Dataset Information

Uncertainty in measurements of the photorespiratory CO₂ compensation point and its impact on models of leaf photosynthesis.

ABSTRACT: Rates of carbon dioxide assimilation through photosynthesis are readily modeled using the Farquhar, von Caemmerer, and Berry (FvCB) model based on the biochemistry of the initial Rubisco-catalyzed reaction of net C₃ photosynthesis. As models of CO₂ assimilation rate are used more broadly for simulating photosynthesis among species and across scales, it is increasingly important that their temperature dependencies are accurately parameterized. A vital component of the FvCB model, the photorespiratory CO₂ compensation point (Γ _*), combines the biochemistry of Rubisco with the stoichiometry of photorespiratory release of CO₂. This report details a comparison of the temperature response of Γ _* measured using different techniques in three important model and crop species (Nicotiana tabacum, Triticum aestivum, and Glycine max). We determined that the different Γ _* determination methods produce different temperature responses in the same species that are large enough to impact higher-scale leaf models of CO₂ assimilation rate. These differences are largest in N. tabacum and could be the result of temperature-dependent increases in the amount of CO₂ lost from photorespiration per Rubisco oxygenation reaction.

SUBMITTER: Walker BJ

PROVIDER: S-EPMC5443873 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Uncertainty in measurements of the photorespiratory CO2 compensation point and its impact on models of leaf photosynthesis.

Walker Berkley J BJ Orr Douglas J DJ Carmo-Silva Elizabete E Parry Martin A J MAJ Bernacchi Carl J CJ Ort Donald R DR

Photosynthesis research 20170328 3

Rates of carbon dioxide assimilation through photosynthesis are readily modeled using the Farquhar, von Caemmerer, and Berry (FvCB) model based on the biochemistry of the initial Rubisco-catalyzed reaction of net C3 photosynthesis. As models of CO2 assimilation rate are used more broadly for simulating photosynthesis among species and across scales, it is increasingly important that their temperature dependencies are accurately parameterized. A vital component of the FvCB m ...[more]

PMID: 28382593

Similar Datasets

Project description:Plants employ photosynthesis to produce sugars for supporting their growth. During photosynthesis, an enzyme Ribulose 1,5 bisphosphate carboxylase/oxygenase (Rubisco) combines its substrate Ribulose 1,5 bisphosphate (RuBP) with CO2 to produce phosphoglycerate (PGA). Alongside, Rubisco also takes up O2 and produce 2-phosphoglycolate (2-PG), a toxic compound broken down into PGA through photorespiration. Photorespiration is not only a resource-demanding process but also results in CO2 loss which affects photosynthetic efficiency in C3 plants. Here, we propose to circumvent photorespiration by adopting the cyanobacterial glycolate decarboxylation pathway into C3 plants. For that, we have integrated the cyanobacterial glycolate decarboxylation pathway into a kinetic model of C3 photosynthetic pathway to evaluate its impact on photosynthesis and photorespiration. Our results show that the cyanobacterial glycolate decarboxylation bypass model exhibits a 10% increase in net photosynthetic rate (A) in comparison with C3 model. Moreover, an increased supply of intercellular CO2 (Ci) from the bypass resulted in a 54.8% increase in PGA while reducing photorespiratory intermediates including glycolate (- 49%) and serine (- 32%). The bypass model, at default conditions, also elucidated a decline in phosphate-based metabolites including RuBP (- 61.3%). The C3 model at elevated level of inorganic phosphate (Pi), exhibited a significant change in RuBP (+ 355%) and PGA (- 98%) which is attributable to the low availability of Ci. Whereas, at elevated Pi, the bypass model exhibited an increase of 73.1% and 33.9% in PGA and RuBP, respectively. Therefore, we deduce a synergistic effect of elevation in CO2 and Pi pool on photosynthesis. We also evaluated the integrative action of CO2, Pi, and Rubisco carboxylation activity (Vcmax) on A and observed that their simultaneous increase raised A by 26%, in the bypass model. Taken together, the study potentiates engineering of cyanobacterial decarboxylation pathway in C3 plants to bypass photorespiration thereby increasing the overall efficiency of photosynthesis.

Dataset Information

Uncertainty in measurements of the photorespiratory CO₂ compensation point and its impact on models of leaf photosynthesis.

Publications

Uncertainty in measurements of the photorespiratory CO<sub>2</sub> compensation point and its impact on models of leaf photosynthesis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets