The critically endangered Protea roupelliae ssp. hamiltonii persists as a single population (of 124 individuals in 2005) within the 26ha Dr Hamilton Reserve in Mpumalanga province, South Africa. Between 2000 and 2005, no recruitment had been observed. In order to aid the recovery of this species, aspects of its reproduction and conservation were studied, namely; (a) the relationship between the demographics and the reproductive capacity of the population, (b) the relationship between achene mass and germination, (c) methods of propagating the species ex-situ, (d) the ex-situ seed storage of the species and (e) methods of establishing seedlings in-situ (the reserve) in order to augment the small population. The reason for the decline of the species has been attributed to the reported high levels of herbivory before an antelope proof fence was erected. The survival and reproductive capacity of the species is sensitive to herbivory as browsing decreases canopy size and both achene production and germination were found to be significantly related to canopy size. The number of cones produced per plant (R2= 0.532; P<0.005), number of achenes filled with embryos (filled achenes) (R2=0.178; P=0.014), the mass of the achenes produced within a cone (R2=0.127; P=0.041) and the germination percentage of filled achenes (R2=0.200; P=0.009) increased with the plant canopy area. While the number of days for 50% of the achenes to germinate (T50) (R2=0.231; P=0.005), peak day of germination (R2=0.208; P=0.008) and mean days until germination (R2=0.270; P=0.002) decreased with plant canopy area. However, the percentage of filled achenes (seed set) did not increase with plant canopy area (R2=0.044; P=0.241). Each plant had a degree of autonomy in the mass of the achenes produced which was significantly different between plants (P<0.05). The mass of individual achenes from various plants was not related to the germination (rate or viability) of that achene. However, the germination percentage of filled achenes (R2=0.133; P=0.037), the peak value of germination (Czabator 1962) (P.V.) (R2=0.403; P<0.001), the T50 (R2=0.209; P=0.0074) and the mean number of days for achenes to germinate (R2=0.178; P=0.014) were all significantly related to the mean mass of the achenes produced within cones harvested from different plants. The achenes not filled with an embryo had a higher variation in mass and were significantly lighter than filled achenes (P<0.05). Mean seed set (n=33 cones) was 36.08±2.31% (±S.E) filled achenes per cone. By sorting achenes using a simple achene mass based selection method, a sample containing 93.67±1.46% filled achenes was selected per plant. Overall, the filled achenes had high germination percentages ranging from 57.67% to 97.00%, however, germination was sensitive to various pre-treatments. Soaking achenes in water for 48 hours before germination decreased the P.V. from 3.69 to 1.22 and germination percentage from 94.06% to 82.11% compared with un-soaked achenes. However, when embryos were excised from the seed coat after 48 hours soaking, both the P.V. and the germination percentage increased further to 6.03 and 97.00% respectively. Excised embryos did not germinate normally in-vitro when plated on various media but dedifferentiated into callus on all media tested (including growth regulator free media). The most effective regeneration via adventitious somatic embryogenesis (but not statistically significant) occurred on a growth regulator free medium (containing 2.21g.l-1 Murashige & Skoog (1962) salts with vitamins, 30.00g.l-1 sucrose and 3.00g.l-1 Gelrite® with a pH of 4.20) producing a mean of 4.66±1.09 (±S.E.) embryos per explant. Secondary somatic embryogenesis also occurred on a growth regulator free medium (containing 2.21g.l-1 Murashige & Skoog (1962) salts with vitamins, 30.00g.l-1 sucrose and 3.00g.l-1 Gelrite® with a pH of 5.20). The somatic embryos developed into plantlets (generally un-rooted) on media containing a high gibberellic acid to cytokinin ratio (3:1 by mass) and a growth regulator free medium (containing 2.21g.l-1 Murashige & Skoog (1962) salts with vitamins, 30.00g.l-1 sucrose and 3.00g.l-1 Gelrite® with a pH of 5.20). Limited success (5.77%) was achieved in rooting shoots (from somatic embryos) and transferring them to a greenhouse environment. Other vegetative propagation techniques were attempted, including the rooting of stem cuttings and direct shoot organogenesis but these were unsuccessful. As the achenes of Protea species are not long lived in-situ, the ex-situ conservation of achenes (and therefore the species) was tested. Achenes had low water contents (9.27±0.10%) and were therefore categorised as orthodox seeds (Roberts 1973). Germination percentages were high in all tested storage regimes (Ambient, 25°C, 4°C, -70°C and -196°C), including those at ultra-low storage temperatures and after 18 months ranged between 86.81% and 92.23%. Evidence of loss of germination vigour was found in achenes from the Ambient and 25°C storage regimes. After 12 months of storage, the quality of stored achenes under all storage regimes was thoroughly tested. Those achenes germinated successfully and produced seedlings that grew well under greenhouse conditions. Those seedlings were of high enough quality to be transplanted back into the Dr Hamilton Reserve, where growth and survival continued successfully. This showed convincingly that seed storage is an effective tool in the future ex-situ conservation of Protea roupelliae ssp. hamiltonii. Population augmentation was effective when planting achenes directly in-situ or transplanting ex-situ propagated seedlings in-situ (transplants), but varied between the two methods. Planted achenes had a low seedling emergence (less than an estimated 10% of planted, viable achenes emerged) and survival after one year was 76.41% and 69.81% after two years. However, 96.44% of the transplants survived after the first year and 95.37% after the second year. Additionally the leaf production rate of transplanted seedlings was superior to seedlings that originated from planted achenes. Through this project 1707 Protea roupelliae ssp. hamiltonii transplants have been planted into the Dr Hamilton Reserve. Although these individuals have not yet reached a reproductive size, the population numbers in-situ have increased considerably. Intensive intervention has worked in aiding the recovery of the Protea roupelliae ssp. hamiltonii population in-situ, however new threats to the population have been identified and still need to be mitigated. Key words: critically endangered species, propagation, reproductive output, population augmentation, seed storage.

Thesis (Ph.D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1998. / Bibliography: leaves 173-184.

Thesis (Ph.D.)--University of Western Australia, 2004.

Thesis (Ph. D.)--University of Western Australia, 2003. / Title from PDF title page (viewed on July 9, 2005). Includes bibliographical references (p. 193-213).

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 exotic blooms of the indigenous South African flowering plants and the biodiversity of the floral material available, have led to a high demand for these flowers on the international market. A wide variety of high-quality flowers, of which Protea cynaroides L. is an important component, are exported from South Africa. However, because of the high demand for the export market the producers are unable to supply enough plant material. Therefore, due to the limited supply, poorer quality flowers are exported which results in lower prices obtained. One of the reasons for the lack of flowers available for export is that being a woody perennial, P. cynaroides require a longer period of time to grow when conventional propagation methods are used. Micro propagation of P. cynaroides may become the most suitable alternative propagation method for rapid production and to ensure high standards of quality. In this study, Stage I (establishment) and Stage 2 (multiplication) of micro propagation were investigated. Establishment (Stage I) of the explants was achieved by using Murashige and Skoog medium with the addition of 30 mg.1-1 GA3. However, it was found that browning of the explant tissues caused by phenolic oxidation was a major problem during the establishment stage, as the browning of many explants led to the inability of the axillary buds to sprout which resulted in death. Browning of tissues occurs when phenolic compounds are oxidized, this usually happens when the plant tissues are stressed or injured during explant preparations. Therefore, methods to control oxidation were tested in an experiment which included the use of sterilants (mercuric chloride and sodium hypochlorite) and antioxidants (ascorbic and citric acid). The selection of a few treatments which showed potential in controlling oxidation, followed by further tests, led to positive results. Phenolic oxidation was reduced by stirring the explants in 100 mg.1-1 ascorbic acid and 1500 mg.1-1 citric acid for 1 hour. This was followed by growing the explants in a 16-hour photoperiod which was suitable for the axillary buds to sprout. Subsequently, Stage 2 of micropropagation (multiplication) was successfully done by subculturing the explants from the establishment stage onto the multiplication media. The effects of phosphorous on the growth of the explants were tested by using two media, where no ammonium phosphate was added into one medium, while 1400 mg.1-1 ammonia phosphate was added to the other. Surprising results were obtained when explants in both media grew well, illustrating that P. cynaroides may be tolerant to high levels of phosphorous. However, a possible reason for this is that because no roots were formed by the explants in the multiplication medium, the phosphorous in the medium were not taken up by the explants. These results also illustrated that two-budded explants achieved a higher survival rate and longer mean length than one-budded explants. Investigation into the rooting requirements of the explants, Stage 3 (rooting) of micropropagation must still be achieved. / Dissertation (M Inst Agrar (Horticultural Science))--University of Pretoria, 2006. / Plant Production and Soil Science / unrestricted

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. / xiv, 188, [7] leaves, [58] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / 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 15C. / Thesis (Ph.D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1998

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.

Thesis (Ph.D.)--University of Western Australia, 2006.