Members of the family Chenopodiaceae are routinely used as colonizer plant species to rehabilitate waste and tailings materials on mine sites in the Eastern Goldfields of Western Australia. These are specifically selected for their salt and drought tolerance and also because they are representative of the surrounding natural vegetation. Where these have been sown, competition between several species has been observed. The resulting plant community structure is typically lower in species diversity than the initial seed mixture. This study aimed to determine whether competition was occurring between five of the species commonly used and some of the mechanisms that determine community structure on the rehabilitated areas of waste material. Atriplex bunburyana, Atriplex codonocarpa, Maireana brevifolia, Maireana georgei and Enchylaena tomentosa were selected for the study, which was conducted in three parts. Firstly, different plant densities and species combinations were studied in the field and in a pot trial to determine whether or not competition was occurring and to determine the resources that the plants were competing for. The results of the field trial revealed that competition was occurring, but that it formed only one component of the complex interactions between plant species, density and soil characteristics (i.e. pH and salinity). The pot trial complemented the outcome of the field trial. In addition, it showed that competition was occurring, but was even more pronounced. This was most likely due to the lack of nutrients and the limited availability of space in the pots. / In the second part of this study, the ability of each species to survive and grow when subjected to adverse environmental conditions, such as low moisture availability, high salinity and low light availability, was examined in relation to competition. All five species were treated with different water regimes and soil salinity. Salt played an important role, especially for the Atriplex spp. and M. brevifolia, in ensuring survival when moisture availability was low. The effect of shade on the Maireana species and E. tomentosa was also researched after field observations suggested that M georgei was adversely affected when growing within the canopy of A. bunburyana. The pot trial showed that growth of M. georgei was affected by progressively more shade, whereas E. tomentosa was facilitated by shade. Maireana brevifolia exhibited significant tolerance to low light intensity. In the last part of this three-part study, all five chenopods were screened for allelopathy. Allelopathy may play an important role in determining community structure in successive plant generations. All chenopod species produced allelopathic substances, which were isolated from their leaves. The inhibition of seed germination was found to be speciesspecific and occurred only at certain concentrations. The seed of the Atriplex spp. was not affected by M. georgei and E. tomentosa extracts.

No description available.

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains viii, 65 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 54-57).

Thesis (Ph. D.)--Biology, Georgia Institute of Technology, 2008. / Committee Chair: Kubanek, Julia; Committee Member: Hay, Mark; Committee Member: Jiang, Lin; Committee Member: Pavia, Henrik; Committee Member: Snell, Terry.

Thesis (Ph.D.)--University of Wollongong, 2007. / Typescript. Includes bibliographical references: leaf 133-154.

Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-08-09T21:59:31Z No. of bitstreams: 1 NaamaJAM_DISSERT.pdf: 599336 bytes, checksum: 04da1dc529b48d474733360a8a76b477 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-08-17T22:39:28Z (GMT) No. of bitstreams: 1 NaamaJAM_DISSERT.pdf: 599336 bytes, checksum: 04da1dc529b48d474733360a8a76b477 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-08-17T22:41:33Z (GMT) No. of bitstreams: 1 NaamaJAM_DISSERT.pdf: 599336 bytes, checksum: 04da1dc529b48d474733360a8a76b477 (MD5) / Made available in DSpace on 2017-08-17T22:41:40Z (GMT). No. of bitstreams: 1 NaamaJAM_DISSERT.pdf: 599336 bytes, checksum: 04da1dc529b48d474733360a8a76b477 (MD5) Previous issue date: 2015-02-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The species Allium cepa is widely used in studies such as biological indicator of toxicity and can be affected by other plant extracts through allelopathy. Many toxic plants of livestock interest have allelopathic compounds and cause damage to animal health. Among these plants is Licania rigida (oiticica). The objective of this study was to evaluate the toxic and cytotoxic effects of L. rigida extracts in bulbs of A. cepa. The bulbs were incubated in distilled water (negative control) and at concentration 5 mg/L, 50 mg/L and 300 mg/L of aqueous extracts of dried and fresh leaves. It was evaluated the root growth and relative inibition. With the bulbs blades were made of meristematic root cells for the evaluation of cytotoxicity. The extracts of the dry and fresh leaves in bulbs caused inhibition at concentrations of 5 mg/L and 300 mg/L, while the concentration of 50 mg/L stimulated. It was not observed cytotoxic activity of the aqueous extracts of dried and fresh leaves, because there were no statistically significant differences / Plantas tóxicas de interesse pecuário ocasionam prejuízos relevantes aos produtores. No Nordeste brasileiro, essas plantas causam perdas econômicas diretas e indiretas por prejudicarem a saúde dos animais. Entre estas plantas está incluída a espécie Licania rigida, popularmente denominada oiticica. É encontrada na maioria dos estados do Nordeste e suas folhas podem ser utilizadas na alimentação de caprinos e ovinos na região do semiárido. Foram avaliados os efeitos tóxico, citotóxico e mutagênico de extratos aquosos de folhas de L. rigida em Allium cepa (cebola) e em camundongos Swiss (Mus musculus). Para avaliações em bulbos de cebola (crescimento de raízes e índice mitótico) foram utilizados folhas secas e frescas, no seguinte delineamento experimental: controle negativo: (água destilada); concentração de 5 mg/L, 50 mg/L e 300 mg/L do extrato. E para camundongos foram utilizadas apenas o extrato de folhas secas para avaliação comportamental, de mortalidade (DL50), mutagenicidade (teste do micronúcleo) e citotoxicidade (células binucleadas). Não houve citotoxicidade, mas sim efeito subletal na concentração de 300 mg/L do estrato de folhas frescas e pode ter ocorrido efeito alelopático dos dois tipos de extratos sobre os bulbos de cebola. Em camundongos, o extrato de folhas secas ocasionou mudanças comportamentais e apresentou toxicidade (DL50=502,76 mg/kg). Não foram evidenciadas mutagenicidade e citotoxicidade, pois os resultados entre os tratamentos não apresentaram diferenças estatisticamente significativas (α=0,05) / 2017-08-09

Made available in DSpace on 2014-06-11T19:26:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-21Bitstream added on 2014-06-13T20:34:27Z : No. of bitstreams: 1 bufalo_j_me_botfca.pdf: 2411379 bytes, checksum: 2fce4263cf95244f6d7f29c8bc7250bc (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A família Lamiaceae se destaca pela utilização de muitas de suas espécies como medicinais, condimentares, aromáticas e ornamentais. Entre elas, a Mentha piperita L., produz óleo essencial amplamente utilizado nas indústrias farmacêuticas, de bebidas alcoólicas, alimentícias e de cosméticos. Leonurus sibiricus L., além de medicinal, é conhecida pela produção de terpenóides e substâncias fenólicas com efeitos alelopáticos, apresentando-se também como planta invasora. O presente estudo objetivou avaliar a atividade do extrato metanólico de folhas de L. sibiricus, no desenvolvimento, trocas gasosas e metabólitos do óleo essencial de M. piperita, cultivada em solução nutritiva. Para tanto, foram utilizadas concentrações iguais a 25, 50 e 100 mg L-1 de extrato metanólico das folhas de L. sibiricus no cultivo hidropônico da M. piperita durante parte de seu ciclo de desenvolvimento. As variáveis, comprimento de parte aérea, área foliar, massa seca dos diferentes órgãos, razão de área foliar, razão de massa foliar, área foliar específica, taxa assimilatória líquida, taxa de crescimento relativo, distribuição de massa seca para os diferentes órgãos, trocas gasosas, e composição química dos óleos essenciais foram avaliadas em diferentes épocas. Os resultados obtidos permitiram concluir que as menores concentrações do extrato metanólico de L. sibiricus, 25 e 50 mg L-1, estimularam o desenvolvimento da M. piperita, estimulando a translocação de matéria orgânica nas plantas, enquanto esse processo prejudicado nas plantas cultivadas com 100 mg L-1, pode ter sido responsável por seu menor desenvolvimento. As trocas gasosas da M. piperita foram influenciadas pela presença do extrato metanólico e estimuladas pelas concentrações iguais a 25 e 50 mg L-1 do extrato. O extrato metanólico de L. sibiricus influenciou os teores dos componentes do óleo... / The family Lamiaceae is known for the use of many species as medicinal, condiments, aromatic and ornamental. Among them, Mentha piperita L. essential oil produces widely used in industries pharmaceutical, beverages, food and cosmetics. Leonurus sibiricus L., besides medicinal, produces terpenoids and phenolic substances with allelopathic effects, what explains its invasive behaviour. The present study aimed to evaluate the activity of methanolic extract of leaves of L. sibiricus in the development, gas exchange and metabolites of essential oil of M. piperita, cultivated in nutritive solution. Thus, were used concentrations of 25, 50 and 100 mg L-1 of methanolic extract of leaves of L. sibiricus in the hydroponic cultivation of M. piperita during part of its development cycle. The variables, shoot length, leaf area, dry matter of different organs, leaf area ratio, leaf weight ratio, specific leaf area, net assimilation rate, relative growth rate, dry matter distribution in several organs, gas exchange and composition of essential oils were evaluates at different times. The results showed that low concentrations of methanolic extract of L. sibiricus, 25 and 50 mg L-1, stimulated the development of M. piperita, stimulating the translocation of organic matter in plants, while this process affected in plants grown with 100 mg L-1, may have been responsible for yours less development. The gas exchange of M. piperita were influenced by the presence of methanolic extract and stimulated by concentrations 25 and 50 mg L-1. The methanolic extract of L. sibiricus influenced the levels of the essential oil components of M. piperita, depending on the concentration used, since, at lower concentrations, the plants showed higher levels of menthone and menthol, thus rendering an oil of quality and plants cultivated in the highest concentration showed higher levels of menthyl acetate and menthofuran... (Complete abstract click electronic access below)

CAPES / O objetivo desse trabalho foi analisar a influência de diferentes concentrações dos extratos brutos etanólicos (EET) e diclorometânicos (EDC) das espécies medicinais antimaláricas Bidens pilosa L. (picão-preto), Phyllanthus niruri L. (quebra-pedra), Petiveria alliacea L. (guiné) e Senna hirsuta L. (fedegoso), sobre a germinabilidade (GER), tempo médio de germinação (TMG), velocidade média de germinação (VMG), comprimento de radícula (RAD) e comprimento de hipocótilo (HIP) de Lactuca sativa L. (alface) e Ipomoea grandifolia (Dammer) O´Donel (corda-de-viola). O delineamento utilizado foi inteiramente casualizado, distribuído em um trifatorial (espécie antimalárica vs. extrator vs. concentração). Os bioensaios foram realizados com quatro repetições de 25 sementes, para os testes germinativos, e 10 sementes pré-germinadas, para os bioensaios de crescimento. As sementes germinadas foram contadas diariamente, para a obtenção do TMG e VMG, enquanto a GER, RAD e HIP foram mensurados após 144 horas da aplicação dos extratos. Paralelamente ao estudo de atividade alelopática, objetivou-se também analisar a atividade antioxidante e antimicrobiana dos EET e EDC das quatro espécies antimaláricas utilizadas nos bioensaios, assim como, da espécie Quassia amara L. (quássiaamarga). As análises antioxidantes foram realizadas através de três metodologias distintas, sendo elas: sequestro do radical ABTS•+ e sequestro do radical DPPH•, ambas realizadas com os EET e EDC, e poder antioxidante de redução do Ferro (FRAP), realizada apenas com os EET, assim como o teor de compostos fenólicos totais (TCF). Os EET foram comparados aos antioxidantes comerciais BHT (butil hidroxitolueno), BHA (butil hidroxianisol) e α-tocoferol. Os resultados dos bioensaios dos extratos brutos das plantas antimaláricas, e suas respectivas concentrações, demonstraram efeitos inibitórios, e em alguns casos estimulatórios, de magnitudes diferentes sobre os processos de germinação e/ou crescimento das espécies alvo. O aumento das concentrações dos EET e EDC de P. alliacea e do EET de S. hirsuta, não afetaram o TMG, VMG e GER de corda-de-viola, sendo que o EDC de P. alliacea também não influenciou sobre RAD e HIP da mesma, enquanto o EET de B. Pilosa apresentou ótimos resultados de inibição do RAD e HIP de alface e GER, TMG, VMG, RAD e HIP de corda-de-viola. Em todas as metodologias de atividade antioxidante analisadas, o EET de Q. amara demonstrou-se como o tratamento mais eficaz, seguido do EET de P. niruri, sendo estes, analisados em Cromatografia Líquida de Alta Eficiência de Fase-Reversa (CLAE-FR), evidenciando a presença de rutina, miricetina, quercetina e ácido gálico para ambas as espécies, sendo estes compostos, reconhecidos por suas propriedades antioxidantes. As análises antimicrobianas foram realizadas através da Concentração Inibitória Mínima (CIM) dos extratos das plantas, com concentrações entre 5,0 e 0,88 mg mL-1, em microplacas de 96 poços inoculadas com Baccilus cereus ATCC 11.778. Os EET de Q. amara, P. niruri e S. hirsuta e o EDC de B. pilosa apresentaram concentração inibitória mínima (MIC) = ≤0,088 mg mL-1. Dessa forma, os dados apresentados nesse estudo indicam, em especial, um potencial uso do EET de B. pilosa e do EET de Q. amara como fontes de moléculas com atividade herbicida, antioxidantes e antimicrobianas, sendo estes extratos, importantes fontes para a busca de moléculas que possam ser utilizadas como protótipos para o desenvolvimento de novos produtos nas indústrias de agroquímicos, alimentícia e /ou farmacêutica, requerendo estudos futuros quanto a extração, purificação, isolamento e identificação dos compostos bioativos e seus respectivos mecanismos de ação. / The aim of this study was to analyze the influence of different concentrations of crude ethanol extracts (EET) and dichloromethanic (EDC) of antimalarial medicinal species Bidens pilosa L. (beggartick), Phyllanthus niruri L. (shatter stone), Petiveria alliacea L. (guinea) and Senna hirsuta L. (sicklepod) on germination (GER), mean germination time (TMG), mean speed of germination (VMG), radicle (RAD) and hypocotyls (HIP) of Lactuca sativa L. (lettuce) and Ipomoea grandifolia (Dammer) O'Donel (rope-glory). The experimental design was completely randomized, distributed in a factorial (species antimalarial vs. extractor vs. concentration). Bioassays were performed with four replicates of 25 seeds for germination tests, and 10 pre-germinated seeds for the growth bioassays. Germinated seeds were counted daily for obtaining the TMG and VMG while GER, DAR and HIP were measured after 144 hours of application of the extracts. In parallel to the study of allelopathic activity aimed also to examine the antioxidant and antimicrobial activities of EET and EDC of four malarial species used in bioassays, as well as the species Quassia amara L. (quássia amarga). Analyses antioxidants were performed through three different methodologies, namely: scavenging of ABTS•+, scavenging DPPH•, both performed with EET and EDC, and antioxidant power reduction iron (FRAP), performed with EET, as well as the content of total phenolic compounds (TCF). The EET were compared to commercial antioxidant BHT (butylated hydroxytoluene), BHA (butylated hydroxyanisole) and α-tocopherol. The results of bioassays of extracts of plants antimalarial and their respective concentrations showed inhibitory effects, and in some cases stimulatory, different magnitudes of the processes of germination and/or growth of the target species. Increasing the concentration of EET and EDC of P. alliacea and EET of S. hirsuta, did not show significant results for variables TMG, VMG and GER of corda-de-viola, and the EDC of P. alliacea also did not influence RAD HIP. The EET of B. Pilosa showed excellent results compared to inhibition of RAD and HIP lettuce and GER, TMG, VMG and RAD rope-glory, suggesting the use of this extract for future work of purification, isolation and identification of bioactive substances. In all methods of antioxidant activity analyzed, the EET of Q. amara shown as the most effective treatment, followed by EET of P. niruri, which are analyzed in High Performance Liquid Chromatography Reverse-Phase (HPLC-RP), indicating the presence of rutin, myricetin, quercetin and gallic acid for both species, these compounds being recognized for its antioxidant properties. Analyses were performed using antimicrobial minimum inhibitory concentration (MIC) of the plant extracts with concentrations between 5.0 and 0.88 mg mL-1 in 96-well microplates inoculated with Baccilus cereus ATCC 11.778. The EET of Q. amara, P. niruri and S. hirsuta and EDC of B. pilosa showed minimal inhibitory concentration (MIC) = ≤ 0.088 mg mL-1. Thus, the data presented in this study indicate the potential use of the EET of B. pilosa and EET of Q. amara as sources of molecules having herbicidal activity, antioxidants and antimicrobial properties, and these extracts are important sources for the search of molecules that can be used as a prototype for the development of new products in the agrochemical industries, food and/or pharmaceuticals, requiring future studies on the extraction, purification, isolation and identification of bioactive compounds and their mechanisms of action.

A Artemisia annua L. (Asteraceae) é uma planta herbácea, nativa da Ásia e aclimatada no Brasil. As folhas apresentam até 1,4% do peso seco em artemisinina, sendo fonte abundante desta lactona sesquiterpênica que, conjuntamente aos seus derivados semi-sintéticos, apresentam ação efetiva contra as cepas resistentes das espécies de Plasmodium causadoras da malária. A artemisinina também está sendo testada com sucesso no tratamento de câncer e apresenta-se efetiva contra inúmeros parasitas que afetam a saúde humana e animal. Os objetivos deste trabalho foram determinar as épocas de plantio e colheita da cultivar Artemis de A. annua em Pato Branco-PR, como também, determinar em campo o fotoperíodo crítico e o número de ciclos fotoindutivos necessários para o florescimento desta cultivar. Um segundo experimento foi realizado com o objetivo de determinar o potencial alelopático desta espécie sobre sementes de alface e leiteiro. No experimento em campo, os tratamentos utilizados foram seis diferentes épocas de plantio, sendo as 09 plantas centrais das parcelas colhidas para a determinação da massa seca de folha e caules, relação folha/caule e teor de artemisinina na massa seca de folhas quando 50% das plantas da parcela iniciaram a emissão dos botões florais. O número de ciclos fotoindutivos encontrado para a cultivar Artemis foi de aproximadamente 36 ciclos e o fotoperíodo crítico aproximado foi de 13 horas, que ocorreu em 09/02/2007 em Pato Branco-PR. Esse resultado determinou que a época de colheita para a cultivar Artemis, na região de Pato Branco-PR, deve ser na segunda quinzena do mês de março. O maior rendimento de biomassa nesse experimento ocorreu no plantio de 27/07/2007, 231 dias após o transplantio, mas recomenda-se tomar cuidado com as geadas que podem ocorrer até a primeira quinzena de setembro, sugerindo-se optar pelo plantio na segunda quinzena de setembro, período livre de geadas na região. Os maiores teores de artemisinina (em média 0,80% na matéria seca de folhas) foram obtidos nas épocas que mais vegetaram a campo devido à maior produção de biomassa. Para o experimento de alelopatia, o extrato aquoso bruto foi preparado a partir de folhas frescas na proporção de 1 L de água destilada para 250 g do material. Foram utilizadas as seguintes concentrações do extrato aquoso: 100%, 75%, 50%, 25% e 0% (água destilada). Foram analisadas as variáveis germinabilidade, velocidade média de germinação, tempo médio de germinação, comprimento da radícula e massa seca das plântulas. Extratos aquosos de A. annua apresentaram ação alelopática inibitória sobre a germinação de sementes e o desenvolvimento de plântulas de alface e leiteiro. / The Artemisia annua L. (Asteraceae) is a herbaceous plant, native of Asia and acclimated in Brazil. The leaves are abundant source of artemisinin, a sesquiterpene lactone that, jointly to yours derived semi-synthetic, they present effectiveness action against the resistant stumps of the species of Plasmodium against malaria. The artemisinin is also being tested with success in the cancer treatment and against countless parasites that affect the human and animal health. The objectives of this work went to determine the planting times and crop of the cultivar Artemis of A. annua in Pato Branco-PR, as well as, to determine in field the critical photoperiod and the number of inductive photoperiod for the flowering of this cultivar. A second experiment was accomplished with the objective of determining the allellopathic effect of this species on lettuce seeds and wild poinsettia. In the experiment in field, the treatments were six different transplant times, being the 09 central plants of the portions picked for the determination of the mass dries of leaf and stems, relationship leaf/stems and artemisinin in the mass dries of leaves when 50% of the plants of the portion began the emission of the floral buttons. The number of cycles inductive found for the cultivar Artemis was of approximately 36 cycles and the critical photoperiod was approximately 13 hours, that happened in 09/02/2007 in Pato Branco-PR. This results determines that the crop time for cultivar Artemis, in Pato Branco-PR will be in the second fortnight of the month of March. The largest biomass income in that experiment happened in the planting of 27/07/2007, 231 days after the transplant, but it is recommended to take care with the frost that can happen until the first fortnight of September, suggesting choose for the transplant in the second fortnight of September, period free from frost in the area. The largest artemisinin tenor (0,88% in dry matter leaves) was obtained in the times that more they vegetated to field due to the largest biomass production. Besides this experiment, a second experiment was developed to determine the allellopathic effects of this species on lettuce seeds and wild poinsetia. The aqueous extract was prepared starting from fresh leaves in the proportion of 1 L of water distilled for 250 g of the material, after, the extract was filtrate and centrifuged, being used the sobrenadante. The following concentrations of the extract were used: 100%, 75%, 50%, 25% and 0% (distilled water). They were analyzed the variables germinability, germination velocity, germination time, length of the radicle and weight of the dry matter of the seedlings. Aqueous extracts of A. annua is allellopathic on the germination and development of lettuce and wild poinsettia seedlings.

A Artemisia annua L. (Asteraceae) é uma planta herbácea, nativa da Ásia e aclimatada no Brasil. As folhas apresentam até 1,4% do peso seco em artemisinina, sendo fonte abundante desta lactona sesquiterpênica que, conjuntamente aos seus derivados semi-sintéticos, apresentam ação efetiva contra as cepas resistentes das espécies de Plasmodium causadoras da malária. A artemisinina também está sendo testada com sucesso no tratamento de câncer e apresenta-se efetiva contra inúmeros parasitas que afetam a saúde humana e animal. Os objetivos deste trabalho foram determinar as épocas de plantio e colheita da cultivar Artemis de A. annua em Pato Branco-PR, como também, determinar em campo o fotoperíodo crítico e o número de ciclos fotoindutivos necessários para o florescimento desta cultivar. Um segundo experimento foi realizado com o objetivo de determinar o potencial alelopático desta espécie sobre sementes de alface e leiteiro. No experimento em campo, os tratamentos utilizados foram seis diferentes épocas de plantio, sendo as 09 plantas centrais das parcelas colhidas para a determinação da massa seca de folha e caules, relação folha/caule e teor de artemisinina na massa seca de folhas quando 50% das plantas da parcela iniciaram a emissão dos botões florais. O número de ciclos fotoindutivos encontrado para a cultivar Artemis foi de aproximadamente 36 ciclos e o fotoperíodo crítico aproximado foi de 13 horas, que ocorreu em 09/02/2007 em Pato Branco-PR. Esse resultado determinou que a época de colheita para a cultivar Artemis, na região de Pato Branco-PR, deve ser na segunda quinzena do mês de março. O maior rendimento de biomassa nesse experimento ocorreu no plantio de 27/07/2007, 231 dias após o transplantio, mas recomenda-se tomar cuidado com as geadas que podem ocorrer até a primeira quinzena de setembro, sugerindo-se optar pelo plantio na segunda quinzena de setembro, período livre de geadas na região. Os maiores teores de artemisinina (em média 0,80% na matéria seca de folhas) foram obtidos nas épocas que mais vegetaram a campo devido à maior produção de biomassa. Para o experimento de alelopatia, o extrato aquoso bruto foi preparado a partir de folhas frescas na proporção de 1 L de água destilada para 250 g do material. Foram utilizadas as seguintes concentrações do extrato aquoso: 100%, 75%, 50%, 25% e 0% (água destilada). Foram analisadas as variáveis germinabilidade, velocidade média de germinação, tempo médio de germinação, comprimento da radícula e massa seca das plântulas. Extratos aquosos de A. annua apresentaram ação alelopática inibitória sobre a germinação de sementes e o desenvolvimento de plântulas de alface e leiteiro. / The Artemisia annua L. (Asteraceae) is a herbaceous plant, native of Asia and acclimated in Brazil. The leaves are abundant source of artemisinin, a sesquiterpene lactone that, jointly to yours derived semi-synthetic, they present effectiveness action against the resistant stumps of the species of Plasmodium against malaria. The artemisinin is also being tested with success in the cancer treatment and against countless parasites that affect the human and animal health. The objectives of this work went to determine the planting times and crop of the cultivar Artemis of A. annua in Pato Branco-PR, as well as, to determine in field the critical photoperiod and the number of inductive photoperiod for the flowering of this cultivar. A second experiment was accomplished with the objective of determining the allellopathic effect of this species on lettuce seeds and wild poinsettia. In the experiment in field, the treatments were six different transplant times, being the 09 central plants of the portions picked for the determination of the mass dries of leaf and stems, relationship leaf/stems and artemisinin in the mass dries of leaves when 50% of the plants of the portion began the emission of the floral buttons. The number of cycles inductive found for the cultivar Artemis was of approximately 36 cycles and the critical photoperiod was approximately 13 hours, that happened in 09/02/2007 in Pato Branco-PR. This results determines that the crop time for cultivar Artemis, in Pato Branco-PR will be in the second fortnight of the month of March. The largest biomass income in that experiment happened in the planting of 27/07/2007, 231 days after the transplant, but it is recommended to take care with the frost that can happen until the first fortnight of September, suggesting choose for the transplant in the second fortnight of September, period free from frost in the area. The largest artemisinin tenor (0,88% in dry matter leaves) was obtained in the times that more they vegetated to field due to the largest biomass production. Besides this experiment, a second experiment was developed to determine the allellopathic effects of this species on lettuce seeds and wild poinsetia. The aqueous extract was prepared starting from fresh leaves in the proportion of 1 L of water distilled for 250 g of the material, after, the extract was filtrate and centrifuged, being used the sobrenadante. The following concentrations of the extract were used: 100%, 75%, 50%, 25% and 0% (distilled water). They were analyzed the variables germinability, germination velocity, germination time, length of the radicle and weight of the dry matter of the seedlings. Aqueous extracts of A. annua is allellopathic on the germination and development of lettuce and wild poinsettia seedlings.