ALT Plant growth at 48 days after sowing. Visual images of plants cultivated under ambient CO2 concentration (381 ± 14 µmol mol−1) (a), total leaf area at 48 days after sowing (b), and total shoot dry weight (c). Visual images of plants cultivated under elevated CO2 concentration (549 ± 23 µmol mol−1) (d), total leaf area (e), and total shoot dry weight (f). Data are presented as mean ± SE, and individual measurements are shown as black dots. ns, not significant (p > 0.05); *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001. Multiple comparisons were performed using Dunnett's two-tailed test based on measurements from six plants per line. Image courtesy of Wataru Yamori, Graduate School of Agricultural and Life Sciences, The University of Tokyo.