Response of respiratory rates in Arabidopsis thaliana plants grown in elevated CO₂

Abstract

Plants can fix carbons by photosynthesis, though they release about half of the fixed carbon by respiration. It was reported that photosynthesis rates per leaf area in many species increased in elevated CO₂. On the other hand, response of respiratory rates in plants grown in elevated CO₂ is poorly understood. In plants, respiratory rates are generally limited by amounts of substrates and ATP consumption rates. If there were any difference of respiratory rate in plants grown in elevated CO₂, it is expected that the difference is due to the change of substrate amounts and/or ATP consumption rates.
The study aim is to clarify the diurnal variation of respiratory rate and its limiting factor in plants grown in elevated CO₂. We grow Arabidopsis thaliana under 390 or 780 ppmv CO₂ and examined respiratory rates in plants at the beginning and end of the night at 20 days after germination. There were clear differences in respiratory responses between growth CO₂ conditions. Furthermore, to investigate factors leading to the difference, we determined amounts of primary metabolites at the beginning and end of the night and at noon using CE-MS.