Elevated CO2 increases root exudation from loblolly pine (Pinus taeda L.) seedlings as an N-mediated response

dc.contributor.authorSchlesinger, William
dc.contributor.authorBernhardt, Emily
dc.contributor.authorPhillips, Richard P.
dc.description.abstractThe degree to which forest ecosystems provide a long-term sink for increasing atmospheric CO2 depends upon the capacity of trees to increase the availability of growth-limiting resources. It has been widely speculated that trees exposed to CO2 enrichment may increase the release of root exudates to soil as a mechanism to stimulate microbes to enhance nutrient availability. As a first test to examine how the atmospheric CO2 and nitrogen availability affect the rates of root exudation, we performed two experiments in which the exudates were collected from loblolly pine (Pinus taeda L.) seedlings that were grown in controlled growth chambers under low and high CO2 and at low and high rates of N supply. Despite the differences in experimental design between the two studies, plants grown at high CO2 were larger, and thus whole plant exudation rates were higher under elevated CO2 (P = 0.019), but the magnitude of this response depended on the N level in both studies. Seedlings increased mass-specific exudation rates in response to elevated CO2 in both experiments, but only at low N supply. Moreover, N supply had a greater impact on the exudation rates than did CO2, with mass-specific exudation rates significantly greater (98% and 69% in Experiments 1 and 2, respectively) in the seedlings grown at low N supply relative to high N supply. These results provide preliminary evidence that loblolly pines alter exudation rates in response to both CO2 concentration and N supply, and support the hypothesis that increased C allocation to root exudates may be a mechanism by which trees could delay progressive N limitation in forested ecosystems.en
dc.identifier.citationPhillips, R.P., E.S. Bernhardt and W.H. Schlesinger 2009. Elevated CO2 increases root exudation from loblolly pine (Pinus taeda L.) seedlings as an N-mediated response. Tree Physiology 29:1513-1523en
dc.publisherOxford University Pressen
dc.rightsCopyright © 2012 Oxford University Pressen
dc.subjectprogressive N limitationen
dc.subjectcarbon sequestrationen
dc.titleElevated CO2 increases root exudation from loblolly pine (Pinus taeda L.) seedlings as an N-mediated responseen


Original bundle

Now showing 1 - 1 of 1
Thumbnail Image
Phillips et al. 2009_final.pdf
371.17 KB
Adobe Portable Document Format


Can’t use the file because of accessibility barriers? Contact us with the title of the item, permanent link, and specifics of your accommodation need.