84 pp. / First Edition Published, 2001 / The noxious weed problem in the western United States has been described as, a biological forest fire racing beyond control because no one wants to be fire boss. Indeed, when small weed infestations are left unchecked, they can grow exponentially and spread across the land much like a slow-moving biological wildfire. However, land consumed by fire usually recovers and is often more productive than before the fire occurred. On the other hand, land consumed by noxious weeds may be irreversibly changed and never again reach its full biological potential.

Pseudocercospora is currently separated from Cercospora largely on the basis of its unthickened scars. The principal aim of this study was to test the validity of this criterion by studying the ultrastructural characteristics of scars of cercosporoid fungi growing on Australian native plants. Transmission electron microscope studies demonstrated considerable variation in scar morphology among species of Pseudocercospora. Scars varied from substantially thickened (as in P. loranthi) to unthickened (as in P. correae), with intermediate types. The external deposit can be too thin to be usually visible under the light microscope, as in Pseudocercospora clematidis, P. hardenbergiae and the Pseudocercospora on Eucalyptus macrorhyncha. The description of Pseudocercospora needs to be modified to permit the inclusion of species with external scar thickening. Wall involvement in conidiophore and conidium ontogeny were also studied at the ultrastructural level for species of Pseudocercospora and Verrucisporota. Conidiophores were generally holoblastic, but enteroblastic ontogeny was observed in several conidiophores of P. correae and P. platylobii. Conidia were always holoblastic, and secession was schizolytic. Proliferation of the conidiogenous cell was variously enteroblastic sympodial, pseudopercurrent or holoblastic sympodial.

Thesis (M.Agr.Stud.) - University of Queensland, 2005. / Includes bibliography.

Indigenous Australians were also known to use plants for medicinal purposes. For thousands of years, Indigenous Australians have used native plants as a source of medicinal agents. Some tribes living in Central Australia still, to this day, prefer to use traditional medicines in favour of the more common and readily available western medicines. A number of plant species endemic to Australia are listed in various Aboriginal pharmacopoeias, with approximately one-third of those species belonging to two genera, Acacia and Eremophila. Of the 1100 recognised species of Acacia, approximately 900 occur in Australia. At least thirty of these species were utilised by the Indigenous Australians as a source of medicine. Extracts of 8 Acacia species were screened using four frontline bioassays. These were the brine shrimp lethality test, the crown gall tumour assays, the disc diffusion antibiotic assay and the seed germination test to determine if any of the species were biologically active. Of all the species screened, Acacia pruinocarpa showed the most promise. The species demonstrated significant activity at concentrations at low as 3.7ppm, which is well below the standard 400ppm exhibited by potassium dichromate (Sam, 1993). Acacia adsurgens and A. dictophleba were the next two promising species exhibiting activity at concentrations of 16.12ppm and 37ppm respectively. This was a trend that was also observed in the Lettuce seed germination test for allelopathy with these three species showing the most promise. Interestingly the potency of A. pruinocarpa extract decreased significantly when it was re- screened after being put through a polyamide column. It can therefore be suggested that as tannins are removed by the polyamide column, the biological activity exhibited by A. pruinocarpa is a result of the tannin content in the species (2%), although more testing is required. / Both A. pruinocarpa and A. adsurgens showed promise as anti-tumour activity when used in the Crown Gall Tumour Assay (CGTA). Acacia pruinocarpa and A. adsurgens both exhibited significant activity when compared to the control producing inhibition percentages of 31% and 37% respectively. Surprisingly, only one of the Acacia species tested inhibited pathogenic growth when tested on the common pathogens Staphylococcus aureus, Streptococcus pyogens and Candida albicans. Acacia bivenosa was the only species to exhibit any activity when tested on the pathogens. This activity, however is not considered to be significant, as the species was only active against one of pathogens tested, Staphylococcus aureus. In order to be considered to be significant, a species must be active against two or more pathogens. It is however, worthy of further evaluation. Acacia species are among the large number of plants that have long been regarded sources of biological activity. This study was guided by the indigenous use of Acacia species as sources of medicine, which led to the use of front-line bioassays. All of the species tested exhibited some form of biological activity. Acacia pruinocarpa demonstrated the most promise as a source of novel biologically active compounds exhibiting activity at very low concentrations. Such compounds have not been determined as it was outside the scope of this study to identify the active constituents of this species. However, it has been suggested that tannins are responsible for eliciting some of the activity observed in A. pruinocarpa. All of the species screened in this study are worthy of further evaluation. The bioassays used in this study are good examples of front-line bioassays. All of the tests used in the study fulfil the criterion, which defines a good test.

Experiments were conducted to evaluate the reproductive biology, cytology and phenology of the Australian everlasting daisy Rhodanthe anthemoides and related species. The principal objective was the development of new cultivars with novel bract colours and an assessment of intra-specific variation, mutation breeding and inter-specific hybridisation with R. diffusa, R. manglesii and R. chlorocephala subsp. rosea was carried out.R. anthemoides is a variable eastern state species and plants collected from the New England region of N.S.W have a chromosome number of 2n=22 as does R. diffusa. Other distinct morphological types of R.anthemoides, mostly from the Alpine regions of N.S.W, returned counts of 2n-22 indicating that this species is cytologically divergent and in need of botanical revision with the recognition of at least one new species.R. anthemoides is outbreeding and features a conspicuous involcure, protandry and long stigmatic papillae which aid in pollen presentation and favours insect pollination. The stigma in this species becomes receptive before it is fully exposed and remains receptive for at least 8 days. All of the above species are strongly self-compatible and in R. anthemoides the SI system functions by inhibiting pollen tube penetration of the stigma. (For complete abstract open document)

Thesis (Ph.D.) - University of Queensland, 2003. / Includes bibliography.

Thesis (M.Sc.(Crop Science) North-West University, Mafikeng Campus, 2011

3 pp. / Tips for Arizona's Rural Landowners Series -- Plants Unit / The Tips for Arizona's Rural Landowners Fact Sheet Series is intended to educate homeowners who have recently purchased small acreages in Arizona. The purpose of the series is to give homeowners information about living in rural settings. The Plant Unit includes fact sheets on Arizona's native plant law, small-scale gardening, pasture establishment, invasive plants, and assessing plant damage.

Thesis (M.Phil.)--University of Queensland, 2003. / Includes bibliography.

Orientador: Reinaldo José Fazzio Feres / Banca: Marineide Rosa Vieira / Banca: Gustavo Quevedo Romero / Resumo: Pouco se conhece a respeito da influência do tamanho (idade) da planta sobre a acarofauna. Durante a ontogenia de determinadas plantas nativas, a qualidade, quantidade e duração dos recursos disponíveis para a comunidade de ácaros podem se alterar. Plantas nativas, de diferentes idades, consorciadas ou nas vizinhanças de um monocultivo, podem favorecer o aumento da densidade de espécies-praga, ou então, de seus agentes controladores. O conhecimento básico em relação à ocorrência sazonal dos ácaros, em plantas de diferentes idades, também pode fornecer dados para elaboração de programas de manejo ecológico a serem implantados com sucesso no futuro. Este estudo teve como objetivo verificar se existe diferença na riqueza e densidade das espécies de ácaros associadas com plantas de Hymenaea martiana Hayne de diferentes tamanhos, bem como a ocorrência sazonal dessas espécies. Foram realizadas coletas quinzenais em 15 plantas de H. martiana, ordenadas por gradiente de altura e perímetro do tronco a 10 cm do solo, de um fragmento de Mata Estacional Semidecidual com transição para o Cerrado, durante o período de março de 2007 a março de 2008. Os ácaros foram coletados e montados em lâminas com meio de Hoyer. Foram registrados 116.910 ácaros pertencentes a 28 espécies de 24 gêneros e 13 famílias. A densidade de Chiapacheylus edentatus De Leon, Euseius cf. errabundus, Pronematus sp., Brevipalpus phoenicis (Geijskes) e Tarsonemus sp. aumentou com o aumento da altura da planta, e a de Aberoptus sp., Euseius sibelius (DeLeon), Typhlodromalus aripo De Leon e Phytoseius nahuatlensis De Leon diminuiu. O pico da densidade total foi registrado no período pré-desfolha, em todas as plantas. Isso ocorreu em abril nas plantas adultas e em julho nas jovens. A maior densidade de fitófagos foi registrada no período pré-desfolha em todas as plantas. Estes dados sugerem... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Little is known about the mite fauna on plants of different sizes (ages). During the ontogeny of certain native plants, the quality, amount and duration of resources available to the mite community can change. Native plants, of different ages, associated or in the surroundings of a monoculture, can favor the increase of mite pest densities or their controlling agents. The basic knowledge in relation to the seasonal occurrence of mites, in plants of different ages, can also provide data for elaboration of programs of ecological management to be implanted with success in the future. The aim of this study was to verify if there is any difference in the richness and density of mites on plants of Hymenaea martiana of different sizes, and the seasonal occurrence of the mite species. Samplings were performed every two weeks, in 15 plants of Hymenaea martiana, sorted by height gradient and perimeter of the trunk at 10 cm from the soil, of a fragment of Semidecidual Seasonal Forest with transition to Cerrado, from March of 2007 to March of 2008. The mites were mounted in microscopy slides using Hoyer's medium. There were registered 116,910 mites of 28 species, belonging to 13 families. The density of Chiapacheylus edentatus De Leon, Euseius cf. errabundus, Pronematus sp., Brevipalpus phoenicis (Geijskes) and Tarsonemus sp. increased with the increase of the plant height whereas the density of Aberoptus sp., Euseius sibelius (DeLeon), Typhlodromalus aripo De Leon and Phytoseius nahuatlensis De Leon decreased. In all plants the peaks of total and phytophagous densities were registered in the period previous to defoliation, which occurred in April in the adult plants and in July in the young plants. These data suggest these native areas can supply food and shelter for phytophagous mites and their natural enemies and that... (Complete abstract click electronic access below) / Mestre