Acclimation of the respiration/photosynthesis ratio to temperature: insights from a model
1999
Dewar, Roderick | Medlyn, Belinda E. | Mcmurtrie, Ross E. | Unité de bioclimatologie ; Institut National de la Recherche Agronomique (INRA) | The University of Edinburgh | University of New South Wales [Sydney] (UNSW)
International audience
Mostrar más [+] Menos [-]Inglés. Based on short-term experiments, many plant growth models - including those used in global change research - assume that an increase in temperature stimulates plant respiration (R) more than photosynthesis (P), leading to an increase in the R/P ratio. Longer-term experiments, however, have demonstrated that R/P is relatively insensitive to growth temperature. We show that both types of temperature response may be reconciled within a simple substrate-based model of giant acclimation to temperature, in which respiration is effectively limited by the supply of carbohydrates fixed through photosynthesis. The short-term, positive temperature response of R/P reflects the transient dynamics of the nonstructural carbohydrate and protein pools; the insensitivity of R/P to temperature on longer time-scales reflects the steady-state behaviour of these pools. Thus the substrate approach may provide a basis for predicting plant respiration responses to temperature that is more robust than the current modelling paradigm based on the extrapolation of results from short-term experiments. The present model predicts that the acclimated R/P depends mainly on the internal allocation of carbohydrates to protein synthesis, a better understanding of which is therefore required to underpin the wider use of a constant R/P as an alternative modelling paradigm in global change research.
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