Synergistic effect of heat and drought on leaf VOC emissions and root exudates in Norway spruce saplings
preprint
OA: closed
Abstract
Compound droughts, i.e. the co-occurrences of heat and drought, represent a serious challenge for temperate forest trees leading to significant losses in forest biomass. We studied the physiological response of Norway spruce ( Picea abies ) saplings to heat and drought individually, and in combination. Continuous measurements of leaf gas exchange and VOC emission allowed us to identify fast-response reactions, while discrete VOC and root exudate samplings added qualitative information on compositional changes. Additionally, we used 13 CO 2 and 2 H 2 O label pulses to investigate C-allocation and root water uptake in response to stress. Heat as well as drought reduced assimilation rates in the saplings, whereas transpiration, leaf VOC emission and root exudation rates increased in response to heat. Drought alone increased VOC emission but decreased exudation rates. Combined heat and drought triggered an amplified response in both processes despite negative net CO 2 assimilation rates. Label incorporation showed compromised water uptake capacity of drought-stressed plants and illustrated de novo C-allocation to VOC emission and root exudates. The results point at the high susceptibility of Norway spruce saplings to drought and heat. Combined stress resulted in synergistic responses in VOC emissions and root exudates, showing the detrimental effect of compound droughts on Norway spruce. Highlight In this study, we found synergistic effects of heat and drought on carbon losses from leaf VOC emission and root exudates despite negative assimilation rates in Norway spruce saplings.
Full text
2,113 characters
· extracted from
oa-doi-fallback
· click to expand
Abstract
Compound droughts, i.e. the co-occurrences of heat and drought, represent a serious challenge for temperate forest trees leading to significant losses in forest biomass.
We studied the physiological response of Norway spruce (Picea abies) saplings to heat and drought individually, and in combination. Continuous measurements of leaf gas exchange and VOC emission allowed us to identify fast-response reactions, while discrete VOC and root exudate samplings added qualitative information on compositional changes. Additionally, we used 13CO2 and 2H2O label pulses to investigate C-allocation and root water uptake in response to stress.
Heat as well as drought reduced assimilation rates in the saplings, whereas transpiration, leaf VOC emission and root exudation rates increased in response to heat. Drought alone increased VOC emission but decreased exudation rates. Combined heat and drought triggered an amplified response in both processes despite negative net CO2 assimilation rates. Label incorporation showed compromised water uptake capacity of drought-stressed plants and illustrated de novo C-allocation to VOC emission and root exudates.
The results point at the high susceptibility of Norway spruce saplings to drought and heat. Combined stress resulted in synergistic responses in VOC emissions and root exudates, showing the detrimental effect of compound droughts on Norway spruce.
Highlight In this study, we found synergistic effects of heat and drought on carbon losses from leaf VOC emission and root exudates despite negative assimilation rates in Norway spruce saplings.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
mirjam.meischner{at}cep.uni-freiburg.de, clara.stock{at}cep.uni-freiburg.de, stefanie.dumberger{at}cep.uni-freiburg.de, juergen.kreuzwieser{at}ctp.uni-freiburg.de, simon.haberstroh{at}cep.uni-freiburg.de, c.werner{at}cep.uni-freiburg.de
Abbreviations
- A
- net assimilation rate
- E
- transpiration rate
- Fig.
- figure
- VOC
- volatile organic compound
- VWC
- soil volumetric water content
- Ψleaf
- leaf water potential
Text is read by the "Ask this paper" AI Q&A widget below. Extraction quality varies by source — PMC NXML preserves structure cleanly, OA-HTML may include some navigation residue, and OA-PDF can have broken hyphenation. The publisher copy (via DOI) is the canonical version.
My notes (saved in your browser only)
Ask this paper
Answers must be backed by verbatim quotes from this paper's full text. Hallucinated quotes are dropped automatically; if no verbatim passage answers the question, we say so. How this works
Citation neighborhood (no data yet)
We don't have any in-corpus citations linked to this paper yet. This is a recent paper (2026) — citers typically take a year or two to land, and the OpenAlex reference graph may still be filling in.
Source provenance
- europepmc
- last seen: 2026-05-20T01:45:00.602351+00:00