Determination of the process of water loss from leafy vegetables on the basis of cell turgor pressrure and physical properties of cell

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In order to explain the process of water loss from leafy vegetables, cell turgor pressure and physical properties of cell membrane were measured. Spinach samples were used. The range of outside diameter of capillary used for pressure probe method was found appropriate from 5 to 9 microns. Turgor pressure of spinach was 0.4 Mpa two days after harvest and it became 0.03 Mpa at the condition of 5% water loss.The membrane water permeability was estimated by measuring NMR water proton relaxation time, and it was 6.3 x 10^<-5> m s^<-1> after 4 day storage and 7.8 x 10^<-5> m s^<-1> after 7 day storage. Measurement was repeated and membrane permeability showed 4.9〜5.3 x 10^<-5> m s^<-1> after 1 day storage and 6.4〜6.7 x 10^<-5> m s^<-1> after 6 day storage. Furthermore, a new measurement system using micro-channel was developed to measure osmotic water permeability, that is, membrane hydraulic conductivity. The data obtained by this system showed that membrane hydraulic conductivity of harvested leaf decreased during the first 24 h then it increased.