Fig. 3.

1 week online leaf patch clamp pressure (P_p) recordings (A) together with the corresponding r.h. (B) and ambient T (C) diurnal changes performed in the late summer of 2007. The plant was watered only sporadically in the weeks before the measurements. The soil was extremely dry. From 10.00 h on 28 August onwards the plant was watered continuously (c. 400 l d⁻¹) up to the end of the experiments on 3 September. Weather conditions: 28 August sunny, cloudy sky and rain throughout 29 August to 1 September except a few hours of sunshine on 31 August. Light irradiance was, on average, below 45 μmol photons m⁻² s⁻¹ at ground level. 2 and 3 September were partly sunny. Note that peaking of the P_p values on 29 August was much higher (particularly at 0.2 m height) than on 2 and 3 September despite comparable diurnal changes of T and r.h.. This was most probably due to the efficient watering of the plant. Asterisks in (A) show the short-time interruption of data transmission for unknown reasons. For further details, see text.