Both authors contributed equally to this work.
Drought effects on allocation of recent carbon: from beech leaves to soil CO2 efflux
Article first published online: 19 OCT 2009
© The Authors (2009). Journal compilation © New Phytologist (2009)
Special Issue: Featured papers on ‘Weeds - bridging the gap between evolutionary ecology and crop science’
Volume 184, Issue 4, pages 950–961, December 2009
How to Cite
Ruehr, N. K., Offermann, C. A., Gessler, A., Winkler, J. B., Ferrio, J. P., Buchmann, N. and Barnard, R. L. (2009), Drought effects on allocation of recent carbon: from beech leaves to soil CO2 efflux. New Phytologist, 184: 950–961. doi: 10.1111/j.1469-8137.2009.03044.x
- Issue published online: 6 NOV 2009
- Article first published online: 19 OCT 2009
- Received: 24 March 2009, Accepted: 23 July 2009
- Fagus sylvatica;
- soil microbes;
- water stress
- •Recent studies have highlighted a direct, fast transfer of recently assimilated C from the tree canopy to the soil. However, the effect of environmental changes on this flux remains largely unknown.
- •We investigated the effects of drought on the translocation of recently assimilated C, by pulse-labelling 1.5-yr-old beech tree mesocosms with 13CO2. 13C signatures were then measured daily for 1 wk in leaves, twigs, coarse and fine root water-soluble and total organic matter, phloem organic matter, soil microbial biomass and soil CO2 efflux.
- •Drought reduced C assimilation and doubled the residence time of recently assimilated C in leaf biomass. In phloem organic matter, the 13C label peaked immediately after labelling then decayed exponentially in the control treatment, while under drought it peaked 4 d after labelling. In soil microbial biomass, the label peaked 1 d after labelling in the control treatment, whereas under drought no peak was measured. Two days after labelling, drought decreased the contribution of recently assimilated C to soil CO2 efflux by 33%.
- •Our study showed that drought reduced the coupling between canopy photosynthesis and belowground processes. This will probably affect soil biogeochemical cycling, with potential consequences including slower soil nitrogen cycling and changes in C-sequestration potential under future climate conditions.