Direct uptake of organically derived carbon by grass roots and allocation in leaves and phytoliths: <sup>13</sup>C labeling evidence
In the rhizosphere, the uptake of low-molecular-weight carbon (C) and nitrogen (N) by plant roots has been well documented. While organic N uptake relative to total uptake is important, organic C uptake is supposed to be low relative to the plant's C budget. Recently, radiocarbon analyses demon...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-03-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/1693/2016/bg-13-1693-2016.pdf |
| _version_ | 1811323601513611264 |
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| author | A. Alexandre J. Balesdent P. Cazevieille C. Chevassus-Rosset P. Signoret J.-C. Mazur A. Harutyunyan E. Doelsch I. Basile-Doelsch H. Miche G. M. Santos |
| author_facet | A. Alexandre J. Balesdent P. Cazevieille C. Chevassus-Rosset P. Signoret J.-C. Mazur A. Harutyunyan E. Doelsch I. Basile-Doelsch H. Miche G. M. Santos |
| author_sort | A. Alexandre |
| collection | DOAJ |
| description | In the rhizosphere, the uptake of low-molecular-weight carbon (C) and
nitrogen (N) by plant roots has been well documented. While organic N uptake
relative to total uptake is important, organic C uptake is supposed to be low
relative to the plant's C budget. Recently, radiocarbon analyses demonstrated
that a fraction of C from the soil was occluded in amorphous silica
micrometric particles that precipitate in plant cells (phytoliths). Here, we
investigated whether and to what extent organically derived C absorbed by
grass roots can feed the C occluded in phytoliths. For this purpose we added
<sup>13</sup>C- and <sup>15</sup>N-labeled amino acids (AAs) to the silicon-rich
hydroponic solution of the grass <i>Festuca arundinacea</i>. The experiment
was designed to prevent C leakage from the labeled nutritive solution to the
chamber atmosphere. After 14 days of growth, the <sup>13</sup>C and <sup>15</sup>N
enrichments (<sup>13</sup>C excess and <sup>15</sup>N excess) in the roots, stems and
leaves as well as phytoliths were measured relative to a control experiment
in which no labeled AAs were added. Additionally, the <sup>13</sup>C excess was
measured at the molecular level, in AAs extracted from roots and stems and
leaves. The net uptake of labeled AA-derived <sup>13</sup>C reached 4.5 % of the total AA
<sup>13</sup>C supply. The amount of AA-derived <sup>13</sup>C fixed in the plant was
minor but not nil (0.28 and 0.10 % of total C in roots and stems/leaves,
respectively). Phenylalanine and methionine that were supplied in high
amounts to the nutritive solution were more <sup>13</sup>C-enriched than other AAs
in the plant. This strongly suggested that part of AA-derived <sup>13</sup>C was
absorbed and translocated into the plant in its original AA form. In
phytoliths, AA-derived <sup>13</sup>C was detected. Its concentration was on the
same order of magnitude as in bulk stems and leaves (0.15 % of the
phytolith C). This finding strengthens the body of evidences showing that
part of organic compounds occluded in phytoliths can be fed by C entering the
plant through the roots. Although this experiment was done in nutrient
solution and its relevance for soil C uptake assessment is therefore limited,
we discuss plausible forms of AA-derived <sup>13</sup>C absorbed and translocated
in the plant and eventually fixed in phytoliths, and implications of our
results for our understanding of the C cycle at the soil–plant–atmosphere
interface |
| first_indexed | 2024-04-13T13:58:04Z |
| format | Article |
| id | doaj.art-c72c6ee790724006ba6fe0a17d472436 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-04-13T13:58:04Z |
| publishDate | 2016-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-c72c6ee790724006ba6fe0a17d4724362022-12-22T02:44:08ZengCopernicus PublicationsBiogeosciences1726-41701726-41892016-03-011351693170310.5194/bg-13-1693-2016Direct uptake of organically derived carbon by grass roots and allocation in leaves and phytoliths: <sup>13</sup>C labeling evidenceA. Alexandre0J. Balesdent1P. Cazevieille2C. Chevassus-Rosset3P. Signoret4J.-C. Mazur5A. Harutyunyan6E. Doelsch7I. Basile-Doelsch8H. Miche9G. M. Santos10Aix-Marseille Université, CNRS, IRD, INRA, CEREGE UM34, 13545 Aix en Provence, FranceAix-Marseille Université, CNRS, IRD, INRA, CEREGE UM34, 13545 Aix en Provence, FranceCIRAD, UPR Recyclage et risque, 34398 Montpellier, FranceCIRAD, UPR Recyclage et risque, 34398 Montpellier, FranceINRA UR 1119 GSE, 13100 Aix-en-Provence, FranceAix-Marseille Université, CNRS, IRD, INRA, CEREGE UM34, 13545 Aix en Provence, FranceDepartment of Earth System Science, University of California, B321 Croul Hall, Irvine, CA 92697-3100, USACIRAD, UPR Recyclage et risque, 34398 Montpellier, FranceAix-Marseille Université, CNRS, IRD, INRA, CEREGE UM34, 13545 Aix en Provence, FranceAix-Marseille Université, CNRS, IRD, INRA, CEREGE UM34, 13545 Aix en Provence, FranceDepartment of Earth System Science, University of California, B321 Croul Hall, Irvine, CA 92697-3100, USAIn the rhizosphere, the uptake of low-molecular-weight carbon (C) and nitrogen (N) by plant roots has been well documented. While organic N uptake relative to total uptake is important, organic C uptake is supposed to be low relative to the plant's C budget. Recently, radiocarbon analyses demonstrated that a fraction of C from the soil was occluded in amorphous silica micrometric particles that precipitate in plant cells (phytoliths). Here, we investigated whether and to what extent organically derived C absorbed by grass roots can feed the C occluded in phytoliths. For this purpose we added <sup>13</sup>C- and <sup>15</sup>N-labeled amino acids (AAs) to the silicon-rich hydroponic solution of the grass <i>Festuca arundinacea</i>. The experiment was designed to prevent C leakage from the labeled nutritive solution to the chamber atmosphere. After 14 days of growth, the <sup>13</sup>C and <sup>15</sup>N enrichments (<sup>13</sup>C excess and <sup>15</sup>N excess) in the roots, stems and leaves as well as phytoliths were measured relative to a control experiment in which no labeled AAs were added. Additionally, the <sup>13</sup>C excess was measured at the molecular level, in AAs extracted from roots and stems and leaves. The net uptake of labeled AA-derived <sup>13</sup>C reached 4.5 % of the total AA <sup>13</sup>C supply. The amount of AA-derived <sup>13</sup>C fixed in the plant was minor but not nil (0.28 and 0.10 % of total C in roots and stems/leaves, respectively). Phenylalanine and methionine that were supplied in high amounts to the nutritive solution were more <sup>13</sup>C-enriched than other AAs in the plant. This strongly suggested that part of AA-derived <sup>13</sup>C was absorbed and translocated into the plant in its original AA form. In phytoliths, AA-derived <sup>13</sup>C was detected. Its concentration was on the same order of magnitude as in bulk stems and leaves (0.15 % of the phytolith C). This finding strengthens the body of evidences showing that part of organic compounds occluded in phytoliths can be fed by C entering the plant through the roots. Although this experiment was done in nutrient solution and its relevance for soil C uptake assessment is therefore limited, we discuss plausible forms of AA-derived <sup>13</sup>C absorbed and translocated in the plant and eventually fixed in phytoliths, and implications of our results for our understanding of the C cycle at the soil–plant–atmosphere interfacehttp://www.biogeosciences.net/13/1693/2016/bg-13-1693-2016.pdf |
| spellingShingle | A. Alexandre J. Balesdent P. Cazevieille C. Chevassus-Rosset P. Signoret J.-C. Mazur A. Harutyunyan E. Doelsch I. Basile-Doelsch H. Miche G. M. Santos Direct uptake of organically derived carbon by grass roots and allocation in leaves and phytoliths: <sup>13</sup>C labeling evidence Biogeosciences |
| title | Direct uptake of organically derived carbon by grass roots and allocation in leaves and phytoliths: <sup>13</sup>C labeling evidence |
| title_full | Direct uptake of organically derived carbon by grass roots and allocation in leaves and phytoliths: <sup>13</sup>C labeling evidence |
| title_fullStr | Direct uptake of organically derived carbon by grass roots and allocation in leaves and phytoliths: <sup>13</sup>C labeling evidence |
| title_full_unstemmed | Direct uptake of organically derived carbon by grass roots and allocation in leaves and phytoliths: <sup>13</sup>C labeling evidence |
| title_short | Direct uptake of organically derived carbon by grass roots and allocation in leaves and phytoliths: <sup>13</sup>C labeling evidence |
| title_sort | direct uptake of organically derived carbon by grass roots and allocation in leaves and phytoliths sup 13 sup c labeling evidence |
| url | http://www.biogeosciences.net/13/1693/2016/bg-13-1693-2016.pdf |
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