Journal of Experimental Botany Mechanism for increased leaf growth in elevated CO;

The effect of exposure to elevated CO2 on the pro-cesses of leaf cell production and leaf cell expansion was studied using primary leaves of Phaseolus vulgahs L. Cell division and expansion were separated tempor-ally by exposing seedlings to dim red light for 10 d (when leaf cell division was completed) followed by exposure to bright white light for 14 d (when leaf growth was entirely dependent on cell expansion). When plants were exposed to elevated CO2 during the phase of cell expansion, epidermal cell size and leaf area development were stimulated. Three pieces of evidence suggest that this occurred as a result of increased cell wall loosening and extensibility, (i) cell wall extensibility (WEx, measured as tensio