Figure 1.

Leaf conductance to water vapour as a function of the relative water deficit (RWD). Each point represents an individual measurement obtained from leaf drying curves at 30 °C with a total of 12 leaves. An exponential four-parameter sigmoid curve is fitted merely to guide the eye. The RWD at maximum stomatal closure is marked by the transition between the declining phase and the plateau phase of leaf conductances. After maximum stomatal closure, leaf conductances remained at a minimum and were constant.