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Photosynthetic plasticity of a tropical tree species, Tabebuia rosea, in response to elevated temperature and [CO2]
  • Martijn Slot,
  • Sami Rifai,
  • Klaus Winter
Martijn Slot
Smithsonian Tropical Research Institute
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Sami Rifai
Oxford University
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Klaus Winter
Smithsonian Tropical Research Institute
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Abstract

Atmospheric and climate change will expose tropical forests to conditions they have not experienced in millions of years. To better understand the consequences of this change we studied photosynthetic acclimation of the neotropical tree species Tabebuia rosea to combined 4°C warming and twice-ambient (800 ppm) CO2. We measured temperature responses of the maximum rates of ribulose 1,5-bisphosphate carboxylation (VCMax), photosynthetic electron transport (JMax), net photosynthesis (PNet), and stomatal conductance (gs), and fitted the data using a probabilistic Bayesian approach. To evaluate short-term acclimation plants were then switched between treatment and control conditions and re-measured after 1–2 weeks. Consistent with acclimation, the optimum temperatures (TOpt) for VCMax, JMax and PNet were 1–5°C higher in treatment than in control plants, while photosynthetic capacity (VCMax, JMax, and PNet at TOpt) was 8–25% lower. Likewise, moving control plants to treatment conditions moderately increased temperature optima and decreased photosynthetic capacity. Stomatal density and sensitivity to leaf-to-air vapor pressure deficit were not affected by growth conditions, and treatment plants did not exhibit stronger stomatal limitations. Collectively, these results illustrate the strong photosynthetic plasticity of this tropical tree species as even fully-developed leaves of saplings transferred to extreme conditions partially acclimated.

Peer review status:ACCEPTED

19 Feb 2021Submitted to Plant, Cell & Environment
20 Feb 2021Assigned to Editor
20 Feb 2021Submission Checks Completed
02 Mar 2021Reviewer(s) Assigned
02 Mar 2021Review(s) Completed, Editorial Evaluation Pending
03 Mar 2021Editorial Decision: Accept