Data analysis
Vulnerability curves were plotted and fitted using SigmaPlot 14 (Systat
Software Inc., Erkrath, Germany). After testing data for normal
distribution and homogeneity of variance, a one-way ANOVA was applied to
test for significant difference between xylem embolism resistance of a
detached leaf, and a leaf attached to a short or long branch. An
independent t-test was applied to determine whether the optical and
pneumatic method differed. Statistics were performed in SPSS 22 (IBM,
Armonk, New York, USA), and all graphs were drawn in SigmaPlot.