Table 1.

Overview of model parameters.

Parameter	(Default) value	Description
DC	300 μm2 s−1	Auxin diffusion constant inside cells (Laskowski et al., 2008)
DW	44 μm2 s−1	Auxin diffusion constant in apoplast (Jones et al., 2009)
Pout,high	20 μm s−1	Effective efflux permeability, high value (Grieneisen et al., 2007; Laskowski et al., 2008)
Pout,low	5 μm s−1	Effective efflux permeability, low value (Grieneisen et al., 2007; Laskowski et al., 2008)
Pout,bg	1 μm s−1	Effective efflux permeability, background value (due to misplaced PINs Grieneisen et al., 2007; Laskowski et al., 2008)
Pin	20 μm s−1	Effective influx permeability (Grieneisen et al., 2007; Laskowski et al., 2008)
Cv	Concentration	The average auxin concentration in the vascular tissue is normalized to 1 Cv. (Strictly speaking, Cv is not a parameter.)
p	0 Cv μm–3 s−1	Auxin production rate; default: no production. Estimates for reasonable rates based on (Ljung et al., 2001), scaled relative to total concentrations (Marchant et al., 2002): order $10^{-4}{C}_v$.
l	100 μm	Cell length
wC	20 μm	Width of cortical cells
wx	10 μm	Width of other cells
dW	0.2 μm	Wall thickness (Jones et al., 2009)
dp	2 μm	Pixel size for the cells’ interior
t	0.5, 1, 2.5 s	Integration time step (dependent on interval between measurements)