Does long-term cultivation of saplings under elevated CO2 concentration influence their photosynthetic response to temperature?

Abstract

Elevated CO2 instantaneously increases temperature optima of Amax due to reduced photorespiration and limitation of photosynthesis by RuBP regeneration. However, this increase disappears when plants are exposed to identical CO2 concentrations. In addition, increased heat-stress tolerance of primary photochemistry in plants grown at elevated CO2 is unlikely. The hypothesis that long-term cultivation at elevated CO2 leads to acclimation of photosynthesis to higher temperatures is therefore rejected. Nevertheless, incorporating acclimation mechanisms into models simulating carbon flux between the atmosphere and vegetation is necessary.

Contrasting acclimation abilities of two dominant boreal conifers to elevated CO2 and temperature

“…However, although these acclimation responses are common, photosynthetic responses to the treatments varied between the species. Across an 8 °C growth temperature gradient and an almost doubling of CO 2 concentration, photosynthesis in Pinus sylvestris was remarkably stable, in agreement with an earlier long‐term CO 2 experiment in the same species (Šigut et al, ). Values of A opt were similar across the treatments; the relationship between Φ PSII and Φ NPQ was unaffected by treatments; and although T opt and T max increased in the warmer treatments, these shifts were small.…”

Available Energy Partitioning During Drought at Two Norway Spruce Forests and a European Beech Forest in Central Europe

“…For example, the α values calculated using the equations in Figure at a reference g s value of 10 mm/s, α ref , were 0.69, 0.61, and 0.77 at the WNS, DNS, and EB sites, respectively. This suggests that LE at the spruce sites is more tightly controlled by surface characteristics (e.g., stomatal closure, soil moisture, and LAI) than at the EB site, which is probably due to the higher leaf stomatal conductance of beech trees (Egli et al, ; Šigut et al, ). The high rainfall, high soil moisture, and high LAI at the WNS site resulted in AE exerting a greater control over LE than at the DNS site ( α ref at the WNS site was 12% greater than at the DNS site).…”

“…Journal of Geophysical Research: Atmospheres stomatal conductance of beech trees (Egli et al, 1998;Šigut et al, 2015). The high rainfall, high soil moisture, and high LAI at the WNS site resulted in AE exerting a greater control over LE than at the DNS site (α ref at the WNS site was 12% greater than at the DNS site).…”

Elevated-CO2 Response of Stomata and Its Dependence on Environmental Factors

“…The combined effects of elevated CO 2 and high temperatures have also been reported in some studies. While there are exceptional cases (e.g., Bernacchi et al, 2007 ), elevated CO 2 decreases g s , thus increasing leaf temperature because lower transpiration releases less heat ( Kim et al, 2006 ; Negi et al, 2014 ; Šigut et al, 2015 ). As a consequence, elevated CO 2 with high temperatures may play an antagonistic role by exaggerating heat damage partly due to decreased g s ( Warren et al, 2011 ).…”

“…The main factors controlling stomatal opening processes include Ca 2+ level, guard cell turgor, and hormones ( Assmann, 1999 ; Lawson et al, 2014 ). Stomatal behavior may be affected by environmental factors, such as water status (e.g., soil water deficit, vapor pressure deficit [VPD]), temperature, CO 2 concentrations, and light either alone and/or in combination (e.g., Lee et al, 2008 ; Perez-Martin et al, 2009 ; Hubbart et al, 2013 ; Laanemets et al, 2013 ; Šigut et al, 2015 ). Furthermore, stomatal short-term behavior (e.g., stomatal closure) and a long-term developmental (e.g., stomatal size and its density) responses to environmental changes might occur together, depending on species and genotypes ( Gray et al, 2000 ; Ainsworth and Rogers, 2007 ; Haworth et al, 2013 ; DaMatta et al, 2016 ).…”