Fine-root respiration in a loblolly pine and sweetgum forest growing in elevated CO2.
New Phytol
; 160(3): 511-522, 2003 Dec.
Article
em En
| MEDLINE
| ID: mdl-33873663
ABSTRACT
⢠The loss of carbon below-ground through respiration of fine roots may be modified by global change. Here we tested the hypothesis that a reduction in N concentration of tree fine-roots grown in an elevated atmospheric CO2 concentration would reduce maintenance respiration and that more energy would be used for root growth and N uptake. We partitioned total fine-root respiration (RT ) between maintenance (RM ), growth (RG ), and N uptake respiration (RN ) for loblolly pine (Pinus taeda) and sweetgum (Liquidambar styraciflua) forests exposed to elevated CO2 . ⢠A substantial increase in fine-root production contributed to a 151% increase in RG for loblolly pine in elevated CO2 . Root specific RM for pine was 24% lower under elevated CO2 but when extrapolated to the entire forest, no treatment effect could be detected. ⢠R G (< 10%) and RN (< 3%) were small components of RM in both forests. Maintenance respiration was the vast majority of RT , and contributed 92% and 86% of these totals at the pine and sweetgum forests, respectively. ⢠The hypothesis was rejected because the majority of fine-root respiration was used for maintenance and was not reduced by changes in root N concentration in elevated CO2 . Because of its large contribution to RT and total soil CO2 efflux, changes in RM caused by warming may greatly alter carbon losses from forests to the atmosphere.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article