Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patterns
Título del documento: Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patterns
Revista: Scientia agricola
Base de datos: PERIÓDICA
Número de sistema: 000357865
ISSN: 0103-9016
Autores: 1
2
3
Instituciones: 1Empresa Brasileira de Pesquisa Agropecuaria, Pecuaria Sudeste, Sao Carlos, Sao Paulo. Brasil
2The James Hutton Institute, Aberdeen. Reino Unido
3Universidade de Sao Paulo, Escola Superior de Agricultura "Luiz de Queiroz", Piracicaba, Sao Paulo. Brasil
Año:
Periodo: Sep-Oct
Volumen: 69
Número: 5
País: Brasil
Idioma: Inglés
Tipo de documento: Artículo
Enfoque: Experimental, analítico
Resumen en inglés 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
Disciplinas: Agrociencias
Palabras clave: Gramíneas,
Fisiología vegetal,
Forraje,
Panicum maximum,
Trasquila,
Adaptación,
Nitrógeno,
Plantas C4,
Fotosíntesis
Keyword: Agricultural sciences,
Gramineae,
Plant physiology,
Feedstuff,
Panicum maximum,
Clipping,
Adaptation,
C4 plants,
Nitrogen,
Photosynthesis
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