Growth, cell walls, and UDP-Glc dehydrogenase activity of Arabidopsis thaliana grown in elevated carbon dioxide

Abstract

Summary The impact of elevated CO 2 (1000 μmol/mol) was assessed on the common weed, Arabidopsis thaliana (Landsberg erecta), which is used as a model plant system. Elevated CO 2 stimulated relative growth rate (RGR) and leaf area gain of Arabidopsis beginning from the cotyledon stage and continuing through the juvenile stage. This early advantage in growth enabled the plants grown in elevated CO 2 to gain more DW despite similar RGRs throughout the latter stages of development. The greater accumulation of DW in leaves grown in elevated CO 2 resulted in a lower specific leaf area (SLA). However, the amount of cell wall investment per unit of leaf area, specific “wall” area (SWA), was similar indicating that elevated CO 2 did not affect the distribution of cell carbon to the cell wall of leaves beyond that needed for cell and leaf expansion. Furthermore, cell wall composition changed with time due to developmental changes and was not affected by elevated CO 2 . Associated with the increase in RGR by elevated CO 2 was a concomitant increase in the activity of UDP-Glc dehydrogenase (E.C. 1.1.1.22), a key enzyme in the nucleotide-sugar interconversion pathway necessary for biosynthesis of many cell-wall polysaccharides.