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Updated: Jun 18, 2026

A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function
Published on: November 21, 2015
Differential response of aspen and birch trees to heat stress under elevated carbon dioxide
Joseph N T Darbah1, Thomas D Sharkey, Carlo Calfapietra
1Michigan Technological University, Houghton, MI 49931, USA. darbah@ohio.edu
Abstract:
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 degrees 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.
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