Stimulated Leaf Dark Respiration in Tomato in an Elevated Carbon Dioxide Atmosphere

It is widely accepted that leaf dark respiration is a determining factor for the growth and maintenance of plant tissues and the carbon cycle. However, the underlying effect and mechanism of elevated CO 2 concentrations ([CO 2 ]) on dark respiration remain unclear. In this study, tomato plants grown at elevated [CO 2 ] showed consistently higher leaf dark respiratory rate, as compared with ambient control plants. The increased respiratory capacity was driven by a greater abundance of proteins, carbohydrates and transcripts involved in pathways of glycolysis carbohydrate metabolism, the tricarboxylic acid cycle and mitochondrial electron transport energy metabolism. This study provides substantial evidence in support of the concept that leaf dark respiration is increased by elevated [CO 2 ] in tomato plants and suggests that the increased availability of carbohydrates and the increased energy status are involved in the increased rate of dark respiration in response to elevated [CO 2 ].