Thesis (Ph. D. of Philosophy)--University of Western Sydney, Hawkesbury, 1997. / "A thesis submitted in fulfilment of the requirement for the degree of Doctor of Philosophy." Includes bibliographical references (p. 183-205).

Thesis (Ph. D.)--University of Western Sydney, Hawkesbury, 1996. / Includes bibliographical references (p. 165-187).

Thesis (Ph.D.)--Flinders University, School of Biological Sciences. / Typescript bound. Includes bibliographical references. Also available online.

Thesis (Ph.D.) -- University of Western Sydney, 2008. / A thesis submitted to the University of Western Sydney, College of Health and Science, Centre for Plant and Food Science, in fulfilment of the requirements for the degree of Doctor of Philosophy. Includes bibliographical references.

With the increased usage and production of engineered nanoparticles (ENPs), entry into the environment and hence contact with plant root systems is inevitable. Nano zinc oxide (nZnO) is widely used in commercial products, such as sunscreens, paints and coatings due to its high antimicrobial properties and wide electrical band-gap. Disposal down drains and into greywater leads to particle entry into the environment via waste water systems. Here, ENPs could potentially interact with plant root systems, which may lead to uptake, translocation and accumulation within plant tissues, and in the case of edible crops have consequences on human health. This study aimed to identify mechanisms of toxicity by employing whole-cell biosensors in conjunction with model bacteria and plant species. Furthermore, zeta potential (ZP), particle size, reactive oxygen species (ROS) release and solubility of the particles were determined and linked to both plant and bacterial toxicity. In Escherichia coli bacteria, it was demonstrated that growth inhibition from nano-scale ZnO treatment was similar to that from the bulk-scale ZnO and ionic zinc treatments, with the concentrations leading to 50 % inhibition (IC50) demonstrated to be 251, 282 and 298 mg/L for bulk, nano-scale and ZnSO4, respectively. It was demonstrated that the mode of nZnO toxicity in E. coli was bacteriostatic rather than bacteriotoxic. In barley plants, biomass was negatively impacted by up to 50 %, and significantly more zinc was able to enter root tissues as a result of hydroponic nZnO treatment, with 47 mg/L zinc detected in root tissues after 7 days treatment with 500 mg/L nZnO. Comparison of particle characteristics revealed that ROS, solubility, ZP, size and concentration were involved in toxicity, with ZP (charge) identified as a key parameter in both plant and bacterial toxicity.

A Amazônia é tida como a região de maior biodiversidade do Planeta. No entanto, pouco se sabe a respeito da diversidade de ácaros plantícolas nesta região. Dentre estes ácaros estão espécies fitófagas, generalistas e predadoras. Este último grupo é de grande interesse, pois pode haver espécies promissoras para uso em programas de controle biológico de pragas. Já os fitófagos são indesejados devido ao dano que algumas espécies podem causar como é o caso do ácaro-branco Polyphagotarsonemus latus (Banks), o principal ácaro praga na região de Manaus, sobretudo em pimentão. Assim, o objetivo deste trabalho foi determinar a diversidade de ácaros associados às frutíferas nativas da região Amazônica e testar formas alternativas e sustentáveis para o controle do ácaro-branco em pimentão nesta região. Foram realizadas coletas no campus da Universidade Federal do Amazonas (UFAM), na fazenda Experimental da UFAM e no município de Anamã, Iranduba e Manacapurú. Os ácaros retirados de cada amostra foram montados, identificados e quantificados. Para o controle do ácaro-branco foram feitos testes com ácaros predadores nativos da região e com extratos aquoso de folha e inflorescência de Piper aduncum L. Foram coletadas 81 espécies de ácaros das famílias Tetranychidae, Tenuipalpidae, Tarsonemidae, Phytoseiidae e Ascidae. Nenhum dos predadores estudados mostrou-se eficiente para o controle do ácaro-branco, apresentando baixa sobrevivência e taxa de oviposição, quando alimentados com esta praga. Extratos aquosos a base de P. aduncum em altas cocentrações mostraram-se promissores para o controle de P. latus, sendo seletivo ao ácaro predador Amblyseius largoensis (Muma). / The Amazon region is considered the most biodiverse on the planet. In however, little is known about the diversity of plants mites in this region. Among these mites are phytophagous species, generalist and predators. This latter group is of great interest because there may be promising species for use in biological control programs of pests. Since the phytophagous are unwanted because of the damage that some species can cause as is the case of broad mite Polyphagotarsonemus latus (Banks), the main mite pest in the Manaus region, especially in pepper. Thus, the objective was to determine the diversity mites associated with fruit native to the Amazon region and test alternative and sustainable ways to control the mite in peppers in this region. Collections were made on the campus of Universidade Federal do Amazonas-UFAM (Federal University of Amazon), in the experimental farm of UFAM and at the municipality of Anamã, Iranduba and Manacapuru. Mites removed from each sample were mounted, identified and quantified. To the broad mite control, were tested native predatory mite and aqueous extracts of leaf and inflorescence of Piper aduncum L. We collected 81 species of mites of the families Tetranychidae, Tenuipalpidae, Tarsonemidae, Phytoseiidae and Ascidae. None of the predators studied was efficient to control the mite, with low survival and oviposition rate when fed with this pest. Aqueous extracts the basis of P. aduncum in high cocentrações proved promising for the control of P. latus, being selective to predatory mite Amblyseius largoensis (Muma).

A Amazônia é tida como a região de maior biodiversidade do Planeta. No entanto, pouco se sabe a respeito da diversidade de ácaros plantícolas nesta região. Dentre estes ácaros estão espécies fitófagas, generalistas e predadoras. Este último grupo é de grande interesse, pois pode haver espécies promissoras para uso em programas de controle biológico de pragas. Já os fitófagos são indesejados devido ao dano que algumas espécies podem causar como é o caso do ácaro-branco Polyphagotarsonemus latus (Banks), o principal ácaro praga na região de Manaus, sobretudo em pimentão. Assim, o objetivo deste trabalho foi determinar a diversidade de ácaros associados às frutíferas nativas da região Amazônica e testar formas alternativas e sustentáveis para o controle do ácaro-branco em pimentão nesta região. Foram realizadas coletas no campus da Universidade Federal do Amazonas (UFAM), na fazenda Experimental da UFAM e no município de Anamã, Iranduba e Manacapurú. Os ácaros retirados de cada amostra foram montados, identificados e quantificados. Para o controle do ácaro-branco foram feitos testes com ácaros predadores nativos da região e com extratos aquoso de folha e inflorescência de Piper aduncum L. Foram coletadas 81 espécies de ácaros das famílias Tetranychidae, Tenuipalpidae, Tarsonemidae, Phytoseiidae e Ascidae. Nenhum dos predadores estudados mostrou-se eficiente para o controle do ácaro-branco, apresentando baixa sobrevivência e taxa de oviposição, quando alimentados com esta praga. Extratos aquosos a base de P. aduncum em altas cocentrações mostraram-se promissores para o controle de P. latus, sendo seletivo ao ácaro predador Amblyseius largoensis (Muma). / The Amazon region is considered the most biodiverse on the planet. In however, little is known about the diversity of plants mites in this region. Among these mites are phytophagous species, generalist and predators. This latter group is of great interest because there may be promising species for use in biological control programs of pests. Since the phytophagous are unwanted because of the damage that some species can cause as is the case of broad mite Polyphagotarsonemus latus (Banks), the main mite pest in the Manaus region, especially in pepper. Thus, the objective was to determine the diversity mites associated with fruit native to the Amazon region and test alternative and sustainable ways to control the mite in peppers in this region. Collections were made on the campus of Universidade Federal do Amazonas-UFAM (Federal University of Amazon), in the experimental farm of UFAM and at the municipality of Anamã, Iranduba and Manacapuru. Mites removed from each sample were mounted, identified and quantified. To the broad mite control, were tested native predatory mite and aqueous extracts of leaf and inflorescence of Piper aduncum L. We collected 81 species of mites of the families Tetranychidae, Tenuipalpidae, Tarsonemidae, Phytoseiidae and Ascidae. None of the predators studied was efficient to control the mite, with low survival and oviposition rate when fed with this pest. Aqueous extracts the basis of P. aduncum in high cocentrações proved promising for the control of P. latus, being selective to predatory mite Amblyseius largoensis (Muma).

Soil salinity and the arid climate in Libya are major constraints in agriculture and predominantly in foodstuff production which are limiting wheat production and yield. The effect of pre-sowing seed treatments with 50 mM of KCl, NaCl, CaCl2, and distilled water as hydropriming on germination and early seedling growth in two wheat (Triticum aestivum L.) cultivars S-24 (tolerant) and Slambo (untested before) under 0, 100, 200 and 300 mM NaCl concentrations was examined. CaCl2 was the only priming treatment that significantly improved the germination percentage, germination rate, and mean germination time in both cultivars under almost all NaCl concentrations. Thus, priming with CaCl2 was selected for further experiments. In the greenhouse, seeds primed with 50 mM of CaCl2 also improved the emergence percentage, emergence rate, shoot and root length, and fresh and dry weight of shoots and roots of both cultivars under all NaCl concentration except at 300 mM where the emergence was completely inhibited. The response of wheat cultivars to three compost treatments including cow manure compost (CC), greenwaste compost (GC) and 50:50 mixture (mix) between them and sand at percentage inclusions of 10 and 30 % by weight under 0, 100, 200, and 300 mM of NaCl was also investigated. Among all compost treatments, 30% GC and 30% mix were the best treatment and improved almost all growth parameters under salt stress, and 30% GC was also the only treatment that had any emergence at 300 mM NaCl. 30% GC and 30% mix were selected for further experiments. The effect of the combination of the selected priming agent (CaCl2) and the best two compost treatments (30% GC and 30% mix) on the emergence and early seedling growth of both cultivars was tested. The results showed that all the treatments enhanced plant growth parameters including seedling ion uptake in both cultivars, with preference to primed seeds sown in 30% GC. The treatments had the following order of the performance of both cultivars under salt stress. Primed seeds sown in 30% GC > unprimed seeds sown in 30% GC > primed seeds sown in 30% mix > unprimed seeds sown in 30% mix. This enhancement is possibly due to the provision of Ca2+ and / or the improvement in the availability of water as both of them were improved by the application of priming and compost.