Journal Article

Variation in below-ground carbon fluxes along a Populus hybridization gradient

Hart, Stephen C, LeRoy, Carri J, Whitham, Thomas G, Fischer, Dylan G

2007

Overview

Here, soil CO₂ efflux, minirhizotron fine root production (FRP), and estimated total below-ground carbon allocation (TBCA) were examined along an elevation and hybridization gradient between two cottonwood species. FRP was 72% greater under high-elevation Populus angustifolia, but soil CO₂ efflux and TBCA were 62% and 94% greater, respectively, under low-elevation stands dominated by Populus fremontii, with a hybrid stand showing intermediate values. Differences between the responses of FRP, soil CO₂ efflux and TBCA may potentially be explained in terms of genetic controls; while plant species and hybridization explained variance in carbon flux, we found only weak correlations of FRP and TBCA with soil moisture, and no correlations with soil temperature or nitrogen availability. Soil CO₂ efflux and TBCA were uncorrelated with FRP, suggesting that, although below-ground carbon fluxes may change along environmental and genetic gradients, major components of below-ground carbon flux may be decoupled.

• Publisher: Oxford, UK : Blackwell Publishing Ltd,Blackwell Science,Blackwell Publishing Ltd
• Subject: carbon / Carbon Dioxide / Carbon Dioxide - metabolism / cottonwood / Ecological genetics / elevation gradient / fine root production / Forest soils / Genetic Variation / genetics / genetics x environment / genetics × environment / Hybridity / hybridization / Hybridization, Genetic / metabolism / minirhizotron / Models, Biological / nitrogen / Plant genetics / Plant Roots / Plant Roots - metabolism / Populus / Populus - genetics / Populus - metabolism / Populus angustifolia / Populus fremontii / Regression Analysis / root production / Soil / soil CO2 efflux / soil CO₂ efflux / Soil temperature / Soil temperature regimes / Soil water / Soil water content / Temperature / total below-ground carbon allocation