EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Plant water use strategies drive the fate of newly fixed carbon in an experimental rainforest under drought

Jianbei Huang1, Nemiah Ladd2, Laura Meredith3,4, Christiane Werner2, Marco Lehmann5, and the the coauthors*
Jianbei Huang et al.
  • 1Max-Planck-Institute for Biogeochemistry Jena, BGC Processes, Jena, Germany (
  • 2Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
  • 3School of Natural Resources and the Environment, University of Arizona, 1064 E. Lowell St., Tucson, Arizona, 85721, USA.
  • 4Biosphere 2, University of Arizona, 32540 S. Biosphere Rd., Oracle, Arizona, 85739, USA.
  • 5Swiss Federal Research Institute WSL, 8903 Birmensdorf, Switzerland.
  • *A full list of authors appears at the end of the abstract

Nonstructural carbohydrates (NSCs) play a crucial role in plant functioning and survival. Nonetheless, substantial knowledge gaps remain regarding NSC mobilization and transport in forests experiencing more frequent extreme droughts. We combined drought manipulation and 13CO2 pulse-labeling in an enclosed rainforest, and assessed changes in tissue NSC content and allocation of recent photosynthates in eight species that represent ecosystem biomass and cover different positions and hydraulic strategies. Drought reduced starch in leaves but not in stem phloem and roots across species. However, soluble sugars remained constant or increased in understory plants and anisohydric trees, and decreased only in leaves of isohydric trees with relatively constant leaf water potential and sap flow. Drought slowed export and transport of recent photosynthates, not only for anisohydric species with a strong decrease in leaf water potential and sap flow but also for isohydric species with a strong decrease in photosynthetic supply and carbohydrate levels.  We provide evidence that tropical plants under drought mobilize starch to buffer carbon deficiency, while regulating local utilization, export and transport of soluble sugars depending on position and isohydricity. We highlight the importance of plant functional types for understanding NSC dynamics and their role in determining forest carbon balance under drought. 

the coauthors:

Jianbei Huang, S. Nemiah Ladd, Johannes Ingrisch, Angelika Kübert, Laura K. Meredith, Joost van Haren, Ines Bamberger, L. Erik Daber, Kathrin Kühnhammer, Kinzie Bailey, Jia Hu, Jane Fudyma, Lingling Shi, Michaela A. Dippold, Kathiravan Meeran, Luke Miller, Michael J. O'Brien, Hui Yang, David Herrera-Ramírez, Henrik Hartmann, Susan Trumbore, Michael Bahn, Christiane Werner, and Marco M. Lehmann

How to cite: Huang, J., Ladd, N., Meredith, L., Werner, C., and Lehmann, M. and the the coauthors: Plant water use strategies drive the fate of newly fixed carbon in an experimental rainforest under drought, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13892,, 2023.