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| Titel |
Influence of pCO2 on carbon allocation in nodulated Medicago sativa L. |
| VerfasserIn |
Gabriela Pereyra, Henrik Hartmann, Waldemar Ziegler, Beate Michalzik, Miquel Gonzalez-Meler, Susan Trumbore |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250135368
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| Publikation (Nr.) |
 EGU/EGU2016-16223.pdf |
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| Zusammenfassung |
| Atmospheric CO$_2$ concentrations (\textit{p}CO$_2$) have been related to changes in plant carbon (C) availability and photosynthetic capacity, yet there is no clear consensus as to the effect of \textit{p}CO$_2$ on the plant C balance and on nitrogen fixation in symbiotic systems. We investigated how different \textit{p}CO$_2$ (Pleistocene: 170 ppm, ambient: 400 ppm and projected future: 700 ppm) influence C allocation in nodulated Medicago sativa L. \newline
We labeled 17 week old plants with depleted $^{13}$C (-34.7$\pm$1.2\permil\) and traced the label over a 9-day period, to assess the redistribution of newly assimilated C across different sinks, including nodules. We analyzed N concentrations in plant tissues and found no significant differences in leaves and roots across treatments. However, growth and C fixation rates increased with \textit{p}CO$_2$, and differences were greatest between 170 ppm and 700 ppm. Across \textit{p}CO$_2$ treatments we observed a $^{13}$C-enrichment in roots compared to leaves. We further observed the highest $^{13}$C depletion of non-structural carbohydrates (NSCs) and respired CO$_2$ in tissues of plants grown at 700 ppm, especially in leaves and nodules.\newline
Our preliminary results suggest that sink organs like roots and nodules are fed with newly-assimilated NSCs from leaves to support respiration, and especially in 170 ppm plants represented a major respiratory loss of newly assimilated C ($\approx$ 35{\%} of the total plant respiration). Our results suggest that although plant metabolic processes like photosynthesis and respiration are affected by changes in \textit{p}CO$_2$, nitrogen acquisition in such a symbiotic system is not.\newline |
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