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| Queiroz,Helena Müller; Sodek,Ladaslav; Haddad,Claudia Regina Baptista. |
| Soybean plants cultivated with 50, 100 and 200 mM of NaCl, revealed that root growth was less affected by salinity than shoots. Salinity led to a reduction in leaf area and an increase in water content of the roots. These factors could contribute to the adaptation of the plant, improving its hydration. Although nitrate and free amino acid levels were reduced by salt treatment in roots, protein content of leaves was not altered. Salinity led to alterations in xylem amino acid composition, with increases in Ser, Ala, Gaba and Pro and a decrease in Asn. Similar changes were seen for Asn and Ser in roots together with a much stronger increase in Gaba. It is suggested that the decline in Asn reflects its conversion to Ala and Gaba (via Glu) in the roots while... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soybean; Stress; Amino acid transport; Asparagine; Alanine; Γ-aminobutyrate. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132012000600002 |
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| Haddad,Claudia Regina Baptista; Lemos,Damiani Pereira; Mazzafera,Paulo. |
| In comparison to deciduous species, evergreen plants have lower leaf nutrient contents and higher leaf life span, important mechanisms for nutrient economy, allowing the colonization of low fertility soils. Strategies to conserve nitrogen in two semideciduous tropical forest tree species, with different leaf life spans were analyzed. The hypothesis was the fact that the two species would present different nitrogen conservation mechanisms in relation to chemical (total nitrogen, protein, chlorophyll, and proteolytic activity), functional (leaf life span, N-use efficiency, and N-resorption efficiency), morphological (specific leaf mass) leaf characteristics, and total nitrogen in the soil. Hymenaea courbaril L. presented lower nitrogen compounds in leaves,... |
| Tipo: Info:eu-repo/semantics/report |
Palavras-chave: Leaf life span; Specific leaf mass; N-resorption efficiency; N-use efficiency; Atlantic forest. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000400018 |
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| Lima,Ana Lúcia da Silva; Zanella,Fábio; Schiavianto,Marlene Aparecida; Haddad,Claudia Regina Baptista. |
| Prior to abscission, nutrients are redeployed from leaves and redistributed to other parts of the plant. Data comparing nutrient resorption to soil fertility and leaf life span remains controversial in the literature. We compared nitrogen (N) conservation mechanisms among four legume trees with different leaf life spans (Hymenaea courbaril L. var. stilbocarpa (Hayne) Lee et Lang., Lonchocarpus guilleminianus (Tul.) Malme, Enterolobium contortisiliquum (Vell.) Morong and Peltophorum dubium (Spreng.) Taub.), from a semideciduous tropical forest, remnant of the Atlantic Forest. We hypothesized that these mechanisms differ among the four species and are affected by their leaf life span and by the availability of N, both as a mineral in the soil and, in the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Leaf life span; Nitrogen fixation; Nitrogen resorption efficiency; Nitrogen resorption proficiency; Nitrogen-use efficiency. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062006000300012 |
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| Corte,Guilherme Nascimento; Macchiaverni,Patrícia; Fabbro,Inácio Maria Dal; Haddad,Claudia Regina Baptista. |
| Evergreen species of temperate regions are dominant in low-nutrient soils. This feature is attributed to more efficient mechanisms of nutrient economy. Nevertheless, the cashew (Anacardium occidentale- Anacardiaceae), a deciduous species, is native to regions in Brazil with sandy soil, whilst the annatto (Bixa orellana- Bixaceae), classified as an evergreen species native to tropical America, grows spontaneously in regions with more humid soils. Evergreens contain robust leaves that can resist adverse conditions for longer. The physical aspects of the leaves and mechanisms of nutrient economy between the two species were compared, in order to verify whether the deciduous species had more efficient mechanisms that might explain its occurrence in regions of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Leaf deciduity; Nitrogen resorption proficiency; Nitrogen use efficiency; Leaf rupture strain. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000600014 |
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| Lima,Ana Lúcia da Silva; Zanella,Fábio; Schiavinato,Marlene Aparecida; Haddad,Claudia Regina Baptista. |
| In general, perennial species contain higher concentrations of certain secondary compounds, such as phenolics, lower levels of nitrogenous compounds, and greater specific leaf mass (SLM) than deciduous species. The aim of this study was to verify whether the comparative data reported in the literature regarding deciduous and evergreen species, also applies to four selected species of a semideciduous tropical forest (a remnant of the Atlantic Forest). The four species chosen for this study, each with apparently different leaf life spans, were two semideciduous (Hymenaea courbaril L. var. stilbocarpa (Hayne) Lee et Lang., and Lonchocarpus guilleminianus (Tul.) Malme, and two deciduous (Enterolobium contortisiliquum (Vell.) Morong., and Peltophorum dubium... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Leaf life span; Specific leaf mass; Total nitrogen; Tannins; Atlantic forest. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000100007 |
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