Stored carbon partly fuels fine-root respiration but is not used for production of new fine roots
Article first published online: 7 MAY 2013
No claim to original US government works. New Phytologist © 2013 New Phytologist Trust
Volume 199, Issue 2, pages 420–430, July 2013
How to Cite
Lynch, D. J., Matamala, R., Iversen, C. M., Norby, R. J. and Gonzalez-Meler, M. A. (2013), Stored carbon partly fuels fine-root respiration but is not used for production of new fine roots. New Phytologist, 199: 420–430. doi: 10.1111/nph.12290
- Issue published online: 19 JUN 2013
- Article first published online: 7 MAY 2013
- Manuscript Accepted: 17 MAR 2013
- Manuscript Received: 30 JAN 2013
- United States Department of Energy, Office of Science, Biological and Environmental Research program. Grant Number: ER65188
- National Science Foundation. Grant Number: DEB-0919276
- National Science Foundation IGERT. Grant Number: DGE-0549245
- US Department of Energy, Office of Science, Office of Biological and Environmental Research, Terrestrial Ecosystem Science Division. Grant Number: DE-AC02-06CH11357
- 13 C ;
- fine roots;
- free-air CO2 enrichment (FACE);
- post-carboxylation fractionation;
- root respiration;
- root turnover;
- stored carbon (C);
- Liquidambar styraciflua
- The relative use of new photosynthate compared to stored carbon (C) for the production and maintenance of fine roots, and the rate of C turnover in heterogeneous fine-root populations, are poorly understood.
- We followed the relaxation of a 13C tracer in fine roots in a Liquidambar styraciflua plantation at the conclusion of a free-air CO2 enrichment experiment. Goals included quantifying the relative fractions of new photosynthate vs stored C used in root growth and root respiration, as well as the turnover rate of fine-root C fixed during [CO2] fumigation.
- New fine-root growth was largely from recent photosynthate, while nearly one-quarter of respired C was from a storage pool. Changes in the isotopic composition of the fine-root population over two full growing seasons indicated heterogeneous C pools; < 10% of root C had a residence time < 3 months, while a majority of root C had a residence time > 2 yr.
- Compared to a one-pool model, a two-pool model for C turnover in fine roots (with 5 and 0.37 yr−1 turnover times) doubles the fine-root contribution to forest NPP (9–13%) and supports the 50% root-to-soil transfer rate often used in models.