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Physiological acclimation dampens initial effects of elevated temperature and atmospheric CO 2 concentration in mature boreal Norway spruce
Author(s) -
Lamba Shubhangi,
Hall Marianne,
Räntfors Mats,
Chaudhary Nitin,
Linder Sune,
Way Danielle,
Uddling Johan,
Wallin Göran
Publication year - 2018
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.13079
Subject(s) - acclimatization , stomatal conductance , photosynthesis , boreal , respiration , taiga , carbon dioxide , vapour pressure deficit , shoot , botany , chemistry , transpiration , environmental science , biology , ecology
Physiological processes of terrestrial plants regulate the land–atmosphere exchange of carbon, water, and energy, yet few studies have explored the acclimation responses of mature boreal conifer trees to climate change. Here we explored the acclimation responses of photosynthesis, respiration, and stomatal conductance to elevated temperature and/or CO 2 concentration ([CO 2 ]) in a 3‐year field experiment with mature boreal Norway spruce. We found that elevated [CO 2 ] decreased photosynthetic carboxylation capacity (−23% at 25 °C) and increased shoot respiration (+64% at 15 °C), while warming had no significant effects. Shoot respiration, but not photosynthetic capacity, exhibited seasonal acclimation. Stomatal conductance at light saturation and a vapour pressure deficit of 1 kPa was unaffected by elevated [CO 2 ] but significantly decreased (−27%) by warming, and the ratio of intercellular to ambient [CO 2 ] was enhanced (+17%) by elevated [CO 2 ] and decreased (−12%) by warming. Many of these responses differ from those typically observed in temperate tree species. Our results show that long‐term physiological acclimation dampens the initial stimulation of plant net carbon assimilation to elevated [CO 2 ], and of plant water use to warming. Models that do not account for these responses may thus overestimate the impacts of climate change on future boreal vegetation–atmosphere interactions.