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Changes in root architecture under elevated concentrations of CO 2 and nitrogen reflect alternate soil exploration strategies
Author(s) -
Beidler Katilyn V.,
Taylor Benton N.,
Strand Allan E.,
Cooper Emily R.,
Schönholz Marcos,
Pritchard Seth G.
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13123
Subject(s) - nutrient , litter , ecosystem , nutrient cycle , ectomycorrhiza , botany , biology , nitrogen , agronomy , symbiosis , environmental science , ecology , chemistry , mycorrhiza , organic chemistry , genetics , bacteria
Summary Predicting the response of fine roots to increased atmospheric CO 2 concentration has important implications for carbon (C) and nutrient cycling in forest ecosystems. Root architecture is known to play an important role in how trees acquire soil resources in changing environments. However, the effects of elevated CO 2 on the fine‐root architecture of trees remain unclear. We investigated the architectural response of fine roots exposed to 14 yr of CO 2 enrichment and 6 yr of nitrogen (N) fertilization in a Pinus taeda (loblolly pine) forest. Root traits reflecting geometry, topology and uptake function were measured on intact fine‐root branches removed from soil monoliths and the litter layer. CO 2 enrichment resulted in the development of a fine‐root pool that was less dichotomous and more exploratory under N‐limited conditions. The per cent mycorrhizal colonization did not differ among treatments, suggesting that root growth and acclimation to elevated CO 2 were quantitatively more important than increased mycorrhizal associations. Our findings emphasize the importance of architectural plasticity in response to environmental change and suggest that changes in root architecture may allow trees to effectively exploit larger volumes of soil, thereby pre‐empting progressive nutrient limitations.