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| Titel |
Pinus sylvestris switches respiration substrates under shading but not during drought |
| VerfasserIn |
Henrik Hartmann, Sarah Fischer, Stefan Hanf, Torsten Frosch, Jürgen Poppp, Susan Trumbore |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105163
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| Publikation (Nr.) |
 EGU/EGU2015-4616.pdf |
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| Zusammenfassung |
| Reduced carbon assimilation during prolonged drought forces trees to rely on stored carbon
to maintain vital processes like respiration. It has been shown, however, that the use of
carbohydrates, a major carbon storage pool and main respiratory substrate in plants, strongly
declines with deceasing plant hydration. Yet, no empirical evidence has been produced to
what degree other carbon storage compounds like lipids and proteins may fuel respiration
during drought.
We exposed young scots pine trees to carbon limitation using either drought or shading
and assessed respiratory substrate use by monitoring the respiratory quotient, δ13C of
respired CO2and concentrations of the major storage compounds, i.e. carbohydrates (COH),
lipids and amino acids.
Generally, respiration was dominated by the most abundant substrate. Only shaded trees
shifted from carbohydrate-dominated to lipid-dominated respiration and showed progressive
carbohydrate depletion. In drought trees respiration was strongly reduced and fueled with
carbohydrates from also strongly reduced carbon assimilation. Initial COH content was
maintained during drought probably due to reduced COH mobilization and use
and the maintained COH content may have prevented lipid catabolism via sugar
signaling.
Our results suggest that respiratory substrates other than carbohydrates are used under
carbohydrate limitation but not during drought. Thus, respiratory substrate change cannot
provide an efficient means to counterbalance carbon limitation under natural drought. |
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