Добірка наукової літератури з теми "Proteaceae"

Cytological data for 188 species in 65 genera of Proteaceae were collated from the literature. Excluding the occasional infrageneric polyploid, Proteaceae have seven confirmed character states for chromosome number (n = 14, 13, 12, 11, 10, 7, 5). Genera of subfamily Persoonioideae are x = 7, and, on a cytoevolutionary doctrine of ‘paleo-polyploidy’ in angiosperm families, these low chromosome number taxa were hypothesised to represent the ancestral genome of Proteaceae. Chief supporting evidence for this hypothesis is the ancient origin of Persoonioideae in Proteaceae phylogeny. However all current genomes in Proteaceae have features that suggest that they are derived, including those of Persoonioideae with their ‘genomic obesity’, and by reference to the chromosomes of Bellendenoideae (n = 5) and the outgroup Platanaceae (n = 21), quite probably their number is also a derived character state. Furthermore the high chromosome number genera of Proteaceae in subfamilies Proteoideae and Grevilleoideae (n = 14, 13, 12, 11, 10) have genomic lengths that are far smaller than would be expected from a doubling of the chromosomes of Persoonioideae, and, so far as any information is available, these genera are also genetic diploids. This paper questions ‘paleo-polyploidy’ as a general cytogenetic mechanism for plant macroevolution at the levels of genus, tribe and sub-family in Proteaceae. It is proposed that diploid cytoevolutionary processes of chromosome number increase and decrease from a primitive genome of FN = 24, with specific examples of x = 12 and x = 21, can explain the cytological phenomena in the family.

The American Proteaceae are outliers from the main centres of diversity of the family in Australia and South Africa. There are about 83 species in eight genera which all belong to the monophyletic subfamily Grevilleoideae. Three genera, Embothrium, Oreocallis and Lomatia, are placed in the tribe Embothrieae (sensu Johnson and Briggs), four Euplassa, Gevuina, Panopsis and Roupala in the Macadamieae and the single genus Orites in the Oriteae. There are five genera endemic to America and three also have species in Australia and New Guinea (Gevuina, Lomatia and Orites). The Proteaceae appear to have arrived in South America via two routes. The larger genera Euplassa, Panopsis and Roupala, which are all endemic to America and have a general distribution in northern South America and south-eastern Brazil, are derived from Gondwanaland before it separated from South America. The remaining genera are distributed either in temperate South America or in the high Andes and appear to have arrived more recently via the Australia–Antarctica–South American connection. Three of these genera have species in both regions. The centres of species diversity of Euplassa, Panopsis and Roupala fall outside hypothesised forest refugia, indicating that they are not true rainforest species but species of seasonal habitats like those achieved at higher altitudes where they are commonly found. Two genera,Panopsis and Roupala, have reached Central America after the central American land bridge was formed six million years ago. The exact relationship to genera on other continents is still unclear and there is a need for a cladistic biogeographic analysis of the group based on both morphological and molecular data.

Abstract Over 650 Proteaceae occur in south-western Australia, contributing to the region’s exceptionally high biodiversity. Most Proteaceae occur exclusively on severely nutrient-impoverished, acidic soils (calcifuge), whilst only few also occur on young, calcareous soils (soil-indifferent), higher in calcium (Ca) and phosphorus (P). The calcifuge habit of Proteaceae is explained by Ca-enhanced P toxicity, putatively linked to the leaf cell-specific allocation of Ca and P. Separation of these elements is essential to avoid the deleterious precipitation of Ca-phosphate. We used quantitative X-ray microanalysis to determine leaf cell-specific nutrient concentrations of two calcifuge and two soil-indifferent Proteaceae grown in hydroponics at a range of Ca and P concentrations. Calcium enhanced the preferential allocation of P to palisade mesophyll (PM) cells under high P conditions, without a significant change in whole leaf [P]. Calcifuges showed a greater PM [P] compared with soil-indifferent species, corresponding to their greater sensitivity. This study advances our mechanistic understanding of Ca-enhanced P toxicity, supporting the proposed model, and demonstrating its role in the calcifuge distribution of Proteaceae. This furthers our understanding of nutrient interactions at the cellular level and highlights its importance to plant functioning.

Proteaceae pollen appeared in New Zealand during the Late Cretaceous and increased in diversity until the Early–mid Eocene. Diversity then decreased, reducing to the present two species in the Early Pleistocene. Proteaceae macrofossils extend back to the Early Paleocene. Twelve parataxa of Proteaceae dispersed cuticle are documented. These include two new parataxa of unknown affinity from the Paleocene, and nine new parataxa from the Miocene and one previously recorded from Western Australia. Three of these are identified as species of Helicia, Macadamia and Musgravea, one has affinities with Gevuininae–Hicksbeachia, and one with Tribe Embothrieae.

Dissertation (PhD (Agric))--University of Stellenbosch, 2002.
ENGLISH ABSTRACT: Fungi belonging to the genus Botryosphaeria are heterotrophic micromycetes that can be pathogens on woody plants. They cause serious, and in some cases devastating losses to crops through leaf necrosis, stem cankers and plant death. The Proteaceae cut-flower industry in South Africa accounts for 70% of the national cut-flower enterprise. Botryosphaeria diseases are a major impediment to production and trade of Proteaceae and there is an urgent need to investigate the etiology, epidemiology and control of these diseases. Losses of one of the most important proteas, P. magnifica, amount to 50% or more, locally. The main aims of this study were therefore to establish the etiology and aspects of epidemiology of Botryosphaeria stem cankers on P. magnifica and other Proteaceae, and to investigate methods of disease control. Although there is a vast body of information pertaining to this fungus, which was reviewed in Chapter 1, there is relatively little information available on Botryosphaeria on Proteaceae. The taxonomy of Botryosphaeria requires thorough review, and molecular techniques need to be employed to resolve species identities. In Chapter 2, it was found that Phyllachora proteae, a leaf pathogen of proteas, produced a Fusicoccum anamorph, which is described as F. proteae. A sphaeropsis-like synanamorph was associated with F. proteae and a new combination for P. proteae is proposed in Botryosphaeria, as B. proteae. The taxonomy of Botryosphaeria is in disarray at both the generic and the specific level. In Chapter 3 the taxonomic history of Botryosphaeria is reviewed, and the genus circumscribed and distinguished from other morphologically similar genera. Although several anamorph genera have been linked to Botryosphaeria, based on morphological observations and phylogenetic analysis of lTS rDNA sequence data, two anamorph genera are now recognised, those with pigmented conidia (Diplodia), and those with hyaline conidia (Fusicoccum). Botryosphaeria proteae should thus be excluded from Botryosphaeria. Several pathogenic Botryosphaeria spp. have an endophytic phase within their hosts. They are therefore imported unwittingly into other countries where they may pose a risk to agriculture and indigenous vegetation. The current global distribution of Botryosphaeria spp. associated with Proteaceae is clarified and a key to these taxa associated with Proteaceae is provided in Chapter 4. Five Botryosphaeria spp. are associated with cut-flower Proteaceae worldwide viz. B. lute a, B. obtusa, B. protearum, B. proteae and B. rib is. B. protearum is described as a new species. A thorough understanding of disease epidemiology is essential to effect a reduction of losses. In Chapter 5, I show that on P. magnifica, lesions caused by Botryosphaeria protearum, which lead to the formation of stem cankers, are initiated in the mid-rib vein or margin of leaves. Koch's postulates were satisfied and it was found that the number of lesions that developed from artificial inoculations correlated with starch levels present in leaves at the time of inoculation. In Chapter 6 it is shown that B. protearum exists as an endophyte in leaves of P. magnifica in naturally occurring as well as cultivated plants. In natural stands of proteas stem cankers are rare, but in cultivated plantations the incidence is high. Nutritional analyses indicate that higher levels of nitrogen occur in leaves of cultivated plants in spring, which could enhance disease development. High levels of sodium in the leaves of wild plants may restrict disease development. The severe economic losses caused by B. protearum make the search for improved methods of disease control essential. Fungicide applications form an important component of an integrated approach to disease management. In Chapter 7, in vitro tests demonstrate that tebuconazole, benomyl, prochloraz me, iprodione and fenarimol reduce the mycelial growth of B. protearum effectively. In the field there was a 25-85% reduction in the occurrence of stem cankers by applying fungicides or sanitation pruning. The best control was achieved by using benomyl, bitertanol, fenarimol, iprodione, prochloraz manganese chloride alternated with mancozeb and tebuconazole prophylactically. If sanitation pruning is combined with regular applications of fungicides, disease can be combated.
AFRIKAANSE OPSOMMING: Mikrofungi wat tot die genus Botryosphaeria behoort, is heterotrofiese organismes, wat patogenies op houtagtige plante kan wees. Hulle veroorsaak ernstige, en in sommige gevalle, verwoestende verliese, deur blaarnekrose, stamkankers en plantafsterwing. Die Proteaceae snyblom-industrie in Suid-Afrika maak 70% van die nasionale snyblomindustrie uit. Botryosphaeria siektes is 'n belangrike struikelblok in die produksie en handeldryf van Proteaceae, en daar is 'n ernstige behoefte om die etiologie, epidemiologie en beheer van siektes te ondersoek. Verliese van een van die belangrikste proteas, P. magnifica, beloop plaaslik 50% of meer. Die hoof doelstellings van hierdie studie was dus om die etiologie en epidemiologie van Botryosphaeria stamkankers op P. magnifica en ander Proteaceae vas te stel en metodes van siektebeheer te ondersoek. Hoewel daar 'n wye hoeveelheid inligting rakende die swam bestaan, wat in Hoofstuk I hersien is, is daar relatief min inligting oor Botryosphaeria op Proteaceae beskikbaar. Die taksonomie van Botryosphaeria benodig deeglike hersiening, en molekulêre tegnieke word benodig om spesie-identiteite op te klaar. In Hoofstuk 2 is gevind dat Phyllachora proteae, 'n blaarpatogeen van proteas, 'n Fusicoccum anamorf produseer, wat as F. proteae beskryf word. 'n Sphaeropsis-agtige synanamorf is met F. proteae geassosieer en 'n nuwe kombinasie vir P. proteae is as B. proteae in Botryosphaeria voorgestel. Die taksonomie van Botryosphaeria is, beide op die genus- as die spesievlak, in wanorde. In Hoofstuk 3 word die taksonomiese geskiedenis van Botryosphaeria hersien, en die genus word omskryf en van ander morfologies soortgelyke genera onderskei. Hoewel verskeie anamorf genera al met Botryosphaeria op grond van morfologiese waarnemings en filogenetiese analise van ITS rDNA volgorde data verbind is, word twee anamorf genera nou herken, dié met gepigmenteerde konidia (Diplodia), en dié met deurskynende konidia (Fusicoccum). Botryosphaeria proteae moet dus van Botryosphaeria uitgesluit word. Verskeie patogeniese Botryosphaeria spp. het 'n endofitiese fase in hul lewenssiklus. Hulle word dus onwetend in ander lande ingevoer waar hulle 'n gevaar vir landbou en inheemse plantegroei kan inhou. Die huidige wêreldverspreiding van Botryosphaeria spp. wat met Proteaceae geassosieer word is opgeklaar, en in Hoofstuk 4 word 'n sleutel tot die taksa wat met Proteaceae geassosieer word verskaf. Vyf Botryosphaeria spp. word met snyblom Proteaceae wêreldwyd geassosieer, naamlik B. lutea, B. protearum, B. proteae, B. ribis en B. obtusa. B. protearum word as 'n nuwe spesie beskryf. 'n Deeglike kennis van siekte-epidemiologie is noodsaaklik ten einde verliese te verminder. In Hoofstuk 5 dui ek aan dat letsels wat lei tot stamkankers, veroorsaak deur Botryosphaeria protearum op P. magnifica, in die hoofnerf of rant van blare ontstaan. Koch se postulate is uitgevoer en daar is vasgestel dat die aantal letsels wat vanuit kunsmatige inokulasies ontwikkel het korreleer met die styselvlakke teenwoordig in die blare ten tye van die inokulasie. In Hoofstuk 6 word getoon dat B. protearum as 'n endofiet in die blare van P. magnifica. In natuurlike standplase van proteas is stamkankers skaars, maar in verboude plantasies is die voorkoms hoog. Voedingsanalises dui aan dat hoër vlakke van stikstof in die blare van verboude plante in die lente voorkom, wat siekte-ontwikkeling moontlik kan bevorder. Hoë vlakke van natrium in die blare van natuurlike plante mag siekteontwikkeling beperk. Die ernstige ekonomiese verliese wat deur B. protearum veroorsaak word, maak die soektog na verbeterde metodes van siektebeheer noodsaaklik. Fungisiedtoedienings maak 'n belangrike deel uit van 'n geïntegreerde benadering tot siektebeheer. In Hoofstuk 7 dui in vitro toetse aan dat tebuconazole, benomyl, prochloraz me, iprodione en fenarimol die miseliumgroei van B. protearum effektief verminder. 'n Vermindering van 25-85% is aangetoon in die voorkoms van stamkankers in die veld, deur die toediening van fungisiedes en sanitasiesnoei. Die beste beheer is verkry deur die voorkomende toediening van benomyl, bitertanol, fenarimol, iprodione en prochloraz manganese chloride, afgewissel met mancozeb en tebuconazole, op plante in die veld. Indien sanitasiesnoei met gereelde toedienings van fungisiedes gekombineer word, kan die siekte bekamp word.

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.

Thesis (MSc)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: This thesis consists of four chapters that present research findings on Colletotrichum diseases associated with Proteaceae worldwide. The first chapter is a review of literature regarding the taxonomy and histology of Colletotrichum species associated with Proteaceae. The literature is not restricted to Proteaceae hosts, as information regarding Colletotrichum on Proteaceae is very limited. In chapter two, Colletotrichum spp. associated with proteaceous hosts growing in various parts of the world were identified based on morphology, sequence data of the internal transcribed spacer region (ITS-I, ITS-2), the 5.8S gene, and partial sequences of the B-tubulin gene. Four species of Colletotrichum were associated with Proteaceae. Colletotrichum gloeosporioides was isolated from Protea cynaroides cultivated in South Africa and Zimbabwe and from a Leucospermum sp. in Portugal, but is known to occur worldwide on numerous hosts. A recently described species, C. boninense, was associated with Zimbabwean and Australian Proteaceae, but also occurred on a Eucalyptus sp. in South Africa. This represents a major geographical and host extension for the species, and a description of the African strains is provided. Colletotrichum crassipes was represented by a single isolate obtained from a Dryandra plant in Madeira. Colletotrichum acutatum was isolated from Protea and Leucadendron in South Africa as well as from other proteaceous hosts occurring elsewhere. Colletotrichum acutatum f. sp. hakea was isolated from Hakea in South Africa. In chapter three, pathogenicity of these Colletotrichum species to certain proteas was established, relative aggressiveness of the different species tested and host response to them were compared as well as the effect that wounding had on host response. From the results obtained it is concluded that C. acutatum and C. gloeosporioides are the primary pathogens associated with Colletotrichum leaf necrosis, and C. acutatum is the main cause of anthracnose and stem necrosis of Proteaceae in South Africa. A histological study was performed in chapter four in response to the findings from the previous chapter. The behaviour of two C. acutatum isolates (one originating from Protea and the other from Hakea, C. acuataum f.sp. hakea) was studied on inoculated Protea leaf surfaces using light and scanning electron microscopy. Colletotrichum acutatum from Protea formed melanised appressoria on the leaf surface, whereas C. acutatum from Hakea formed very low numbers of both melanised and unmelanised appressoria. Most of the appressoria formed by C. acutatum from Protea were formed on the cell junctions and on the periclinal walls of the epidermal cells. From this study it is clear that C. acutatum f. sp. hakea is not a pathogen of Protea. Consequently the current use of this isolate as a biological control agent of Hakea in South Africa poses no threat to indigenous Protea species. Colletotrichum acutatum from Protea (although closely related to C. acutatum f. sp. hakea), is a pathogen of Protea, which was confirmed by histological observations. In conclusion, the present study has shown that several species of Colletotrichum are associated with diseased Proteaceae. These species differed in their pathogenicity and aggressiveness when inoculated onto certain protea cultivars. These differences could be partially explained by examining the behaviour of C. acutatum on the leaf surface. It is clear, however, that the distribution of the different species, their aggressrveness on different Proteaceae and their modes of infection needs to be investigated further. This work provides a basis for future research on the long-term effective management of these pathogens in fynbos production.
AFRIKAANSE OPSOMMING: Hierdie tesis bestaan uit vier hoofstukke wat handeloor navorsing van Colletotrichum siektes van Proteaceae wêreldwyd. Die eerste hoofstuk is 'n oorsig van literatuur rakende die taksonomie en histologie van die Colletotrichum spesies wat met Proteaceae geassosieer word. Die literatuur oorsig is nie beperk tot die Proteaceae nie aangesien baie min inligting rakende Colletotrichum op Proteaceae bestaan. In die tweede hoofstuk word die Colletotrichum spesies wat met proteas in verskeie dele van die wêreld geassosieer word, op grond van morfologie, DNS volgorde data van die interne getranskribeerde spasieerder area ("ITS-I, ITS-2"), die 5.8S geen, en gedeeltelike DNS volgordes van die B-tubulin geen geïdentifiseer. Vier Colletotrichum spesies is met die Proteaceae geassosieer. Colletotrichum gloeosporioides is geïsoleer vanaf Protea cynaroides wat in Suid-Afrika en Zimbabwe gekweek is en vanaf 'n Leucospermum sp. in Portugal, maar is bekend op verskeie gashere wêreldwyd. 'n Spesie wat onlangs beskryf is, C. boninense, is met Zimbabwiese en Australiaanse Proteaceae geassosieer, maar kom ook op 'n Eucalyptus sp. in Suid-Afrika voor. Dit is 'n groot uitbreiding van die geografiese voorkoms en gasheerreeks van hierdie spesie en 'n beskrywing van die Afrikaanse rasse word gegee. Colletotrichum crassipes is verteenwoordig deur 'n enkele isolaat wat vanaf 'n Dryandra plant in Madeira verkry is. Colletotrichum acutatum is vanaf Protea en Leucadendron in Suid-Afrika asook vanaf ander proteas wat elders voorkom, geïsoleer. Colletotrichum acutatum f. sp. hakea is vanaf Hakea in Suid-Afrika geïsoleer. In hoofstuk drie is die patogenisiteit van hierdie Colletotrichum spesies teenoor sekere proteas getoets, die relatiewe aggressiwiteit van die verskillende spesies is vergelyk, asook die gasheer se reaksie teenoor die spesies en die effek wat verwonding op die gasheer gehad het. Daar kan afgelei word vanaf die resultate dat C. acutatum en C. gloeosporioides die primêre patogene is wat met Colletotrichum blaarnekrose geassosieer word, en dat C. acutatum die hoof oorsaak is van antraknose en lootnekrose van Proteaceae in Suid-Afrika. 'n Histologiese studie is in hoofstuk vier uitgevoer in reaksie op die bevindings van die vorige hoofstuk. Die gedrag van twee C. acutatum isolate (een vanaf Protea en die ander vanaf Hakea, C. acutatum f.sp. hakea) op die oppervlaktes van geïnokuleerde Protea blare is bestudeer deur gebruik te maak van lig- en skandeer-elektronmikroskopie. Colletotrichum acutatum vanaf Protea vorm gemelaniseerde appressoria op die blaaroppervlak, terwyl C. acutatum vanaf Hakea klein hoeveelhede van beide gemelaniseerde en ongemelaniseerde appressoria vorm. Meeste van die appressoria wat deur C. acutatum vanaf Protea gevorm word, vorm op die aanhegtingspunte tussen selle en op die periklinale wande van die epidermale selle. Vanuit hierdie studie is dit duidelik dat C. acutatum f. sp. hakea nie 'n patogeen van Protea is nie. Gevolglik hou die huidige gebruik van hierdie isolaat as biologiese beheer agent van Hakea in Suid-Afrika geen gevaar in vir inheemse Protea spesies nie. Colletotrichum acutatum vanaf Protea (alhoewel dit naverwant is aan C. acutatum f. sp. hakea) is 'n patogeen van Protea en hierdie stelling is ook bevestig deur histologiese waarnemmgs. Ter samevatting het hierdie studie getoon dat verskeie Colletotrichum spesies geassosieer word met siektes van Proteaceae. Hierdie spesies het van mekaar verskil rakende patogenisiteit en aggressiwiteit nadat hulle op sekere protea kultivars geïnokuleer is. Hierdie verskille kon gedeeltelik verklaar word deur die gedrag van C. acutatum op die blaaroppervlaktes van verskillende protea kultivars. Dit is duidelik dat die verspreiding van die verskillende spesies, hulle aggressiwiteit op verskillende Proteaceae en hul infeksie metodes verder ondersoek moet word. Hierdie studie verskaf 'n basis vir toekomstige navorsing rakende lang-termyn effektiewe bestuur van hierdie patogene in fynbos aanplantings.

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, 2004.
ENGLISH ABSTRACT: The exomorphology and size of Leucadendron pollen was examined using a scanning electron and light microscope respectively. Pollen was found to have a consistent triangular shape with three apertures. Pollen grain size however, show difference between species, sections and subsections on Leucadendron. Pollen of all species examined had a woven appearance like the intertwined threads of a fabric with orbicules present on the surface of L. chamelaea, L. elimense subsp. elimense and L. galpinii. Pollen viability was successfully assessed using a solidified agar medium containing 2g agar and 109 sucrose. Pollen germination for all species was found to be above 55% viability. A diallellayout of crosses has demonstrated conclusively that fecundity differs when crossing between species of the genus Leucadendron. Artificial hand pollination was applied successfully on Leucadendron and showed repeatedly that seed set following intraspecific crosses between the male and female inflorescence of the same species gave the same high rate of seed set as found in nature. However, seed numbers declined sharply when crossing between species of the section 'Leucadendron'. Seed set following crosses between species of different sections or sub-sections was the lowest and in most cross combinations there was no seed harvested or no seed germination. The diallellayout was useful in identifying incompatible species and for locating possible incompatibility barriers to interspecific seed development. The morphology of the stigma was examined with a scanning electron microscope. Stigma appearance of all species had a consistent round to oval shape, except for L. rubrum, which had an elongated shape. Stigma surfaces of all species were densely covered with a large number of unicellular papilar cells on the swollen base. The aniline blue staining technique, together with the fluorescent microscope technique was used to follow the growth of the pollen tube following compatible and incompatible cross combinations. Pollen on the stigmas of compatible and incompatible species examined showed signs of germination. Pollen tubes grew between the papilla cells in all directions and only the most vigorous ones reached the upper part of the style. From the upper region of the style, yellow green tubes grew cohesively in the middle of the style towards the ovule. In compatible combinations a not more than 4 tubes reached the ovule region, but was difficult to observe when they entered the micropyle for fertilization. In incompatible species a large number of abnormalities occurred beyond the upper region of the style.
AFRIKAANSE OPSOMMING: Die morfologie en grootte van Leucadendron stuifmeel is deur middel van 'n skandeerelektron - en ligmikroskoop bestudeer. Baie klein verskille in stuifmeel morfologie het voorgekom. Diverse verskille in stuifmeelgrootte het wel voorgekom tussen spesies, groepe en subgroepe van Leucadendron. Stuifmeelvorm was deurgaans driehoekig en die oppervlakte van die stuifmeelkorrel het die voorkoms van geweefde vesels gehad. Klein, bolvormige struktuurtjies was teen verskillende digthede oor die stuifmeeloppervlak van L. chamelaea, L. elimense subsp. elimense en L. galpinii versprei. Stuifmeelkiemkragtigheid is bepaal deur dit op soliede agar medium te ontkiem en was deurgaans bo 55% kiemkragtig. Onderlings dialleliese kruisings van Leucadendron spesies het variasie in saad set getoon. Handbestuiwing is suksesvol uitgevoer en saadset in intraspesie kruisings hoog en soortgelyk aan natuurlike bestuiwing. Saadset en saad ontwikkeling het drasties verswak toe verder vewante spesies as ouers gebruik. As gevolg van hulondeurdringbare saadhuid is neutagtige sade gewoonlik moeiliker ontkiembaar. Die diallel uitleg was ook nuttig om verenigbare en onverenigbare kruisingskombinasies te identifiseer en om onverenigbaarheidskanse op te spoor. 'n Skandeerelektronmiskoop is gebruik om die morfologie van die stigma te bestudeer. Stigmas was deurgaans rond tot ovaalvormig, behalwe die van L. rubrum wat 'n verlengde voorkoms gehad het. Die stigma bestaan uit 'n groot aantal eensellige papilla, wat dig teen mekaar gepak is op 'n geswolle basis. Aniline-blou fluoresserende kleurstof en 'n fluoressensie mikroskoop is gebruik om die pad van die stuifmeelbuis in verenigbare en onverenigbare kruisingskombinasies in Leucadendron te volg. Stuifmeelontkieming het in alle kruisingskombinasies geskied. Stuifmeelbuise het in alle rigtings tussen die papilla gegroei en slegs die mees kiemkragtige stuifmeelbuise het die boonste deel van die styl bereik. In die styl het die buise dig teen mekaar gegroei en was dit moeilik telbaar. 'n Maksimum van vier buise het die vrugbeginsel bereik, maar dit was moeilik om verder te volg nadat hulle die poortjie bereik het. In onverenigbare kruisingskombinasies het stuifmeelbuise abnormale groeipatrone in die boonste gedeelte van die styl getoon.

The anatomy of leaves was described for 91 species In the Grevilleeae and 15 species in the Persooniinae. The anatomy of the stem-node-leaf continuum was described for 57 species in the Grevilleeae and 6 species in the Persooniinae. Anatomical features were discussed in the context of taxonomic relationships in genera and, briefly, at higher levels. In Hakea, anatomical data supported the groupings proposed by taxonomists. In Grevillea, recognised natural groups were supported and anatomical features were useful in demonstrating homologies in the leaves of some Groups. In Persoonia anatomy supported some proposed groupings but, in others, anatomical characteristics showed considerable diversity. The variability of character states, homologies and homoplasies and the suitability of anatomical data for cladistic analyses was considered. A preliminary cladistic analysis was made and discussed.

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).

Includes bibliographical references
Serotinous (canopy-stored seed) Proteaceae, Protea obtusifolia and Leucadendron meridianum occur on shallow, alkaline soils overlying limestone, and P.susannae and L.coniferum on adjacent, deep, weakly acidic sands, in fire-prone fynbos. Seed reciprocal transplants were used to test whether regeneration niche requirements were determinants of adult distributions. There were no germination niche differences, but limestone species showed greater seedling mortality on the transplanted colluvial sands than limestone. There were also greater relative growth rates of seedlings on their own soil than counterparts on transplanted soil.

South-western Australia is a globally significant hotspot of plant species diversity, with high endemism and many rare plant species. Proteaceae is a major component of the south-western flora, though little is known about how its diversity developed. This prompted the present study to investigate changes in the abundance and diversity of Proteaceae, in south-western Australia, by concurrently studying three sediment sequences of different ages over the Cainozoic and a modern pollen rain study. Modern pollen-vegetation relationships in the two Proteaceae species rich nodes of the northern and southern sandplains were quantified. It was found that Proteaceous genera can contribute up to 50% of the total pollen rain. Banksia/Dryandra pollen was the most abundant with Isopogon, Petrophile and Lambertia also commonly noted. The vegetation and environmental setting during three pivotal periods of the Cainozoic: Holocene, Pliocene and Eocene, were investigated. Eocene sediment from Lake Lefroy confirmed the presence of a Nothofagus dominated rainforest in the Middle to Late Eocene. At this time Proteaceae species were at least as diverse as today, if not more so, contributing up to a maximum of 42% of the total pollen rain. Taxa recorded included: Banksieaeidites arcuatus, Propylipollis biporus, Proteacidites confragosus, Proteacidites crassus, Proteacidites nasus and Proteacidites pachypolus. Several taxa remain undescribed and unnamed. This study also identified that Proteaceae pollen representation varies across small lateral distances. Thus as samples varied spatially and temporally, single core samples are not sufficient to identify spatial patterns in Proteaceae or other low pollen producing taxa. Some 7.91 cm of laminated Pliocene sediment from Yallalie, south-western Australia, was also examined. It covers 84 years of record and confirmed other regional reports that south-western Australia was covered by a rich vegetation mosaic consisting of heathy and wet rainforest elements. Although Proteaceae species were a consistent component of the pollen counts, diversity and abundance (maximum of 5%) was low throughout the studied section. Banksia/Dryandra types were most commonly noted. A 2 m core was retrieved from Two Mile Lake, near the Stirling Ranges and provided an early Holocene vegetation history. Geochemical and palynological evidence recorded little change, suggesting the environment of deposition was relatively uniform. Proteaceae species were noted throughout the core, though in low numbers, at a maximum of 3.5 % of the total pollen rain. Banksia/Dryandra was the most abundant while Isopogon, Lambertia, Petrophile and Franklandia were also noted. A regression model was developed through the modern pollen rain study to predict the number of Proteaceae in the vegetation. This was also applied to the fossil pollen records. The estimated number of Proteaceae species in the Eocene suggests a maximum of 20 and a minimum of 10 taxa. For the Pliocene record, an estimated 7 - 9 species was found and for the Holocene pollen, between 7 - 8 were present. Thus the Eocene was similar in Proteaceae diversity to today. The results from the Pliocene and Holocene suggest that Proteaceae diversity was lower than today. Findings of this research indicate that Proteaceae species are an important and consistent component of vegetation in south-western Australia over the Cainozoic. It is likely that both changing pollination mechanisms and changes in associated vegetation are important in the determining the dispersal of Proteaceaous pollen. By understanding how the vegetation has changed and developed in south-western Australia, present vegetation can be managed to include intra-specific variation and ensure the majority of species are conserved for present and future generations to enjoy.

An understanding of the role of genetic and ecological factors that influence demographic change is paramount for the conservation of plant populations. These genetic and ecological factors often act in concert to influence reproductive success and thus the ability of a species to maintain its presence in the community. Paramount among the array of factors influencing a species' fitness are mating system considerations and their interaction with ecological processes. Both mating systems and ecological processes are influenced by intrinsic and extrinsic forces that may operate synergistically to constrain pollen transfer, gametic union and the provisioning of progeny. Plants respond to these constraining forces, which typically vacillate, through mechanisms that minimise random effects while maximising the quality and quantity of progeny.Mating system values indicated that B. tricuspis is an obligate outbreeder. The extent to which populations of this Banksia indulged in mixed mating was associated with habitat disturbance and its impact on pollinators. A reduction in outcrossing in one disturbed population was ascribed to an increase in inbreeding promoted through pollinator/pollen limitation. Conversely, a reduction in the diversity of pollinator types which enhanced the opportunity for outbreeding was the favoured interpretation of elevated outcrossing in another disturbed population.Disparity in outcrossing among inflorescences was driven by pollinator/pollen limitation considerations. Inconsistency among outcrossing values between inflorescences was ascribed to incongruity in floral attractiveness and sympatric assortative pollinator/pollen limitations. Augmentation of the floral display, as inferred through greater inflorescence size and presentation height, was positively associated with maternal fecundity and progeny fitness. This advance in quality and ++
quantity was attained despite greater attractive displays increasing the probability of geitonogamous and consanguineous matings. This accomplishment indicated that attractiveness of the floral display in B. tricuspis enhanced the opportunity for sorting among possible mates, a proposition supported by the increased abandonment of zygotes with increasing display effort. The increases in maternal fecundity and progeny provisioning with increasing inflorescence size and height indicated that maternal resource considerations were not limiting reproductive success.Attractiveness of the floral display was also credited with the moderation of pollinator/pollen limitations within an inflorescence. The apparent increase in floral display with progress of the 'advancing front' towards the peduncle significantly altered pollinator foraging behaviour and differentially enhanced the opportunity for pollen receipt and export, especially of pollen types which promoted outbreeding. Commensurate with this moderation in pollinator/pollen limitation was an increase in maternal fecundity and progeny provisioning, although selection among zygotes was tempered and outbreeding declined slightly. The availability of nutritional resources within an inflorescence and sink strength relationships are submitted as proximate causes for this moderation, which conforms with the notion of mate choice and the proposition that the genetic threshold determining selection alternates with resource provisions.Scenarios propelled by selection among compatible mates which are commensurate with maternal resource considerations imply a high level of intrinsic control over reproductive success in B. tricuspis. Reproductive synchrony, continuity and predicability in fecundity and the compensatory repartitioning of resources following floral damage also signify a high level of intrinsic control. This control is ++
required to mitigate extrinsic proximate constraints which impinge on reproductive success thereby synchronising maternal investment with resources and maximising fitness. The randomness of pollination was advanced as the proximate constraint affecting reproductive success in this species. This constraint was mitigated firstly by a mating system which sorted among compatible mates and tolerated deleterious matings, and secondly through an decrease in the opportunity for deleterious matings afforded by increases in the attractiveness of the floral display.The production of 'surplus' flowers by B. tricuspis was proposed as the principal adaptive response to the forces constraining reproductive success. 'Surplus' flowers primarily served, at various levels of organisation with the species, to enhance attractiveness, thereby moderating the influence of pollinator/pollen limitations on plant fitness. Maternal fecundity and progeny fitness within and between inflorescences was augmented by increases in attractiveness while conversely, at the population level, decreases in attractiveness deleteriously impinged on fitness. 'Surplus' flowers also conferred other functional advantages in this species which operated synergistically with the enhancement to floral attractiveness. These advantages were primarily related to the opportunities that 'surplus' flowers conferred for selective abortion and bet hedging.Caution is required in attributing 'surplus' flowers primarily to the mitigation of pollinator/pollen limitation considerations as other forces may represent stronger selective process. While the attractiveness of the floral display undoubtedly increases fitness, it also inherently increases the opportunity for floral damage by birds and insects as the discrimination among displays by damaging agents was driven by attractiveness cues. The impact of floral herbivores ranged ++
from minimal for parrots and cockatoos to severe for insects, with the pattern of floral damage by both birds being determined by the pattern of insect floral herbivory. The predicability in floral damage between seasons and serial adjustment between successive reproductive development stages in B. tricuspis, as evident by compensatory responses in fecundity, moderates the influence of floral damage as a selective force influencing reproductive success.The production of 'surplus' flowers in B. tricuspis has facilitated the development of intrinsic maternal processes which, in reply to genetic and ecological stimuli, operate to maximise fitness through mitigating the deleterious impacts on reproductive success of floral damage and pollinator/pollen limitations. These maternal processes strategically maximise the utilisation of maternal resources and allow progeny with low fitness expectations to be tolerated. Ultimately, these maternal processes and deterministic genetic and ecological stimuli promote reproductive assurance which contributes to population and species persistence through advances in fitness.