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No allelopathic effect of the invader Acacia dealbata on the potential infectivity of arbuscular mycorrhizal fungi from native soils

Lorenzo, Paula; Rodríguez-Echeverría, Susana; Freitas, H.
Fonte: Elsevier Masson SAS Publicador: Elsevier Masson SAS
Tipo: Artigo de Revista Científica
ENG
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The invasion success of the leguminous tree Acacia dealbata Link has been related to the release of novel chemical compounds that affect both native plant performance and native soil bacterial communities. However, the allelopathic effect of A. dealbata on arbuscular mycorrhizal fungi (AMF) has not been explored. We used natural leachates from invasive A. dealbata and native soils to assess the bioactivity of these chemicals on AMF colonization of Plantago lanceolata in native soils. The highly mycorrhizal P. lanceolata was used as a model-test species to estimate the infectivity of AM fungi. Acacia leachates did not affect mycorrhizal colonization in any of the native soils studied. Either the leachates released by A. dealbata do not have an antifungal effect or the analyzed soils contained AMF species resistant to those allelochemicals. Our results appeal for further research to elucidate the role of native AMF in the invasion process of A. dealbata.; This work was supported by the project MUTUALNET (PTDC/BIA BEC/103507/2008), from the European Union and the Portuguese Foundation for Science and Technology and by post-doctoral research grant from the Spanish Ministerio de Educación (Programa Nacional de Movilidad de Recursos Humanos del Plan Nacional de I-Dþi 2008e2011...

Avaliação do potencial alelopático de genótipos de aveia no final do ciclo; Evaluation of allelopathic potential of oat genotypes at the end of life cycle

Jacobi, Ubirata Soares; Fleck, Nilson Gilberto
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
POR
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Em sistemas de cultivo em semeadura direta, a aveia é uma das culturas de inverno mais importantes entre as que são utilizadas para formação de cobertura morta. Nos tecidos da aveia existem aleloquímicos, o que torna importante o entendimento deste fenômeno nesta cultura. Através da análise da palha de resíduos de genótipos de aveia, bem como dos seus aleloquímicos, poder-se-á obter uma avaliação ampla do seu potencial alelopático. Nesta análise, pode-se verificar que os genótipos de aveia mantém o potencial alelopático no final do ciclo de vida, revelando-se com maior efeito alelopático UFRGS 6, UFRGS 9, UFRGS 10 e UPF 13. Ao mesmo tempo, os genótipos que exibem menor efeito alelopático são UFRGS 12, UFRGS 17, UFRGS 884077 e UPF 12. Os efeitos produzidos por compostos aleloquímicos (ácidos fenólicos) são similares aos provocados pelos extratos dos genótipos de aveia, mostrando uma relação entre o efeito alelopático dessas substâncias e os genótipos testados. Os aleloquímicos apresentam maior fitotoxicidade para as infestantes do que para as culturas, assim como ocorre com os resíduos de genótipos de aveia.; In no-till cropping systems, oat represents one of the winter most important crops among those that are used to form cover crops. The presence of allelochemicals in its tissues point to the importance of understanding this phenomenon in the crop. By analyzing the straw of oat genotypes and its allelochemicals...

Allelopathic potential and survey of natural seed bank under the canopy of Copaifera Langsdorffii Desf

Silva, Regildo Márcio Gonçalves da; Santos, Valter Henrique Marinho dos; Borges, Fabiano Marcelino; Melo, Fabiano de Fátima Queiroz; Silva, Luciana Pereira
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 641-653
POR
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The aim of this study was to evaluate the allelopathic effect of soil samples collected under the canopies of three specimens of Copaifera langsdorffii the germination of Lactuca sativa and survey the natural seed bank according to seasonality. To test the allelopathic effect was carried experiments of pre and post-emergence with seeds of L. sativa and to quantify the stock of seeds, soil samples were collected from three specimens at three distances from the stem (1, 2 and 3 m) and at three depths (0-5, 5-10 and 10-15cm) in the region of savanna in the dry and wet seasons. The samples tested in bioassay of pre-emergence no significant influence on germinability, mean germination time and mean germination speed, but showed a difference in the synchronism of germination, these data were independent of sampling station. In test for post-emergence was observed statistical difference in the parameters evaluate (length of primary roots and hypocotyls) in both seasons. To quantify the natural seed bank were macroscopic analysis of each soil sample with the help of stereoscopic microscope. The analysis of the natural seed bank showed a larger number of seeds in the 0-5cm and in distance of 2m for both seasons. The results suggest the presence of allelochemical substances in soil samples collected under the canopy of Copaifera langsdorffii.; O objetivo deste trabalho foi avaliar o efeito alelopático de amostras de solo coletadas sob a copa de três espécimes de Copaifera langsdorffii na germinação de Lactuca sativa e realizar o levantamento do banco natural de sementes de acordo com a sazonalidade. Para testar o efeito alelopático realizou-se experimentos de pré e pós-emergência com sementes de L. sativa e para quantificar o estoque de sementes...

Efeito alelopático de folhas de Solanum lycocarpum A. St.-Hil. (Solanaceae) na germinação e crescimento de Sesamum indicum L. (Pedaliaceae) sob diferentes temperaturas; Allelopathic effect of Solanum lycocarpum A. St.-Hil. leaves on the germination and growth of Sesamum indicum L. (Pedaliaceae) under different temperatures

Oliveira, Sarah Christina Caldas; Ferreira, Alfredo Gui; Borghetti, Fabian
Fonte: Universidade Federal do Rio Grande do Sul - Instituto de Biociências Publicador: Universidade Federal do Rio Grande do Sul - Instituto de Biociências
Tipo: Artigo de Revista Científica
POR
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Alelopatia pode ser definida como o efeito maléfico ou benéfico que uma planta exerce sobre a outra por meio de compostos químicos liberados no ambiente. Diversas espécies do gênero Solanum apresentam evidências de propriedades alelopáticas. S. lycocarpum A. St.-Hil (lobeira) é espécie de ampla distribuição em ambientes perturbados do Cerrado. No presente trabalho foram investigados efeitos alelopáticos de extratos de folhas de lobeira na germinação e no crescimento do gergelim (Sesamum indicum L.). Extratos aquosos das folhas foram preparados nas concentrações de 1%, 2%, 3%, 4% e 5% (p/v). A osmolaridade dos extratos foi medida e soluções de polietileno glicol (PEG 6000), de osmolaridade similar, foram preparadas para avaliar possíveis efeitos osmóticos dos extratos aquosos. Nos testes de germinação, as sementes de gergelim foram colocadas em placas de Petri forradas com papel de filtro com a solução a ser testada e observadas a cada 8h. Para os experimemtos de crescimento, sementes de gergelim foram germinadas em água e posteriormente dispostas para crescimento nos extratos. Após 5 dias, foram medidos os comprimentos da parte aérea e radicular das plântulas. Todos os experimentos foram conduzidos a 22ºC...

Effect of crop residues applied isolated or in combination on the germination and seedling growth of horse purslane (Trianthema portulacastrum)

Khaliq,A.; Matloob,A.; Farooq,M.; Mushtaq,M.N.; Khan,M.B.
Fonte: Sociedade Brasileira da Ciência das Plantas Daninhas Publicador: Sociedade Brasileira da Ciência das Plantas Daninhas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2011 EN
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Soil incorporation of crop residues can lead to weed suppression by posing allelopathic and physical effects. Allelopathic potential of the crops sorghum, sunflower, brassica applied as sole or in combination for horse purslane (Trianthema portulacastrum) suppression was evaluated in a pot investigation. Chopped crop residues alone and in combination were incorporated at 6 g kg-1 soil (12 t ha-1), and a weedy check was maintained. Germination traits time to start germination; time to 50% emergence, mean emergence time, emergence index and final germination percentage were negatively influenced by residue incorporation. Crop residues also exerted a pronounced negative influence on the shoot and root length of horse purslane. Significant suppression in leaf and root score and leaf area per plant was also observed. A combination of sorghum and sunflower residues accounted for maximum (71%) seedling mortality. Soil incorporation of allelopathic crop residues can be employed for horse purslane management.

Comparative allelopathic potential of metabolites of two Alternanthera species against germination and seedling growth of rice

Mehmood,A.; Tanveer,A.; Nadeem,M.A.; Zahir,Z.A.
Fonte: Sociedade Brasileira da Ciência das Plantas Daninhas Publicador: Sociedade Brasileira da Ciência das Plantas Daninhas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 EN
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A laboratory study was conducted to investigate the allelopathic effect of aqueous extracts of plant parts of Alternanthera philoxeroides and A. sessilis and soil incorporated residues on germination and seedling growth of rice (Oryza sativa). Aqueous extracts prepared from different plant parts of Alternanthera species delayed rice germination. Alternanthera philoxeroides and A. sessilis inhibited rice germination by 9-100% and 4-49%, respectively. Germination of rice seeds was reduced with increasing concentration of aqueous leaf extracts of both weed species. Early seedling growth (root and shoot lengths) and seedling vigor index were significantly reduced by 5% aqueous leaf extract compared with distilled water treated control. Germination, root and shoot lengths, root and shoot dry weights and seedling vigor index of rice were drastically reduced by 3 and 4% in residue infested soil compared with residue free soil. The inhibitory effect of A. philoxeroides in terms of germination and seedling growth of rice was greater than that of A. sessilis. Five percent aqueous leaf extract and 4% residue infested soil of A. philoxeroides caused complete failure of rice seed germination. Alternanthera philoxeroides contained water soluble phenolics...

Allelopathic interference of Sapindus saponaria root and mature leaf aqueous extracts on diaspore germination and seedling growth of Lactuca sativa and Allium cepa

Grisi,Patrícia Umeda; Gualtieri,Sônia Cristina Juliano; Ranal,Marli Aparecida; Santana,Denise Garcia
Fonte: Sociedade Botânica de São Paulo Publicador: Sociedade Botânica de São Paulo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
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Sapindus saponaria (soapberry) is a species that presents a great diversity of chemical compounds, such as saponins; however, few studies have examined the allelopathic effect of this species. Therefore, this study provides an evaluation of the allelopathic potential of aqueous extracts of the roots and mature leaves of S. saponaria on the germination of diaspores and seedlings growth of lettuce (Lactuca sativa) and onion (Allium cepa). The aqueous extract was prepared in the proportion of 100 g of dry plant material in 1,000 mL of distilled water (a concentration of 10% w v-1), and diluted with distilled water to 7.5, 5.0 and 2.5% concentrations. The mature leaf extracts caused delay and decrease in the germination process of the lettuce and onion diaspores, with inhibitory effect concentration-dependent, while the root extracts showed no allelopathic effects on the germination process. Both extracts caused abnormalities and inhibited the growth of shoot and root seedlings.

Allelopathic effects of Sonchus oleraceus L. on the germination and seedling growth of crop and weed species

Gomaa,Nasr Hassan; Hassan,Mahmoud Omar; Fahmy,Gamal Mohammad; González,Luís; Hammouda,Ola; Atteya,Atteya Mostafa
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2014 EN
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We assessed the allelopathic effects of the aqueous extract of Sonchus oleraceus dry shoots on the germination and seedling growth of Trifolium alexandrinum, three weed species (Brassica nigra, Chenopodium murale and Melilotus indicus) and S. oleraceus itself. We assayed four different concentrations of the aqueous extract (w v-1): 1%, 2%, 3% and 4%. To determine whether the effects of the extract were attributable to the presence of allelopathic compounds, its osmotic potential or both, we prepared concentrations of polyethylene glycol (PEG) with osmotic potentials equivalent to those of the aqueous extract. All concentrations of the plant extract completely inhibited the germination and seedling growth of C. murale. The lowest concentration of the plant extract partially inhibited germination and seedling growth of B. nigra, M. indicus and S. oleraceus, whereas the higher concentrations inhibited those parameters completely. The germination of T. alexandrinum was not affected by the aqueous extract at 1% or 2%. In general, the aqueous extracts were more effective in inhibiting seed germination and seedling growth than were the PEG solutions. Phytochemical analyses revealed that phenols and alkaloids were the most abundant compounds in S. oleraceus dry matter. Our results suggest that the aqueous extract of S. oleraceus has an allelopathic effect on some weeds...

Allelopathic effect of essential oils of medicinal plants in Bidens pilosa L.

Alves,M.C.S.; Medeiros Filho,S.; Manoel Neto,A.; Brito,R.C.; Araujo,R.C.
Fonte: Sociedade Brasileira de Plantas Medicinais Publicador: Sociedade Brasileira de Plantas Medicinais
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
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We determined the inhibitory allelopathic effects of the volatile extracts of Cinnamomum zeylanicum Ness, Lippia sidoides Cham. and Cymbopogum nardus L. on seed germination and root growth of seedlings of Bidens pilosa. The experiment was conducted at the Seed Analysis Laboratory of the Department of Plant Science, Federal University of Ceará. For this end, we used oils at the concentrations of 0.01, 0.02, 0.04 and 0.08% (v/v). Five treatments were used for each of the oils arranged in a completely randomized design with four replications of 25 seeds. The seeds were sown in Petri dishes lined with filter paper moistened with distilled water and, aiming at the indirect contact with each oil, two sheets of filter paper were placed on top of the lid, in which three (3) mL of each oil solution were added. Then, the dishes were incubated in a germination chamber at 25°C. The pH did not contribute to alter the results; the volatile extracts of essential oils of C. zeylanicum, L. sidoides and C. nardus inhibited seed germination and root growth of seedlings of B. pilosa, which shows allelopathic potential; and the concentration of 0.08% of oils caused the overall deterioration of the roots and death of seedlings of B. pilosa.

Comparative allelopathic effects of Cryptocarya moschata and Ocotea odorifera aqueous extracts on Lactuca sativa

Prichoa,Franciele Carla; Leyser,Gabriela; Oliveira,José Vladimir de; Cansian,Rogério Luis
Fonte: Editora da Universidade Estadual de Maringá - EDUEM Publicador: Editora da Universidade Estadual de Maringá - EDUEM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2013 EN
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The aim of this work was to compare the allelopathic effects of aqueous leaf extracts from Cryptocarya moschata and Ocotea odorifera on the seed germination and initial growth of Lactuca sativa (lettuce). The extracts were prepared by cold maceration, which was accomplished by adding distilled water to the dried plant material 1:10 (w v-1) and grinding. The treatment concentrations (0, 0.25, 0.5, 0.75 and 1%) were obtained by dissolving the dried crude extract in distilled water. The allelopathic potential of the dried Ocotea odorifera and Cryptocarya moschata leaves on Lactuca sativa was observed through reduction of the percentage of seeds that germinated, the index of germination and the length of the roots as well as structural abnormalities in L. sativa seedlings. For both extracts, the extract concentration and allelopathic effect were highly correlated. However, the C. moschata extract had no effect on caulicle length at the different tested concentrations.

Allelopathic effects of Ulva pertusa, Corallina pilulifera and Sargassum thunbergii on the growth of the dinoflagellates Heterosigma akashiwo and Alexandrium tamarense

Wang, Renjun; Xiao, Hui; Zhang, Peiyu; Qu, Liang; Cai, Hengjiang; Tang, Xuexi
Fonte: Kluwer Academic Publishers Publicador: Kluwer Academic Publishers
Tipo: Artigo de Revista Científica
EN
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The allelopathic effects of fresh tissue, dry powder and aqueous extracts of three macroalgae, Ulva pertusa, Corallina pilulifera and Sargassum thunbergii, on the growth of the dinoflagellates Heterosigma akashiwo and Alexandrium tamarense were evaluated using coexistence culture systems in which concentrations of the three macroalga were varied. The results of the coexistence assay showed that the growth of the two microalgae was strongly inhibited by using fresh tissue, dry powder and aqueous extracts of the three macroalga; the allelochemicals were lethal to H. akashiwo at relatively higher concentrations of the three macroalga. The macroalgae showing the most allelopathic effect on H. akashiwo and A. tamarense using fresh tissue were U. pertusa and S. thunbergii, using dry powder were S. thunbergii and U. pertusa, and using aqueous extracts were U. pertusa and C. pilulifera. We also examined the potential allelopathic effect on the two microalgae of culture filtrate of the three macroalga; culture medium filtrate initially exhibited no inhibitory effects when first added but inhibitory effects became apparent under semi-continuous addition, which suggested that continuous release of small quantities of rapidly degradable allelochemicals from the fresh macroalgal tissue were essential to effectively inhibit the growth of the two microalgae.

Allelopathic Effects of Litter Axonopus compressus against Two Weedy Species and Its Persistence in Soil

Samedani, B.; Juraimi, A. S.; Rafii, M. Y.; Anuar, A. R.; Sheikh Awadz, S. A.; Anwar, M. P.
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Publicado em 23/10/2013 EN
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This study investigated the allelopathic effect of Axonopus compressus litter on Asystasia gangetica and Pennisetum polystachion. In experiment 1 the bioassays with 0, 10, 30, and 50 g L−1 of aqueous A. compressus litter leachate were conducted. Experiment 2 was carried out by incorporating 0, 10, 20, 30, 40, and 50 g L−1 of A. compressus litter leachate into soil. In experiment 3, the fate of A. compressus litter leachate phenolics in the soil was investigated. A. compressus leachates did not affect the germination percentage of A. gangetica and P. polystachion, but delayed germination of A. gangetica seeds and decreased seed germination time of P. polystachion. A. compressus litter leachates affected weeds hypocotyl length. Hypocotyl length reductions of 18 and 31% were observed at the highest concentration (50 g L−1) compared to the control in A. gangetica and P. polystachion, respectively. When concentration of A. compressus litter leachate-amended soil increased A. gangetica and P. polystachion seedling shoot length, root length, seedling weight and chlorophyll concentration were not affected. The 5-week decomposition study of A. compressus showed that the phenolic compounds in A. compressus litter abruptly decreased about 52% after two weeks and remained steady until the end of the incubation.

Efeito de cascas de café e de arroz dispostas nas camadas do solo sobre a germinação e o crescimento inicial do Caruru-de-mancha; Allelopathic Effect of Coffee and Rice husks arranged in soil layers on the germination and initial growth of Amaranthus viridis

Fonte: Sociedade Brasileira da Ciência das Plantas Daninhas Publicador: Sociedade Brasileira da Ciência das Plantas Daninhas
Tipo: Artigo de Revista Científica
PT_BR
Relevância na Pesquisa
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Studies of plant residue effects involving mulches to control weeds in perennial crops are difficult to carry out due to the need to differentiate between allelopathy and competition. Many researches, nowadays, refer to criteria proving allelopathy. This work was established under greenhouse conditions to determine the allelopathic effects of coffee and rice husks on Amaranthus viridis through their arrangements in soil layers. The experimental design was a randomized block with four replications, arranged in a 3 x 3 factorial scheme, with coffee and rice husks and expanded vermiculite being one factor and their residues placed on the top and incorporated into the soil surface and into the bottom, as the other factor. One additional treatment without mulching was used. Overall, plant residues inhibited seed germination and stimulated growth of slender amaranth. Rice husk showed lower emergent velocity index and seed germination than coffee husk. Coffee husk placed on the top provided greater growth and higher dry matter weight of slender amaranth, followed by husk incorporation into the soil surface.

Alelopatia de adubos verdes sobre feijoeiro comum (Phaseolus vulgaris L.); Allelophathy of green manures on common bean plants (Phaseolus vulgaris L.

Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica
PT_BR
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This study aimed at evaluating the allelopathic effect of species used as cover crops in no-tillage system on common bean crop. It was conducted in the greenhouse and at the Seed Analysis Laboratory in the Agricultural Department of the Federal University of Lavras, Brazil. The cover crop species used in the experiment were sunn hemp, jack bean, pigeon pea, black oat, sorghum and millet, with and without intercropping, with their straws collected at the early grain filling stage. The aqueous extracts of 5% and 10% (w/v) obtained from those straws were placed in plastic boxes (Gerbox®-type) containing common bean seeds. The straws were also laid on the substrate surface sown with common bean in plastic pots and installed in the greenhouse for chemical and physical effects evaluation of the cover crops. Considering most of the variables studied, it was not verified any damage by either using of mulch or by applying allelopathic extracts. When used as mulch or when applied as aqueous extracts, residues from the intercropping between sunn hemp and sorghum positively affected the common bean plant, benefiting its initial growth.

Atividades alelopáticas de nim sobre o crescimento de sorgo, alface e picão-preto; Allelopathic activities of nim on the growth of sorghum, lettuce and Bidens pilosa

Fonte: Universidade Federal de Lavras Publicador: Universidade Federal de Lavras
Tipo: Artigo de Revista Científica
PT_BR
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The search for alternatives for the synthetic herbicides, as the natural products from plants, may increase one more element to the handling of the harmful plants of the cultures. The aim of this work was to verify the allelopathic effects of neem (Azadirachta indica A. Juss.) upon sorghum, lettuce, and Bidens pilosa L. (beggustick) seeds germination and seedlings growth. Aqueous, methanolic, and hexanolic extracts, in the concentrations of 10, 5 and 2,5% (w/v) of nim leaves, were used to irrigate seeds of the plant test, in gerbox boxes, staying in incubator, type BOD. Germination percentages of lettuce seeds and beggustick irrigated with aqueous and methanolic extracts, respectively, were the most harmful to the development of the plants; for sorghum, independently of the used extractor, the increase of the concentration caused reduction of the germination percentages. The aqueous extract caused larger detrimental effect on the index of germination speed for the three studied species. For the sorghum, independently of the appraised concentration, the aqueous extract was the most harmful, differing from the other extractors, with averages of 8.00; 12.986 and 14.68, for the extractors distilled water, hexanol and methanol, respectively. When the biomass accumulation was analyzed for beggustick plants and sorghum...

The Allelopathic Effect of Eucalyptus Leaf Extract on Grass Forage Seed

Carvalho,F.P.; Melo,C.A.D.; Machado,M.S.; Dias,D.C.F.S.; Alvarenga,E.M.
Fonte: Sociedade Brasileira da Ciência das Plantas Daninhas Publicador: Sociedade Brasileira da Ciência das Plantas Daninhas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
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This study aimed to evaluate the allelopathic effect of various concentrations of an aqueous extract of eucalyptus leaves on Urochloa decumbens and Panicum maximum seeds. The extract was prepared from Eucalyptus urograndis leaves that were milled and mixed with distilled water in a 1:9 milled leaves: water ratio to obtain an extract with a defined concentration of 100%. In addition, dilutions of 50%, 25% and 12.5% were prepared, and a 0% dilution was used as a control. The experiment followed a completely randomized design, with four replicates, each of 50 seeds of U. decumbens and 50 seeds of P. maximum, arranged on filter paper moistened with each concentration of extract in a Gerbox plastic box. The results demonstrated the allelopathic potential of E. urograndis aqueous extracts applied to the seeds of U. decumbens and P. maximum. The 50% and 100% concentrations of leaf extract most strongly inhibited the germination, vigor and seedling growth of U. decumbens and P. maximum. The germination speed index and the root length were the characteristics that were most affected by the potentially allelopathic substances contained in the eucalyptus extracts at all concentrations.

Hydroxamic acids in Secale cereale L. and the relationship with their antifeedant and allelopathic properties

Bravo, Héctor R.; Argandoña Cortés, Víctor Hugo; Pizarro, Lorena; Villarroel, Elisa; Copaja Castillo, Sylvia Violeta
Fonte: VERLAG Z NATURFORSCH Publicador: VERLAG Z NATURFORSCH
Tipo: Artículo de revista
EN
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Contents of the hydroxamic acids 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) in leaves and roots of 14 cultivars of rye, Secale cereale L., were determined. Dynamics of accumulation in three cultivars were evaluated. DIBOA was the main cyclic hydroxamic acid in leaves but the contents differed significantly between the cultivars. Both DIBOA and DIMBOA were present in the roots. Maximum concentration of DIBOA in leaves and DIMBOA in roots was reached between 48-54 h and 54-72 h after germination, respectively. Antifeedant activity of DIBOA towards the aphid Rhopalosiphum padi and the feeding behavior were studied by electronic recording in barley leaves treated with different contents of DIBOA. The deleterious activity of DI-BOA could arise by starvation and/or a toxic effect. Additionally, allelopathic potential of pure DIBOA and aqueous extracts of leaves and roots of rye (Tetra-Baer) on the germination of lettuce (Lactuca sativa) and rye (Tetra-Baer) seeds was evaluated. A high percentage of germination inhibition of pure DIBOA and the extracts of leaves and roots was observed. The activity is in agreement with the contents of hydroxamic acids in the plants. The substrates had no allelopathic effect on rye seeds.

Ação alelopática de alguns extratos de plantas daninhas na germinação do arroz (Oryza sativa L. cv. IAC - 165); Allelopathic action of some weed extracts on rice germination

Castro, Paulo R.C.; Rodrigues, João D.; Maimoni-Rodella, Rita C.S.; Rabelo, Julio C.; Veiga, Renato F.A.; Lima, Giuseppina P.P.; Jureidini, Pedro; Denadai, Irene A.M.
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 01/01/1984 POR
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The present study was carried out to evaluate the possible allelopathic effects of Cynodon dactylon, Cyperus rotundus and Sorghum halepense on seed germination of Oryza sativa cv. IAC-165. Extracts from roots of Cynodon dactylon and Sorghum halepense and from tubers of Cyperus rotundas were used to evaluate the effects on rice seed germination. Aqueous solution of these organs, obtained by homogenization, filtration and centrifugation, were introduced on Petri dishes containing rice seeds. The evaluation of germination and initial growth showed a strong negative allelopathic effect of all three weeds studied.; O efeito do extrato aquoso de três plantas daninhas, Cynodon dactylon (l.)Pers., Cyperus rotundus l. e Sorghum halepense (l.) Pers. sobre a germinação e o crescimento de plântulas de arroz (Oryza salina L. cv. IAC-165) foi estudado, com a finalidade de investigar a sensibilidade do arroz aos efeitos alelopáticos dessas plantas. Foram utilizados, na preparação dos extratos, raizes de Cynodon daclylon, tubérculos de Cyperus rolundus: e riomas de Sorglun halepense, os quais foram homoneizados em solução aquosa, submetidos a filtração e centrifugação. O sobrenadante foi aplicado no substrato de germinação das sementes...

Allelopathic effect of melissa, lemongrass, lavender and rosemary on germination and vigor of lettuce seeds; Efeito alelopático de melissa, capim-cidreira, lavanda e alecrim na germinação e vigor de sementes de alface

Teixeira, Daniela Aparecida; UNESP-Campus Botucatu; Bonfim, Filipe Pereira Giardini; UNESP/FCA- Botucatu
Fonte: Universidade Federal de Santa Catarina Publicador: Universidade Federal de Santa Catarina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 29/09/2014 POR
Relevância na Pesquisa
591.8897%
http://dx.doi.org/10.5007/2175-7925.2014v27n4p37The objective of this study was to evaluate the influence of four herbal plants on the germination and vigor of lettuce seeds, using aqueous preparations and teas of Melissa officinalis L. (melissa), Rosmarinus officinalis L. (rosemary), Lavandula angustifolia Mill. (lavender) and Cymbopogon citratus (DC.) Stapf. (lemongrass). A randomized complete block design was used with 9 treatments and 4 repetitions. The treatments were: melissa tea, melissa aqueous preparation, rosemary tea, rosemary aqueous preparation, lavender tea, lavender aqueous preparation, lemongrass tea, lemongrass aqueous preparation and control. The variables evaluated were: germination speed index, percentage of abnormal plants, percentage of germinated plants, fresh matter, dry matter, shoot length and radicle length. Lemongrass showed negative allelopathic effects on germination and vigor of L. sativa L. Melissa tea had a stimulatory effect.; http://dx.doi.org/10.5007/2175-7925.2014v27n4p37Objetivou-se, neste estudo, avaliar a influência na germinação e vigor de sementes de alface (Lactuca sativa L.) de macerados e infusões de Melissa officinalis L. (melissa), Rosmarinus officinalis L. (alecrim), Lavandula angustifolia Mill. (lavanda) e Cymbopogon citratus (DC.) Stapf. (capim-cidreira). O delineamento estatístico utilizado foi inteiramente casualizado...

Atividade alelopática do exsudato radicular de Jatropha curcas L. sobre plântulas de Brassica napus L., Glycine max L., Zea mays L. e Helianthus annuus L.; Allelopathic activity of the root exudate of Jatropha curcas L. on seedlings of Brassica napus L., Glycine max L., Zea mays L. and Helianthus annuus L.

da Silva, Paulo Sérgio Siberti; Universidade Estadual “Júlio de Mesquita Filho”, Botucatu, SP.; Fortes, Andréa Maria Teixeira; Universidade Estadual do Oeste do Paraná, Cascavel, PR.; Pilatti, Daiane Maria; Universidade Estadual do Oeste do Paran
Fonte: Universidade Federal de Santa Catarina Publicador: Universidade Federal de Santa Catarina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; Formato: application/pdf
Publicado em 24/12/2012 POR
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382.96227%
http://dx.doi.org/10.5007/2178-4574.2012n41p32 O objetivo foi avaliar o efeito do exsudato radicular de J. curcas sobre a germinação e crescimento inicial das plântulas de B. napus, G. max, Z. mays e H. annuus. Utilizaram-se rolos de papel germitest e placas de Petri com papel filtro onde se adicionou, respectivamente, por repetição, 15 e cinco sementes de J. curcas para germinar durante oito dias para obtenção do exsudato radicular. Após este período, as plântulas foram descartadas e 50 sementes de G. max, H. annuus e Z. mays foram adicionadas para germinar por sete dias nos rolos de papel e 25 sementes de B. napus, por oito dias nas placas de Petri. Foram realizadas quatro repetições e os experimentos foram acondicionados em câmara de germinação com fotoperíodo e temperatura controlados. O delineamento experimental foi inteiramente casualizado e avaliaram-se os parâmetros porcentagem de germinação, tempo médio de germinação, velocidade média de germinação e comprimento da maior raiz. Após análise estatística (teste de Tukey 5% de probabilidade) concluiu-se que J. curcas exerceu efeito alelopático diverso sobre as espécies testadas, apresentando efeito positivo sobre plântulas de G. max (tempo e velocidade médios de germinação...