Water and Solute Permeability of Plant Cuticles: Measurement and ...

76 4 Water Permeability
Water permeance (m/s)
3.0e-7
2.5e-7
2.0e-7
1.5e-7
1.0e-7
5.0e-8
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
Partial vapour pressure in receiver
Na + , pH 9
Na + pH 6
Ca 2+
pH 3, 6, 8
Na + pH 3
Fig. 4.6 Effect of partial pressure of water vapour in the receiver on water permeance (Pw) of Citrus
aurantium polymer matrix membranes at 25 ◦ C. Data were taken from Schönherr and Schmidt
(1979). The aqueous donor contained CaCl2 or NaCl at 0.01moll −1 , and was buffered at pH 3, 6,
8 or 9. The same set of membranes was used with all pH values and salt solutions. Permeance was
measured using tritiated water in the donor
Fig. 4.7 Sorption of water at 25 ◦ C by ethyl cellulose, MX from Citrus aurantium leaves, tomato
(Lycopersicon esculentum) fruit and tomato cutin, as affected by partial pressure of water vapour.
Data were taken from Wellons and Stannett (1966) and Chamel et al. (1991) for EC and MX
respectively