Photosynthetic temperature responses of tree species in Rwanda: evidence of pronounced negative effects of high temperature in montane rainforest climax species

Angelica Vårhammar, Göran Wallin, Christopher M. Mclean, Mirindi Eric Dusenge, Belinda E. Medlyn, Thomas B. Hasper, Donat Nsabimana, Johan Uddling*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)
42 Downloads (Pure)

Abstract

The sensitivity of photosynthetic metabolism to temperature has been identified as a key uncertainty for projecting the magnitude of the terrestrial feedback on future climate change. While temperature responses of photosynthetic capacities have been comparatively well investigated in temperate species, the responses of tropical tree species remain unexplored. We compared the responses of seedlings of native cold-adapted tropical montane rainforest tree species with those of exotic warm-adapted plantation species, all growing in an intermediate temperature common garden in Rwanda. Leaf gas exchange responses to carbon dioxide (CO2) at different temperatures (20-40°C) were used to assess the temperature responses of biochemical photosynthetic capacities. Analyses revealed a lower optimum temperature for photosynthetic electron transport rates than for Rubisco carboxylation rates, along with lower electron transport optima in the native cold-adapted than in the exotic warm-adapted species. The photosynthetic optimum temperatures were generally exceeded by daytime peak leaf temperatures, in particular in the native montane rainforest climax species. This study thus provides evidence of pronounced negative effects of high temperature in tropical trees and indicates high susceptibility of montane rainforest climax species to future global warming.

Original languageEnglish
Pages (from-to)1000-1012
Number of pages13
JournalNew Phytologist
Volume206
Issue number3
DOIs
Publication statusPublished - May 2015

Bibliographical note

Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • Africa
  • leaf energy balance
  • maximum rate of electron transport ( Jmax )
  • optimum temperature ( Topt )
  • stomatal con- ductance ( gs )
  • the maximum carboxylation rate of oxygenase ( V cmax )
  • tropical montane rainforest

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