Using combined measurements of gas exchange and chlorophyll fluorescence to estimate parameters of a biochemical C₃ photosynthesis model: a critical appraisal and a new integrated approach applied to leaves in a wheat (Triticum aestivum) canopy

Abstract

We appraised the literature and described an approach to estimate the parameters of the Farquhar, von Caemmerer and Berry model using measured CO2 assimilation rate (A) and photosystem II (PSII) electron transport efficiency (F2). The approach uses curve fitting to data of A and F2 at various levels of incident irradiance (Iinc), intercellular CO2 (Ci) and O2. Estimated parameters include day respiration (Rd), conversion efficiency of Iinc into linear electron transport of PSII under limiting light [k2(LL)], electron transport capacity (Jmax), curvature factor (q) for the non-rectangular hyperbolic response of electron flux to Iinc, ribulose 1·5-bisphosphate carboxylase/oxygenase (Rubisco) CO2/O2 specificity (Sc/o), Rubisco carboxylation capacity (Vcmax), rate of triose phosphate utilization (Tp) and mesophyll conductance (gm). The method is used to analyse combined gas exchange and chlorophyll fluorescence measurements on leaves of various ages and positions in wheat plants grown at two nitrogen levels. Estimated Sc/o (25°C) was 3.13 mbar mbar -1 ; Rd was lower than respiration in the dark; Jmax was lower and q was higher at 2% than at 21% O2; k2(LL), Vcmax, Jmax and Tp correlated to leaf nitrogen content; and gm decreased with increasing Ci and with decreasing Iinc. Based on the parameter estimates, we surmised that there was some alternative electron transport.

The Mechanistic Basis of Internal Conductance: A Theoretical Analysis of Mesophyll Cell Photosynthesis and CO2 Diffusion

“…2 across the Chloroplast Membrane May Explain the Decrease of g i with Increasing CO 2 A number of studies (Flexas et al, 2007;Hassiotou et al, 2009;Vrábl et al, 2009;Yin et al, 2009) have shown a similar response to CO 2 as that shown in Figure 6D (i.e. the internal conductance first increases rapidly and then slowly decreases as the CO 2 concentration increases).…”

A single locus confers tolerance to continuous light and allows substantial yield increase in tomato

“…The parameters of the FvCB model 39 , were estimated combining gas exchange and chlorophyll fluorescence data according to ref. 69, with some modifications (see Supplementary Methods for details).…”

Foliar photochemical processes and carbon metabolism under favourable and adverse winter conditions in a Mediterranean mixed forest, Catalonia (Spain)

“…We estimated R n during the day after darkening the leaf for at least 30 min. R d was estimated from the light-response curves with the combined GE and CF measurements proposed by Yin et al (2009), named the CF method. This method amended the Kok method (Kok, 1948) by substituting the A/PPFD relationship with A/(PPFD × PSII /4)).…”

“…This method amended the Kok method (Kok, 1948) by substituting the A/PPFD relationship with A/(PPFD × PSII /4)). See Yin et al (2009) for details. The effective quantum yield of CO 2 ( CO 2 , unitless) can be calculated using the estimated α L , R d , together with A net and PPDF as follows:…”