Table 1.

Root architectural parameters of Medicago truncatula.

symbol	parameter name	units	value [mean, s.d.]
tap root
r	initial tip elongation rate	cm d−1	[2.83, 0]
a	root radius	cm	[0.03, 0.003]
la	length of apical zone	cm	[4.33, 4.61]
lb	length of basal zone	cm	[0.26, 0.24]
ln	internodal distance	cm	[0.26, 0.24]
nob	maximal number of branches	_	178
σ	expected change of root tip heading	rad cm−1	0.20
type	type of tropism	—	1
N	strength of tropism	—	1.5
dx	spatial resolution along root axis	cm	0.05
first-order laterals
r	initial tip elongation rate	cm d−1	[0.98, 0.29]
a	root radius	cm	[0.02, 0.01]
θ	insertion angle	rad	[1.41, 0]
la	length of apical zone	cm	[1.63, 1.69]
lb	length of basal zone	cm	[1.04, 1.24]
ln	internodal distance	cm	[0.82, 1.53]
nob	maximal number of branches	_	2
σ	expected change of root tip heading	rad cm−1	0.30
type	type of tropism	—	1
N	strength of tropism	—	1
dx	spatial resolution along root axis	cm	0.05
second-order laterals
r	initial tip elongation rate	cm d−1	[1.54, 0.28]
a	root radius	cm	[0.01, 0.004]
θ	insertion angle	rad	[1.48, 0]
K	maximal root length	cm	[0.59, 0.78]
σ	expected change of root tip heading	rad cm−1	0.4
type	type of tropism	—	1
N	strength of tropism	—	0
dx	spatial resolution along root axis	cm	0.05