Limited thermal acclimation of photosynthesis in tropical montane tree species.

Autor: Dusenge ME; Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.; School of Forestry, Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda.; Department of Biology, The University of Western Ontario, London, ON, Canada.; Gothenburg Global Biodiversity Centre (GGBC), University of Gothenburg, Gothenburg, Sweden., Wittemann M; Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.; Gothenburg Global Biodiversity Centre (GGBC), University of Gothenburg, Gothenburg, Sweden.; Department of Biology, College of Science and Technology, University of Rwanda, Huye, Rwanda., Mujawamariya M; Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.; Department of Biology, College of Science and Technology, University of Rwanda, Huye, Rwanda., Ntawuhiganayo EB; Department of Biology, College of Science and Technology, University of Rwanda, Huye, Rwanda.; World Agroforestry (ICRAF), Huye, Rwanda., Zibera E; School of Forestry, Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda., Ntirugulirwa B; Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.; Department of Biology, College of Science and Technology, University of Rwanda, Huye, Rwanda.; Rwanda Agriculture and Animal Resources Development Board, Kigali, Rwanda., Way DA; Department of Biology, The University of Western Ontario, London, ON, Canada.; Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, Australia.; Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, USA.; Nicholas School of the Environment, Duke University, Durham, NC, USA., Nsabimana D; School of Forestry, Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda., Uddling J; Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.; Gothenburg Global Biodiversity Centre (GGBC), University of Gothenburg, Gothenburg, Sweden., Wallin G; Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
Jazyk: angličtina
Zdroj: Global change biology [Glob Chang Biol] 2021 Oct; Vol. 27 (19), pp. 4860-4878. Date of Electronic Publication: 2021 Jul 16.
DOI: 10.1111/gcb.15790
Abstrakt: The temperature sensitivity of physiological processes and growth of tropical trees remains a key uncertainty in predicting how tropical forests will adjust to future climates. In particular, our knowledge regarding warming responses of photosynthesis, and its underlying biochemical mechanisms, is very limited. We grew seedlings of two tropical montane rainforest tree species, the early-successional species Harungana montana and the late-successional species Syzygium guineense, at three different sites along an elevation gradient, differing by 6.8℃ in daytime ambient air temperature. Their physiological and growth performance was investigated at each site. The optimum temperature of net photosynthesis (T optA ) did not significantly increase in warm-grown trees in either species. Similarly, the thermal optima (T optV and T optJ ) and activation energies (E aV and E aJ ) of maximum Rubisco carboxylation capacity (V cmax ) and maximum electron transport rate (J max ) were largely unaffected by warming. However, V cmax , J max and foliar dark respiration (R d ) at 25℃ were significantly reduced by warming in both species, and this decline was partly associated with concomitant reduction in total leaf nitrogen content. The ratio of J max /V cmax decreased with increasing leaf temperature for both species, but the ratio at 25℃ was constant across sites. Furthermore, in H. montana, stomatal conductance at 25℃ remained constant across the different temperature treatments, while in S. guineense it increased with warming. Total dry biomass increased with warming in H. montana but remained constant in S. guineense. The biomass allocated to roots, stem and leaves was not affected by warming in H. montana, whereas the biomass allocated to roots significantly increased in S. guineense. Overall, our findings show that in these two tropical montane rainforest tree species, the capacity to acclimate the thermal optimum of photosynthesis is limited while warming-induced reductions in respiration and photosynthetic capacity rates are tightly coupled and linked to responses of leaf nitrogen.
(© 2021 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
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