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Nitrogen and Phosphorus Retranslocation of Leaves and Stemwood in a Mature Eucalyptus Forest Exposed to 5 Years of Elevated CO(2)
Elevated CO(2) affects C cycling processes which in turn can influence the nitrogen (N) and phosphorus (P) concentrations of plant tissues. Given differences in how N and P are used by plants, we asked if their stoichiometry in leaves and wood was maintained or altered in a long-term elevated CO(2)...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6554339/ https://www.ncbi.nlm.nih.gov/pubmed/31214212 http://dx.doi.org/10.3389/fpls.2019.00664 |
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author | Crous, Kristine Y. Wujeska-Klause, Agnieszka Jiang, Mingkai Medlyn, Belinda E. Ellsworth, David S. |
author_facet | Crous, Kristine Y. Wujeska-Klause, Agnieszka Jiang, Mingkai Medlyn, Belinda E. Ellsworth, David S. |
author_sort | Crous, Kristine Y. |
collection | PubMed |
description | Elevated CO(2) affects C cycling processes which in turn can influence the nitrogen (N) and phosphorus (P) concentrations of plant tissues. Given differences in how N and P are used by plants, we asked if their stoichiometry in leaves and wood was maintained or altered in a long-term elevated CO(2) experiment in a mature Eucalyptus forest on a low P soil (EucFACE). We measured N and P concentrations in green leaves at different ages at the top of mature trees across 6 years including 5 years in elevated CO(2). N and P concentrations in green and senesced leaves and wood were determined to evaluate both spatial and temporal variation of leaf N and P concentrations, including the N and P retranslocation in leaves and wood. Leaf P concentrations were 32% lower in old mature leaves compared to newly flushed leaves with no effect of elevated CO(2) on leaf P. By contrast, elevated CO(2) significantly decreased leaf N concentrations in newly flushed leaves but this effect disappeared as leaves matured. As such, newly flushed leaves had 9% lower N:P ratios in elevated CO(2) and N:P ratios were not different in mature green leaves (CO(2) by Age effect, P = 0.02). Over time, leaf N and P concentrations in the upper canopy slightly declined in both CO(2) treatments compared to before the start of the experiment. P retranslocation in leaves was 50%, almost double that of N retranslocation (29%), indicating that this site was P-limited and that P retranslocation was an important mechanism in this ecosystem to retain P in plants. As P-limited trees tend to store relatively more N than P, we found an increased N:P ratio in sapwood in response to elevated CO(2) (P < 0.01), implying N accumulation in live wood. The flexible stoichiometric ratios we observed can have important implications for how plants adjust to variable environmental conditions including climate change. Hence, variable nutrient stoichiometry should be accounted for in large-scale Earth Systems models invoking biogeochemical processes. |
format | Online Article Text |
id | pubmed-6554339 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-65543392019-06-18 Nitrogen and Phosphorus Retranslocation of Leaves and Stemwood in a Mature Eucalyptus Forest Exposed to 5 Years of Elevated CO(2) Crous, Kristine Y. Wujeska-Klause, Agnieszka Jiang, Mingkai Medlyn, Belinda E. Ellsworth, David S. Front Plant Sci Plant Science Elevated CO(2) affects C cycling processes which in turn can influence the nitrogen (N) and phosphorus (P) concentrations of plant tissues. Given differences in how N and P are used by plants, we asked if their stoichiometry in leaves and wood was maintained or altered in a long-term elevated CO(2) experiment in a mature Eucalyptus forest on a low P soil (EucFACE). We measured N and P concentrations in green leaves at different ages at the top of mature trees across 6 years including 5 years in elevated CO(2). N and P concentrations in green and senesced leaves and wood were determined to evaluate both spatial and temporal variation of leaf N and P concentrations, including the N and P retranslocation in leaves and wood. Leaf P concentrations were 32% lower in old mature leaves compared to newly flushed leaves with no effect of elevated CO(2) on leaf P. By contrast, elevated CO(2) significantly decreased leaf N concentrations in newly flushed leaves but this effect disappeared as leaves matured. As such, newly flushed leaves had 9% lower N:P ratios in elevated CO(2) and N:P ratios were not different in mature green leaves (CO(2) by Age effect, P = 0.02). Over time, leaf N and P concentrations in the upper canopy slightly declined in both CO(2) treatments compared to before the start of the experiment. P retranslocation in leaves was 50%, almost double that of N retranslocation (29%), indicating that this site was P-limited and that P retranslocation was an important mechanism in this ecosystem to retain P in plants. As P-limited trees tend to store relatively more N than P, we found an increased N:P ratio in sapwood in response to elevated CO(2) (P < 0.01), implying N accumulation in live wood. The flexible stoichiometric ratios we observed can have important implications for how plants adjust to variable environmental conditions including climate change. Hence, variable nutrient stoichiometry should be accounted for in large-scale Earth Systems models invoking biogeochemical processes. Frontiers Media S.A. 2019-05-31 /pmc/articles/PMC6554339/ /pubmed/31214212 http://dx.doi.org/10.3389/fpls.2019.00664 Text en Copyright © 2019 Crous, Wujeska-Klause, Jiang, Medlyn and Ellsworth. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Plant Science Crous, Kristine Y. Wujeska-Klause, Agnieszka Jiang, Mingkai Medlyn, Belinda E. Ellsworth, David S. Nitrogen and Phosphorus Retranslocation of Leaves and Stemwood in a Mature Eucalyptus Forest Exposed to 5 Years of Elevated CO(2) |
title | Nitrogen and Phosphorus Retranslocation of Leaves and Stemwood in a Mature Eucalyptus Forest Exposed to 5 Years of Elevated CO(2) |
title_full | Nitrogen and Phosphorus Retranslocation of Leaves and Stemwood in a Mature Eucalyptus Forest Exposed to 5 Years of Elevated CO(2) |
title_fullStr | Nitrogen and Phosphorus Retranslocation of Leaves and Stemwood in a Mature Eucalyptus Forest Exposed to 5 Years of Elevated CO(2) |
title_full_unstemmed | Nitrogen and Phosphorus Retranslocation of Leaves and Stemwood in a Mature Eucalyptus Forest Exposed to 5 Years of Elevated CO(2) |
title_short | Nitrogen and Phosphorus Retranslocation of Leaves and Stemwood in a Mature Eucalyptus Forest Exposed to 5 Years of Elevated CO(2) |
title_sort | nitrogen and phosphorus retranslocation of leaves and stemwood in a mature eucalyptus forest exposed to 5 years of elevated co(2) |
topic | Plant Science |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6554339/ https://www.ncbi.nlm.nih.gov/pubmed/31214212 http://dx.doi.org/10.3389/fpls.2019.00664 |
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