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| Borghetti,Fabian; Lima,Elisa Coutinho de; Silva,Lucas de Carvalho Ramos. |
| Most studies conducted to test the allelopathic activity of plant parts have made use of water as solvent. However, the presence of polar, water-soluble substances, such as proteins and carbohydrates, tends to hamper the purification of active compounds. In this study, we present a simple purification procedure that separates the active fraction of the extract from the undesirable substances, thus facilitating the search for active molecules through standard chromatographic methods. Aqueous leaf extracts of three Cerrado species (Caryocar brasiliense, Qualea parviflora and Eugenia dysenterica) were prepared at 5% concentration (w/v) and stored at 4ºC (crude extracts). After 24 h, these solutions were filtered and freeze-dried. The powder obtained was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Allelopathy; Cerrado; Freeze-drying; Leaf extract; Purification. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062013000100007 |
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| Reigosa,Manuel; Gomes,Anabele Stefânia; Ferreira,Alfredo Gui; Borghetti,Fabian. |
| In this article, we review allelopathy studies conducted in Brazil or involving plant species that occur in the country. Conceptions and misconceptions associated with allelopathy, as well as some international criteria to be applied in allelopathic research, are presented and discussed. We observed a sharp increase in the number of papers on this subject conducted in Brazil between 1991 and 2010. However, most studies are conducted under laboratory conditions, lack a clear hypothesis or a solid justification, and typically make use of target species that do not co-exist with the donor species under natural conditions. We also found that most studies do not take the additional steps in order to purify and identify the bioactive molecules. We recommend that... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Allelopathy; Allelochemicals; Competition; Interference; Phytotoxicity; Weed control. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062013000400001 |
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| Schmidt,Isabel Belloni; Sampaio,Alexandre Bonesso; Borghetti,Fabian. |
| Heteropterys pteropetala é um arbusto comum no Cerrado. A dispersão dos diásporos ocorre na estação seca, quando queimadas são comuns. Investigamos efeitos da época de queima na reprodução sexuada e estrutura populacional deste espécie em um cerrado sensu stricto na Reserva Ecológica do IBGE, Brasília, DF, Brasil. As parcelas selecionadas para este estudo têm sido submetidas a queimas bienais em três meses diferentes (junho, agosto, setembro). A parcela controle é protegida do fogo. Quantificou-se o número de diásporos dispersos mensalmente, testou-se efeitos de altas temperaturas na viabilidade e na germinação, mediu-se a altura e diâmetro basal de todos os indivíduos encontrados em 1 ha/parcela, e estimou-se a distribuição espacial dos indivíduos e a... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heteropterys pteropetala; Cerrado; Fogo; Estrutura populacional; Germinação. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062005000400027 |
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| Borghetti,Fabian; Noda,Fabio Nakamura; Sá,Cezar Martins de. |
| Freshly harvested sunflower seeds (Helianthus annuus L., Asteraceae) present physiological dormancy localized at the embrionary axis which prevents germination at low temperatures. However, dormant embryos reach about 100 % germination when incubated with the phytohormone ethylene during imbibition. To examine whether proteinase activities are implicated in the breaking of dormancy by ethylene, dormant embryos were treated with the proteinase inhibitors leupeptin, E64 and the proteasome specific inhibitor clasto-lactacystin ß-lactone (lactacystin). A few embryos (< 10 %) germinated at 10 ºC in absence of ethylene but ethylene-treated embryos reached high germinability (~90 %) in the presence of leupeptin, E64, water and DMSO. On the other hand,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Helianthus annuus; Dormancy; Ethylene; Lactacystin; Proteasome. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202002000200007 |
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