Table 4.

Parameters (±95% CI) of the regression lines obtained by plotting the natural logarithm of the permeances (P) versus the molar volumes (MV) (Figs 5, 6) according to equation 3

Correlation: lnP versus MV	β (mol cm−3)	lnP0 (m s−1)	r2
CM, pH 1	0.0089±0.004	–24.9±0.6	0.91
CM, pH 6	0.0221±0.006	–24.4±0.6	0.96
CM, pH 11	0.0069±0.004	–24.7±0.4	0.83
MX, pH 6	0.0159±0.005	–22.3±0.5	0.94
Water film (thickness 4.6 μm)	0.0055±0.002	–8.1±0.2	0.94

The size selectivity (β) is given by the slope and the intercept is equal to the permeance (P₀) of a hypothetical molecule of zero molar volume. CM, native isolated cuticle; MX, dewaxed isolated cuticle.