Fig. 5

Phenotypes and CAT activity of the nca1a/nca1b single and double mutants under normal air and high CO₂ conditions. The plants were hydroponically grown in an environment-controlled growth chamber for 15 d (temperature: 30 °C day/25 °C night; light intensity: 600 μmol m^− 2 s^− 1; humidity: 60%), under normal air condition 400 ppm CO₂ (A); air enriched with 3500 ppm CO₂ (B); CAT activity under normal air condition (C); CAT activity under 3500 ppm CO₂ (D). Data represent means ± SD of at least three replicate experiments. Different letters on the top of columns indicate significant difference at p < 0.05 according to Duncan’s multiple range test