Table 1.

Glossary of water use efficiency and water use parameters

Parameter	Abbreviation	Calculations
Carbon isotope composition	δ13C	$\frac{13C}{12C}$
Instantaneous leaf‐level water use efficiency	WUEi	$\frac{A}{E}$
Absolute vegetative (rosette) water use	VWU	slope 1 of linear regression $\text{slope}=\frac{\text{rSWC}}{\mathrm{day}}-\text{intercept}$
Calculated plant water use	cPWU	VWU * days of flowering
Measured plant water use	mPWU	∑daily added water
Mean daily water use	‐	average of daily added water over the life time of the plant
Water productivity calculated or measured	cWP/mWP	$\frac{\text{seed biomass}}{\text{cPWU}\vee \text{mPWU}}$
Transpiration efficiency calculated or measured	cTE/mTE	$\frac{\text{above ground biomass}}{\text{cPWU}\vee \text{mPWU}}$
Dehydration plasticity (VWU plasticity)	DP	segmented regression $\frac{\left(\text{slope}1-\text{slope}2\right)}{\text{slope}1}$

Abbreviations: A: carbon assimilation; C: carbon; cPWU: calculated lifetime plant water use E: evaporation; mPWU: measured plant water use; rSWC: relative soil water content; VWU: vegetative water use; WUE: water‐use efficiency.