Abscisic acid is not necessarily required for the induction of patchy stomatal closure

Patchy stomatal closure was observed in leaves of transgenic plants of Nicotiana plumbaginifolia producing antibodies that block the action of abscisic acid, Stomatal patchiness was induced by leaf detachment and subsequent water loss, Stomatal closure was followed by an irreversible reduction of maximal chlorophyll fluorescence, The degree of deviation from the A/c(i)-curve is correlated with steady-state diffusion conductance before leaf detachment, It is concluded that a heterogeneous sensitivity of stomata to abscisic acid is not directly involved in the induction of patchy stomatal closure.