Submitted by (edna.saturno@ufrpe.br) on 2016-06-17T15:46:02Z No. of bitstreams: 1 Helton Soriano Bezerra de Oliveira.pdf: 608876 bytes, checksum: b11ad3adcdbf097206eeabe19459bed4 (MD5) / Made available in DSpace on 2016-06-17T15:46:02Z (GMT). No. of bitstreams: 1 Helton Soriano Bezerra de Oliveira.pdf: 608876 bytes, checksum: b11ad3adcdbf097206eeabe19459bed4 (MD5) Previous issue date: 2012-06-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Some laboratory studies had shown that microcystins exert allelopathic effects on organisms of the aquatic biota. However, the experimental designs rarely test concentrations found in natural environments (above 10 μg.L-1), which makes uncertain the action of microcystins as allelopathic compounds. Our study aimed to evaluate the effects of microcystins in concentrations usually found in natural conditions on the growth of strains of green microalgae (Monoraphidium convolutum and Scenedesmus acuminatus). For this purpose mixed cultures containing cyanobacteria and green algae were analyzed. Cultures of microalgae with the addition of crude extracts of cyanobacteria microcystin-producing and non-microcystin-producing were also performed. Two non-clonal axenic strains of cyanobacteria were used: Microcystis aeruginosa (microcystin-producing – MC+) and Microcystis panniformis (non-producer-producing – MC-). The experiments were conducted under controlled laboratory conditions (Erlenmeyers with a capacity of 1000 mL, with 600 mL of final volume of culture in BG11 medium at pH 7.4, temperature 24 ± 1 ° C, photoperiod 14h: 10h (light:dark), 40 μmol.m-2.s-1 light intensity). It was observed that in mixed cultures, both green microalgae and cyanobacteria had their growth reduced, which was observed when analyzing variations in specific growth rate. The microcystin production by M. aeruginosa (MC +) increased when it was in cultured together with M. convolutum. However when cultured with S. acuminatus the production did not change. The growth of green microalgae has not changed in treatments with addition of crude cell extracts of M. aeruginosa (MC +) containing 5μg.L-1 and 10μg.L-1 of total microcystins. Similarly, for the treatments with addition of crude cell extracts of M. panniformis (MC-) the growth of these green microalgae did not change. Our results do not support of the allelopathic function of microcystins, at least in the growth of these green microalgae. / Alguns estudos em laboratório mostram que as microcistinas exercem efeitos alelopáticos sobre organismos da biota aquática. No entanto, os desenhos experimentais testam concentrações dificilmente encontradas nos ambientes naturais (acima 10 μg.L-1), o que torna imprecisa a afirmação das microcistinas atuarem como compostos alelopáticos. Nosso estudo teve por objetivo avaliar os efeitos das microcistinas, em concentrações usualmente encontradas em condições naturais, sobre o crescimento de linhagens de microalgas verdes (Monoraphidium convolutum e Scenedesmus acuminatus). Para tanto foram realizados cultivos mistos, entre cianobactérias e microalgas verdes e cultivos dessas microalgas verdes com adição de extratos brutos de cianobactérias produtoras e não-produtoras de microcistinas. Foram utilizadas duas linhagens clonais não-axênicas de cianobactérias: Microcystis aeruginosa (produtora de microcistinas – MC+) e Microcystis panniformis (não-produtora – MC-). Os experimentos foram desenvolvidos sob condições controladas em laboratório (erlenmeyers com capacidade 1000 mL, com 600 mL de volume final de cultura, em meio BG11, pH 7,4 temperatura 24 ± 1°C, 14h:10h fotoperíodo (claro:escura), 40μmol.m-2.s-1 de intensidade luminosa). Foi observado que em cultivos mistos, tanto as microalgas verdes quanto as cianobactérias apresentam redução de crescimento atribuída a alterações na taxa de crescimento específico. M. aeruginosa (MC+) teve a produção de microcistinas elevada no cultivo com M. convolutum, no entanto, com S. acuminatus a produção não foi alterada. O crescimento das microalgas verdes não foi alterado nos tratamentos com adição de extrato brutos de células de M. aeruginosa (MC+) contendo 5μg.L-1 e 10μg.L-1 de microcistinas totais. Igualmente, para os tratamentos com extratos de M. panniformis (MC-) o crescimento dessas microalgas verdes não foi alterado. Os nossos resultados não suportam a função alelopática das microcistinas, pelo menos sobre o crescimento dessas microalgas verdes.

Orientador: Ricardo Ribeiro Rodrigues / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T15:03:54Z (GMT). No. of bitstreams: 1 Souza_FlavianaMalufde_D.pdf: 1240667 bytes, checksum: 7ce64c73162dd8df01a650e6144d90aa (MD5) Previous issue date: 2007 / Resumo: As interações das árvores do dossel com as plantas que se estabelecem sob suas copas e suas conseqüências na organização da comunidade são pouco conhecidas para as florestas tropicais. Neste trabalho, investigamos como a deciduidade e a síndrome de dispersão das árvores do dossel podem influenciar a estrutura e riqueza da comunidade arbustivo-arbórea do subosque em um remanescente de Floresta Estacional Semidecidual, localizado na Estação Ecológica dos Caetetus, Gália - SP. Em uma parcela permanente 10,24 há amostramos todas as árvores do dossel (dossel e emergentes) e os indivíduos com diâmetro à altura do peito '> ou =' 4,8com situados sob suas copas. As espécies decíduas apresentaram maior abundância relativa e maior proporção de espécies secundárias iniciais sob suas copas do que as espécies perenifólias. Dentre os grupos de dispersão das árvores do dossel, as espécies autocóricas apresentaram maior abundância relativa de indivíduos coespecificos sob suas copas, enquanto as espécies anemocóricas e zoocóricas não diferiram entre si. A abundância relativa de indivíduos zoocóricos embaixo das copas não diferiu entre os grupos de dispersão, mas a riqueza de espécies zoocóricas foi maior sob as espécies zoocóricas do dossel. Esses resultados indicam que a deciduidade pode favorecer a sobrevivência e ao crescimento das espécies mais exigentes em relação à luz como secundárias iniciais, provavelmente em decorrência do aumento na quantidade e na qualidade da luz que chega ao subosque ...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: In tropical Forest, the consequence of interactions between canopy and understory plants to the community organization are poorly understood. We insvestigated how deciduousness and dispersal syndromes of canopy tree species could influence the community structure and species richness in a Seasonal Semideciduous Forest located at Caetetus Ecological Station Reserve, in central-western São Paulo state, Brazil. In a 10,24 ha permanent plot, we sampled all overstory trees (canopy and emergent trees) and the trees with dameter at breaster height '> ou =' 4,8 cm under their crowns (understory trees). Deciduos canopy trees showed higher relative abundance and proportion of early secondary species under their crowns than evergreen trees. Autochorous canopy trees presented higher relative abundance of cosnpecific individuals under their crowns, while there was no difference between wind and animal-dispersed canopy trees. The relative abundance of animal-dispersed trees in the understory did not differ among dispersal guilds, but estimated zoochorous species richness was higher under zoochorus canopy trees. The results suggest that the deciduousness of canopy trees may facilitate the survival and establishment of species with higher requeriments, most possibly by providing an increase in the amount and quality of the light that reaches the understory when canopy trees are leafless ...Note: The complete abstract is available with the full electronic digital thesis or dissertations / Doutorado / Doutor em Biologia Vegetal

Submitted by Neusa Fagundes (neusa.fagundes@unioeste.br) on 2018-07-10T19:03:49Z No. of bitstreams: 2 Erly_Porto2018.pdf: 629278 bytes, checksum: 0e4cf8a84230328bfeaab2b5e568a733 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-07-10T19:03:49Z (GMT). No. of bitstreams: 2 Erly_Porto2018.pdf: 629278 bytes, checksum: 0e4cf8a84230328bfeaab2b5e568a733 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Plant species can interact with each other through the production and release of chemical compounds released into the environment, such an event is known as allelopathy. The objective of the present study was to investigate the allelopathic action and oxidative stress of the aqueous extract of Bauhinia forficata L. on seeds during the germination process and seedlings during the Phaseolus vulgaris development phase. The germination behavior, allelopathic activity index, initial growth and activity of antioxidant enzymes were studied at different times of seed imbibition, in the cotyledon (reserve tissue) and in the embryonic axis and seedlings, for aerial part and root target species. The results indicated that during the germination phase there was negative interference of B. forficata extracts on the seeds for germination, speed index and mean germination time, as well as the allelopathic activity index. In relation to the enzymatic activity, a high enzyme activity was observed at the beginning of seed imbibition, between 3 and 6 hours for the cotyledon and high activity in the embryonic axis at the end of the germination process, between 12 and 24 hours of imbibition. The increase of the extract proportions of the leaves of B. forficata affected the enzymatic activities in the germination process of the bean seeds, resulting in a delay of the germination. As for the development phase, there was reduction of the average length and dry mass of the root as the proportion of extract used increased. the levels of lipid peroxidation for both shoot and root were high, as well as the activity of the catalase enzyme for the roots was also elevated when submitted to the treatments with the presence of the extract. Thus, the increase in the proportion of B. forficata extract negatively affected the initial development, being the primary root elongation more sensitive, causing severe damage to the membranes of the bean seedlings roots. / As espécies vegetais podem interagir entre si por meio da produção e liberação de compostos químicos liberados no ambiente, tal evento é conhecido como alelopatia. Desta forma, o objetivo do presente estudo foi investigar a ação alelopática e o estresse oxidativo do extrato aquoso de Bauhinia forficata L. sobre sementes de Phaseolus vulgaris, durante o processo de germinação e desenvolvimento das plântulas. Para isso, foram avaliados o comportamento germinativo, o índice de atividade alelopática, o crescimento inicial e a atividade de enzimas antioxidantes em diferentes tempos de embebição das sementes, no cotilédone (tecido de reserva) e no eixo embrionário e plântulas, para a parte aérea e raiz da espécie alvo. Os resultados indicaram que durante a fase de germinação houve interferência negativa dos extratos de B. forficata sobre as sementes para as variáveis: germinação, índice de velocidade e tempo médio de germinação, como também para o índice de atividade alelopática. Em relação a atividade enzimática, foi verificado uma alta atividade das enzimas no início da embebição das sementes, entre 3 e 6 horas para o cotilédone e elevada atividade no eixo embrionário ao final do processo germinativo, entre 12 e 24 horas de embebição. O aumento das proporções de extrato das folhas de B. forficata afetaram as atividades enzimáticas no processo germinativo das sementes de feijão resultando um atraso da germinação. Já para a fase de desenvolvimento, houve redução do comprimento médio e massa seca da raiz conforme o aumento das proporções de extrato utilizados. Os níveis de peroxidação lipídica tanto para parte aérea e raiz foram elevados, assim como a atividade da enzima catalase para as raízes também foi elevado quando submetidos aos tratamentos com a presença do extrato. Desta forma, o aumento das proporções de extrato de B. forficata L. afetou negativamente o desenvolvimento inicial, sendo o alongamento da raiz primaria mais sensível, provocando danos acentuados as membranas das raízes de plântulas de feijão.

A agricultura moderna exige que as operações de manejo das plantas daninhas sejam economicamente viáveis, e principalmente seguras em termos de minimização da contaminação ambiental. A preocupação sobre a utilização intensiva de herbicidas sintéticos tem sido debatida constantemente, de tal forma que pesquisas têm sido desenvolvidas estrategicamente para a descoberta de novas moléculas herbicidas, baseadas em produtos naturais, para aplicação direta como agente de controle ou utilização indireta como aleloquímico. O solo é habitado por uma grande variedade de microrganismos, sendo que a maioria deles não foi estudada e identificada até o momento, conseqüentemente muitas pesquisas ainda podem ser desenvolvidas com o objetivo de explorar metabólitos secundários produzidos por estes microrganismos. Sendo assim, foi desenvolvida a presente pesquisa com o objetivo de testar e desenvolver uma fase inicial na seleção e descoberta de microrganismos do solo (actinomicetos) com potencial de produção de compostos fitoinibitórios. O método geral de seleção constituiu-se na coleta de amostras de solo de 0-20 cm de profundidade, a partir de áreas com diferentes sistemas de manejo e/ou vegetação. Estas amostras de solo foram então submetidas ao isolamento de actinomicetos (10 g de solo de cada amostra) através da diluição em série e plaqueamento em meio seletivo. Foram isoladas e cultivadas em meio líquido glicerina-caseína 103 colônias, sendo que, a solução de metabólitos acelular foi obtida por centrifugação e filtragem. A partir das soluções contendo os metabólitos foi conduzido um teste de germinação (screening primário) através de bioensaios de laboratório, utilizando como plantas teste pepino (Cucumis sativa) e sorgo (Sorghum bicolor). Com o objetivo de verificar a concentração do meio de cultura que exerceria o mínimo de efeito na germinação e crescimento/desenvolvimento das plântulas, foi realizado um teste de germinação com o meio de cultura sem os metabólitos microbiológicos, sendo avaliado através de análise de regressão dos resultados obtidos. O screening secundário foi realizado em condições de câmara-de-crescimento e consistiu na aplicação do meio de cultura acelular em condições de pré e pós-emergência das plantas de pepino e sorgo. Os screenings primário e secundário resultaram na seleção de sete microrganismos produtores de composto fitoinibitórios, estes utilizados para condução do experimento em condições de casa-de-vegetação, sendo aplicadas as soluções de metabólitos em condições de pré e pós-emergência das plantas de pepino, sorgo, picão-preto (Bidens pilosa) e capim colchão (Digitaria ciliaris). A conclusão principal desta pesquisa foi de que o método para seleção de isolados de actinomicetos, com potencial de produção de fitotoxicinas é adequado, e pode ser utilizado em um programa de descoberta de novos compostos com potencial herbicida, no entanto, os resultados obtidos não permitiram isolar actinomicetos com suficiente potencial fitoinibitório, para ser utilizado de forma direta em um programa de manejo de plantas daninhas na agricultura. / The modern agriculture requires that the weed management practices are economically feasible, and mainly safe for the minimization of the environmental contamination. The concern on the intensive use of synthetic herbicides has been debated constantly, in such way that researches have been developed strategically for the discovery of new herbicides molecules, based on natural products, either for direct application as control agent, or for indirect use as allelochemical. The soil is colonized by a great variety of microorganisms, however most of them were not studied and identified at the moment, consequently many researches still can be done, with the objective of exploring secondary metabolites produced by these microorganisms. Therefore, it was developed this research with the objective of testing and developing a initial process in the selection and discovery of soil microorganisms (actinomycetes) with potential of producing phytoinhibitory compounds. The general method used in the research consisted of soil sampling at 0-20 cm depth, from areas that had been cultivated with different cropping systems and/or vegetation. These soil samples were submitted to actinomycets isolation (10 g of soil per sample) through series dilution in selective medium. It was isolated and cultivated in liquid casein-glycerin medium 103 colonies, being the no cellular metabolite solution obtained by centrifugation and filtration. From the solutions containing the metabolites it was conducted a germination test (primary screening) through a laboratory bioassay with test plants of cucumber (Cucumis sativus) and sorghum (Sorghum bicolor). Objectifying to verify each of the cultivation medium concentrations that would cause the minimum effect on germination and growth/development of seedlings, it was also conducted a germination test with medium without the microbial metabolites, being evaluated through regression analysis results. The secondary screening was done in the growth chamber conditions, and consisted of application of no cellular medium in pre and post emergence conditions of the plants of sorghum and cucumber. The primary and secondary screening resulted in the selection of seven microorganisms producers of phytoinhibitory compounds, these used to conduct an experiment in the greenhouse, being sprayed the metabolic solutions in pre and post emergence conditions of cucumber, sorghum, Bidens pilosa and Digitaria ciliaris. The main conclusion of the research was that the method used for actinomycets selection and isolation, with potential of phytotoxins production is adequate and can be used in a new compounds discovery program with potential herbicide effects; however the results obtained did not allow isolating actinomycets with enough phytoinhibitory potential to be directly used in a program of weed management in agriculture.

Les interactions allélopathiques sont définies comme la libération par un organisme de composés chimiques inhibant les compétiteurs. Dans les milieux aquatiques, elles sont reconnues comme un facteur de la dynamique des communautés de phytoplancton. Malgré les conditions favorables créées par l'organisation des microorganismes en biofilms, l'allélopathie a été beaucoup moins étudiée dans les communautés de microorganismes phototrophes benthiques. L'objectif de cette thèse était d'étudier des interactions allélopathiques, au travers d'un cas particulier, entre les microorganismes dans les biofilms phototrophes d'eau douce. Ainsi le travail s'est focalisé sur les effets allélopathiques d'une algue verte filamenteuse, Uronema confervicolum Lagerheim, sur des diatomées benthiques. L'hypothèse principale est que, dans certaines conditions, U. confervicolum libère suffisamment de composés allélopathiques pour inhiber significativement le développement des diatomées épiphytes. Cette hypothèse soulève trois questions (i) quels sont les composés allélopathiques, (ii) leur production dépend-elle des conditions environnementales et (iii) quel est l'effet des composés allélopathiques produits sur les diatomées ? Cette interaction a été étudiée au travers de multiples approches. L'activité d'extraits de biomasse algale et de filtrat de culture a été testée sur la croissance, la photosynthèse, l'adhésion et la motilité des diatomées. Les techniques de fractionnement guidé par bioessais et de profilage métabolomique ont été utilisées pour identifier les composés allélopathiques produits. Les effets des facteurs environnementaux (limitations en nutriment, apports de lumière et de gaz) et de la phase de croissance sur la production et la libération de différents composés allélopathiques ont également été étudiés. Une étude approfondie de l'effet sur les diatomées des composés allélopathiques anti-adhésion a été réalisée en combinant le profilage métabolomique, la transcriptomique et la microscopie électronique à balayage. Les extraits d'U. confervicolum ont montré un effet négatif sur la croissance, la photosynthèse, l'adhésion et la motilité des diatomées. Deux acides gras polyinsaturés (acides linoléique et a-linolénique) ont été identifiés comme des composés allélopathiques inhibant la croissance et la photosynthèse des diatomées. L'inhibition de l'adhésion des diatomées est, par contre, causée par d'autres composés allélopathiques non identifiés. L'augmentation de l'intensité lumineuse a accru la production de composés allélopathiques, à l'instar des composés défensifs des plantes. Cependant, aucune des théories classiques sur les défenses chimiques des plantes n'a permis d'expliquer l'ensemble des résultats obtenus sur les questions de régulation. En plus de l'inhibition de l'adhésion, le filtrat d'U. confervicolum inhibe la formation de la matrice constituée de substances polymériques extracellulaires, impacte le métabolisme énergétique et induit une modification globale du transcriptome et du métabolome des diatomées. Une partie des gènes et métabolites les plus fortement impliqués dans la réponse des diatomées à l'inhibition de l'adhésion ont été identifiés. Ce travail a permis de mieux évaluer l'activité allélopathique de l'algue verte filamenteuse U. confervicolum et son impact potentiel sur la structure et le fonctionnement des biofilms phototrophes. D'autres approches seront nécessaires, à l'avenir, pour mieux comprendre le rôle global de l'allélopathie dans des biofilms phototrophes complexes. / Allelopathic interactions are defined as the release, by an organism, of chemicals that inhibit competitors. In aquatic environments, they are recognised as a driver of phytoplankton community dynamics. Despite the favourable conditions created by the organisation of microorganisms in biofilms, allelopathy has been much less studied in benthic phototrophic microorganism communities. The objective of this thesis was to increase our comprehension of allelopathic interactions amongst phototrophic microorganisms in biofilms by analysing several aspects of a specific allelopathic interaction. The model chosen was the allelopathic effect of Uronema confervicolum Lagerheim, a filamentous green alga isolated from river biofilms, on diatoms from the same environment. The main hypothesis was that, at least in specific environmental conditions, U. confervicolum produce and release sufficiently large amounts of allelopathic compounds to inhibit significantly the development of epiphytic diatoms. Three questions arised from this hypothesis: (i) what are the allelopathic compounds implied, (ii) do their production and release depend on environmental factors and (iii) what is the effect of these compounds on epiphytic diatoms? This interaction has been studied using multiple approaches. Activity of algal biomass extracts and culture filtrates have been tested on diatom growth, photosynthesis, adhesion and motility. Bioassay-guided fractionation and metabolomic profiling have been used to identify the allelopathic compounds produced. The effect of environmental factors (nutrient limitation, light and gas supply) and growth phase on the production and release of the different allelopathic compounds have also been studied. In-depth study of the effect of anti-adhesion allelochemicals on diatom by combining metabolomic profiling, transcriptomics and scanning electron microscopy have been carried out. The extracts of U. confervicolum exhibited negative effects on diatoms growth, photosynthesis, adhesion and motility in bioassays. Two polyunsaturated fatty acids (linoleic and a-linolenic acids) have been identified as allelopathic compounds affecting growth and photosynthesis but not adhesion ability of diatoms. The inhibition of diatom adhesion was caused by other allelopathic compounds, unidentified so far. Increasing light intensity enhanced the production of U. confervicolum allelopathic compounds as predicted by plant defence theories, but the regulation of allelopathic activity was not completely explainable by any classic plant defence theory. Finally, beside an inhibition of diatom adhesion U. confervicolum filtrate was also found to inhibit the formation of diatom extracellular polymeric substances matrix, affect energy metabolism and induce global modification of diatom transcriptome and metabolome. Some of the genes and metabolites implied in the response of diatoms to adhesion inhibition have been identified. These results indicate the strong potential of the filamentous green alga U. confervicolum to impact biofilm community by its allelopathic activity. Results on the allelopathic activity of this alga and the effect on diatoms in laboratory experiments provide the basis for further experiments to access the role of allelopathy in complex biofilms. These findings will encourage researchers working on biofilms to consider allelopathy when phototrophic biofilm ecology is studied.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21831号 / 農博第2344号 / 新制||農||1068(附属図書館) / 学位論文||H31||N5203(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 平井 伸博, 准教授 赤松 美紀, 教授 縄田 栄治 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Water cost is one of the key deterrents in making algal biofuels a feasible alternative to traditional petroleum fuels. Research into recycling of algal media was conducted in a laboratory setting at the California Polytechnic State University in San Luis Obispo. A growth assay was created to allow for algal cultures, specifically Ward’s Chlorella sp., to proliferate in sealed culture vessels. Bold’s Basal Medium (BBM) was selected as the media due to its extensive use with freshwater algal strains. However, this medium can limit algal growth through nutrient limitation and it became necessary to augment the original recipe. 50mM of sodium bicarbonate was added to the media in order to buffer the purging of 100% CO2 into the culture vessel. The resultant pH of the CO2 saturated media was 6.25. The elemental? composition of Chlorella vulgaris was compared with the nutrient content of BBM to estimate possible nutrient limitations which could occur throughout growth (Oh Hama, 1988). From this analysis, the nitrogen and phosphorus concentration in BBM was augmented by a factor of three (BBM3N3P). Further, vitamins, specifically cyanocobalamin, thiamine HCL, and biotin, were incorporated after conducting a comparison growth study with BBM 3N3P. The average maximum specific growth rates for the normal BBM and for the vitamin-enhanced BBM were 0.689 +/- 0.0818 and 0.887 +/- 0.1901 (mean +/- std. deviation) per day, respectively. This difference was proved significant by a t-test with a p-value equal to 0.041. A standardized methodology for conducting a regrowth potential experiment was outlined by the research. One phase of this methodology included reintroduction of nutrients consumed during the first round of growth. Prior to continuing with this methodology the effect of supplementing trace metals and micronutrients into the culture was investigated. At a p-value of 0.0956, there was no significant difference between BBM 3N3P + vitamins and the same media with eight times the trace metal and micronutrient concentration. This allowed for up to seven rounds of regrowth with no inhibition caused from the restoration of these nutrients. A final regrowth was conducted on BBM 3N3P + vitamins + 50 mM bicarbonate. A significant difference existed between both the Round 1 and Round 2 cultures, as well as between the Round 2 cultures and their respective controls. This signified the possible release of allelochemicals by the Chlorella sp.. A preliminary investigation into the possible use of anaerobic digester effluent as a primary source of nutrients for algal cultures was also conducted. The digestate (diluted 50% v/v with a saline make-up) grew significantly faster than the controls (p-value<0.001). Further, after the introduction of trace metals and micronutrients the digestate columns outlived the control columns increasing the feasibility of using digestate to supplemental algal cultures.

<p>Juglone is a 1,4-naphthoquinone (1,4-NQ) and the allelochemical responsible for the well-known toxic effects of black walnut (<i>Juglans nigra</i>)<i> </i>and other members of the Juglandaceae. Juglone affects a variety of weed species via a mode of action unlike any commercially available herbicides, and thus has the potential to be used as a new natural product-based herbicide. However, lack of knowledge about its metabolism precludes introducing juglone biosynthesis traits into resistant crops through biotechnology. Herein, we established that juglone is derived from the phylloquinone pathway at the level of the intermediate 1,4-dihydroxy-2-naphthoic acid (DHNA). Phylloquinone is a primary 1,4-NQ made by all plants for photosynthetic electron transport. Despite the fundamental importance of phylloquinone, there are still unanswered questions about the subcellular architecture of the phylloquinone pathway. In chapter 3, we show that <i>o</i>-succinylbenzoate CoA-ligase is localized to both chloroplasts and peroxisomes and that its activity is vital in both organelles. The required dual localization of CoA ligase activity is a theme common to other plant pathways with CoA metabolic steps occurring in peroxisomes and thus leads us to propose a revised model of the phylloquinone pathway. Lastly, given the potential of introducing juglone biosynthesis as part of novel weed management strategies, we investigated the circumstances, costs, and benefits of producing allelochemicals in crops using an evolutionary game theory model. Together, this work (i) shows that the phylloquinone pathway provides crops with the biosynthetic framework to produce juglone, (ii) sheds new light on the phylloquinone pathway architecture, and (iii) reveals the circumstances in which producing an allelochemical will be an evolutionarily stable strategy. We envision these results will assist biotechnological efforts to utilize juglone as a novel, natural product-based herbicide.</p>

One theory concerning the invasiveness of exotic plants suggests that they exude allelopathic compounds that are novel in areas being invaded. Here, I tested for allelopathic effects of root exudates of the invasive plant Heracleum mantegazzianum (giant hogweed) in a series of experiments both in vitro and in the garden, and compared them with effects of its native congener H. sphondylium (common hogweed) and two less related native species. Moreover, I addressed intraspecific variability of allelopathy by comparing effects of 41 different maternal lines of H. mantegazzianum sampled from several areas and populations within the Czech Republic. Not only the effects, but also the identity of allelopathic compounds was investigated. In order to test also for the interaction of allelochemicals with soil microorganisms, I analysed the composition of soil microbial communities expressed as phospholipid and neutral lipid fatty acids (PLFA and NLFA, respectively) together with nutrient conditions and light availability at invaded sites in the Czech Republic. The results show that H. mantegazzianum is able to exert phytotoxic effects in vitro as well as in the garden experiment; however, its effects did not differ from the inhibition caused by the native species tested. Variation partitioning among areas,...

Population growth in regions of the Intermountain West has resulted in rapid growth of residential neighborhoods. In Utah, the landscapes associated with these expanding neighborhoods consume vast quantities of treated water. This is a concern in all states of the Intermountain West, as water becomes increasingly scarce. Traditionally used turfgrasses, trees and other plants in Intermountain West landscapes require significant amounts of supplemental water considering the intense sunlight, dry winds and sparse rainfall typical of the region. Characterizing the interactions between turfgrass and tree species in these landscapes can aid in the identification of candidate species that consume less nutritional and water resources, while maintaining satisfactory appearance. A study was conducted investigating the nature of interactions between tree and turfgrass species in a constructed landscape of the Intermountain West. An experiment was performed investigating differences in rooting length and volume between combinations of two tree (Robinia pseudoacacia L., Gleditsia triacanthos var. inermis L.) and three turfgrass [Poa pratensis L., Buchlöe dactyloides (Nutt.) Engelm., Festuca arundinacea Schreb.] species. A minirhizotron system was used to obtain root images at three times during the growing seasons of 2006 and 2007 at depths from 1-15 cm in each tree-turfgrass rooting zone. Images were analyzed to determine combined total volume, length, and surface area of turfgrass and tree roots. This research shows that root growth differences occur in turfgrass-tree combinations containing all three turfgrass species. Buffalograss best resisted possible root growth inhibition, regardless of tree combination. Further evidence shows that Robinia secondary growth is vulnerable to presence of turfgrass in proximity.