Supplementary material to "How plant water status drives tree source water partitioning"

Abstract

The relationship between the loss of volume of water from storage tissues in trees with declining (more negative) water potential shows a desorption curve (Steppe, 2018; Zweifel et al., 2000). This curves will improve understanding of the use of stored water from elastic tissues, and the transition to threshold values of water potential value to release of water by embolism (Steppe, 2018).We investigate the relationship between midday leaf water potential and tree water deficit during ΔW= 0 following method described by Dietrich et al., (2018). We first normalized the ΔW by dividing the 15 min value by the highest observed value. Then, we computed the daily average of the normalized values. We obtained the normalized values of midday water potential following the same steps. The relationship was investigated by fitting a sigmoidal function in R, using 'nls'. The reported R 2 was obtained by transforming this logistic regression into a linear relationship. We calculated the modeled values for relative Ψ midday and compared them with the observed values during this sixteen days. Fig.S1. -Desorption curve during ΔW= 0.