Differential response of aspen and birch trees to heat stress under elevated carbon dioxide

• Published in: Environmental pollution (1987) Vol. 158; no. 4; pp. 1008 - 1014
• Main Authors: Darbah, Joseph N.T., Sharkey, Thomas D., Calfapietra, Carlo, Karnosky, David F.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2010; Elsevier
• Subjects: air pollution; air temperature; Animal, plant and microbial ecology; Applied ecology; Aspen; Betula - drug effects; Betula - metabolism; Betula papyrifera; Biological and medical sciences; Birch; carbon dioxide; Carbon Dioxide - metabolism; Ecotoxicology, biological effects of pollution; electron transfer; elevated atmospheric gases; forest trees; Free air carbon dioxide Enrichment; Fundamental and applied biological sciences. Psychology; gas exchange; General aspects; Global Warming; heat stress; heat tolerance; Hot Temperature; Isoprene; Photosynthesis; Photosynthesis - drug effects; Plant Transpiration - drug effects; Populus - drug effects; Populus - metabolism; Populus tremuloides; stomatal conductance; Stomatal conductance, thermotolerance; Stress, Physiological - drug effects; Free air carbon dioxide Enrichment; Birch; Photosynthesis; Stomatal conductance, thermotolerance; Aspen; Isoprene; Temperature; Carbon compound; Stomatal conductance; Carbon dioxide; Environmental factor; Woody plant; Stress; Salicaceae; Heat; Pollution; thermotolerance; Dicotyledones; Angiospermae; Tree; Environment; Spermatophyta; Populus; Betula; Betulaceae
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2009.10.019

The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO 2 and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO 2 protected photosynthesis of both species against moderate heat stress. Elevated CO 2 increased carboxylation capacity, photosynthetic electron transport capacity, and triose phosphate use in both birch and aspen trees. High temperature (36–39 °C) decreased all of these parameters in birch regardless of CO 2 treatment, but only photosynthetic electron transport and triose phosphate use at ambient CO 2 were reduced in aspen. Among the two aspen clones tested, 271 showed higher thermotolerance than 42E possibly because of the higher isoprene-emission, especially under elevated CO 2. Our results indicate that isoprene-emitting trees may have a competitive advantage over non-isoprene emitting ones as temperatures rise, indicating that biological diversity may be affected in some ecosystems because of heat tolerance mechanisms. We report that elevated CO 2 confers increased thermotolerance on both aspen and birch trees while isoprene production in aspen confers further thermotolerance in aspen.