| Registro completo |
| Provedor de dados: |
Scientia Agricola
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| País: |
Brazil
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| Título: |
Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patterns
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| Autores: |
Santos,Patricia Menezes
Thornton,Barry
Corsi,Moacyr
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| Data: |
2012-10-01
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| Ano: |
2012
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| Palavras-chave: |
Clipping height
Guineagrass
Organic reserves
Regrowth
Tropical grass
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| Resumo: |
Dry mass production and persistence of Panicum maximum pastures depends on nitrogen supply. Defoliation influences N uptake and allocation patterns yet its effects on plasticity of N dynamics in P. maximum have not been investigated. Stable isotopes of N (15N) were used in order to test the hypothesis that defoliation in terms of proportion of the leaf area removed effects N mobilisation, uptake and allocation patterns in P. maximum. The plants were initially cut weekly to a height of either 0.15 m or 0.30 m for seven weeks. Eight weeks after the first defoliation, all plants were defoliated for a final time to remove 0, 25, 50, 75 or 100 % of the area of each individual leaf blade of the main tiller. Root N uptake was reduced when all leaf area was removed, but more lenient defoliation improved N uptake due to a positive effect on specific N uptake. Young leaves, side tillers and roots were the main sinks for N from root uptake. Roots of P. maximum became a net source of N for mobilisation immediately after severe defoliation. Root uptake was the main source of N for new growth in P. maximum plants. Allocation pattern of mobilised N was different from that of N derived from root uptake. It was concluded that adaptation of P. maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation, but changes in N dynamics did not offset negative impacts of complete defoliation of the plants.
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| Tipo: |
Info:eu-repo/semantics/article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162012000500002
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| Editor: |
São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
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| Relação: |
10.1590/S0103-90162012000500002
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| Formato: |
text/html
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| Fonte: |
Scientia Agricola v.69 n.5 2012
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| Direitos: |
info:eu-repo/semantics/openAccess
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