Growth in elevated CO₂ enhances temperature response of photosynthesis in wheat

Abstract

The temperature dependence of C(3) photosynthesis may be altered by the growth environment. The effects of long-term growth in elevated CO(2) on photosynthesis temperature response have been investigated in wheat (Triticum aestivum L.) grown in controlled chambers with 370 or 700 mumol mol(-1) CO(2) from sowing through to anthesis. Gas exchange was measured in flag leaves at ear emergence, and the parameters of a biochemical photosynthesis model were determined along with their temperature responses. Elevated CO(2) slightly decreased the CO(2) compensation point and increased the rate of respiration in the light and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) V(cmax), although the latter effect was reversed at 15 degrees C. With elevated CO(2), J(max) decreased in the 15-25 degrees C temperature range and increased at 30 and 35 degrees C. The temperature response (activation energy) of V(cmax) and J(max) increased with growth in elevated CO(2). CO(2) enrichment decreased the ribulose 1,5-bisphosphate (RuBP)-limited photosynthesis rates at lower temperatures and increased Rubisco- and RuBP-limited rates at higher temperatures. The results show that the photosynthesis temperature response is enhanced by growth in elevated CO(2). We conclude that if temperature acclimation and factors such as nutrients or water availability do not modify or negate this enhancement, the effects of future increases in air CO(2) on photosynthetic electron transport and Rubisco kinetics may improve the photosynthetic response of wheat to global warming.

Optimizing the photosynthetic parameter Vcmax by assimilating MODIS-fPAR and MODIS-NDVI with a process-based ecosystem model

“…The area with insufficient irrigation and alkila-saline soil are mostly in the southeast portion of the NCP, and has photosynthetic capabilities lower than 50 mol C m −2 s −1 . This is similar to reports by Alonso et al (2009), wherein the V cmax of wheat was 93.2 mol C m −2 s −1 in areas with sufficient irrigation and nutrition, and Kothavala et al (2005), wherein the photosynthetic value for wheat grown in silt-clay soil with the daily temperature range −3.7 to 33.9 • C and the annual precipitation 835 mm was 93 mol C m −2 s −1 .…”

“…Although both parameters are tightly correlated with a plant's photosynthetic capacity, carboxylation capacity (V cmax ) has been measured and studied more extensively (Wullschleger, 1993;Leuning, 1997;Kattge and Knorr, 2007). At the leaf scale, the key photosynthetic parameters, V cmax and J max , can be calculated by fitting the CO 2 response curve to the measured photosynthetic rate and intercellular CO 2 concentration (Muller et al, 2005;Alonso et al, 2009). At the regional scale, the photosynthetic rate and intercellular CO 2 concentration are unavailable for each pixel; thus, it is impossible to obtain photosynthetic parameter patterns using a CO 2 response curve.…”

Biochemical acclimation, stomatal limitation and precipitation patterns underlie decreases in photosynthetic stimulation of soybean (Glycine max) at elevated [CO2] and temperatures under fully open air field conditions

“…Here, the combined acclimation of V c,max@25 and J max@25 and the shift in V c,max@25 /J max@25 are consistent with a shift toward RuBP regeneration limited photosynthesis at elevated [CO 2 ] (e.g. [1,13,19] [37,41] longer term growth at elevated [CO 2 ] and elevated temperature can be less than additive with respect to A as seen here and in some other enclosure studies [6,58].…”

“…Acclimation of V c,max and J max to combined increases in [CO 2 ] and temperature varies substantially across species and experiments [3,[41][42][43]. Moderately elevated temperature alone (i.e.…”

Proteomics application of crops in the context of climatic changes

“…Exposure to elevated CO 2 could shorten the growing-season of most annual crops by increasing the efficiency of photosynthesis due to enrichment of the substrate CO 2 (Ainsworth, Rogers, Vodkin, Walter, & Schurr, 2006). Elevated CO 2 may also improve the photosynthetic response of wheat indirectly by increasing the atmospheric temperature, as indicated by acceleration of the RuBisCO-limited photosynthetic rate at higher temperatures (Alonso, Pérez, & Martínez-Carrasco, 2009). On the other hand, longer treatment of plants with high CO 2 may hamper photosynthesis (Kim, Lieffering, Miura, Kobayashi, & Okada, 2001).…”