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Regulation and acclimation of leaf gas exchange in a piñon–juniper woodland exposed to three different precipitation regimes
Author(s) -
LIMOUSIN JEANMARC,
BICKFORD CHRISTOPHER P.,
DICKMAN LEE T.,
PANGLE ROBERT E.,
HUDSON PATRICK J.,
BOUTZ AMANDA L.,
GEHRES NATHAN,
OSUNA JESSICA L.,
POCKMAN WILLIAM T.,
MCDOWELL NATE G.
Publication year - 2013
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12089
Subject(s) - photosynthesis , stomatal conductance , juniper , precipitation , acclimatization , transpiration , carbon dioxide , water use efficiency , environmental science , agronomy , botany , biology , ecology , geography , meteorology
Leaf gas‐exchange regulation plays a central role in the ability of trees to survive drought, but forecasting the future response of gas exchange to prolonged drought is hampered by our lack of knowledge regarding potential acclimation. To investigate whether leaf gas‐exchange rates and sensitivity to drought acclimate to precipitation regimes, we measured the seasonal variations of leaf gas exchange in a mature piñon–juniper P inus edulis – J uniperus monosperma woodland after 3 years of precipitation manipulation. We compared trees receiving ambient precipitation with those in an irrigated treatment (+30% of ambient precipitation) and a partial rainfall exclusion (−45%). Treatments significantly affected leaf water potential, stomatal conductance and photosynthesis for both isohydric piñon and anisohydric juniper. Leaf gas exchange acclimated to the precipitation regimes in both species. Maximum gas‐exchange rates under well‐watered conditions, leaf‐specific hydraulic conductance and leaf water potential at zero photosynthetic assimilation all decreased with decreasing precipitation. Despite their distinct drought resistance and stomatal regulation strategies, both species experienced hydraulic limitation on leaf gas exchange when precipitation decreased, leading to an intraspecific trade‐off between maximum photosynthetic assimilation and resistance of photosynthesis to drought. This response will be most detrimental to the carbon balance of piñon under predicted increases in aridity in the southwestern USA .