Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patterns
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 hypothes...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Universidade de São Paulo
2012-10-01
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| Series: | Scientia Agricola |
| Subjects: | |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162012000500002 |
| _version_ | 1818062002224889856 |
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| author | Patricia Menezes Santos Barry Thornton Moacyr Corsi |
| author_facet | Patricia Menezes Santos Barry Thornton Moacyr Corsi |
| author_sort | Patricia Menezes Santos |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-10T13:57:17Z |
| format | Article |
| id | doaj.art-8b885ec65c8844249bbd4002e2fe57a3 |
| institution | Directory Open Access Journal |
| issn | 0103-9016 1678-992X |
| language | English |
| last_indexed | 2024-12-10T13:57:17Z |
| publishDate | 2012-10-01 |
| publisher | Universidade de São Paulo |
| record_format | Article |
| series | Scientia Agricola |
| spelling | doaj.art-8b885ec65c8844249bbd4002e2fe57a32022-12-22T01:45:56ZengUniversidade de São PauloScientia Agricola0103-90161678-992X2012-10-0169529329910.1590/S0103-90162012000500002Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patternsPatricia Menezes SantosBarry ThorntonMoacyr CorsiDry 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.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162012000500002clipping heightguineagrassorganic reservesregrowthtropical grass |
| spellingShingle | Patricia Menezes Santos Barry Thornton Moacyr Corsi Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patterns Scientia Agricola clipping height guineagrass organic reserves regrowth tropical grass |
| title | Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patterns |
| title_full | Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patterns |
| title_fullStr | Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patterns |
| title_full_unstemmed | Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patterns |
| title_short | Adaptation of the C4 grass Panicum maximum to defoliation is related to plasticity of N uptake, mobilisation and allocation patterns |
| title_sort | adaptation of the c4 grass panicum maximum to defoliation is related to plasticity of n uptake mobilisation and allocation patterns |
| topic | clipping height guineagrass organic reserves regrowth tropical grass |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162012000500002 |
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