Fig. 9. Photosynthetic electrons (%) consumed/dissipated by CO₂ assimilation (TPS), photorespiration (PR), the Mehler reaction and other reactions at 850 µmol photons m^–2 s^–1 in controls (–0·6 MPa) and water‐stressed (–1·8 MPa) wild type tomato (A, B) and the hp‐1 mutant (C, D). The area of the circles represents 100 % of photosynthetic electrons formed; these are 97 (A) and 32 (B) µmol e^– m^–1 s^–1 in wild‐type leaves, and 112 (C) and 45 (D) µmol e^– m^–1 s^–1 in leaves of the hp‐1 mutant (see Fig. 4). The fractions of electrons (%) that are consumed/dissipated by different reactions are derived from Fig. 6 and from Haupt‐Herting et al. (2001) for CO₂ assimilation (TPS), and from Figs 5 and 7 for photorespiration (PR) and the Mehler reaction (MR). Electron consumption that cannot be allocated to specific reactions is termed ‘others’.