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Co-permeability of 3H-labeled water and 14C-labeled organic acids across isolated plant cuticles. Investigating cuticular paths of diffusion and predicting cuticular transpiration

Niederl, S., Kirsch, T., Riederer, M., Schreiber, L.
Plant physiology 1998 v.116 no.1 pp. 117-123
Prunus laurocerasus, Ginkgo biloba, Juglans regia, Hedera helix, Philodendron bipinnatifidum, Camellia sinensis, Euonymus japonicus, Monstera deliciosa, Citrus limon, Liriodendron tulipifera, Pyrus communis, Solanum lycopersicum var. lycopersicum, leaves, plant cuticle, cell membranes, membrane permeability, transpiration, diffusion, benzoic acid, salicylic acid, 2,4-D, nutrient transport, measurement, radiolabeling
Penetration of 3H-labeled water (3H2O) and the 14C-labeled organic acids benzoic acid ([14C]BA), salicylic acid ([14C]SA), and 2,4-dichlorophenoxyacetic acid ([14C]2,4-D) were measured simultaneously in isolated cuticular membranes of Prunus laurocerasus L., Ginkgo biloba L., and Juglans regia L. For each of the three pairs of compounds (3H2O/[14C]BA, 3H2O/[14C]SA, and 3H2O/[14C]2,4-D) rates of cuticular water penetration were highly correlated with the rates of penetration of the organic acids. Therefore, water and organic acids penetrated the cuticles by the same routes. With the combination 3H2O/[14C]BA, co-permeability was measured with isolated cuticles of nine other plant species. Permeances of 3H2O of all 12 investigated species were highly correlated with the permeances of [14C]BA (r2 = 0.95). Thus, cuticular transpiration can be predicted from BA permeance. The application of this experimental method, together with the established prediction equation, offers the opportunity to answer several important questions about cuticular transport physiology in future investigations.