Skip to Main Content
Experimental evidence of two mechanisms coupling leaf-level C assimilation to rhizosphere CO2 releaseAuthor(s): Zachary Kayler; Claudia Keitel; Kirstin Jansen; Arthur Gessler
Source: Environmental and Experimental Botany
Publication Series: Scientific Journal (JRNL)
Station: Northern Research Station
View PDF (955.0 KB)
DescriptionThe time span needed for carbon fixed by plants to induce belowground responses of root and rhizosphere microbial metabolic processing is of high importance for quantifying the coupling between plant canopy physiology and soil biogeochemistry, but recent observations of a rapid link cannot be explained by new assimilate transport by phloem mass flow alone. We performed 13CO2 labeling experiments designed to test if belowground respiration response to photosynthesis is faster than the arrival of new assimilates and to shed light on potential mechanisms. We provide experimental evidence that at least two mechanisms are employed by plants to couple rhizosphere respiration to canopy assimilation. We observed a fast increase of belowground respiration with the onset of photosynthesis, which we assume is induced by pressure concentration waves travelling through the phloem. A second, much later occurring, peak in respiration is fueled by new assimilates labeled with 13C. Plants and the rhizosphere are thus more tightly coupled than previously thought. Ultimately, the addition of a faster assimilate delivery mechanism to our conceptual framework of ecosystem dynamics will lead to a better understanding of belowground carbon and nutrient cycling and subsequent ecosystem response to disturbance and environmental stress.
- Check the Northern Research Station web site to request a printed copy of this publication.
- Our on-line publications are scanned and captured using Adobe Acrobat.
- During the capture process some typographical errors may occur.
- Please contact Sharon Hobrla, email@example.com if you notice any errors which make this publication unusable.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationKayler, Zachary; Keitel, Claudia; Jansen, Kirstin; Gessler, Arthur. 2017. Experimental evidence of two mechanisms coupling leaf-level C assimilation to rhizosphere CO2 release. Environmental and Experimental Botany. 135: 21-26. https://doi.org/10.1016/j.envexpbot.2016.12.002.
KeywordsSpeed of link, Phloem transport, Soil respiration, Pressure concentration wave, Carbon isotope, Rhizosphere
- Soil DIC uptake and fixation in Pinus taeda seedlings and its C contribution to plant tissues and ectomycorrhizal fungi
- Impact of interspecific competition and drought on the allocation of new assimilates in trees
- Parasitism by Cuscuta pentagona attenuates host plant defenses against insect herbivores
XML: View XML