| Title: | Characterization of hydrophilic and lipophilic pathways of Hedera helix L. cuticular membranes: permeation of water and uncharged organic compounds |
| Author(s): | Popp C; Burghardt M; Friedmann A; Riederer M; |
| Address: | "Julius-von-Sachs-Insitut fur Biowissenschaften, Lehrstuhl fur Botanik II, Universitat Wurzburg, Julius-von-Sachs-Platz 3, D-97082 Wurzburg, Germany" |
| ISSN/ISBN: | 0022-0957 (Print) 0022-0957 (Linking) |
| Abstract: | "The permeability of astomatous leaf cuticular membranes of Hedera helix L. was measured for uncharged hydrophilic (octanol/water partition coefficient log K(O/W) < or =0) and lipophilic compounds (log K(O/W) >0). The set of compounds included lipophilic plant protection agents, hydrophilic carbohydrates, and the volatile compounds water and ethanol. Plotting the mobility of the model compounds versus the molar volume resulted in a clear differentiation between a lipophilic and a hydrophilic pathway. The size selectivity of the lipophilic pathway was described by the free volume theory. The pronounced tortuosity of the diffusional path was caused by cuticular waxes, leading to an increase in permeance for the lipophilic compounds after wax extraction. The size selectivity of the hydrophilic pathway was described by hindered diffusion in narrow pores of molecular dimensions. A distinct increase in size selectivity was observed for hydrophilic compounds with a molar volume higher than 110 cm3 mol(-1). Correspondingly, the size distribution of passable hydrophilic pathways was interpreted as a normal distribution with a mean pore radius of 0.3 nm and a standard deviation of 0.02 nm. The increased permeance of the hydrophilic compounds by the removal of cuticular waxes was attributed to an increase in the porosity, a decrease in the tortuosity, and a widening of the pore size distribution. Cuticular transpiration resulted from the permeation of water across the hydrophilic pathway. The far-reaching implications of two parallel pathways for the establishment of correlations between cuticular structure, chemistry, and function are discussed" |
| Keywords: | Diffusion Hedera/cytology/*metabolism Lipids/*analysis/*chemistry Permeability/drug effects Plant Epidermis/drug effects/*metabolism Plant Leaves/cytology Plant Transpiration Static Electricity Surface-Active Agents/pharmacology Temperature Water/*metabol; |
| Notes: | "MedlinePopp, Christian Burghardt, Markus Friedmann, Adrian Riederer, Markus eng Research Support, Non-U.S. Gov't England 2005/09/07 J Exp Bot. 2005 Nov; 56(421):2797-806. doi: 10.1093/jxb/eri272. Epub 2005 Sep 5" |
