Molecular diffusion water exchange in compartments of tissue water of maize

For studying water exchange in compartments of tissue water of maize, kinetic curves of dilution of tritium labeled water (3Н) were used, with the incubation of plant tissues in it. By resolving the summary kinetic curves into components, we determined the constants of membranes’ permeability for exchange diffusion flux in two compartments of tissue water – membranerestricted water and water of higher mobility in free space of cell envelopes, and quantitative content of symplastic and apoplastic water in the plant tissues. Significant differences of rates of water-exchange processes in the symplast and apoplast of maize types with various genotypes were found at the temperatures of 20, 30, 40 and 50°С. In the Pioneer hybrid these figures vary in the intervals of 1,83–3,67 s-1·10-4 and 0,91–1,33 s-1·10-3, whereas in self-pollinated line А-204 the intervals are 1,80–3,51 and 1,12–1,48 accordingly. Peculiar features of water exchange reactions suggest the higher physiological constancy of the Pioneer hybrid under thermal action.