Fig. 1.

Net 24 h CO₂ uptake (μmol m⁻²s⁻¹), diel stomatal conductance (mmol m⁻² s⁻¹) and diel malic acid (mmol m⁻²) pattern for young fully expanded leaves of Aechmea ‘Maya’ at ambient (380 µmol mol⁻¹) and elevated (700 µmol mol⁻¹) CO₂. Gas exchange curves are representative of five replicate runs with s.e. <10 %. Malic acid data are means ± s.e. (n = 10 plants). The four different phases of CAM are indicated and the grey line shows a phase shift caused by CO₂ elevation.