Root pressure
We estimated root pressure with bubble manometers on five individuals of each liana species (n=80) as described by Ewers et al. (1997). During the night prior to measurement, we cut one lateral branch and we attached a manometer with a tight-fitting vinyl tube. Each manometer consists of a glass tube of 1 mm internal diameter closed at the distal end, filled with distilled water in basal half and air bubble in the distal part. We measured the length of bubble at pre-dawn (Lpd, in m) and then we immediately cut the vinyl tubing and we measured the bubble length again, representing the atmospheric pressure (Latm, in m). We estimated root pressure (PR, in kPa) using the ideal gas law (Ewers, et al. 1990; Tibbetts & Ewers, 2000) as:
PR= 100 [(Latm / Lpd) - 1] Equation 3.
We estimated the maximum height for reverting embolism (hc) by a given root pressure near the stem base (PRb, in kPa) (Ewers et al., 1997; Tibbetts & Ewers, 2000) as follows:
hc= (Pr -Pc)/10 Equation 4.