Table II.

Sensitivity analysis test values

Variable values tested for the mathematical model sensitivity analysis. Boldface values were those used to calculate typical root growth condition results.

Variable	Physical Significance	Values Tested
rmax	Maximum root radius at z = 10 mm	rmax = 0.3 mm, 0.5 mm, 0.7 mm
phloem_stop	Distance from root tip that the protophloem source extends into the growth zone (mm)	phloem_stop = 2.1 mm, 4.1 mm, 6.1 mm
	Hydraulic conductivity	K: 1.3×10−10 m−1 s−1 MPa−1
		K9: =1.3×10−9 m−1 s−1 MPa−1
		K11: =1.3×10−11 m−1 s−1 MPa−1
L	Relative elemental growth rate	See Figure 8D for data used in simulations
rs	Radius of protophloem sources	rs = 0.07 mm
ra	Radial distance of sources from the center axis	ra= rmax/4
Ψs	Ψ value of source cells	Ψs = 0 MPa, –0.2 MPa (Pritchard, 1996; Pritchard et al., 1996), −0.46 MPa (Warmbrodt, 1987)
Ψboundary	Ψ value of root boundary	Varies from −0.27 MPa for z = 2.5 mm, increasing (becoming less negative) to −0.15 MPa at z = 12 mm (Pritchard et al., 1996)
Ψsoln	Ψ value of solution boundary	Ψsoln = −0.005 MPa (Pritchard et al., 1996)