Table I.

Dimensions and mean water transport parameters of whole roots used in the pressure chamber measurements

At 14 d after sowing, ΔP of 0.3, 0.5, and 0.7 MPa was applied to detopped root systems to induce a water flux. The flow rate at each pressure was plotted against ΔP, and the slope of the linear regression gave L_r. Normalizing flow rate by surface area gave Lp_r. Required ΔP is the pressure that was needed to induce a flow rate through detopped root systems that was equivalent to midday transpiration. Values are means ± se (n = 6–8). Asterisks denote significant differences by Tukey's test (P < 0.05).

Parameter	Narrow-Leafed Lupin	Yellow Lupin	Wheat
Total length (m)	2.3 ± 0.1	1.9 ± 0.2	5.2 ± 0.5*
Surface area (m2 × 10−3)	8.2 ± 0.6	7.1 ± 0.6	7.0 ± 0.5
Transpiration (g h−1)	0.6 ± 0.05	0.4 ± 0.04*	0.6 ± 0.01
Required ΔP (MPa)	0.31 ± 0.045*	0.25 ± 0.05*	0.41 ± 0.09*
Lr (m3 s−1 MPa−1 × 10−10)	10.61 ± 1.02	8.24 ± 0.88	3.96 ± 0.58*
ΔP intercept (kPa)	180*	100*	−3*
Lpr (m s−1 MPa−1 × 10−8)	13.12 ± 1.7	11.66 ± 1.1	5.74 ± 0.8*