Evaluating a new method to estimate the rate of leaf respiration in the light by analysis of combined gas exchange and chlorophyll fluorescence measurements

Abstract

Day respiration (Rd) is an important parameter in leaf ecophysiology. It is difficult to measure directly and is indirectly estimated from gas exchange (GE) measurements of the net photosynthetic rate (A), commonly using the Laisk method or the Kok method. Recently a new method was proposed to estimate Rd indirectly from combined GE and chlorophyll fluorescence (CF) measurements across a range of low irradiances. Here this method is tested for estimating Rd in five C3 and one C4 crop species. Values estimated by this new method agreed with those by the Laisk method for the C3 species. The Laisk method, however, is only valid for C3 species and requires measurements at very low CO2 levels. In contrast, the new method can be applied to both C3 and C4 plants and at any CO2 level. The Rd estimates by the new method were consistently somewhat higher than those by the Kok method, because using CF data corrects for errors due to any non-linearity between A and irradiance of the used data range. Like the Kok and Laisk methods, the new method is based on the assumption that Rd varies little with light intensity, which is still subject to debate. Theoretically, the new method, like the Kok method, works best for non-photorespiratory conditions. As CF information is required, data for the new method are usually collected using a small leaf chamber, whereas the Kok and Laisk methods use only GE data, allowing the use of a larger chamber to reduce the noise-to-signal ratio of GE measurements.

Suppression of Chloroplastic Alkenal/One Oxidoreductase Represses the Carbon Catabolic Pathway in Arabidopsis Leaves during Night

“…Furthermore, the dark respiration rate is largely suppressed (about 80%) under illumination compared with under darkness, because TCA cycle activity and the supply of hexose molecules like Glc and Suc to glycolysis are inhibited under illumination (Brooks and Farquhar, 1985;Villar et al, 1995;Shapiro et al, 2004;Tcherkez et al, 2005Tcherkez et al, , 2008Yin et al, 2011). These reports indicate that the carbon flow from photosynthesis to glycolysis and the TCA cycle is severely restricted under illumination, compared with that occurring under darkness.…”

Estimating Daytime Ecosystem Respiration to Improve Estimates of Gross Primary Production of a Temperate Forest

“…Although this type of inhibition has been widely reported, the reason remains unclear [8],[34]–[35]. Some studies suggest that light inhibition is merely a phenomenon caused by internal CO 2 re-fixation [36]–[37].…”

Can the Responses of Photosynthesis and Stomatal Conductance to Water and Nitrogen Stress Combinations Be Modeled Using a Single Set of Parameters?

“…The Kok method tends to underestimate R d (Sharp et al, 1984; Yin et al, 2011). Therefore, R d was also estimated from the linear regression of A n against ( I inc Φ 2 /4) (the Yin method hereafter) (Yin et al, 2009, 2011) using data available from the combined measurement of gas exchange and chlorophyll fluorescence, in order to establish the calibration relationship between values of R d estimated by the two methods. As combined gas exchange and chlorophyll fluorescence data were used only in part of our measurements, all the R d estimated based on the Kok method was then corrected according to the established calibration relationship to obtain R d estimates for all treatments.…”