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| Sosnovsky,Alejandro; Quirós,Rolando. |
| El estado trófico de las lagunas pampeanas es influenciado tanto por la fertilidad de los suelos y las condiciones hidrometeorológicas como por las actividades humanas. El clima de la región pampeana alterna relativamente extensos períodos de sequía y de inundación. El uso de fertilizantes en las áreas con un intensivo uso agrícola puede afectar el estado trófico de los cuerpos de agua a través del aporte de nutrientes. Entre diciembre de 1999 y abril de 2002 se estudiaron siete pequeñas lagunas situadas en el NO de la provincia de Buenos Aires. Se analizaron las variaciones en la profundidad máxima, la conductividad, las concentraciones de nutrientes y la clorofila a. Las lluvias fueron intensas durante los años 2000 y 2001. Durante el año 2000, éstas... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lagos someros; Pampas; Eutrofización. |
| Ano: 2006 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1667-782X2006000200003 |
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| Mäder,Geraldo; Castro,Luana; Bonatto,Sandro Luis; Freitas,Loreta Brandão de. |
| Abstract Non-indigenous plants exhibit different attributes that make them aggressive competitors with indigenous plants and serious threats to biodiversity.Senecio madagascariensis (fireweed, Asteraceae), a native from southern Africa, is a strong competitor in agricultural activities and has toxic alkaloids that may result in high cattle mortality. In Brazil, this weed was collected for the first time in 1995 and has since spread quickly throughout the Pampas region. To better understand the invasion of the fireweed in South America, we used a genetic characterization with internal transcribed spacer (ITS) and microsatellite markers. Based on the ITS data, the southern Brazil populations of S. madagascariensis shared genetic homology with samples taken... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Microsatellites; ITS; Pampas; Weed; Spread. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572016000100135 |
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| Rodrigues,Daniele M.; Turchetto,Caroline; Callegari-Jacques,Sidia M.; Freitas,Loreta B.. |
| ABSTRACT The reproductive system of flowering plants can be highly variable, affecting their biology, gene flow and genetic variability among populations. Petunia secreta is a rare annual endemic species of Pedra do Segredo, located in the municipality of Caçapava do Sul, state of Rio Grande do Sul, Brazil. Although rare, the species possesses a high level of genetic variability. We investigated the reproductive system of P. secreta, including fruit production and seed germinability, in order to determine if its reproductive system can explain its genetic diversity. We sampled five populations and conducted five greenhouse hand-pollination treatments: 1) autonomous apomixis; 2) self-pollination; 3) hand self-pollination; 4) geitonogamy; and 5)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Endogamy; Pampas; Petunia; Reproductive success; Reproductive system; Seed germinability. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062018000200180 |
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