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Nonstructural leaf carbohydrates dynamics of Pinus edulis during drought-induced tree mortality reveal role for carbon metabolism in mortality mechanism

New Phytologist

By:
, , , , , , and
DOI: 10.1111/nph.12102

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Abstract

* Vegetation change is expected with global climate change, potentially altering ecosystem function and climate feedbacks. However, causes of plant mortality, which are central to vegetation change, are understudied, and physiological mechanisms remain unclear, particularly the roles of carbon metabolism and xylem function. * We report analysis of foliar nonstructural carbohydrates (NSCs) and associated physiology from a previous experiment where earlier drought-induced mortality of Pinus edulis at elevated temperatures was associated with greater cumulative respiration. Here, we predicted faster NSC decline for warmed trees than for ambient-temperature trees. * Foliar NSC in droughted trees declined by 30% through mortality and was lower than in watered controls. NSC decline resulted primarily from decreased sugar concentrations. Starch initially declined, and then increased above pre-drought concentrations before mortality. Although temperature did not affect NSC and sugar, starch concentrations ceased declining and increased earlier with higher temperatures. * Reduced foliar NSC during lethal drought indicates a carbon metabolism role in mortality mechanism. Although carbohydrates were not completely exhausted at mortality, temperature differences in starch accumulation timing suggest that carbon metabolism changes are associated with time to death. Drought mortality appears to be related to temperature-dependent carbon dynamics concurrent with increasing hydraulic stress in P. edulis and potentially other similar species.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Nonstructural leaf carbohydrates dynamics of Pinus edulis during drought-induced tree mortality reveal role for carbon metabolism in mortality mechanism
Series title:
New Phytologist
DOI:
10.1111/nph.12102
Volume
197
Issue:
4
Year Published:
2013
Language:
English
Publisher:
New Phytologist Trust
Contributing office(s):
Forest and Rangeland Ecosystem Science Center
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
New Phytologist
First page:
1142
Last page:
1151