in die seisoen of vroeër by hoër temperature ontwikkel het, het nie betekenisvol verskil in antosianienkonsentrasie nie. Gevolglik is lig en temperatuur klaarblyklik van mindere belang vir Protea kleurontwikkeling. Soos met Leucadendron die geval was, word kleurontwikkeling in Protea dus ook intern gereguleer.

M.Sc. (Botany) / Please refer to full text to view abstract

M.Sc. (Botany) / Please refer to full text to view abstract

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Successful biological invasions take place when species introduced to regions outside their natural dispersal range overcome several barriers and establish, persist, proliferate and spread potentially resulting in major threats to biodiversity. The success of invasive alien plants depends on species-specific traits and characteristics of the introduced environment. In this thesis I explore which species traits are important and which environmental barriers need to be overcome for an invasion to occur using Proteaceae as a test case. Firstly, I assessed the global introduction history and invasion ecology of Proteaceae - a large plant family with many taxa that have been widely disseminated by humans, but with few known invaders. This revealed that at least 402 species (i.e. 24% of 1674 species in this family) are known to have been moved by humans out of their native ranges, 58 species (14%) have become naturalized and 8 species (2%) are invasive. The probability of naturalization was greatest for species with large native range sizes, low susceptibility to Phytophthora root-rot disease, larger seeds, mammal-dispersed seeds and those with the capacity to resprout after fire or other disturbances. The probability of naturalized species becoming invasive was greater for species with larger range sizes, species used as barrier plants, taller species, species with smaller seeds, serotinous species, and those that regenerated mainly through re-seeding. Secondly, I looked at mechanisms underlying naturalization on a regional scale, using species which are not already classified as major invaders. At least 26 non-native Proteaceae species have been introduced to, and are cultivated in, South Africa. Propagule pressure facilitated the naturalization of Hakea salicifolia populations in climatically suitable areas, but in suboptimal climates human-mediated land disturbance and land management activities are important for naturalization. Similar drivers are important for naturalization of other alien Proteaceae: a long residence time, fire regimes, poor land management, and propagule pressure were important mechanisms for naturalization. Thirdly, I determined whether reproduction, which in part drives propagule pressure, serves as a barrier for naturalization. I examined several Australian Proteaceae species introduced to South Africa and observed that all species were heavily utilized by native nectar-feeding birds and insects. The five Banksia species that were assessed are self-compatible but four species have a significantly higher reproductive output when pollinators visit inflorescences. Fruit production in H. salicifolia does not differ between naturally-pollinated and autonomously-fertilized flowers. Moreover, no significant difference in fruit production was observed between the five pollination treatments (i.e. natural, pollen-supplementation, autonomous, hand-selfed and hand-crossed treatments) and naturalized and non-naturalized populations. However, pollen limitation was detected in non-naturalized populations which received fewer pollinator visits than naturalized populations. Thus, reproduction limits but is not a fundamental barrier to invasion for H. salicifolia. I conclude that reproductive success of the studied Proteaceae, which is a key barrier determining invasiveness, is not limited by autonomous seed set or mutualisms in the introduced range. In this thesis I highlight biogeographical characteristics, a set of life-history traits and ecological traits as important determinants of invasiveness. These traits are in turn dependent on the stage of invasion. Characteristics of the recipient environment are also important drivers of invasions. This study provides a better understanding of plant invasions in general, but the patterns and processes of invasions highlighted in this thesis will be particularly useful for the current and future management of alien Proteaceae in South Africa and elsewhere, as well as, other species that are adapted to Mediterranean and nutrient poor ecosystems. For example, combining traits of invasiveness and susceptible environments will help to identify which non-native species pose a high risk of becoming invasive (e.g. species with large home ranges and barrier plants) and which conditions in the target area are likely to facilitate or exacerbate invasions (e.g. strong climate match and high propagule pressure). / AFRIKAANSE OPSOMMING: Suksesvolle biologiese indringing vind plaas wanneer ʼn spesie geïntroduseer word in ʼn area buite sy natuurlike verspreidings area, sekere versperrings oorkom, vestig, bly voortbestaan, vermenigvuldig en versprei en potensieel ʼn groot bedreiging inhou vir biodiversiteit. Die sukses van uitheemse indringer plante hang af van spesifieke kenmerke van die spesie en kenmerke van die omgewing waarin dit geïntroduseer word. In hierdie tesis maak ek gebruik van Proteaceae om te ondersoek watter kenmerke is belangrik en watter omgewing versperrings moet oorkom word vir indringing om plaas te vind. Ten eerste assesseer ek die wêreldwye introduksie geskiedenis en indringers ekologie van Proteaceae – ʼn groot plant familie wat wyd gebruik word deur mense, maar met min indringer spesies. Dit het gewys dat mense ten minste 402 spesies (dus 24% van die 1674 spesies in die familie) uit die inheemse areas verskuif het, 58 spesies (14%) genaturaliseer het en 8 spesies (2%) indringers geword het. Die moontlikheid van naturalisasie was die grootste vir spesies met ʼn groot inheemse streek, lae vatbaarheid vir Phytophthora wortelvrot, groter sade, dier verspreide sade en die met ʼn vermoë om weer uit te spruit na ʼn vuur of ander versteuring. Die moontlikheid van genaturaliseerde spesies om indringers te word, was groter vir spesies met groter streek grootte, spesies wat as versperring plante gebruik word, hoër spesies, spesies met kleiner sade, serotiniese spesies, en die wat hoofsaaklik voortbestaan as saadspruiters. Tweedens, het ek gekyk na onderliggende meganismes op ʼn regionale skaal, deur gebruik te maak van spesies wat nie alreeds as belangrike indringers geklassifiseer is nie. Ten minste 26 nie-inheemse Proteaceae spesies is alreeds geïntroduseer en word gekultiveer in Suid Afrika. Propaguul druk fasiliteer die naturalisering van Hakea salicifolia populasies in areas met geskikte klimaat, terwyl in areas met ʼn sub optimale klimaat, versteurings deur mense en grond bestuurs aktiwiteite belangrik is vir naturalisering. Die selfde drywers is belangrik vir die naturalisering van ander uitheemse Proteaceae: lang verblyftyd, vuur bestel, swak land bestuur en propaguul druk. Derdens het ek bepaal of reproduksie, wat gedeeltelik propaguul druk dryf, ʼn versperring is vir naturalisasie. Ek het gekyk na verskeie Australiese Proteaceae spesies wat geïntroduseer is in Suid Afrika, en het gevind dat al die spesies besoek word deur inheemse nektar etende voëls en insekte. Die vyf Banksia spesies wat geassesseer is, kan self bestuif, maar vier van die spesies het ʼn betekenisvolle hoër reproduksie wanneer bloeiwyses deur bestuiwers besoek word. Vrug produksie verskil nie tussen natuurlik bestuifde en self bestuifde blomme in H. salicifolia nie. Verder was daar geen verskil tussen vrug produksie van die vyf bestuiwings behandelinge (naamlik: natuurlik, stuifmeel bygevoeg, self, hand self en hand kruis) en tussen genaturaliseerde en nie genaturaliseerde populasies. Ewenwel, stuifmeel beperking is gevind in nie-genaturaliseerde populasies wat egter ook minder besoeke ontvang het dan die genaturaliseerde populasies. Dus, reproduksie kan die verspreiding beperk maar is nie ʼn fundamentele versperring vir indringing van H. salicifolia nie. My konklusies is dat die reproduktiewe sukses, wat andersins ʼn sleutel versperring is vir indringing, in die bestudeerde Proteaceae nie beperk word deur outonomiese saad produksie of mutualismes in die geïntroduseerde gebied nie. In hierdie tesis beklemtoon ek die biogeografiese karakters, lewens geskiedenis kenmerke en ekologiese kenmerke as belangrike bepalers van indringing. Hierdie kenmerke is op hulle beurt weer afhanklik van die stadium van indringing. Karakters van die ontvangende omgewing is ook belangrike dryfvere van indringing. Hierdie studie verbeter hoe ons plant indringing in die algemeen verstaan, maar die patrone en prosesse van indringing wat beklemtoon word in hierdie tesis sal besonder bruikbaar wees vir huidige en toekomstige bestuur van uitheemse Proteaceae in Suid Afrika en op ander plekke, asook vir ander spesies wat aangepas is tot Mediterreense en nutriënt arm ekosisteme. Byvoorbeeld, die kombinasie van kenmerke van indringing en vatbare omgewings sal help om te identifiseer watter uitheemse spesies ʼn hoë risiko inhou om ʼn indringer te word (byvoorbeeld spesies met ʼn groot streek grootte en versperring spesies) en watter kondisies in die teiken area die waarskynlikste indringing fasiliteer of vererger (byvoorbeeld sterk klimaat ooreenstemming en hoë propaguul druk).

Thesis (Ph.D.)--University of Wollongong, 2007. / Typescript. Includes bibliographical references: p. 128-139.

Thesis (MScAgric)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.

The basic mineral nutritional requirements of Proteaceae are not well understood.They are generally assumed to require low levels of nutrients and be susceptible to nutrient (especially Phosphorus) toxicity.This project aimed to estimate the general nutritional requirements of Proteaceae for optimum growth, with special emphasis on the Phosphorus requirement. Potted plants were grown in soilless growth media with controlled release fertiliser and were watered according to need in a naturally lit greenhouse. The nutrient requirements of Proteaceae were found to vary among species but were not lower than the reported requirements for the Ericaceae, another heath family. The variables of growth media and plant development were found to be important factors affecting the critical Phosphorus concentration and need consideration in the derivation of the Phosphorus requirement of Banksia ericifolia. / Doctor of Philosophy (PhD)

Thesis (Ph.D.) -- University of Western Sydney, 2000. / "A thesis submitted in fulfilment of the requirement for the degree of Doctor of Philosophy, Horticulture, University of Western Sydney, Australia, December 2000" Bibliography : leaves 206-230.

Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: p. 262-287.