Biochemical model of C3 photosynthesis applied to wheat at different temperatures. (2nd June 2017)

• Record Type: Journal Article
• Authors: Silva‐Pérez, Viridiana; Furbank, Robert T.; Condon, Anthony G.; Evans, John R.
• Is Part Of: Plant, cell and environment. Volume 40:Number 8(2017)
• Page Start: 1552
• Page End: 1564
• Publication Date: 2017-06-02
• Subjects: activation energy -- CO2 compensation point -- CO2 response curves -- Michaelis–Menten kinetic constants -- respiration -- Rubisco -- Triticum aestivum; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.12953
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: We examined the effects of leaf temperature on the estimation of maximal Rubisco capacity ( V cmax ) from gas exchange measurements of wheat leaves using a C3 photosynthesis model. Cultivars of spring wheat ( Triticum aestivum (L)) and triticale ( X Triticosecale Wittmack) were grown in a greenhouse or in the field and measured at a range of temperatures under controlled conditions in a growth cabinet (2 and 21% O2 ) or in the field using natural diurnal variation in temperature, respectively. Published Rubisco kinetic constants for tobacco did not describe the observed CO2 response curves well as temperature varied. By assuming values for the Rubisco Michaelis–Menten constants for CO2 ( K c ) and O2 ( K o ) at 25 °C derived from tobacco and the activation energies of V cmax from wheat and respiration in the light, R d, from tobacco, we derived activation energies for K c and K o (93.7 and 33.6 kJ mol −1, respectively) that considerably improved the fit of the model to observed data. We confirmed that temperature dependence of dark respiration for wheat was well described by the activation energy for R d from tobacco. The new parameters improved the estimation of V cmax under field conditions, where temperatures increased through the day. Abstract : Photosynthetic characters can be quantified from gas exchange measurements using the Farquhar, von Caemmerer and Berry model of C3 photosynthesis. However, for wheat, the effect of temperature was inadequately described using tobacco Rubisco kinetic parameters. New activation energy values were derived that are more appropriate for modelling wheat photosynthesis.